Re: [time-nuts] Antenna for t-bolt
The elevation angle filter is based on the satellite position, not the actual direction the signals come from.
If you have reflections and multipath, but the satellite is otherwise high in the sky, you are out of luck regardless of elevation angle filter.
Of course, the higher the sat, the less likely you will have reflections from roofs and such, so it is definitely not useless, but it is not the same as having a good antenna in the first place.
Didier KO4BB
------Original Message------
From: Hal Murray
Sender: time-nuts-bounces@febo.com
To: Time-Nuts
ReplyTo: Time-Nuts
Subject: Re: [time-nuts] Antenna for t-bolt
Sent: Apr 3, 2012 12:15 AM
caf@omen.com said:
Presumably a timing antenna would block low elevation signals to reduce
multipath.
Maybe, but there is a software aspect to the filter. You get to select the
elevation angle.
I don't remember seeing any specs about the filtering angles of various
antennas. Has anybody seen something like that?
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Of course the elevation mask is only software and doesn't prevent the bad
signal from entering the antenna but then the signal will not despread and
should cause no harm to the computations.
On Tue, Apr 3, 2012 at 9:19 PM, shalimr9@gmail.com wrote:
The elevation angle filter is based on the satellite position, not the
actual direction the signals come from.
If you have reflections and multipath, but the satellite is otherwise high
in the sky, you are out of luck regardless of elevation angle filter.
Of course, the higher the sat, the less likely you will have reflections
from roofs and such, so it is definitely not useless, but it is not the
same as having a good antenna in the first place.
Didier KO4BB
------Original Message------
From: Hal Murray
Sender: time-nuts-bounces@febo.com
To: Time-Nuts
ReplyTo: Time-Nuts
Subject: Re: [time-nuts] Antenna for t-bolt
Sent: Apr 3, 2012 12:15 AM
caf@omen.com said:
Presumably a timing antenna would block low elevation signals to reduce
multipath.
Maybe, but there is a software aspect to the filter. You get to select the
elevation angle.
I don't remember seeing any specs about the filtering angles of various
antennas. Has anybody seen something like that?
--
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time-nuts mailing list -- time-nuts@febo.com
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Sent from my BlackBerry Wireless thingy while I do other things...
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If the satellite is above the mask, the signal will be used in computing a solution even if it got in through reflexions and multipath. That's why a good antenna with choke rings is desirable.
Didier KO4BB
Sent from my BlackBerry Wireless thingy while I do other things...
-----Original Message-----
From: Azelio Boriani azelio.boriani@screen.it
Sender: time-nuts-bounces@febo.com
Date: Tue, 3 Apr 2012 21:27:26
To: Discussion of precise time and frequency measurementtime-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Antenna for t-bolt
Of course the elevation mask is only software and doesn't prevent the bad
signal from entering the antenna but then the signal will not despread and
should cause no harm to the computations.
On Tue, Apr 3, 2012 at 9:19 PM, shalimr9@gmail.com wrote:
The elevation angle filter is based on the satellite position, not the
actual direction the signals come from.
If you have reflections and multipath, but the satellite is otherwise high
in the sky, you are out of luck regardless of elevation angle filter.
Of course, the higher the sat, the less likely you will have reflections
from roofs and such, so it is definitely not useless, but it is not the
same as having a good antenna in the first place.
Didier KO4BB
------Original Message------
From: Hal Murray
Sender: time-nuts-bounces@febo.com
To: Time-Nuts
ReplyTo: Time-Nuts
Subject: Re: [time-nuts] Antenna for t-bolt
Sent: Apr 3, 2012 12:15 AM
caf@omen.com said:
Presumably a timing antenna would block low elevation signals to reduce
multipath.
Maybe, but there is a software aspect to the filter. You get to select the
elevation angle.
I don't remember seeing any specs about the filtering angles of various
antennas. Has anybody seen something like that?
--
These are my opinions, not necessarily my employer's. I hate spam.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
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and follow the instructions there.
Sent from my BlackBerry Wireless thingy while I do other things...
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Absolutely true, that's why it is advisable to dare with the elevation mask
and set it rather high (upto 20 deg?) if the antenna is clear above but
there is the possibility for multipath or reflections (i.e. surrounded by
buildings). Of course the choke rings antenna is better... guess how much
the Trimble Zephyr gained starting at $250? It's gone for $1050: we can say
that 10 degrees more of elevation mask are worth $800. Anyway, the Zephyr
antenna doesn't have rings but there should be a sort of absorbing plane
made by those expensive microwave absorbing sheets.
On Tue, Apr 3, 2012 at 9:38 PM, shalimr9@gmail.com wrote:
If the satellite is above the mask, the signal will be used in computing a
solution even if it got in through reflexions and multipath. That's why a
good antenna with choke rings is desirable.
Didier KO4BB
Sent from my BlackBerry Wireless thingy while I do other things...
-----Original Message-----
From: Azelio Boriani azelio.boriani@screen.it
Sender: time-nuts-bounces@febo.com
Date: Tue, 3 Apr 2012 21:27:26
To: Discussion of precise time and frequency measurement<
time-nuts@febo.com>
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Antenna for t-bolt
Of course the elevation mask is only software and doesn't prevent the bad
signal from entering the antenna but then the signal will not despread and
should cause no harm to the computations.
On Tue, Apr 3, 2012 at 9:19 PM, shalimr9@gmail.com wrote:
The elevation angle filter is based on the satellite position, not the
actual direction the signals come from.
If you have reflections and multipath, but the satellite is otherwise
high
in the sky, you are out of luck regardless of elevation angle filter.
Of course, the higher the sat, the less likely you will have reflections
from roofs and such, so it is definitely not useless, but it is not the
same as having a good antenna in the first place.
Didier KO4BB
------Original Message------
From: Hal Murray
Sender: time-nuts-bounces@febo.com
To: Time-Nuts
ReplyTo: Time-Nuts
Subject: Re: [time-nuts] Antenna for t-bolt
Sent: Apr 3, 2012 12:15 AM
caf@omen.com said:
Presumably a timing antenna would block low elevation signals to reduce
multipath.
Maybe, but there is a software aspect to the filter. You get to select
the
elevation angle.
I don't remember seeing any specs about the filtering angles of various
antennas. Has anybody seen something like that?
--
These are my opinions, not necessarily my employer's. I hate spam.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Sent from my BlackBerry Wireless thingy while I do other things...
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
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and follow the instructions there.
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To unsubscribe, go to
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Typical chokerings are L1/L2 geodetic antennas. There is however "simple"
L1-only chokerings available from time to time on *bay. I have often seen
them as low as in the $50 range. Orginal use I think was for DGPS
reference stations. Most seem to be the Aeroantenna model in the url
below.
http://www.aeroantenna.com/PDF/AT575-90_G.pdf
However they have usually been rebadged by Novatel, CMC or Leica.
--
Björn
If the satellite is above the mask, the signal will be used in computing a
solution even if it got in through reflexions and multipath. That's why a
good antenna with choke rings is desirable.
Didier KO4BB
Yes, there was an antenna with the "sting" months ago, now that I see your
PDF I remember but can't remember the price and the brand.
On Tue, Apr 3, 2012 at 10:05 PM, bg@lysator.liu.se wrote:
Typical chokerings are L1/L2 geodetic antennas. There is however "simple"
L1-only chokerings available from time to time on *bay. I have often seen
them as low as in the $50 range. Orginal use I think was for DGPS
reference stations. Most seem to be the Aeroantenna model in the url
below.
http://www.aeroantenna.com/PDF/AT575-90_G.pdf
However they have usually been rebadged by Novatel, CMC or Leica.
--
Björn
If the satellite is above the mask, the signal will be used in computing
a
solution even if it got in through reflexions and multipath. That's why a
good antenna with choke rings is desirable.
Didier KO4BB
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
The great thing about this antenna is that even if doesn't work you can always throw it in the air and get some great UFO photos.
Thomas Knox
Date: Tue, 3 Apr 2012 22:21:18 +0200
From: azelio.boriani@screen.it
To: time-nuts@febo.com
Subject: Re: [time-nuts] Antenna for t-bolt
Yes, there was an antenna with the "sting" months ago, now that I see your
PDF I remember but can't remember the price and the brand.
On Tue, Apr 3, 2012 at 10:05 PM, bg@lysator.liu.se wrote:
Typical chokerings are L1/L2 geodetic antennas. There is however "simple"
L1-only chokerings available from time to time on *bay. I have often seen
them as low as in the $50 range. Orginal use I think was for DGPS
reference stations. Most seem to be the Aeroantenna model in the url
below.
http://www.aeroantenna.com/PDF/AT575-90_G.pdf
However they have usually been rebadged by Novatel, CMC or Leica.
--
Björn
If the satellite is above the mask, the signal will be used in computing
a
solution even if it got in through reflexions and multipath. That's why a
good antenna with choke rings is desirable.
Didier KO4BB
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
On Tue, 3 Apr 2012 22:05:22 +0200
bg@lysator.liu.se wrote:
It might be a stupid question, but what is the spike at the top for?
Attila Kinali
--
Why does it take years to find the answers to
the questions one should have asked long ago?
It might be a stupid question, but what is the spike at the top for?
It's just plastic; not for lightning. For me it keeps birds from sitting
on the top of the radome and dropping liquid gps signal attenuators.
/tvb
On Tue, 3 Apr 2012 22:05:22 +0200
bg@lysator.liu.se wrote:
It might be a stupid question, but what is the spike at the top for?
Attila Kinali
It is there to make birds feel unconfortable.
--
Björn