BK
Bob kb8tq
Thu, Nov 21, 2019 10:18 PM
Hi
If you have a survey device like a Trimble NetRS then you must have a high gain antenna.
If you want to feed it from the Trimble, you need an antenna that runs on 12V. It also needs to
be an L1 / L2 antenna.
If all you have a TBolt timing receiver, then you want a 20 db gain antenna that runs on 5V and
that is an L1 only device.
If you have some of each, then a 50 db antenna fed off of the NetRS / split / padded down to feed
the TBolt is your best bet.
Noise figure it what matters. The preamp in the antenna either does or does not have enough gain
to set the noise figure for the system. As long as it can do that job reception will not improve with
added gain.
If you are installing a system in a cell site, then the signals from the tower are going to be an issue
into your GPS antenna. Even wandering around the house, your cell phone may / can / might
be an issue. It all depends on how far the cell tower is, just where you are standing, and how far
away the GPS antenna is ….
Bob
On Nov 21, 2019, at 4:09 PM, Taka Kamiya via time-nuts time-nuts@lists.febo.com wrote:
So.... concensus is, 50dB gain antenna is too much gain, unless feed line is too long, reception is poor, or there are other circumstances extra gain is desired?
(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG
On Thursday, November 21, 2019, 3:00:14 PM EST, Bob kb8tq <kb8tq@n1k.org> wrote:
Hi
That is indeed the gotcha. Once you get past a certain amount of gain in the
preamp, the C/N levels don’t change enough to notice. Looking today vs looking
tomorrow is unlikely to be of any help if you are after a fraction of a db.
About the only way to check would be to fast switch an attenuator in and out of
the signal path. Watch things for a minute at one setting and then do the same at
another setting. Run for a while and log all the deltas. If you see a degradation of
more than a few tenths of a db, you are getting towards the minimum gain point.
Indeed there are some receivers that have an AGC built in. IF your receiver has one
and IF you can get at it, that would be a great way to work this out. Indeed anybody
who makes it past both of those constraints has a pretty unique device.
====
Simple answer for a 50 db antenna is to put an attenuator in after the DC has
been eliminated from the circuit. It’s not idea, but it’s the best you can do. Running
a great big splitter is one great way to come up with attenuation …..
Bob
On Nov 21, 2019, at 10:29 AM, John Ackermann N8UR jra@febo.com wrote:
Bob, this is a great summary, thanks!
One related question, especially with mixed systems -- how do you tell
if you have optimum signal level at the receiver?
Most show some sort of SNR or Cn value. What should we look for? What
are the indication of too much signal? One issue in particular is how
to handle a modern GPS that expects modest antenna gain when it's
plugged into a system with a 50dB gain antenna at the top.
Thanks!
John
On 11/21/19 8:00 AM, Bob kb8tq wrote:
Hi
Way back in time, the first gear out there to use what we now look at as “normal” antennas
was survey gear. For various reasons they decided on a 12V power supply and 40 to 50 db
of gain in the preamp mounted in the antenna. They also got into L1 / L2 pretty quickly.
A bit later the cell phone (and later broadcast) guys got into this. In a location with a lot of
RF (like a cell site) having a lot of gain at the antenna didn’t work all that well. IMD issues
got into the act pretty quickly. In addition, front end filtering was required to reduce overload
issues. The focus was on L1 only so filtering was relatively easy.
There is a whole separate set of antennas that put a big chunk of the RF portion of the radio
in the antenna. Those still survive here and there. I have one of them and probably a couple
of dozen of the more “normal” antennas.
As time marched on, supplying 12V to antennas became a bit less popular. Most of the cell
guys went over to a 5V antenna supply. The net result was 12V 50 db survey antennas that did
L1/L2 and much smaller 5V 25 db antennas for “timing”. The timing antennas didn’t do L1/L2 so
not going to work for survey. The survey antennas had way to much gain and no filtering so
not going to work for a cell site.
Indeed things did and do get crossed up in various pro and basement systems. With care and
the right set of circumstances things may work. In other cases the result can be an ongoing set
of systems issues over an entire network of stations.
Prices for a good new survey antenna are up in the many thousands of dollars range. They have
very stable phase centers and (usually) test results to allow correction of any residual phase
issues. This is part of what lets you get into the “couple of mm” range on a survey.
For timing, you have to dig a bit and answer a few questions. Is your concern how close you
are to BIH? If so you will need to know all the delays in your system. This includes the delays
in the antenna filters and the preamp. Is your concern (or measure) the ADEV at 1 second?
If so the delays are not a concern. Your antenna choice may be a bit different depending on
this focus.
Bob
On Nov 21, 2019, at 1:25 AM, Taka Kamiya via time-nuts time-nuts@lists.febo.com wrote:
I have been looking antennas. Prices seem to range less than 30 dollars to more than 500 dollars. Some are 20db gain and some are 40 db gain. Some are specified as marine use only. Some are specified as timing use. Some doesn't say anything at all. Power supplies are different.
Other than obvious, antenna is an antenna, isn't it? It captures L1 signal, amplify it and send it down the coax. What makes one more costly than others? What makes one timing antenna and one navigation antenna? It doesn't make sense to me.
I did some simple experiment with 26db, 40db, and magnetic stick on type. I didn't really see significant difference. Signal level itself even wasn't all that different. I have nearly a clear sky view 360 degrees above 30 degrees above horizon. In some directions, clear view to horizon. My feed is Timewave type. So It may not be the best but nearly ideal.
Can someone shed light on this topic? (of course, I know some antenna has integrated receiver. I am not talking about those)
(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.
Hi
If you have a survey device like a Trimble NetRS then you *must* have a high gain antenna.
If you want to feed it from the Trimble, you need an antenna that runs on 12V. It also needs to
be an L1 / L2 antenna.
If all you have a TBolt timing receiver, then you want a 20 db gain antenna that runs on 5V and
that is an L1 only device.
If you have some of each, then a 50 db antenna fed off of the NetRS / split / padded down to feed
the TBolt is your best bet.
Noise figure it what matters. The preamp in the antenna either does or does not have enough gain
to set the noise figure for the system. As long as it can do that job reception will not improve with
added gain.
If you are installing a system in a cell site, then the signals from the tower are going to be an issue
into your GPS antenna. Even wandering around the house, your cell phone may / can / might
be an issue. It all depends on how far the cell tower is, just where you are standing, and how far
away the GPS antenna is ….
Bob
> On Nov 21, 2019, at 4:09 PM, Taka Kamiya via time-nuts <time-nuts@lists.febo.com> wrote:
>
> So.... concensus is, 50dB gain antenna is too much gain, unless feed line is too long, reception is poor, or there are other circumstances extra gain is desired?
>
> ---------------------------------------
> (Mr.) Taka Kamiya
> KB4EMF / ex JF2DKG
>
>
> On Thursday, November 21, 2019, 3:00:14 PM EST, Bob kb8tq <kb8tq@n1k.org> wrote:
>
> Hi
>
> That is indeed the gotcha. Once you get past a certain amount of gain in the
> preamp, the C/N levels don’t change enough to notice. Looking today vs looking
> tomorrow is unlikely to be of any help if you are after a fraction of a db.
>
> About the only way to check would be to fast switch an attenuator in and out of
> the signal path. Watch things for a minute at one setting and then do the same at
> another setting. Run for a while and log all the deltas. If you see a degradation of
> more than a few tenths of a db, you are getting towards the minimum gain point.
>
> Indeed there are some receivers that have an AGC built in. *IF* your receiver has one
> and *IF* you can get at it, that would be a great way to work this out. Indeed anybody
> who makes it past both of those constraints has a pretty unique device.
>
> ====
>
> Simple answer for a 50 db antenna is to put an attenuator in after the DC has
> been eliminated from the circuit. It’s not idea, but it’s the best you can do. Running
> a great big splitter is one great way to come up with attenuation …..
>
> Bob
>
>
>> On Nov 21, 2019, at 10:29 AM, John Ackermann N8UR <jra@febo.com> wrote:
>>
>> Bob, this is a great summary, thanks!
>>
>> One related question, especially with mixed systems -- how do you tell
>> if you have optimum signal level at the receiver?
>>
>> Most show some sort of SNR or Cn value. What should we look for? What
>> are the indication of *too much* signal? One issue in particular is how
>> to handle a modern GPS that expects modest antenna gain when it's
>> plugged into a system with a 50dB gain antenna at the top.
>>
>> Thanks!
>> John
>> ----
>>
>> On 11/21/19 8:00 AM, Bob kb8tq wrote:
>>> Hi
>>>
>>> Way back in time, the first gear out there to use what we now look at as “normal” antennas
>>> was survey gear. For various reasons they decided on a 12V power supply and 40 to 50 db
>>> of gain in the preamp mounted in the antenna. They also got into L1 / L2 pretty quickly.
>>>
>>> A bit later the cell phone (and later broadcast) guys got into this. In a location with a lot of
>>> RF (like a cell site) having a lot of gain at the antenna didn’t work all that well. IMD issues
>>> got into the act pretty quickly. In addition, front end filtering was required to reduce overload
>>> issues. The focus was on L1 only so filtering was relatively easy.
>>>
>>> There is a whole separate set of antennas that put a big chunk of the RF portion of the radio
>>> in the antenna. Those still survive here and there. I have one of them and probably a couple
>>> of dozen of the more “normal” antennas.
>>>
>>> As time marched on, supplying 12V to antennas became a bit less popular. Most of the cell
>>> guys went over to a 5V antenna supply. The net result was 12V 50 db survey antennas that did
>>> L1/L2 and much smaller 5V 25 db antennas for “timing”. The timing antennas didn’t do L1/L2 so
>>> not going to work for survey. The survey antennas had way to much gain and no filtering so
>>> not going to work for a cell site.
>>>
>>> Indeed things did and do get crossed up in various pro and basement systems. With care and
>>> the right set of circumstances things may work. In other cases the result can be an ongoing set
>>> of systems issues over an entire network of stations.
>>>
>>> Prices for a good new survey antenna are up in the many thousands of dollars range. They have
>>> very stable phase centers and (usually) test results to allow correction of any residual phase
>>> issues. This is part of what lets you get into the “couple of mm” range on a survey.
>>>
>>> For timing, you have to dig a bit and answer a few questions. Is your concern how close you
>>> are to BIH? If so you will need to know all the delays in your system. This includes the delays
>>> in the antenna filters and the preamp. Is your concern (or measure) the ADEV at 1 second?
>>> If so the delays are not a concern. Your antenna choice may be a bit different depending on
>>> this focus.
>>>
>>> Bob
>>>
>>>
>>>
>>>> On Nov 21, 2019, at 1:25 AM, Taka Kamiya via time-nuts <time-nuts@lists.febo.com> wrote:
>>>>
>>>> I have been looking antennas. Prices seem to range less than 30 dollars to more than 500 dollars. Some are 20db gain and some are 40 db gain. Some are specified as marine use only. Some are specified as timing use. Some doesn't say anything at all. Power supplies are different.
>>>> Other than obvious, antenna is an antenna, isn't it? It captures L1 signal, amplify it and send it down the coax. What makes one more costly than others? What makes one timing antenna and one navigation antenna? It doesn't make sense to me.
>>>>
>>>> I did some simple experiment with 26db, 40db, and magnetic stick on type. I didn't really see significant difference. Signal level itself even wasn't all that different. I have nearly a clear sky view 360 degrees above 30 degrees above horizon. In some directions, clear view to horizon. My feed is Timewave type. So It may not be the best but nearly ideal.
>>>>
>>>> Can someone shed light on this topic? (of course, I know some antenna has integrated receiver. I am not talking about those)
>>>>
>>>> ---------------------------------------
>>>> (Mr.) Taka Kamiya
>>>> KB4EMF / ex JF2DKG
>>>> _______________________________________________
>>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>>> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>>> and follow the instructions there.
>>>
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>> and follow the instructions there.
>>>
>>
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts@lists.febo.com
>> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
DW
Dana Whitlow
Thu, Nov 21, 2019 10:25 PM
Most modern GPS receivers are very quiet even barefoot. So, one could
argue that one should
not have much more LNA gain in the antenna than required to make up for
feedline loss, which
should be easily calculable. While excess gain in the antenna can improve
overall system noise
figure a small amount, it will degrade intermod performance, which is
likely to be a worse problem
than simple weak signals. It's likely that the cure is worse than the
disease, as my doctor likes to
say.
Dana
On Thu, Nov 21, 2019 at 4:00 PM Taka Kamiya via time-nuts <
time-nuts@lists.febo.com> wrote:
So.... concensus is, 50dB gain antenna is too much gain, unless feed line
is too long, reception is poor, or there are other circumstances extra gain
is desired?
(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG
On Thursday, November 21, 2019, 3:00:14 PM EST, Bob kb8tq <
kb8tq@n1k.org> wrote:
Hi
That is indeed the gotcha. Once you get past a certain amount of gain in
the
preamp, the C/N levels don’t change enough to notice. Looking today vs
looking
tomorrow is unlikely to be of any help if you are after a fraction of a
db.
About the only way to check would be to fast switch an attenuator in and
out of
the signal path. Watch things for a minute at one setting and then do the
same at
another setting. Run for a while and log all the deltas. If you see a
degradation of
more than a few tenths of a db, you are getting towards the minimum gain
point.
Indeed there are some receivers that have an AGC built in. IF your
receiver has one
and IF you can get at it, that would be a great way to work this out.
Indeed anybody
who makes it past both of those constraints has a pretty unique device.
====
Simple answer for a 50 db antenna is to put an attenuator in after the DC
has
been eliminated from the circuit. It’s not idea, but it’s the best you can
do. Running
a great big splitter is one great way to come up with attenuation …..
Bob
On Nov 21, 2019, at 10:29 AM, John Ackermann N8UR jra@febo.com wrote:
Bob, this is a great summary, thanks!
One related question, especially with mixed systems -- how do you tell
if you have optimum signal level at the receiver?
Most show some sort of SNR or Cn value. What should we look for? What
are the indication of too much signal? One issue in particular is how
to handle a modern GPS that expects modest antenna gain when it's
plugged into a system with a 50dB gain antenna at the top.
Thanks!
John
On 11/21/19 8:00 AM, Bob kb8tq wrote:
Hi
Way back in time, the first gear out there to use what we now look at
was survey gear. For various reasons they decided on a 12V power supply
of gain in the preamp mounted in the antenna. They also got into L1 /
A bit later the cell phone (and later broadcast) guys got into this. In
RF (like a cell site) having a lot of gain at the antenna didn’t work
all that well. IMD issues
got into the act pretty quickly. In addition, front end filtering was
required to reduce overload
issues. The focus was on L1 only so filtering was relatively easy.
There is a whole separate set of antennas that put a big chunk of the
in the antenna. Those still survive here and there. I have one of them
of dozen of the more “normal” antennas.
As time marched on, supplying 12V to antennas became a bit less
popular. Most of the cell
guys went over to a 5V antenna supply. The net result was 12V 50 db
L1/L2 and much smaller 5V 25 db antennas for “timing”. The timing
antennas didn’t do L1/L2 so
not going to work for survey. The survey antennas had way to much gain
not going to work for a cell site.
Indeed things did and do get crossed up in various pro and basement
the right set of circumstances things may work. In other cases the
result can be an ongoing set
of systems issues over an entire network of stations.
Prices for a good new survey antenna are up in the many thousands of
very stable phase centers and (usually) test results to allow
correction of any residual phase
issues. This is part of what lets you get into the “couple of mm” range
For timing, you have to dig a bit and answer a few questions. Is your
are to BIH? If so you will need to know all the delays in your system.
in the antenna filters and the preamp. Is your concern (or measure) the
If so the delays are not a concern. Your antenna choice may be a bit
On Nov 21, 2019, at 1:25 AM, Taka Kamiya via time-nuts <
I have been looking antennas. Prices seem to range less than 30
dollars to more than 500 dollars. Some are 20db gain and some are 40 db
gain. Some are specified as marine use only. Some are specified as timing
use. Some doesn't say anything at all. Power supplies are different.
Other than obvious, antenna is an antenna, isn't it? It captures L1
signal, amplify it and send it down the coax. What makes one more costly
than others? What makes one timing antenna and one navigation antenna? It
doesn't make sense to me.
I did some simple experiment with 26db, 40db, and magnetic stick on
type. I didn't really see significant difference. Signal level itself
even wasn't all that different. I have nearly a clear sky view 360 degrees
above 30 degrees above horizon. In some directions, clear view to
horizon. My feed is Timewave type. So It may not be the best but nearly
ideal.
Can someone shed light on this topic? (of course, I know some antenna
has integrated receiver. I am not talking about those)
and follow the instructions there.
and follow the instructions there.
and follow the instructions there.
Most modern GPS receivers are very quiet even barefoot. So, one could
argue that one should
not have much more LNA gain in the antenna than required to make up for
feedline loss, which
should be easily calculable. While excess gain in the antenna can improve
overall system noise
figure a small amount, it will degrade intermod performance, which is
likely to be a worse problem
than simple weak signals. It's likely that the cure is worse than the
disease, as my doctor likes to
say.
Dana
On Thu, Nov 21, 2019 at 4:00 PM Taka Kamiya via time-nuts <
time-nuts@lists.febo.com> wrote:
> So.... concensus is, 50dB gain antenna is too much gain, unless feed line
> is too long, reception is poor, or there are other circumstances extra gain
> is desired?
>
> ---------------------------------------
> (Mr.) Taka Kamiya
> KB4EMF / ex JF2DKG
>
>
> On Thursday, November 21, 2019, 3:00:14 PM EST, Bob kb8tq <
> kb8tq@n1k.org> wrote:
>
> Hi
>
> That is indeed the gotcha. Once you get past a certain amount of gain in
> the
> preamp, the C/N levels don’t change enough to notice. Looking today vs
> looking
> tomorrow is unlikely to be of any help if you are after a fraction of a
> db.
>
> About the only way to check would be to fast switch an attenuator in and
> out of
> the signal path. Watch things for a minute at one setting and then do the
> same at
> another setting. Run for a while and log all the deltas. If you see a
> degradation of
> more than a few tenths of a db, you are getting towards the minimum gain
> point.
>
> Indeed there are some receivers that have an AGC built in. *IF* your
> receiver has one
> and *IF* you can get at it, that would be a great way to work this out.
> Indeed anybody
> who makes it past both of those constraints has a pretty unique device.
>
> ====
>
> Simple answer for a 50 db antenna is to put an attenuator in after the DC
> has
> been eliminated from the circuit. It’s not idea, but it’s the best you can
> do. Running
> a great big splitter is one great way to come up with attenuation …..
>
> Bob
>
>
> > On Nov 21, 2019, at 10:29 AM, John Ackermann N8UR <jra@febo.com> wrote:
> >
> > Bob, this is a great summary, thanks!
> >
> > One related question, especially with mixed systems -- how do you tell
> > if you have optimum signal level at the receiver?
> >
> > Most show some sort of SNR or Cn value. What should we look for? What
> > are the indication of *too much* signal? One issue in particular is how
> > to handle a modern GPS that expects modest antenna gain when it's
> > plugged into a system with a 50dB gain antenna at the top.
> >
> > Thanks!
> > John
> > ----
> >
> > On 11/21/19 8:00 AM, Bob kb8tq wrote:
> >> Hi
> >>
> >> Way back in time, the first gear out there to use what we now look at
> as “normal” antennas
> >> was survey gear. For various reasons they decided on a 12V power supply
> and 40 to 50 db
> >> of gain in the preamp mounted in the antenna. They also got into L1 /
> L2 pretty quickly.
> >>
> >> A bit later the cell phone (and later broadcast) guys got into this. In
> a location with a lot of
> >> RF (like a cell site) having a lot of gain at the antenna didn’t work
> all that well. IMD issues
> >> got into the act pretty quickly. In addition, front end filtering was
> required to reduce overload
> >> issues. The focus was on L1 only so filtering was relatively easy.
> >>
> >> There is a whole separate set of antennas that put a big chunk of the
> RF portion of the radio
> >> in the antenna. Those still survive here and there. I have one of them
> and probably a couple
> >> of dozen of the more “normal” antennas.
> >>
> >> As time marched on, supplying 12V to antennas became a bit less
> popular. Most of the cell
> >> guys went over to a 5V antenna supply. The net result was 12V 50 db
> survey antennas that did
> >> L1/L2 and much smaller 5V 25 db antennas for “timing”. The timing
> antennas didn’t do L1/L2 so
> >> not going to work for survey. The survey antennas had way to much gain
> and no filtering so
> >> not going to work for a cell site.
> >>
> >> Indeed things did and do get crossed up in various pro and basement
> systems. With care and
> >> the right set of circumstances things may work. In other cases the
> result can be an ongoing set
> >> of systems issues over an entire network of stations.
> >>
> >> Prices for a good new survey antenna are up in the many thousands of
> dollars range. They have
> >> very stable phase centers and (usually) test results to allow
> correction of any residual phase
> >> issues. This is part of what lets you get into the “couple of mm” range
> on a survey.
> >>
> >> For timing, you have to dig a bit and answer a few questions. Is your
> concern how close you
> >> are to BIH? If so you will need to know all the delays in your system.
> This includes the delays
> >> in the antenna filters and the preamp. Is your concern (or measure) the
> ADEV at 1 second?
> >> If so the delays are not a concern. Your antenna choice may be a bit
> different depending on
> >> this focus.
> >>
> >> Bob
> >>
> >>
> >>
> >>> On Nov 21, 2019, at 1:25 AM, Taka Kamiya via time-nuts <
> time-nuts@lists.febo.com> wrote:
> >>>
> >>> I have been looking antennas. Prices seem to range less than 30
> dollars to more than 500 dollars. Some are 20db gain and some are 40 db
> gain. Some are specified as marine use only. Some are specified as timing
> use. Some doesn't say anything at all. Power supplies are different.
> >>> Other than obvious, antenna is an antenna, isn't it? It captures L1
> signal, amplify it and send it down the coax. What makes one more costly
> than others? What makes one timing antenna and one navigation antenna? It
> doesn't make sense to me.
> >>>
> >>> I did some simple experiment with 26db, 40db, and magnetic stick on
> type. I didn't really see significant difference. Signal level itself
> even wasn't all that different. I have nearly a clear sky view 360 degrees
> above 30 degrees above horizon. In some directions, clear view to
> horizon. My feed is Timewave type. So It may not be the best but nearly
> ideal.
> >>>
> >>> Can someone shed light on this topic? (of course, I know some antenna
> has integrated receiver. I am not talking about those)
> >>>
> >>> ---------------------------------------
> >>> (Mr.) Taka Kamiya
> >>> KB4EMF / ex JF2DKG
> >>> _______________________________________________
> >>> time-nuts mailing list -- time-nuts@lists.febo.com
> >>> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> >>> and follow the instructions there.
> >>
> >>
> >> _______________________________________________
> >> time-nuts mailing list -- time-nuts@lists.febo.com
> >> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> >> and follow the instructions there.
> >>
> >
> >
> > _______________________________________________
> > time-nuts mailing list -- time-nuts@lists.febo.com
> > To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> > and follow the instructions there.
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>
MD
Magnus Danielson
Fri, Nov 22, 2019 9:01 AM
Hi,
You would probably want to have three antennas and receivers, and we
talk about choke-ring antennas and two-frequency receivers. You should
have your receivers hooked up to a common clock, such as a rubidium clock.
The continental drift is measureable by GPS, and is in the range of
mm/year. You would need quite a bit of data and post-process it with
reference to other data to be able to draw good conclusions.
You can however to some degree detect rotation, but you have to realize
that the distance between the antennas becomes the limitation to it's
ability to detect rotation and rotation speed. Realize that sagging of
antenna mounts can introduce false sense of rotation. Rotation will
probably not provide very useful info.
Remember to do a baseline measurement down at Baseline Rd. :)
Cheers,
Magnus
On 2019-11-21 21:13, Eric Scace wrote:
I need another project like a hole in the head — but curiosity
continues to nag me.
I moved to Boulder CO a few months ago. The “curiosity” is to
determine the position of two antennas at either end of my house and
monitor it over time, with the idea that one could see plate movement
in 3 dimensions plus rotation around the axes.
What hardware/software would be suitable for a TimeNuts
(PositionNuts?) project like this?
— Eric K3NA
On 11/21/19 8:00 AM, Bob kb8tq wrote:
Hi
Way back in time, the first gear out there to use what we now look at
as “normal” antennas was survey gear. For various reasons they
decided on a 12V power supply and 40 to 50 db
of gain in the preamp mounted in the antenna. They also got into L1 /
L2 pretty quickly.
A bit later the cell phone (and later broadcast) guys got into this.
In a location with a lot of RF (like a cell site) having a lot of
gain at the antenna didn’t work all that well. IMD issues got into
the act pretty quickly. In addition, front end filtering was required
to reduce overload
issues. The focus was on L1 only so filtering was relatively easy.
There is a whole separate set of antennas that put a big chunk of the
RF portion of the radio
in the antenna. Those still survive here and there. I have one of
them and probably a couple
of dozen of the more “normal” antennas.
As time marched on, supplying 12V to antennas became a bit less
popular. Most of the cell guys went over to a 5V antenna supply. The
net result was 12V 50 db survey antennas that did L1/L2 and much
smaller 5V 25 db antennas for “timing”. The timing antennas didn’t do
L1/L2 so
not going to work for survey. The survey antennas had way to much
gain and no filtering so not going to work for a cell site.
Indeed things did and do get crossed up in various pro and basement
systems. With care and
the right set of circumstances things may work. In other cases the
result can be an ongoing set
of systems issues over an entire network of stations.
Prices for a good new survey antenna are up in the many thousands of
dollars range. They have
very stable phase centers and (usually) test results to allow
correction of any residual phase issues. This is part of what lets
you get into the “couple of mm” range on a survey.
For timing, you have to dig a bit and answer a few questions. Is your
concern how close you
are to BIH? If so you will need to know all the delays in your
system. This includes the delays
in the antenna filters and the preamp. Is your concern (or measure)
the ADEV at 1 second?
If so the delays are not a concern. Your antenna choice may be a bit
different depending on
this focus.
Bob
Hi,
You would probably want to have three antennas and receivers, and we
talk about choke-ring antennas and two-frequency receivers. You should
have your receivers hooked up to a common clock, such as a rubidium clock.
The continental drift is measureable by GPS, and is in the range of
mm/year. You would need quite a bit of data and post-process it with
reference to other data to be able to draw good conclusions.
You can however to some degree detect rotation, but you have to realize
that the distance between the antennas becomes the limitation to it's
ability to detect rotation and rotation speed. Realize that sagging of
antenna mounts can introduce false sense of rotation. Rotation will
probably not provide very useful info.
Remember to do a baseline measurement down at Baseline Rd. :)
Cheers,
Magnus
On 2019-11-21 21:13, Eric Scace wrote:
> I need another project like a hole in the head — but curiosity
> continues to nag me.
>
> I moved to Boulder CO a few months ago. The “curiosity” is to
> determine the position of two antennas at either end of my house and
> monitor it over time, with the idea that one could see plate movement
> in 3 dimensions plus rotation around the axes.
>
> What hardware/software would be suitable for a TimeNuts
> (PositionNuts?) project like this?
>
> — Eric K3NA
>
>
>> On 11/21/19 8:00 AM, Bob kb8tq wrote:
>> Hi
>>
>> Way back in time, the first gear out there to use what we now look at
>> as “normal” antennas was survey gear. For various reasons they
>> decided on a 12V power supply and 40 to 50 db
>> of gain in the preamp mounted in the antenna. They also got into L1 /
>> L2 pretty quickly.
>> A bit later the cell phone (and later broadcast) guys got into this.
>> In a location with a lot of RF (like a cell site) having a lot of
>> gain at the antenna didn’t work all that well. IMD issues got into
>> the act pretty quickly. In addition, front end filtering was required
>> to reduce overload
>> issues. The focus was on L1 only so filtering was relatively easy.
>>
>> There is a whole separate set of antennas that put a big chunk of the
>> RF portion of the radio
>> in the antenna. Those still survive here and there. I have one of
>> them and probably a couple
>> of dozen of the more “normal” antennas.
>> As time marched on, supplying 12V to antennas became a bit less
>> popular. Most of the cell guys went over to a 5V antenna supply. The
>> net result was 12V 50 db survey antennas that did L1/L2 and much
>> smaller 5V 25 db antennas for “timing”. The timing antennas didn’t do
>> L1/L2 so
>> not going to work for survey. The survey antennas had way to much
>> gain and no filtering so not going to work for a cell site.
>> Indeed things did and do get crossed up in various pro and basement
>> systems. With care and
>> the right set of circumstances things may work. In other cases the
>> result can be an ongoing set
>> of systems issues over an entire network of stations.
>> Prices for a good new survey antenna are up in the many thousands of
>> dollars range. They have
>> very stable phase centers and (usually) test results to allow
>> correction of any residual phase issues. This is part of what lets
>> you get into the “couple of mm” range on a survey.
>> For timing, you have to dig a bit and answer a few questions. Is your
>> concern how close you
>> are to BIH? If so you will need to know all the delays in your
>> system. This includes the delays
>> in the antenna filters and the preamp. Is your concern (or measure)
>> the ADEV at 1 second?
>> If so the delays are not a concern. Your antenna choice may be a bit
>> different depending on
>> this focus.
>>
>> Bob
> _______________________________________________
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
PK
Poul-Henning Kamp
Fri, Nov 22, 2019 9:36 AM
What hardware/software would be suitable for a TimeNuts (PositionNuts?) project like this?
You want 'gpsd' which can collect RINEX files for you, and then run them through
https://webapp.geod.nrcan.gc.ca/geod/tools-outils/ppp.php
Where you remember to pick "ITRF" output.
If you need to convert the result to any other coordinate-system or
projection, 'proj4' is your software.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
--------
> What hardware/software would be suitable for a TimeNuts (PositionNuts?) project like this?
You want 'gpsd' which can collect RINEX files for you, and then run them through
https://webapp.geod.nrcan.gc.ca/geod/tools-outils/ppp.php
Where you remember to pick "ITRF" output.
If you need to convert the result to any other coordinate-system or
projection, 'proj4' is your software.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
BD
Bill Dailey
Fri, Nov 22, 2019 4:07 PM
I would like to tag on to this. I have a large Leica L1 choke ring antenna. It has an indicator for “N”. Not sure why. I placed it on the roof without respect to directionality. I will rotate it with “N” facing north in a month or so to see if there is any effect.
Bill Dailey
Negativity always wins the short game. But positivity wins the long game. - Gary Vaynerchuk
Don’t be easy to understand,
Be impossible to misunderstand
On Nov 21, 2019, at 6:00 PM, Dana Whitlow k8yumdoober@gmail.com wrote:
Most modern GPS receivers are very quiet even barefoot. So, one could
argue that one should
not have much more LNA gain in the antenna than required to make up for
feedline loss, which
should be easily calculable. While excess gain in the antenna can improve
overall system noise
figure a small amount, it will degrade intermod performance, which is
likely to be a worse problem
than simple weak signals. It's likely that the cure is worse than the
disease, as my doctor likes to
say.
Dana
On Thu, Nov 21, 2019 at 4:00 PM Taka Kamiya via time-nuts <
time-nuts@lists.febo.com> wrote:
So.... concensus is, 50dB gain antenna is too much gain, unless feed line
is too long, reception is poor, or there are other circumstances extra gain
is desired?
(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG
On Thursday, November 21, 2019, 3:00:14 PM EST, Bob kb8tq <
kb8tq@n1k.org> wrote:
Hi
That is indeed the gotcha. Once you get past a certain amount of gain in
the
preamp, the C/N levels don’t change enough to notice. Looking today vs
looking
tomorrow is unlikely to be of any help if you are after a fraction of a
db.
About the only way to check would be to fast switch an attenuator in and
out of
the signal path. Watch things for a minute at one setting and then do the
same at
another setting. Run for a while and log all the deltas. If you see a
degradation of
more than a few tenths of a db, you are getting towards the minimum gain
point.
Indeed there are some receivers that have an AGC built in. IF your
receiver has one
and IF you can get at it, that would be a great way to work this out.
Indeed anybody
who makes it past both of those constraints has a pretty unique device.
====
Simple answer for a 50 db antenna is to put an attenuator in after the DC
has
been eliminated from the circuit. It’s not idea, but it’s the best you can
do. Running
a great big splitter is one great way to come up with attenuation …..
Bob
On Nov 21, 2019, at 10:29 AM, John Ackermann N8UR jra@febo.com wrote:
Bob, this is a great summary, thanks!
One related question, especially with mixed systems -- how do you tell
if you have optimum signal level at the receiver?
Most show some sort of SNR or Cn value. What should we look for? What
are the indication of too much signal? One issue in particular is how
to handle a modern GPS that expects modest antenna gain when it's
plugged into a system with a 50dB gain antenna at the top.
Thanks!
John
On 11/21/19 8:00 AM, Bob kb8tq wrote:
Hi
Way back in time, the first gear out there to use what we now look at
was survey gear. For various reasons they decided on a 12V power supply
of gain in the preamp mounted in the antenna. They also got into L1 /
A bit later the cell phone (and later broadcast) guys got into this. In
RF (like a cell site) having a lot of gain at the antenna didn’t work
all that well. IMD issues
got into the act pretty quickly. In addition, front end filtering was
required to reduce overload
issues. The focus was on L1 only so filtering was relatively easy.
There is a whole separate set of antennas that put a big chunk of the
in the antenna. Those still survive here and there. I have one of them
of dozen of the more “normal” antennas.
As time marched on, supplying 12V to antennas became a bit less
popular. Most of the cell
guys went over to a 5V antenna supply. The net result was 12V 50 db
L1/L2 and much smaller 5V 25 db antennas for “timing”. The timing
antennas didn’t do L1/L2 so
not going to work for survey. The survey antennas had way to much gain
not going to work for a cell site.
Indeed things did and do get crossed up in various pro and basement
the right set of circumstances things may work. In other cases the
result can be an ongoing set
of systems issues over an entire network of stations.
Prices for a good new survey antenna are up in the many thousands of
very stable phase centers and (usually) test results to allow
correction of any residual phase
issues. This is part of what lets you get into the “couple of mm” range
For timing, you have to dig a bit and answer a few questions. Is your
are to BIH? If so you will need to know all the delays in your system.
in the antenna filters and the preamp. Is your concern (or measure) the
If so the delays are not a concern. Your antenna choice may be a bit
On Nov 21, 2019, at 1:25 AM, Taka Kamiya via time-nuts <
I have been looking antennas. Prices seem to range less than 30
dollars to more than 500 dollars. Some are 20db gain and some are 40 db
gain. Some are specified as marine use only. Some are specified as timing
use. Some doesn't say anything at all. Power supplies are different.
Other than obvious, antenna is an antenna, isn't it? It captures L1
signal, amplify it and send it down the coax. What makes one more costly
than others? What makes one timing antenna and one navigation antenna? It
doesn't make sense to me.
I did some simple experiment with 26db, 40db, and magnetic stick on
type. I didn't really see significant difference. Signal level itself
even wasn't all that different. I have nearly a clear sky view 360 degrees
above 30 degrees above horizon. In some directions, clear view to
horizon. My feed is Timewave type. So It may not be the best but nearly
ideal.
Can someone shed light on this topic? (of course, I know some antenna
has integrated receiver. I am not talking about those)
and follow the instructions there.
and follow the instructions there.
and follow the instructions there.
I would like to tag on to this. I have a large Leica L1 choke ring antenna. It has an indicator for “N”. Not sure why. I placed it on the roof without respect to directionality. I will rotate it with “N” facing north in a month or so to see if there is any effect.
Bill Dailey
Negativity always wins the short game. But positivity wins the long game. - Gary Vaynerchuk
Don’t be easy to understand,
Be impossible to misunderstand
- Steve Sims
> On Nov 21, 2019, at 6:00 PM, Dana Whitlow <k8yumdoober@gmail.com> wrote:
>
> Most modern GPS receivers are very quiet even barefoot. So, one could
> argue that one should
> not have much more LNA gain in the antenna than required to make up for
> feedline loss, which
> should be easily calculable. While excess gain in the antenna can improve
> overall system noise
> figure a small amount, it will degrade intermod performance, which is
> likely to be a worse problem
> than simple weak signals. It's likely that the cure is worse than the
> disease, as my doctor likes to
> say.
>
> Dana
>
>
>
>> On Thu, Nov 21, 2019 at 4:00 PM Taka Kamiya via time-nuts <
>> time-nuts@lists.febo.com> wrote:
>>
>> So.... concensus is, 50dB gain antenna is too much gain, unless feed line
>> is too long, reception is poor, or there are other circumstances extra gain
>> is desired?
>>
>> ---------------------------------------
>> (Mr.) Taka Kamiya
>> KB4EMF / ex JF2DKG
>>
>>
>> On Thursday, November 21, 2019, 3:00:14 PM EST, Bob kb8tq <
>> kb8tq@n1k.org> wrote:
>>
>> Hi
>>
>> That is indeed the gotcha. Once you get past a certain amount of gain in
>> the
>> preamp, the C/N levels don’t change enough to notice. Looking today vs
>> looking
>> tomorrow is unlikely to be of any help if you are after a fraction of a
>> db.
>>
>> About the only way to check would be to fast switch an attenuator in and
>> out of
>> the signal path. Watch things for a minute at one setting and then do the
>> same at
>> another setting. Run for a while and log all the deltas. If you see a
>> degradation of
>> more than a few tenths of a db, you are getting towards the minimum gain
>> point.
>>
>> Indeed there are some receivers that have an AGC built in. *IF* your
>> receiver has one
>> and *IF* you can get at it, that would be a great way to work this out.
>> Indeed anybody
>> who makes it past both of those constraints has a pretty unique device.
>>
>> ====
>>
>> Simple answer for a 50 db antenna is to put an attenuator in after the DC
>> has
>> been eliminated from the circuit. It’s not idea, but it’s the best you can
>> do. Running
>> a great big splitter is one great way to come up with attenuation …..
>>
>> Bob
>>
>>
>>>> On Nov 21, 2019, at 10:29 AM, John Ackermann N8UR <jra@febo.com> wrote:
>>>
>>> Bob, this is a great summary, thanks!
>>>
>>> One related question, especially with mixed systems -- how do you tell
>>> if you have optimum signal level at the receiver?
>>>
>>> Most show some sort of SNR or Cn value. What should we look for? What
>>> are the indication of *too much* signal? One issue in particular is how
>>> to handle a modern GPS that expects modest antenna gain when it's
>>> plugged into a system with a 50dB gain antenna at the top.
>>>
>>> Thanks!
>>> John
>>> ----
>>>
>>> On 11/21/19 8:00 AM, Bob kb8tq wrote:
>>>> Hi
>>>>
>>>> Way back in time, the first gear out there to use what we now look at
>> as “normal” antennas
>>>> was survey gear. For various reasons they decided on a 12V power supply
>> and 40 to 50 db
>>>> of gain in the preamp mounted in the antenna. They also got into L1 /
>> L2 pretty quickly.
>>>>
>>>> A bit later the cell phone (and later broadcast) guys got into this. In
>> a location with a lot of
>>>> RF (like a cell site) having a lot of gain at the antenna didn’t work
>> all that well. IMD issues
>>>> got into the act pretty quickly. In addition, front end filtering was
>> required to reduce overload
>>>> issues. The focus was on L1 only so filtering was relatively easy.
>>>>
>>>> There is a whole separate set of antennas that put a big chunk of the
>> RF portion of the radio
>>>> in the antenna. Those still survive here and there. I have one of them
>> and probably a couple
>>>> of dozen of the more “normal” antennas.
>>>>
>>>> As time marched on, supplying 12V to antennas became a bit less
>> popular. Most of the cell
>>>> guys went over to a 5V antenna supply. The net result was 12V 50 db
>> survey antennas that did
>>>> L1/L2 and much smaller 5V 25 db antennas for “timing”. The timing
>> antennas didn’t do L1/L2 so
>>>> not going to work for survey. The survey antennas had way to much gain
>> and no filtering so
>>>> not going to work for a cell site.
>>>>
>>>> Indeed things did and do get crossed up in various pro and basement
>> systems. With care and
>>>> the right set of circumstances things may work. In other cases the
>> result can be an ongoing set
>>>> of systems issues over an entire network of stations.
>>>>
>>>> Prices for a good new survey antenna are up in the many thousands of
>> dollars range. They have
>>>> very stable phase centers and (usually) test results to allow
>> correction of any residual phase
>>>> issues. This is part of what lets you get into the “couple of mm” range
>> on a survey.
>>>>
>>>> For timing, you have to dig a bit and answer a few questions. Is your
>> concern how close you
>>>> are to BIH? If so you will need to know all the delays in your system.
>> This includes the delays
>>>> in the antenna filters and the preamp. Is your concern (or measure) the
>> ADEV at 1 second?
>>>> If so the delays are not a concern. Your antenna choice may be a bit
>> different depending on
>>>> this focus.
>>>>
>>>> Bob
>>>>
>>>>
>>>>
>>>>> On Nov 21, 2019, at 1:25 AM, Taka Kamiya via time-nuts <
>> time-nuts@lists.febo.com> wrote:
>>>>>
>>>>> I have been looking antennas. Prices seem to range less than 30
>> dollars to more than 500 dollars. Some are 20db gain and some are 40 db
>> gain. Some are specified as marine use only. Some are specified as timing
>> use. Some doesn't say anything at all. Power supplies are different.
>>>>> Other than obvious, antenna is an antenna, isn't it? It captures L1
>> signal, amplify it and send it down the coax. What makes one more costly
>> than others? What makes one timing antenna and one navigation antenna? It
>> doesn't make sense to me.
>>>>>
>>>>> I did some simple experiment with 26db, 40db, and magnetic stick on
>> type. I didn't really see significant difference. Signal level itself
>> even wasn't all that different. I have nearly a clear sky view 360 degrees
>> above 30 degrees above horizon. In some directions, clear view to
>> horizon. My feed is Timewave type. So It may not be the best but nearly
>> ideal.
>>>>>
>>>>> Can someone shed light on this topic? (of course, I know some antenna
>> has integrated receiver. I am not talking about those)
>>>>>
>>>>> ---------------------------------------
>>>>> (Mr.) Taka Kamiya
>>>>> KB4EMF / ex JF2DKG
>>>>> _______________________________________________
>>>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>>>> To unsubscribe, go to
>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>>>> and follow the instructions there.
>>>>
>>>>
>>>> _______________________________________________
>>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>>> To unsubscribe, go to
>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>>> and follow the instructions there.
>>>>
>>>
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>> To unsubscribe, go to
>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>> and follow the instructions there.
>>
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts@lists.febo.com
>> To unsubscribe, go to
>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts@lists.febo.com
>> To unsubscribe, go to
>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
>>
> _______________________________________________
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
JA
John Ackermann. N8UR
Fri, Nov 22, 2019 5:13 PM
I believe that's to avoid errors from phase center offset -- when the antenna calibrations are done, the measurements are taken with the antenna aligned that way so aiming it in the fields ensures releatability.
On Nov 22, 2019, 12:01 PM, at 12:01 PM, Bill Dailey docdailey@gmail.com wrote:
I would like to tag on to this. I have a large Leica L1 choke ring
antenna. It has an indicator for “N”. Not sure why. I placed it on
the roof without respect to directionality. I will rotate it with “N”
facing north in a month or so to see if there is any effect.
Bill Dailey
Negativity always wins the short game. But positivity wins the long
game. - Gary Vaynerchuk
Don’t be easy to understand,
Be impossible to misunderstand
Most modern GPS receivers are very quiet even barefoot. So, one
argue that one should
not have much more LNA gain in the antenna than required to make up
feedline loss, which
should be easily calculable. While excess gain in the antenna can
overall system noise
figure a small amount, it will degrade intermod performance, which is
likely to be a worse problem
than simple weak signals. It's likely that the cure is worse than
disease, as my doctor likes to
say.
Dana
On Thu, Nov 21, 2019 at 4:00 PM Taka Kamiya via time-nuts <
time-nuts@lists.febo.com> wrote:
So.... concensus is, 50dB gain antenna is too much gain, unless feed
is too long, reception is poor, or there are other circumstances
is desired?
(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG
On Thursday, November 21, 2019, 3:00:14 PM EST, Bob kb8tq <
kb8tq@n1k.org> wrote:
Hi
That is indeed the gotcha. Once you get past a certain amount of
the
preamp, the C/N levels don’t change enough to notice. Looking today
looking
tomorrow is unlikely to be of any help if you are after a fraction
db.
About the only way to check would be to fast switch an attenuator in
out of
the signal path. Watch things for a minute at one setting and then
same at
another setting. Run for a while and log all the deltas. If you see
degradation of
more than a few tenths of a db, you are getting towards the minimum
point.
Indeed there are some receivers that have an AGC built in. IF your
receiver has one
and IF you can get at it, that would be a great way to work this
Indeed anybody
who makes it past both of those constraints has a pretty unique
====
Simple answer for a 50 db antenna is to put an attenuator in after
has
been eliminated from the circuit. It’s not idea, but it’s the best
do. Running
a great big splitter is one great way to come up with attenuation
On Nov 21, 2019, at 10:29 AM, John Ackermann N8UR jra@febo.com
Bob, this is a great summary, thanks!
One related question, especially with mixed systems -- how do you
if you have optimum signal level at the receiver?
Most show some sort of SNR or Cn value. What should we look for?
are the indication of too much signal? One issue in particular
to handle a modern GPS that expects modest antenna gain when it's
plugged into a system with a 50dB gain antenna at the top.
Thanks!
John
On 11/21/19 8:00 AM, Bob kb8tq wrote:
Hi
Way back in time, the first gear out there to use what we now look
was survey gear. For various reasons they decided on a 12V power
of gain in the preamp mounted in the antenna. They also got into
A bit later the cell phone (and later broadcast) guys got into
RF (like a cell site) having a lot of gain at the antenna didn’t
all that well. IMD issues
got into the act pretty quickly. In addition, front end filtering
required to reduce overload
issues. The focus was on L1 only so filtering was relatively easy.
There is a whole separate set of antennas that put a big chunk of
in the antenna. Those still survive here and there. I have one of
of dozen of the more “normal” antennas.
As time marched on, supplying 12V to antennas became a bit less
popular. Most of the cell
guys went over to a 5V antenna supply. The net result was 12V 50
L1/L2 and much smaller 5V 25 db antennas for “timing”. The timing
antennas didn’t do L1/L2 so
not going to work for survey. The survey antennas had way to much
not going to work for a cell site.
Indeed things did and do get crossed up in various pro and
the right set of circumstances things may work. In other cases the
result can be an ongoing set
of systems issues over an entire network of stations.
Prices for a good new survey antenna are up in the many thousands
very stable phase centers and (usually) test results to allow
correction of any residual phase
issues. This is part of what lets you get into the “couple of mm”
For timing, you have to dig a bit and answer a few questions. Is
are to BIH? If so you will need to know all the delays in your
in the antenna filters and the preamp. Is your concern (or
If so the delays are not a concern. Your antenna choice may be a
On Nov 21, 2019, at 1:25 AM, Taka Kamiya via time-nuts <
I have been looking antennas. Prices seem to range less than 30
dollars to more than 500 dollars. Some are 20db gain and some are
gain. Some are specified as marine use only. Some are specified as
use. Some doesn't say anything at all. Power supplies are
Other than obvious, antenna is an antenna, isn't it? It captures
signal, amplify it and send it down the coax. What makes one more
than others? What makes one timing antenna and one navigation
doesn't make sense to me.
I did some simple experiment with 26db, 40db, and magnetic stick
type. I didn't really see significant difference. Signal level
even wasn't all that different. I have nearly a clear sky view 360
above 30 degrees above horizon. In some directions, clear view to
horizon. My feed is Timewave type. So It may not be the best but
Can someone shed light on this topic? (of course, I know some
has integrated receiver. I am not talking about those)
and follow the instructions there.
and follow the instructions there.
and follow the instructions there.
and follow the instructions there.
I believe that's to avoid errors from phase center offset -- when the antenna calibrations are done, the measurements are taken with the antenna aligned that way so aiming it in the fields ensures releatability.
On Nov 22, 2019, 12:01 PM, at 12:01 PM, Bill Dailey <docdailey@gmail.com> wrote:
>I would like to tag on to this. I have a large Leica L1 choke ring
>antenna. It has an indicator for “N”. Not sure why. I placed it on
>the roof without respect to directionality. I will rotate it with “N”
>facing north in a month or so to see if there is any effect.
>
>Bill Dailey
>
>Negativity always wins the short game. But positivity wins the long
>game. - Gary Vaynerchuk
>
>Don’t be easy to understand,
>Be impossible to misunderstand
>- Steve Sims
>
>> On Nov 21, 2019, at 6:00 PM, Dana Whitlow <k8yumdoober@gmail.com>
>wrote:
>>
>> Most modern GPS receivers are very quiet even barefoot. So, one
>could
>> argue that one should
>> not have much more LNA gain in the antenna than required to make up
>for
>> feedline loss, which
>> should be easily calculable. While excess gain in the antenna can
>improve
>> overall system noise
>> figure a small amount, it will degrade intermod performance, which is
>> likely to be a worse problem
>> than simple weak signals. It's likely that the cure is worse than
>the
>> disease, as my doctor likes to
>> say.
>>
>> Dana
>>
>>
>>
>>> On Thu, Nov 21, 2019 at 4:00 PM Taka Kamiya via time-nuts <
>>> time-nuts@lists.febo.com> wrote:
>>>
>>> So.... concensus is, 50dB gain antenna is too much gain, unless feed
>line
>>> is too long, reception is poor, or there are other circumstances
>extra gain
>>> is desired?
>>>
>>> ---------------------------------------
>>> (Mr.) Taka Kamiya
>>> KB4EMF / ex JF2DKG
>>>
>>>
>>> On Thursday, November 21, 2019, 3:00:14 PM EST, Bob kb8tq <
>>> kb8tq@n1k.org> wrote:
>>>
>>> Hi
>>>
>>> That is indeed the gotcha. Once you get past a certain amount of
>gain in
>>> the
>>> preamp, the C/N levels don’t change enough to notice. Looking today
>vs
>>> looking
>>> tomorrow is unlikely to be of any help if you are after a fraction
>of a
>>> db.
>>>
>>> About the only way to check would be to fast switch an attenuator in
>and
>>> out of
>>> the signal path. Watch things for a minute at one setting and then
>do the
>>> same at
>>> another setting. Run for a while and log all the deltas. If you see
>a
>>> degradation of
>>> more than a few tenths of a db, you are getting towards the minimum
>gain
>>> point.
>>>
>>> Indeed there are some receivers that have an AGC built in. *IF* your
>>> receiver has one
>>> and *IF* you can get at it, that would be a great way to work this
>out.
>>> Indeed anybody
>>> who makes it past both of those constraints has a pretty unique
>device.
>>>
>>> ====
>>>
>>> Simple answer for a 50 db antenna is to put an attenuator in after
>the DC
>>> has
>>> been eliminated from the circuit. It’s not idea, but it’s the best
>you can
>>> do. Running
>>> a great big splitter is one great way to come up with attenuation
>…..
>>>
>>> Bob
>>>
>>>
>>>>> On Nov 21, 2019, at 10:29 AM, John Ackermann N8UR <jra@febo.com>
>wrote:
>>>>
>>>> Bob, this is a great summary, thanks!
>>>>
>>>> One related question, especially with mixed systems -- how do you
>tell
>>>> if you have optimum signal level at the receiver?
>>>>
>>>> Most show some sort of SNR or Cn value. What should we look for?
>What
>>>> are the indication of *too much* signal? One issue in particular
>is how
>>>> to handle a modern GPS that expects modest antenna gain when it's
>>>> plugged into a system with a 50dB gain antenna at the top.
>>>>
>>>> Thanks!
>>>> John
>>>> ----
>>>>
>>>> On 11/21/19 8:00 AM, Bob kb8tq wrote:
>>>>> Hi
>>>>>
>>>>> Way back in time, the first gear out there to use what we now look
>at
>>> as “normal” antennas
>>>>> was survey gear. For various reasons they decided on a 12V power
>supply
>>> and 40 to 50 db
>>>>> of gain in the preamp mounted in the antenna. They also got into
>L1 /
>>> L2 pretty quickly.
>>>>>
>>>>> A bit later the cell phone (and later broadcast) guys got into
>this. In
>>> a location with a lot of
>>>>> RF (like a cell site) having a lot of gain at the antenna didn’t
>work
>>> all that well. IMD issues
>>>>> got into the act pretty quickly. In addition, front end filtering
>was
>>> required to reduce overload
>>>>> issues. The focus was on L1 only so filtering was relatively easy.
>>>>>
>>>>> There is a whole separate set of antennas that put a big chunk of
>the
>>> RF portion of the radio
>>>>> in the antenna. Those still survive here and there. I have one of
>them
>>> and probably a couple
>>>>> of dozen of the more “normal” antennas.
>>>>>
>>>>> As time marched on, supplying 12V to antennas became a bit less
>>> popular. Most of the cell
>>>>> guys went over to a 5V antenna supply. The net result was 12V 50
>db
>>> survey antennas that did
>>>>> L1/L2 and much smaller 5V 25 db antennas for “timing”. The timing
>>> antennas didn’t do L1/L2 so
>>>>> not going to work for survey. The survey antennas had way to much
>gain
>>> and no filtering so
>>>>> not going to work for a cell site.
>>>>>
>>>>> Indeed things did and do get crossed up in various pro and
>basement
>>> systems. With care and
>>>>> the right set of circumstances things may work. In other cases the
>>> result can be an ongoing set
>>>>> of systems issues over an entire network of stations.
>>>>>
>>>>> Prices for a good new survey antenna are up in the many thousands
>of
>>> dollars range. They have
>>>>> very stable phase centers and (usually) test results to allow
>>> correction of any residual phase
>>>>> issues. This is part of what lets you get into the “couple of mm”
>range
>>> on a survey.
>>>>>
>>>>> For timing, you have to dig a bit and answer a few questions. Is
>your
>>> concern how close you
>>>>> are to BIH? If so you will need to know all the delays in your
>system.
>>> This includes the delays
>>>>> in the antenna filters and the preamp. Is your concern (or
>measure) the
>>> ADEV at 1 second?
>>>>> If so the delays are not a concern. Your antenna choice may be a
>bit
>>> different depending on
>>>>> this focus.
>>>>>
>>>>> Bob
>>>>>
>>>>>
>>>>>
>>>>>> On Nov 21, 2019, at 1:25 AM, Taka Kamiya via time-nuts <
>>> time-nuts@lists.febo.com> wrote:
>>>>>>
>>>>>> I have been looking antennas. Prices seem to range less than 30
>>> dollars to more than 500 dollars. Some are 20db gain and some are
>40 db
>>> gain. Some are specified as marine use only. Some are specified as
>timing
>>> use. Some doesn't say anything at all. Power supplies are
>different.
>>>>>> Other than obvious, antenna is an antenna, isn't it? It captures
>L1
>>> signal, amplify it and send it down the coax. What makes one more
>costly
>>> than others? What makes one timing antenna and one navigation
>antenna? It
>>> doesn't make sense to me.
>>>>>>
>>>>>> I did some simple experiment with 26db, 40db, and magnetic stick
>on
>>> type. I didn't really see significant difference. Signal level
>itself
>>> even wasn't all that different. I have nearly a clear sky view 360
>degrees
>>> above 30 degrees above horizon. In some directions, clear view to
>>> horizon. My feed is Timewave type. So It may not be the best but
>nearly
>>> ideal.
>>>>>>
>>>>>> Can someone shed light on this topic? (of course, I know some
>antenna
>>> has integrated receiver. I am not talking about those)
>>>>>>
>>>>>> ---------------------------------------
>>>>>> (Mr.) Taka Kamiya
>>>>>> KB4EMF / ex JF2DKG
>>>>>> _______________________________________________
>>>>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>>>>> To unsubscribe, go to
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>>>>> and follow the instructions there.
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>>>> To unsubscribe, go to
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>>>> and follow the instructions there.
>>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>>> To unsubscribe, go to
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>>> and follow the instructions there.
>>>
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>> To unsubscribe, go to
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>> and follow the instructions there.
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>> To unsubscribe, go to
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>> and follow the instructions there.
>>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts@lists.febo.com
>> To unsubscribe, go to
>http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
>_______________________________________________
>time-nuts mailing list -- time-nuts@lists.febo.com
>To unsubscribe, go to
>http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>and follow the instructions there.
BS
Bill Slade
Fri, Nov 22, 2019 5:18 PM
The "N" indeed points north. This is because these large
reference-station choke-ring antennas are often calibrated for phase
center with respect to north. Did you get the phase center calibration
data with your antenna?
Pointing the "N" towards north will not have much effect on timing
accuracy, but mm-level accuracy for positioning requires this.
A note on gain and noise figure: best fix (smallest positioning point
cloud) obtained when full system noise figure is equivalent to the
antenna LNA noise figure. If you are using an antenna with a very short
(few cms) coax to the antenna, amplification in the antenna makes little
sense, unless your GNSS receiver has a noisy front-end. When you have
significant runs of coax between antenna and receiver (meters, 10s of
meters), 10-15 dB of loss is not uncommon. If you have 15dB of loss in
a cable run, your system noise figure will be worse than 15dB. If you
have an antenna with 30 or 40dB of gain and a noise figure of say 1.5 to
2dB, the 15 dB loss in the cable will have a negligible effect on
overall system noise figure and S/N ratio of the GNSS signals at the
receiver will not be degraded by the coax losses.
Too much gain in antenna LNA can render the GNSS receiver susceptible to
interference or saturation of the receiver front-end by noise, depending
on how AGC is implemented and how much gain and what filtering is
present inside the GNSS receiver.
Bill
On 22/11/19 17:07, Bill Dailey wrote:
I would like to tag on to this. I have a large Leica L1 choke ring antenna. It has an indicator for “N”. Not sure why. I placed it on the roof without respect to directionality. I will rotate it with “N” facing north in a month or so to see if there is any effect.
Bill Dailey
Negativity always wins the short game. But positivity wins the long game. - Gary Vaynerchuk
Don’t be easy to understand,
Be impossible to misunderstand
On Nov 21, 2019, at 6:00 PM, Dana Whitlow k8yumdoober@gmail.com wrote:
Most modern GPS receivers are very quiet even barefoot. So, one could
argue that one should
not have much more LNA gain in the antenna than required to make up for
feedline loss, which
should be easily calculable. While excess gain in the antenna can improve
overall system noise
figure a small amount, it will degrade intermod performance, which is
likely to be a worse problem
than simple weak signals. It's likely that the cure is worse than the
disease, as my doctor likes to
say.
Dana
On Thu, Nov 21, 2019 at 4:00 PM Taka Kamiya via time-nuts <
time-nuts@lists.febo.com> wrote:
So.... concensus is, 50dB gain antenna is too much gain, unless feed line
is too long, reception is poor, or there are other circumstances extra gain
is desired?
(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG
On Thursday, November 21, 2019, 3:00:14 PM EST, Bob kb8tq <
kb8tq@n1k.org> wrote:
Hi
That is indeed the gotcha. Once you get past a certain amount of gain in
the
preamp, the C/N levels don’t change enough to notice. Looking today vs
looking
tomorrow is unlikely to be of any help if you are after a fraction of a
db.
About the only way to check would be to fast switch an attenuator in and
out of
the signal path. Watch things for a minute at one setting and then do the
same at
another setting. Run for a while and log all the deltas. If you see a
degradation of
more than a few tenths of a db, you are getting towards the minimum gain
point.
Indeed there are some receivers that have an AGC built in. IF your
receiver has one
and IF you can get at it, that would be a great way to work this out.
Indeed anybody
who makes it past both of those constraints has a pretty unique device.
====
Simple answer for a 50 db antenna is to put an attenuator in after the DC
has
been eliminated from the circuit. It’s not idea, but it’s the best you can
do. Running
a great big splitter is one great way to come up with attenuation …..
Bob
On Nov 21, 2019, at 10:29 AM, John Ackermann N8UR jra@febo.com wrote:
Bob, this is a great summary, thanks!
One related question, especially with mixed systems -- how do you tell
if you have optimum signal level at the receiver?
Most show some sort of SNR or Cn value. What should we look for? What
are the indication of too much signal? One issue in particular is how
to handle a modern GPS that expects modest antenna gain when it's
plugged into a system with a 50dB gain antenna at the top.
Thanks!
John
On 11/21/19 8:00 AM, Bob kb8tq wrote:
Hi
Way back in time, the first gear out there to use what we now look at
was survey gear. For various reasons they decided on a 12V power supply
of gain in the preamp mounted in the antenna. They also got into L1 /
A bit later the cell phone (and later broadcast) guys got into this. In
RF (like a cell site) having a lot of gain at the antenna didn’t work
all that well. IMD issues
got into the act pretty quickly. In addition, front end filtering was
required to reduce overload
issues. The focus was on L1 only so filtering was relatively easy.
There is a whole separate set of antennas that put a big chunk of the
in the antenna. Those still survive here and there. I have one of them
of dozen of the more “normal” antennas.
As time marched on, supplying 12V to antennas became a bit less
popular. Most of the cell
guys went over to a 5V antenna supply. The net result was 12V 50 db
L1/L2 and much smaller 5V 25 db antennas for “timing”. The timing
antennas didn’t do L1/L2 so
not going to work for survey. The survey antennas had way to much gain
not going to work for a cell site.
Indeed things did and do get crossed up in various pro and basement
the right set of circumstances things may work. In other cases the
result can be an ongoing set
of systems issues over an entire network of stations.
Prices for a good new survey antenna are up in the many thousands of
very stable phase centers and (usually) test results to allow
correction of any residual phase
issues. This is part of what lets you get into the “couple of mm” range
For timing, you have to dig a bit and answer a few questions. Is your
are to BIH? If so you will need to know all the delays in your system.
in the antenna filters and the preamp. Is your concern (or measure) the
If so the delays are not a concern. Your antenna choice may be a bit
On Nov 21, 2019, at 1:25 AM, Taka Kamiya via time-nuts <
I have been looking antennas. Prices seem to range less than 30
dollars to more than 500 dollars. Some are 20db gain and some are 40 db
gain. Some are specified as marine use only. Some are specified as timing
use. Some doesn't say anything at all. Power supplies are different.
Other than obvious, antenna is an antenna, isn't it? It captures L1
signal, amplify it and send it down the coax. What makes one more costly
than others? What makes one timing antenna and one navigation antenna? It
doesn't make sense to me.
I did some simple experiment with 26db, 40db, and magnetic stick on
type. I didn't really see significant difference. Signal level itself
even wasn't all that different. I have nearly a clear sky view 360 degrees
above 30 degrees above horizon. In some directions, clear view to
horizon. My feed is Timewave type. So It may not be the best but nearly
ideal.
Can someone shed light on this topic? (of course, I know some antenna
has integrated receiver. I am not talking about those)
and follow the instructions there.
and follow the instructions there.
and follow the instructions there.
The "N" indeed points north. This is because these large
reference-station choke-ring antennas are often calibrated for phase
center with respect to north. Did you get the phase center calibration
data with your antenna?
Pointing the "N" towards north will not have much effect on timing
accuracy, but mm-level accuracy for positioning requires this.
A note on gain and noise figure: best fix (smallest positioning point
cloud) obtained when full system noise figure is equivalent to the
antenna LNA noise figure. If you are using an antenna with a very short
(few cms) coax to the antenna, amplification in the antenna makes little
sense, unless your GNSS receiver has a noisy front-end. When you have
significant runs of coax between antenna and receiver (meters, 10s of
meters), 10-15 dB of loss is not uncommon. If you have 15dB of loss in
a cable run, your system noise figure will be worse than 15dB. If you
have an antenna with 30 or 40dB of gain and a noise figure of say 1.5 to
2dB, the 15 dB loss in the cable will have a negligible effect on
overall system noise figure and S/N ratio of the GNSS signals at the
receiver will not be degraded by the coax losses.
Too much gain in antenna LNA can render the GNSS receiver susceptible to
interference or saturation of the receiver front-end by noise, depending
on how AGC is implemented and how much gain and what filtering is
present inside the GNSS receiver.
Bill
On 22/11/19 17:07, Bill Dailey wrote:
> I would like to tag on to this. I have a large Leica L1 choke ring antenna. It has an indicator for “N”. Not sure why. I placed it on the roof without respect to directionality. I will rotate it with “N” facing north in a month or so to see if there is any effect.
>
> Bill Dailey
>
> Negativity always wins the short game. But positivity wins the long game. - Gary Vaynerchuk
>
> Don’t be easy to understand,
> Be impossible to misunderstand
> - Steve Sims
>
>> On Nov 21, 2019, at 6:00 PM, Dana Whitlow <k8yumdoober@gmail.com> wrote:
>>
>> Most modern GPS receivers are very quiet even barefoot. So, one could
>> argue that one should
>> not have much more LNA gain in the antenna than required to make up for
>> feedline loss, which
>> should be easily calculable. While excess gain in the antenna can improve
>> overall system noise
>> figure a small amount, it will degrade intermod performance, which is
>> likely to be a worse problem
>> than simple weak signals. It's likely that the cure is worse than the
>> disease, as my doctor likes to
>> say.
>>
>> Dana
>>
>>
>>
>>> On Thu, Nov 21, 2019 at 4:00 PM Taka Kamiya via time-nuts <
>>> time-nuts@lists.febo.com> wrote:
>>>
>>> So.... concensus is, 50dB gain antenna is too much gain, unless feed line
>>> is too long, reception is poor, or there are other circumstances extra gain
>>> is desired?
>>>
>>> ---------------------------------------
>>> (Mr.) Taka Kamiya
>>> KB4EMF / ex JF2DKG
>>>
>>>
>>> On Thursday, November 21, 2019, 3:00:14 PM EST, Bob kb8tq <
>>> kb8tq@n1k.org> wrote:
>>>
>>> Hi
>>>
>>> That is indeed the gotcha. Once you get past a certain amount of gain in
>>> the
>>> preamp, the C/N levels don’t change enough to notice. Looking today vs
>>> looking
>>> tomorrow is unlikely to be of any help if you are after a fraction of a
>>> db.
>>>
>>> About the only way to check would be to fast switch an attenuator in and
>>> out of
>>> the signal path. Watch things for a minute at one setting and then do the
>>> same at
>>> another setting. Run for a while and log all the deltas. If you see a
>>> degradation of
>>> more than a few tenths of a db, you are getting towards the minimum gain
>>> point.
>>>
>>> Indeed there are some receivers that have an AGC built in. *IF* your
>>> receiver has one
>>> and *IF* you can get at it, that would be a great way to work this out.
>>> Indeed anybody
>>> who makes it past both of those constraints has a pretty unique device.
>>>
>>> ====
>>>
>>> Simple answer for a 50 db antenna is to put an attenuator in after the DC
>>> has
>>> been eliminated from the circuit. It’s not idea, but it’s the best you can
>>> do. Running
>>> a great big splitter is one great way to come up with attenuation …..
>>>
>>> Bob
>>>
>>>
>>>>> On Nov 21, 2019, at 10:29 AM, John Ackermann N8UR <jra@febo.com> wrote:
>>>> Bob, this is a great summary, thanks!
>>>>
>>>> One related question, especially with mixed systems -- how do you tell
>>>> if you have optimum signal level at the receiver?
>>>>
>>>> Most show some sort of SNR or Cn value. What should we look for? What
>>>> are the indication of *too much* signal? One issue in particular is how
>>>> to handle a modern GPS that expects modest antenna gain when it's
>>>> plugged into a system with a 50dB gain antenna at the top.
>>>>
>>>> Thanks!
>>>> John
>>>> ----
>>>>
>>>> On 11/21/19 8:00 AM, Bob kb8tq wrote:
>>>>> Hi
>>>>>
>>>>> Way back in time, the first gear out there to use what we now look at
>>> as “normal” antennas
>>>>> was survey gear. For various reasons they decided on a 12V power supply
>>> and 40 to 50 db
>>>>> of gain in the preamp mounted in the antenna. They also got into L1 /
>>> L2 pretty quickly.
>>>>> A bit later the cell phone (and later broadcast) guys got into this. In
>>> a location with a lot of
>>>>> RF (like a cell site) having a lot of gain at the antenna didn’t work
>>> all that well. IMD issues
>>>>> got into the act pretty quickly. In addition, front end filtering was
>>> required to reduce overload
>>>>> issues. The focus was on L1 only so filtering was relatively easy.
>>>>>
>>>>> There is a whole separate set of antennas that put a big chunk of the
>>> RF portion of the radio
>>>>> in the antenna. Those still survive here and there. I have one of them
>>> and probably a couple
>>>>> of dozen of the more “normal” antennas.
>>>>>
>>>>> As time marched on, supplying 12V to antennas became a bit less
>>> popular. Most of the cell
>>>>> guys went over to a 5V antenna supply. The net result was 12V 50 db
>>> survey antennas that did
>>>>> L1/L2 and much smaller 5V 25 db antennas for “timing”. The timing
>>> antennas didn’t do L1/L2 so
>>>>> not going to work for survey. The survey antennas had way to much gain
>>> and no filtering so
>>>>> not going to work for a cell site.
>>>>>
>>>>> Indeed things did and do get crossed up in various pro and basement
>>> systems. With care and
>>>>> the right set of circumstances things may work. In other cases the
>>> result can be an ongoing set
>>>>> of systems issues over an entire network of stations.
>>>>>
>>>>> Prices for a good new survey antenna are up in the many thousands of
>>> dollars range. They have
>>>>> very stable phase centers and (usually) test results to allow
>>> correction of any residual phase
>>>>> issues. This is part of what lets you get into the “couple of mm” range
>>> on a survey.
>>>>> For timing, you have to dig a bit and answer a few questions. Is your
>>> concern how close you
>>>>> are to BIH? If so you will need to know all the delays in your system.
>>> This includes the delays
>>>>> in the antenna filters and the preamp. Is your concern (or measure) the
>>> ADEV at 1 second?
>>>>> If so the delays are not a concern. Your antenna choice may be a bit
>>> different depending on
>>>>> this focus.
>>>>>
>>>>> Bob
>>>>>
>>>>>
>>>>>
>>>>>> On Nov 21, 2019, at 1:25 AM, Taka Kamiya via time-nuts <
>>> time-nuts@lists.febo.com> wrote:
>>>>>> I have been looking antennas. Prices seem to range less than 30
>>> dollars to more than 500 dollars. Some are 20db gain and some are 40 db
>>> gain. Some are specified as marine use only. Some are specified as timing
>>> use. Some doesn't say anything at all. Power supplies are different.
>>>>>> Other than obvious, antenna is an antenna, isn't it? It captures L1
>>> signal, amplify it and send it down the coax. What makes one more costly
>>> than others? What makes one timing antenna and one navigation antenna? It
>>> doesn't make sense to me.
>>>>>> I did some simple experiment with 26db, 40db, and magnetic stick on
>>> type. I didn't really see significant difference. Signal level itself
>>> even wasn't all that different. I have nearly a clear sky view 360 degrees
>>> above 30 degrees above horizon. In some directions, clear view to
>>> horizon. My feed is Timewave type. So It may not be the best but nearly
>>> ideal.
>>>>>> Can someone shed light on this topic? (of course, I know some antenna
>>> has integrated receiver. I am not talking about those)
>>>>>> ---------------------------------------
>>>>>> (Mr.) Taka Kamiya
>>>>>> KB4EMF / ex JF2DKG
>>>>>> _______________________________________________
>>>>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>>>>> To unsubscribe, go to
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>>>>> and follow the instructions there.
>>>>>
>>>>> _______________________________________________
>>>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>>>> To unsubscribe, go to
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>>>> and follow the instructions there.
>>>>>
>>>>
>>>> _______________________________________________
>>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>>> To unsubscribe, go to
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>>> and follow the instructions there.
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>> To unsubscribe, go to
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>> and follow the instructions there.
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>> To unsubscribe, go to
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>> and follow the instructions there.
>>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts@lists.febo.com
>> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
> _______________________________________________
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
BK
Bob kb8tq
Fri, Nov 22, 2019 5:30 PM
Hi
If your antenna has test data associated with it (or even if it does not) there may / will
be differences in the phase response for various angles both in the vertical and horizontal
planes. Indeed some antennas have very minor changes vs angle and others move
quite a bit.
To keep this somewhat under control, survey antennas get a mark on them to tell you which
direction to point north. The idea being that if orientation is known, post processing corrections
to eliminate ( or at least reduce) the phase issues are possible. If you are not doing post
processing, there really isn’t much value in the magic “this way north” marking.
Bob
On Nov 22, 2019, at 11:07 AM, Bill Dailey docdailey@gmail.com wrote:
I would like to tag on to this. I have a large Leica L1 choke ring antenna. It has an indicator for “N”. Not sure why. I placed it on the roof without respect to directionality. I will rotate it with “N” facing north in a month or so to see if there is any effect.
Bill Dailey
Negativity always wins the short game. But positivity wins the long game. - Gary Vaynerchuk
Don’t be easy to understand,
Be impossible to misunderstand
On Nov 21, 2019, at 6:00 PM, Dana Whitlow k8yumdoober@gmail.com wrote:
Most modern GPS receivers are very quiet even barefoot. So, one could
argue that one should
not have much more LNA gain in the antenna than required to make up for
feedline loss, which
should be easily calculable. While excess gain in the antenna can improve
overall system noise
figure a small amount, it will degrade intermod performance, which is
likely to be a worse problem
than simple weak signals. It's likely that the cure is worse than the
disease, as my doctor likes to
say.
Dana
On Thu, Nov 21, 2019 at 4:00 PM Taka Kamiya via time-nuts <
time-nuts@lists.febo.com> wrote:
So.... concensus is, 50dB gain antenna is too much gain, unless feed line
is too long, reception is poor, or there are other circumstances extra gain
is desired?
(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG
On Thursday, November 21, 2019, 3:00:14 PM EST, Bob kb8tq <
kb8tq@n1k.org> wrote:
Hi
That is indeed the gotcha. Once you get past a certain amount of gain in
the
preamp, the C/N levels don’t change enough to notice. Looking today vs
looking
tomorrow is unlikely to be of any help if you are after a fraction of a
db.
About the only way to check would be to fast switch an attenuator in and
out of
the signal path. Watch things for a minute at one setting and then do the
same at
another setting. Run for a while and log all the deltas. If you see a
degradation of
more than a few tenths of a db, you are getting towards the minimum gain
point.
Indeed there are some receivers that have an AGC built in. IF your
receiver has one
and IF you can get at it, that would be a great way to work this out.
Indeed anybody
who makes it past both of those constraints has a pretty unique device.
====
Simple answer for a 50 db antenna is to put an attenuator in after the DC
has
been eliminated from the circuit. It’s not idea, but it’s the best you can
do. Running
a great big splitter is one great way to come up with attenuation …..
Bob
On Nov 21, 2019, at 10:29 AM, John Ackermann N8UR jra@febo.com wrote:
Bob, this is a great summary, thanks!
One related question, especially with mixed systems -- how do you tell
if you have optimum signal level at the receiver?
Most show some sort of SNR or Cn value. What should we look for? What
are the indication of too much signal? One issue in particular is how
to handle a modern GPS that expects modest antenna gain when it's
plugged into a system with a 50dB gain antenna at the top.
Thanks!
John
On 11/21/19 8:00 AM, Bob kb8tq wrote:
Hi
Way back in time, the first gear out there to use what we now look at
was survey gear. For various reasons they decided on a 12V power supply
of gain in the preamp mounted in the antenna. They also got into L1 /
A bit later the cell phone (and later broadcast) guys got into this. In
RF (like a cell site) having a lot of gain at the antenna didn’t work
all that well. IMD issues
got into the act pretty quickly. In addition, front end filtering was
required to reduce overload
issues. The focus was on L1 only so filtering was relatively easy.
There is a whole separate set of antennas that put a big chunk of the
in the antenna. Those still survive here and there. I have one of them
of dozen of the more “normal” antennas.
As time marched on, supplying 12V to antennas became a bit less
popular. Most of the cell
guys went over to a 5V antenna supply. The net result was 12V 50 db
L1/L2 and much smaller 5V 25 db antennas for “timing”. The timing
antennas didn’t do L1/L2 so
not going to work for survey. The survey antennas had way to much gain
not going to work for a cell site.
Indeed things did and do get crossed up in various pro and basement
the right set of circumstances things may work. In other cases the
result can be an ongoing set
of systems issues over an entire network of stations.
Prices for a good new survey antenna are up in the many thousands of
very stable phase centers and (usually) test results to allow
correction of any residual phase
issues. This is part of what lets you get into the “couple of mm” range
For timing, you have to dig a bit and answer a few questions. Is your
are to BIH? If so you will need to know all the delays in your system.
in the antenna filters and the preamp. Is your concern (or measure) the
If so the delays are not a concern. Your antenna choice may be a bit
On Nov 21, 2019, at 1:25 AM, Taka Kamiya via time-nuts <
I have been looking antennas. Prices seem to range less than 30
dollars to more than 500 dollars. Some are 20db gain and some are 40 db
gain. Some are specified as marine use only. Some are specified as timing
use. Some doesn't say anything at all. Power supplies are different.
Other than obvious, antenna is an antenna, isn't it? It captures L1
signal, amplify it and send it down the coax. What makes one more costly
than others? What makes one timing antenna and one navigation antenna? It
doesn't make sense to me.
I did some simple experiment with 26db, 40db, and magnetic stick on
type. I didn't really see significant difference. Signal level itself
even wasn't all that different. I have nearly a clear sky view 360 degrees
above 30 degrees above horizon. In some directions, clear view to
horizon. My feed is Timewave type. So It may not be the best but nearly
ideal.
Can someone shed light on this topic? (of course, I know some antenna
has integrated receiver. I am not talking about those)
and follow the instructions there.
and follow the instructions there.
and follow the instructions there.
Hi
If your antenna has test data associated with it (or even if it does not) there may / will
be differences in the phase response for various angles both in the vertical and horizontal
planes. Indeed some antennas have very minor changes vs angle and others move
quite a bit.
To keep this somewhat under control, survey antennas get a mark on them to tell you which
direction to point north. The idea being that if orientation is known, post processing corrections
to eliminate ( or at least reduce) the phase issues are possible. If you are not doing post
processing, there really isn’t much value in the magic “this way north” marking.
Bob
> On Nov 22, 2019, at 11:07 AM, Bill Dailey <docdailey@gmail.com> wrote:
>
> I would like to tag on to this. I have a large Leica L1 choke ring antenna. It has an indicator for “N”. Not sure why. I placed it on the roof without respect to directionality. I will rotate it with “N” facing north in a month or so to see if there is any effect.
>
> Bill Dailey
>
> Negativity always wins the short game. But positivity wins the long game. - Gary Vaynerchuk
>
> Don’t be easy to understand,
> Be impossible to misunderstand
> - Steve Sims
>
>> On Nov 21, 2019, at 6:00 PM, Dana Whitlow <k8yumdoober@gmail.com> wrote:
>>
>> Most modern GPS receivers are very quiet even barefoot. So, one could
>> argue that one should
>> not have much more LNA gain in the antenna than required to make up for
>> feedline loss, which
>> should be easily calculable. While excess gain in the antenna can improve
>> overall system noise
>> figure a small amount, it will degrade intermod performance, which is
>> likely to be a worse problem
>> than simple weak signals. It's likely that the cure is worse than the
>> disease, as my doctor likes to
>> say.
>>
>> Dana
>>
>>
>>
>>> On Thu, Nov 21, 2019 at 4:00 PM Taka Kamiya via time-nuts <
>>> time-nuts@lists.febo.com> wrote:
>>>
>>> So.... concensus is, 50dB gain antenna is too much gain, unless feed line
>>> is too long, reception is poor, or there are other circumstances extra gain
>>> is desired?
>>>
>>> ---------------------------------------
>>> (Mr.) Taka Kamiya
>>> KB4EMF / ex JF2DKG
>>>
>>>
>>> On Thursday, November 21, 2019, 3:00:14 PM EST, Bob kb8tq <
>>> kb8tq@n1k.org> wrote:
>>>
>>> Hi
>>>
>>> That is indeed the gotcha. Once you get past a certain amount of gain in
>>> the
>>> preamp, the C/N levels don’t change enough to notice. Looking today vs
>>> looking
>>> tomorrow is unlikely to be of any help if you are after a fraction of a
>>> db.
>>>
>>> About the only way to check would be to fast switch an attenuator in and
>>> out of
>>> the signal path. Watch things for a minute at one setting and then do the
>>> same at
>>> another setting. Run for a while and log all the deltas. If you see a
>>> degradation of
>>> more than a few tenths of a db, you are getting towards the minimum gain
>>> point.
>>>
>>> Indeed there are some receivers that have an AGC built in. *IF* your
>>> receiver has one
>>> and *IF* you can get at it, that would be a great way to work this out.
>>> Indeed anybody
>>> who makes it past both of those constraints has a pretty unique device.
>>>
>>> ====
>>>
>>> Simple answer for a 50 db antenna is to put an attenuator in after the DC
>>> has
>>> been eliminated from the circuit. It’s not idea, but it’s the best you can
>>> do. Running
>>> a great big splitter is one great way to come up with attenuation …..
>>>
>>> Bob
>>>
>>>
>>>>> On Nov 21, 2019, at 10:29 AM, John Ackermann N8UR <jra@febo.com> wrote:
>>>>
>>>> Bob, this is a great summary, thanks!
>>>>
>>>> One related question, especially with mixed systems -- how do you tell
>>>> if you have optimum signal level at the receiver?
>>>>
>>>> Most show some sort of SNR or Cn value. What should we look for? What
>>>> are the indication of *too much* signal? One issue in particular is how
>>>> to handle a modern GPS that expects modest antenna gain when it's
>>>> plugged into a system with a 50dB gain antenna at the top.
>>>>
>>>> Thanks!
>>>> John
>>>> ----
>>>>
>>>> On 11/21/19 8:00 AM, Bob kb8tq wrote:
>>>>> Hi
>>>>>
>>>>> Way back in time, the first gear out there to use what we now look at
>>> as “normal” antennas
>>>>> was survey gear. For various reasons they decided on a 12V power supply
>>> and 40 to 50 db
>>>>> of gain in the preamp mounted in the antenna. They also got into L1 /
>>> L2 pretty quickly.
>>>>>
>>>>> A bit later the cell phone (and later broadcast) guys got into this. In
>>> a location with a lot of
>>>>> RF (like a cell site) having a lot of gain at the antenna didn’t work
>>> all that well. IMD issues
>>>>> got into the act pretty quickly. In addition, front end filtering was
>>> required to reduce overload
>>>>> issues. The focus was on L1 only so filtering was relatively easy.
>>>>>
>>>>> There is a whole separate set of antennas that put a big chunk of the
>>> RF portion of the radio
>>>>> in the antenna. Those still survive here and there. I have one of them
>>> and probably a couple
>>>>> of dozen of the more “normal” antennas.
>>>>>
>>>>> As time marched on, supplying 12V to antennas became a bit less
>>> popular. Most of the cell
>>>>> guys went over to a 5V antenna supply. The net result was 12V 50 db
>>> survey antennas that did
>>>>> L1/L2 and much smaller 5V 25 db antennas for “timing”. The timing
>>> antennas didn’t do L1/L2 so
>>>>> not going to work for survey. The survey antennas had way to much gain
>>> and no filtering so
>>>>> not going to work for a cell site.
>>>>>
>>>>> Indeed things did and do get crossed up in various pro and basement
>>> systems. With care and
>>>>> the right set of circumstances things may work. In other cases the
>>> result can be an ongoing set
>>>>> of systems issues over an entire network of stations.
>>>>>
>>>>> Prices for a good new survey antenna are up in the many thousands of
>>> dollars range. They have
>>>>> very stable phase centers and (usually) test results to allow
>>> correction of any residual phase
>>>>> issues. This is part of what lets you get into the “couple of mm” range
>>> on a survey.
>>>>>
>>>>> For timing, you have to dig a bit and answer a few questions. Is your
>>> concern how close you
>>>>> are to BIH? If so you will need to know all the delays in your system.
>>> This includes the delays
>>>>> in the antenna filters and the preamp. Is your concern (or measure) the
>>> ADEV at 1 second?
>>>>> If so the delays are not a concern. Your antenna choice may be a bit
>>> different depending on
>>>>> this focus.
>>>>>
>>>>> Bob
>>>>>
>>>>>
>>>>>
>>>>>> On Nov 21, 2019, at 1:25 AM, Taka Kamiya via time-nuts <
>>> time-nuts@lists.febo.com> wrote:
>>>>>>
>>>>>> I have been looking antennas. Prices seem to range less than 30
>>> dollars to more than 500 dollars. Some are 20db gain and some are 40 db
>>> gain. Some are specified as marine use only. Some are specified as timing
>>> use. Some doesn't say anything at all. Power supplies are different.
>>>>>> Other than obvious, antenna is an antenna, isn't it? It captures L1
>>> signal, amplify it and send it down the coax. What makes one more costly
>>> than others? What makes one timing antenna and one navigation antenna? It
>>> doesn't make sense to me.
>>>>>>
>>>>>> I did some simple experiment with 26db, 40db, and magnetic stick on
>>> type. I didn't really see significant difference. Signal level itself
>>> even wasn't all that different. I have nearly a clear sky view 360 degrees
>>> above 30 degrees above horizon. In some directions, clear view to
>>> horizon. My feed is Timewave type. So It may not be the best but nearly
>>> ideal.
>>>>>>
>>>>>> Can someone shed light on this topic? (of course, I know some antenna
>>> has integrated receiver. I am not talking about those)
>>>>>>
>>>>>> ---------------------------------------
>>>>>> (Mr.) Taka Kamiya
>>>>>> KB4EMF / ex JF2DKG
>>>>>> _______________________________________________
>>>>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>>>>> To unsubscribe, go to
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>>>>> and follow the instructions there.
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>>>> To unsubscribe, go to
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>>>> and follow the instructions there.
>>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>>> To unsubscribe, go to
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>>> and follow the instructions there.
>>>
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>> To unsubscribe, go to
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>> and follow the instructions there.
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>> To unsubscribe, go to
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>> and follow the instructions there.
>>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts@lists.febo.com
>> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
> _______________________________________________
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
B
Björn
Fri, Nov 22, 2019 5:35 PM
The N for North is because the phase center offsets are not symmetrical. With a convention to orient the antennas the same way the offset could be corrected.
/Björn
Sent from my iPhone
On 22 Nov 2019, at 17:07, Bill Dailey docdailey@gmail.com wrote:
I would like to tag on to this. I have a large Leica L1 choke ring antenna. It has an indicator for “N”. Not sure why. I placed it on the roof without respect to directionality. I will rotate it with “N” facing north in a month or so to see if there is any effect.
Bill Dailey
Negativity always wins the short game. But positivity wins the long game. - Gary Vaynerchuk
Don’t be easy to understand,
Be impossible to misunderstand
On Nov 21, 2019, at 6:00 PM, Dana Whitlow k8yumdoober@gmail.com wrote:
Most modern GPS receivers are very quiet even barefoot. So, one could
argue that one should
not have much more LNA gain in the antenna than required to make up for
feedline loss, which
should be easily calculable. While excess gain in the antenna can improve
overall system noise
figure a small amount, it will degrade intermod performance, which is
likely to be a worse problem
than simple weak signals. It's likely that the cure is worse than the
disease, as my doctor likes to
say.
Dana
On Thu, Nov 21, 2019 at 4:00 PM Taka Kamiya via time-nuts <
time-nuts@lists.febo.com> wrote:
So.... concensus is, 50dB gain antenna is too much gain, unless feed line
is too long, reception is poor, or there are other circumstances extra gain
is desired?
(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG
On Thursday, November 21, 2019, 3:00:14 PM EST, Bob kb8tq <
kb8tq@n1k.org> wrote:
Hi
That is indeed the gotcha. Once you get past a certain amount of gain in
the
preamp, the C/N levels don’t change enough to notice. Looking today vs
looking
tomorrow is unlikely to be of any help if you are after a fraction of a
db.
About the only way to check would be to fast switch an attenuator in and
out of
the signal path. Watch things for a minute at one setting and then do the
same at
another setting. Run for a while and log all the deltas. If you see a
degradation of
more than a few tenths of a db, you are getting towards the minimum gain
point.
Indeed there are some receivers that have an AGC built in. IF your
receiver has one
and IF you can get at it, that would be a great way to work this out.
Indeed anybody
who makes it past both of those constraints has a pretty unique device.
====
Simple answer for a 50 db antenna is to put an attenuator in after the DC
has
been eliminated from the circuit. It’s not idea, but it’s the best you can
do. Running
a great big splitter is one great way to come up with attenuation …..
Bob
On Nov 21, 2019, at 10:29 AM, John Ackermann N8UR jra@febo.com wrote:
Bob, this is a great summary, thanks!
One related question, especially with mixed systems -- how do you tell
if you have optimum signal level at the receiver?
Most show some sort of SNR or Cn value. What should we look for? What
are the indication of too much signal? One issue in particular is how
to handle a modern GPS that expects modest antenna gain when it's
plugged into a system with a 50dB gain antenna at the top.
Thanks!
John
On 11/21/19 8:00 AM, Bob kb8tq wrote:
Hi
Way back in time, the first gear out there to use what we now look at
was survey gear. For various reasons they decided on a 12V power supply
of gain in the preamp mounted in the antenna. They also got into L1 /
A bit later the cell phone (and later broadcast) guys got into this. In
RF (like a cell site) having a lot of gain at the antenna didn’t work
all that well. IMD issues
got into the act pretty quickly. In addition, front end filtering was
required to reduce overload
issues. The focus was on L1 only so filtering was relatively easy.
There is a whole separate set of antennas that put a big chunk of the
in the antenna. Those still survive here and there. I have one of them
of dozen of the more “normal” antennas.
As time marched on, supplying 12V to antennas became a bit less
popular. Most of the cell
guys went over to a 5V antenna supply. The net result was 12V 50 db
L1/L2 and much smaller 5V 25 db antennas for “timing”. The timing
antennas didn’t do L1/L2 so
not going to work for survey. The survey antennas had way to much gain
not going to work for a cell site.
Indeed things did and do get crossed up in various pro and basement
the right set of circumstances things may work. In other cases the
result can be an ongoing set
of systems issues over an entire network of stations.
Prices for a good new survey antenna are up in the many thousands of
very stable phase centers and (usually) test results to allow
correction of any residual phase
issues. This is part of what lets you get into the “couple of mm” range
For timing, you have to dig a bit and answer a few questions. Is your
are to BIH? If so you will need to know all the delays in your system.
in the antenna filters and the preamp. Is your concern (or measure) the
If so the delays are not a concern. Your antenna choice may be a bit
On Nov 21, 2019, at 1:25 AM, Taka Kamiya via time-nuts <
I have been looking antennas. Prices seem to range less than 30
dollars to more than 500 dollars. Some are 20db gain and some are 40 db
gain. Some are specified as marine use only. Some are specified as timing
use. Some doesn't say anything at all. Power supplies are different.
Other than obvious, antenna is an antenna, isn't it? It captures L1
signal, amplify it and send it down the coax. What makes one more costly
than others? What makes one timing antenna and one navigation antenna? It
doesn't make sense to me.
I did some simple experiment with 26db, 40db, and magnetic stick on
type. I didn't really see significant difference. Signal level itself
even wasn't all that different. I have nearly a clear sky view 360 degrees
above 30 degrees above horizon. In some directions, clear view to
horizon. My feed is Timewave type. So It may not be the best but nearly
ideal.
Can someone shed light on this topic? (of course, I know some antenna
has integrated receiver. I am not talking about those)
and follow the instructions there.
and follow the instructions there.
and follow the instructions there.
The N for North is because the phase center offsets are not symmetrical. With a convention to orient the antennas the same way the offset could be corrected.
/Björn
Sent from my iPhone
> On 22 Nov 2019, at 17:07, Bill Dailey <docdailey@gmail.com> wrote:
>
> I would like to tag on to this. I have a large Leica L1 choke ring antenna. It has an indicator for “N”. Not sure why. I placed it on the roof without respect to directionality. I will rotate it with “N” facing north in a month or so to see if there is any effect.
>
> Bill Dailey
>
> Negativity always wins the short game. But positivity wins the long game. - Gary Vaynerchuk
>
> Don’t be easy to understand,
> Be impossible to misunderstand
> - Steve Sims
>
>> On Nov 21, 2019, at 6:00 PM, Dana Whitlow <k8yumdoober@gmail.com> wrote:
>>
>> Most modern GPS receivers are very quiet even barefoot. So, one could
>> argue that one should
>> not have much more LNA gain in the antenna than required to make up for
>> feedline loss, which
>> should be easily calculable. While excess gain in the antenna can improve
>> overall system noise
>> figure a small amount, it will degrade intermod performance, which is
>> likely to be a worse problem
>> than simple weak signals. It's likely that the cure is worse than the
>> disease, as my doctor likes to
>> say.
>>
>> Dana
>>
>>
>>
>>> On Thu, Nov 21, 2019 at 4:00 PM Taka Kamiya via time-nuts <
>>> time-nuts@lists.febo.com> wrote:
>>>
>>> So.... concensus is, 50dB gain antenna is too much gain, unless feed line
>>> is too long, reception is poor, or there are other circumstances extra gain
>>> is desired?
>>>
>>> ---------------------------------------
>>> (Mr.) Taka Kamiya
>>> KB4EMF / ex JF2DKG
>>>
>>>
>>> On Thursday, November 21, 2019, 3:00:14 PM EST, Bob kb8tq <
>>> kb8tq@n1k.org> wrote:
>>>
>>> Hi
>>>
>>> That is indeed the gotcha. Once you get past a certain amount of gain in
>>> the
>>> preamp, the C/N levels don’t change enough to notice. Looking today vs
>>> looking
>>> tomorrow is unlikely to be of any help if you are after a fraction of a
>>> db.
>>>
>>> About the only way to check would be to fast switch an attenuator in and
>>> out of
>>> the signal path. Watch things for a minute at one setting and then do the
>>> same at
>>> another setting. Run for a while and log all the deltas. If you see a
>>> degradation of
>>> more than a few tenths of a db, you are getting towards the minimum gain
>>> point.
>>>
>>> Indeed there are some receivers that have an AGC built in. *IF* your
>>> receiver has one
>>> and *IF* you can get at it, that would be a great way to work this out.
>>> Indeed anybody
>>> who makes it past both of those constraints has a pretty unique device.
>>>
>>> ====
>>>
>>> Simple answer for a 50 db antenna is to put an attenuator in after the DC
>>> has
>>> been eliminated from the circuit. It’s not idea, but it’s the best you can
>>> do. Running
>>> a great big splitter is one great way to come up with attenuation …..
>>>
>>> Bob
>>>
>>>
>>>>> On Nov 21, 2019, at 10:29 AM, John Ackermann N8UR <jra@febo.com> wrote:
>>>>
>>>> Bob, this is a great summary, thanks!
>>>>
>>>> One related question, especially with mixed systems -- how do you tell
>>>> if you have optimum signal level at the receiver?
>>>>
>>>> Most show some sort of SNR or Cn value. What should we look for? What
>>>> are the indication of *too much* signal? One issue in particular is how
>>>> to handle a modern GPS that expects modest antenna gain when it's
>>>> plugged into a system with a 50dB gain antenna at the top.
>>>>
>>>> Thanks!
>>>> John
>>>> ----
>>>>
>>>>> On 11/21/19 8:00 AM, Bob kb8tq wrote:
>>>>> Hi
>>>>>
>>>>> Way back in time, the first gear out there to use what we now look at
>>> as “normal” antennas
>>>>> was survey gear. For various reasons they decided on a 12V power supply
>>> and 40 to 50 db
>>>>> of gain in the preamp mounted in the antenna. They also got into L1 /
>>> L2 pretty quickly.
>>>>>
>>>>> A bit later the cell phone (and later broadcast) guys got into this. In
>>> a location with a lot of
>>>>> RF (like a cell site) having a lot of gain at the antenna didn’t work
>>> all that well. IMD issues
>>>>> got into the act pretty quickly. In addition, front end filtering was
>>> required to reduce overload
>>>>> issues. The focus was on L1 only so filtering was relatively easy.
>>>>>
>>>>> There is a whole separate set of antennas that put a big chunk of the
>>> RF portion of the radio
>>>>> in the antenna. Those still survive here and there. I have one of them
>>> and probably a couple
>>>>> of dozen of the more “normal” antennas.
>>>>>
>>>>> As time marched on, supplying 12V to antennas became a bit less
>>> popular. Most of the cell
>>>>> guys went over to a 5V antenna supply. The net result was 12V 50 db
>>> survey antennas that did
>>>>> L1/L2 and much smaller 5V 25 db antennas for “timing”. The timing
>>> antennas didn’t do L1/L2 so
>>>>> not going to work for survey. The survey antennas had way to much gain
>>> and no filtering so
>>>>> not going to work for a cell site.
>>>>>
>>>>> Indeed things did and do get crossed up in various pro and basement
>>> systems. With care and
>>>>> the right set of circumstances things may work. In other cases the
>>> result can be an ongoing set
>>>>> of systems issues over an entire network of stations.
>>>>>
>>>>> Prices for a good new survey antenna are up in the many thousands of
>>> dollars range. They have
>>>>> very stable phase centers and (usually) test results to allow
>>> correction of any residual phase
>>>>> issues. This is part of what lets you get into the “couple of mm” range
>>> on a survey.
>>>>>
>>>>> For timing, you have to dig a bit and answer a few questions. Is your
>>> concern how close you
>>>>> are to BIH? If so you will need to know all the delays in your system.
>>> This includes the delays
>>>>> in the antenna filters and the preamp. Is your concern (or measure) the
>>> ADEV at 1 second?
>>>>> If so the delays are not a concern. Your antenna choice may be a bit
>>> different depending on
>>>>> this focus.
>>>>>
>>>>> Bob
>>>>>
>>>>>
>>>>>
>>>>>> On Nov 21, 2019, at 1:25 AM, Taka Kamiya via time-nuts <
>>> time-nuts@lists.febo.com> wrote:
>>>>>>
>>>>>> I have been looking antennas. Prices seem to range less than 30
>>> dollars to more than 500 dollars. Some are 20db gain and some are 40 db
>>> gain. Some are specified as marine use only. Some are specified as timing
>>> use. Some doesn't say anything at all. Power supplies are different.
>>>>>> Other than obvious, antenna is an antenna, isn't it? It captures L1
>>> signal, amplify it and send it down the coax. What makes one more costly
>>> than others? What makes one timing antenna and one navigation antenna? It
>>> doesn't make sense to me.
>>>>>>
>>>>>> I did some simple experiment with 26db, 40db, and magnetic stick on
>>> type. I didn't really see significant difference. Signal level itself
>>> even wasn't all that different. I have nearly a clear sky view 360 degrees
>>> above 30 degrees above horizon. In some directions, clear view to
>>> horizon. My feed is Timewave type. So It may not be the best but nearly
>>> ideal.
>>>>>>
>>>>>> Can someone shed light on this topic? (of course, I know some antenna
>>> has integrated receiver. I am not talking about those)
>>>>>>
>>>>>> ---------------------------------------
>>>>>> (Mr.) Taka Kamiya
>>>>>> KB4EMF / ex JF2DKG
>>>>>> _______________________________________________
>>>>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>>>>> To unsubscribe, go to
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>>>>> and follow the instructions there.
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>>>> To unsubscribe, go to
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>>>> and follow the instructions there.
>>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>>> To unsubscribe, go to
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>>> and follow the instructions there.
>>>
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>> To unsubscribe, go to
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>> and follow the instructions there.
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>> To unsubscribe, go to
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>>> and follow the instructions there.
>>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts@lists.febo.com
>> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
> _______________________________________________
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> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
BD
Bill Dailey, MD, MSEng, MSMI
Fri, Nov 22, 2019 6:02 PM
Interesting. No, there was no data with it.
On Fri, Nov 22, 2019 at 12:00 PM Björn bg@lysator.liu.se wrote:
The N for North is because the phase center offsets are not symmetrical.
With a convention to orient the antennas the same way the offset could be
corrected.
/Björn
Sent from my iPhone
On 22 Nov 2019, at 17:07, Bill Dailey docdailey@gmail.com wrote:
I would like to tag on to this. I have a large Leica L1 choke ring
antenna. It has an indicator for “N”. Not sure why. I placed it on the
roof without respect to directionality. I will rotate it with “N” facing
north in a month or so to see if there is any effect.
Bill Dailey
Negativity always wins the short game. But positivity wins the long
Don’t be easy to understand,
Be impossible to misunderstand
Most modern GPS receivers are very quiet even barefoot. So, one could
argue that one should
not have much more LNA gain in the antenna than required to make up for
feedline loss, which
should be easily calculable. While excess gain in the antenna can
overall system noise
figure a small amount, it will degrade intermod performance, which is
likely to be a worse problem
than simple weak signals. It's likely that the cure is worse than the
disease, as my doctor likes to
say.
Dana
On Thu, Nov 21, 2019 at 4:00 PM Taka Kamiya via time-nuts <
time-nuts@lists.febo.com> wrote:
So.... concensus is, 50dB gain antenna is too much gain, unless feed
is too long, reception is poor, or there are other circumstances extra
is desired?
(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG
On Thursday, November 21, 2019, 3:00:14 PM EST, Bob kb8tq <
kb8tq@n1k.org> wrote:
Hi
That is indeed the gotcha. Once you get past a certain amount of gain
the
preamp, the C/N levels don’t change enough to notice. Looking today vs
looking
tomorrow is unlikely to be of any help if you are after a fraction of a
db.
About the only way to check would be to fast switch an attenuator in
out of
the signal path. Watch things for a minute at one setting and then do
same at
another setting. Run for a while and log all the deltas. If you see a
degradation of
more than a few tenths of a db, you are getting towards the minimum
point.
Indeed there are some receivers that have an AGC built in. IF your
receiver has one
and IF you can get at it, that would be a great way to work this out.
Indeed anybody
who makes it past both of those constraints has a pretty unique device.
====
Simple answer for a 50 db antenna is to put an attenuator in after the
has
been eliminated from the circuit. It’s not idea, but it’s the best you
do. Running
a great big splitter is one great way to come up with attenuation …..
Bob
On Nov 21, 2019, at 10:29 AM, John Ackermann N8UR jra@febo.com
Bob, this is a great summary, thanks!
One related question, especially with mixed systems -- how do you tell
if you have optimum signal level at the receiver?
Most show some sort of SNR or Cn value. What should we look for?
are the indication of too much signal? One issue in particular is
to handle a modern GPS that expects modest antenna gain when it's
plugged into a system with a 50dB gain antenna at the top.
Thanks!
John
On 11/21/19 8:00 AM, Bob kb8tq wrote:
Hi
Way back in time, the first gear out there to use what we now look at
was survey gear. For various reasons they decided on a 12V power
of gain in the preamp mounted in the antenna. They also got into L1 /
A bit later the cell phone (and later broadcast) guys got into this.
RF (like a cell site) having a lot of gain at the antenna didn’t work
all that well. IMD issues
got into the act pretty quickly. In addition, front end filtering was
required to reduce overload
issues. The focus was on L1 only so filtering was relatively easy.
There is a whole separate set of antennas that put a big chunk of the
in the antenna. Those still survive here and there. I have one of
of dozen of the more “normal” antennas.
As time marched on, supplying 12V to antennas became a bit less
popular. Most of the cell
guys went over to a 5V antenna supply. The net result was 12V 50 db
L1/L2 and much smaller 5V 25 db antennas for “timing”. The timing
antennas didn’t do L1/L2 so
not going to work for survey. The survey antennas had way to much
not going to work for a cell site.
Indeed things did and do get crossed up in various pro and basement
the right set of circumstances things may work. In other cases the
result can be an ongoing set
of systems issues over an entire network of stations.
Prices for a good new survey antenna are up in the many thousands of
very stable phase centers and (usually) test results to allow
correction of any residual phase
issues. This is part of what lets you get into the “couple of mm”
For timing, you have to dig a bit and answer a few questions. Is your
are to BIH? If so you will need to know all the delays in your
in the antenna filters and the preamp. Is your concern (or measure)
If so the delays are not a concern. Your antenna choice may be a bit
On Nov 21, 2019, at 1:25 AM, Taka Kamiya via time-nuts <
I have been looking antennas. Prices seem to range less than 30
dollars to more than 500 dollars. Some are 20db gain and some are 40
gain. Some are specified as marine use only. Some are specified as
use. Some doesn't say anything at all. Power supplies are different.
Other than obvious, antenna is an antenna, isn't it? It captures L1
signal, amplify it and send it down the coax. What makes one more
than others? What makes one timing antenna and one navigation
doesn't make sense to me.
I did some simple experiment with 26db, 40db, and magnetic stick on
type. I didn't really see significant difference. Signal level itself
even wasn't all that different. I have nearly a clear sky view 360
above 30 degrees above horizon. In some directions, clear view to
horizon. My feed is Timewave type. So It may not be the best but
Can someone shed light on this topic? (of course, I know some
has integrated receiver. I am not talking about those)
and follow the instructions there.
and follow the instructions there.
and follow the instructions there.
and follow the instructions there.
and follow the instructions there.
Interesting. No, there was no data with it.
On Fri, Nov 22, 2019 at 12:00 PM Björn <bg@lysator.liu.se> wrote:
> The N for North is because the phase center offsets are not symmetrical.
> With a convention to orient the antennas the same way the offset could be
> corrected.
>
> /Björn
>
> Sent from my iPhone
>
> > On 22 Nov 2019, at 17:07, Bill Dailey <docdailey@gmail.com> wrote:
> >
> > I would like to tag on to this. I have a large Leica L1 choke ring
> antenna. It has an indicator for “N”. Not sure why. I placed it on the
> roof without respect to directionality. I will rotate it with “N” facing
> north in a month or so to see if there is any effect.
> >
> > Bill Dailey
> >
> > Negativity always wins the short game. But positivity wins the long
> game. - Gary Vaynerchuk
> >
> > Don’t be easy to understand,
> > Be impossible to misunderstand
> > - Steve Sims
> >
> >> On Nov 21, 2019, at 6:00 PM, Dana Whitlow <k8yumdoober@gmail.com>
> wrote:
> >>
> >> Most modern GPS receivers are very quiet even barefoot. So, one could
> >> argue that one should
> >> not have much more LNA gain in the antenna than required to make up for
> >> feedline loss, which
> >> should be easily calculable. While excess gain in the antenna can
> improve
> >> overall system noise
> >> figure a small amount, it will degrade intermod performance, which is
> >> likely to be a worse problem
> >> than simple weak signals. It's likely that the cure is worse than the
> >> disease, as my doctor likes to
> >> say.
> >>
> >> Dana
> >>
> >>
> >>
> >>> On Thu, Nov 21, 2019 at 4:00 PM Taka Kamiya via time-nuts <
> >>> time-nuts@lists.febo.com> wrote:
> >>>
> >>> So.... concensus is, 50dB gain antenna is too much gain, unless feed
> line
> >>> is too long, reception is poor, or there are other circumstances extra
> gain
> >>> is desired?
> >>>
> >>> ---------------------------------------
> >>> (Mr.) Taka Kamiya
> >>> KB4EMF / ex JF2DKG
> >>>
> >>>
> >>> On Thursday, November 21, 2019, 3:00:14 PM EST, Bob kb8tq <
> >>> kb8tq@n1k.org> wrote:
> >>>
> >>> Hi
> >>>
> >>> That is indeed the gotcha. Once you get past a certain amount of gain
> in
> >>> the
> >>> preamp, the C/N levels don’t change enough to notice. Looking today vs
> >>> looking
> >>> tomorrow is unlikely to be of any help if you are after a fraction of a
> >>> db.
> >>>
> >>> About the only way to check would be to fast switch an attenuator in
> and
> >>> out of
> >>> the signal path. Watch things for a minute at one setting and then do
> the
> >>> same at
> >>> another setting. Run for a while and log all the deltas. If you see a
> >>> degradation of
> >>> more than a few tenths of a db, you are getting towards the minimum
> gain
> >>> point.
> >>>
> >>> Indeed there are some receivers that have an AGC built in. *IF* your
> >>> receiver has one
> >>> and *IF* you can get at it, that would be a great way to work this out.
> >>> Indeed anybody
> >>> who makes it past both of those constraints has a pretty unique device.
> >>>
> >>> ====
> >>>
> >>> Simple answer for a 50 db antenna is to put an attenuator in after the
> DC
> >>> has
> >>> been eliminated from the circuit. It’s not idea, but it’s the best you
> can
> >>> do. Running
> >>> a great big splitter is one great way to come up with attenuation …..
> >>>
> >>> Bob
> >>>
> >>>
> >>>>> On Nov 21, 2019, at 10:29 AM, John Ackermann N8UR <jra@febo.com>
> wrote:
> >>>>
> >>>> Bob, this is a great summary, thanks!
> >>>>
> >>>> One related question, especially with mixed systems -- how do you tell
> >>>> if you have optimum signal level at the receiver?
> >>>>
> >>>> Most show some sort of SNR or Cn value. What should we look for?
> What
> >>>> are the indication of *too much* signal? One issue in particular is
> how
> >>>> to handle a modern GPS that expects modest antenna gain when it's
> >>>> plugged into a system with a 50dB gain antenna at the top.
> >>>>
> >>>> Thanks!
> >>>> John
> >>>> ----
> >>>>
> >>>>> On 11/21/19 8:00 AM, Bob kb8tq wrote:
> >>>>> Hi
> >>>>>
> >>>>> Way back in time, the first gear out there to use what we now look at
> >>> as “normal” antennas
> >>>>> was survey gear. For various reasons they decided on a 12V power
> supply
> >>> and 40 to 50 db
> >>>>> of gain in the preamp mounted in the antenna. They also got into L1 /
> >>> L2 pretty quickly.
> >>>>>
> >>>>> A bit later the cell phone (and later broadcast) guys got into this.
> In
> >>> a location with a lot of
> >>>>> RF (like a cell site) having a lot of gain at the antenna didn’t work
> >>> all that well. IMD issues
> >>>>> got into the act pretty quickly. In addition, front end filtering was
> >>> required to reduce overload
> >>>>> issues. The focus was on L1 only so filtering was relatively easy.
> >>>>>
> >>>>> There is a whole separate set of antennas that put a big chunk of the
> >>> RF portion of the radio
> >>>>> in the antenna. Those still survive here and there. I have one of
> them
> >>> and probably a couple
> >>>>> of dozen of the more “normal” antennas.
> >>>>>
> >>>>> As time marched on, supplying 12V to antennas became a bit less
> >>> popular. Most of the cell
> >>>>> guys went over to a 5V antenna supply. The net result was 12V 50 db
> >>> survey antennas that did
> >>>>> L1/L2 and much smaller 5V 25 db antennas for “timing”. The timing
> >>> antennas didn’t do L1/L2 so
> >>>>> not going to work for survey. The survey antennas had way to much
> gain
> >>> and no filtering so
> >>>>> not going to work for a cell site.
> >>>>>
> >>>>> Indeed things did and do get crossed up in various pro and basement
> >>> systems. With care and
> >>>>> the right set of circumstances things may work. In other cases the
> >>> result can be an ongoing set
> >>>>> of systems issues over an entire network of stations.
> >>>>>
> >>>>> Prices for a good new survey antenna are up in the many thousands of
> >>> dollars range. They have
> >>>>> very stable phase centers and (usually) test results to allow
> >>> correction of any residual phase
> >>>>> issues. This is part of what lets you get into the “couple of mm”
> range
> >>> on a survey.
> >>>>>
> >>>>> For timing, you have to dig a bit and answer a few questions. Is your
> >>> concern how close you
> >>>>> are to BIH? If so you will need to know all the delays in your
> system.
> >>> This includes the delays
> >>>>> in the antenna filters and the preamp. Is your concern (or measure)
> the
> >>> ADEV at 1 second?
> >>>>> If so the delays are not a concern. Your antenna choice may be a bit
> >>> different depending on
> >>>>> this focus.
> >>>>>
> >>>>> Bob
> >>>>>
> >>>>>
> >>>>>
> >>>>>> On Nov 21, 2019, at 1:25 AM, Taka Kamiya via time-nuts <
> >>> time-nuts@lists.febo.com> wrote:
> >>>>>>
> >>>>>> I have been looking antennas. Prices seem to range less than 30
> >>> dollars to more than 500 dollars. Some are 20db gain and some are 40
> db
> >>> gain. Some are specified as marine use only. Some are specified as
> timing
> >>> use. Some doesn't say anything at all. Power supplies are different.
> >>>>>> Other than obvious, antenna is an antenna, isn't it? It captures L1
> >>> signal, amplify it and send it down the coax. What makes one more
> costly
> >>> than others? What makes one timing antenna and one navigation
> antenna? It
> >>> doesn't make sense to me.
> >>>>>>
> >>>>>> I did some simple experiment with 26db, 40db, and magnetic stick on
> >>> type. I didn't really see significant difference. Signal level itself
> >>> even wasn't all that different. I have nearly a clear sky view 360
> degrees
> >>> above 30 degrees above horizon. In some directions, clear view to
> >>> horizon. My feed is Timewave type. So It may not be the best but
> nearly
> >>> ideal.
> >>>>>>
> >>>>>> Can someone shed light on this topic? (of course, I know some
> antenna
> >>> has integrated receiver. I am not talking about those)
> >>>>>>
> >>>>>> ---------------------------------------
> >>>>>> (Mr.) Taka Kamiya
> >>>>>> KB4EMF / ex JF2DKG
> >>>>>> _______________________________________________
> >>>>>> time-nuts mailing list -- time-nuts@lists.febo.com
> >>>>>> To unsubscribe, go to
> >>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> >>>>>> and follow the instructions there.
> >>>>>
> >>>>>
> >>>>> _______________________________________________
> >>>>> time-nuts mailing list -- time-nuts@lists.febo.com
> >>>>> To unsubscribe, go to
> >>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> >>>>> and follow the instructions there.
> >>>>>
> >>>>
> >>>>
> >>>> _______________________________________________
> >>>> time-nuts mailing list -- time-nuts@lists.febo.com
> >>>> To unsubscribe, go to
> >>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> >>>> and follow the instructions there.
> >>>
> >>>
> >>> _______________________________________________
> >>> time-nuts mailing list -- time-nuts@lists.febo.com
> >>> To unsubscribe, go to
> >>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> >>> and follow the instructions there.
> >>>
> >>> _______________________________________________
> >>> time-nuts mailing list -- time-nuts@lists.febo.com
> >>> To unsubscribe, go to
> >>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> >>> and follow the instructions there.
> >>>
> >> _______________________________________________
> >> time-nuts mailing list -- time-nuts@lists.febo.com
> >> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> >> and follow the instructions there.
> > _______________________________________________
> > time-nuts mailing list -- time-nuts@lists.febo.com
> > To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> > and follow the instructions there.
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>
--
Doc
Bill Dailey
KXØO
