Re: [time-nuts] Active antennas for a Thunderbolt...
cfharris@erols.com said:
I suspect that I have just had the bad luck to buy two bad antennas, but I
am naturally curious what happens when the sample set gets larger.
I have 2 TBolts using the small Motorola antenna from TAPR in a not-good
location. The sheet says 24 dB of gain. I have 6 or 9 or ?? feet of RG-6.
They work as expected, that is they work, but not well. The holdover logic
gets tested frequently and surveys take a long time. But they do work.
--
These are my opinions. I hate spam.
Have you any other GPS unit to test your antennae? You can test GPS
antennae with a network analyzer or a spectrum analyzer with the tracking
generator... yes, first you have to find one.
On Mon, Jul 30, 2012 at 5:12 PM, Hal Murray hmurray@megapathdsl.net wrote:
cfharris@erols.com said:
I suspect that I have just had the bad luck to buy two bad antennas, but
I
am naturally curious what happens when the sample set gets larger.
I have 2 TBolts using the small Motorola antenna from TAPR in a not-good
location. The sheet says 24 dB of gain. I have 6 or 9 or ?? feet of RG-6.
They work as expected, that is they work, but not well. The holdover logic
gets tested frequently and surveys take a long time. But they do work.
--
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On a window sill, my Motorola hockey pucks will get a useable satellite
every few minutes, for a few minutes. If the antenna is out in the yard,
it does much better, but all satellite signals are really low.
The system would like another 10 or 20db of gain... which is what the
Trimble bullet antenna would provide if it worked. The 50db Micro Pulse
antena should have been ideal... if it worked.... Sigh!
-Chuck Harris
Hal Murray wrote:
cfharris@erols.com said:
I suspect that I have just had the bad luck to buy two bad antennas, but I
am naturally curious what happens when the sample set gets larger.
I have 2 TBolts using the small Motorola antenna from TAPR in a not-good
location. The sheet says 24 dB of gain. I have 6 or 9 or ?? feet of RG-6.
They work as expected, that is they work, but not well. The holdover logic
gets tested frequently and surveys take a long time. But they do work.
I use one just like auction #180518378555. It is "only" 26dB but the
thing is very reliable. It is a helix antenna inside and the mounting
holes on the bottom line up with a standard iron pipe flange so
mounting is easy. I filled the flang flat them glued autommotive type
gaskit mmaterial to the pipe flange and attached the antenna with four
stainless steel machine screws. The "N" type connector makes it
waterproof, The rg-8 style cable is totally inside either the iron
pipe or metal conduit so it should last forever.
One idea: Possible the ultra-high gain antenna is over loading the
GPS receiver. 50dB is very high
Another idea: If you want gain buy an in-line ampler of the type made
for satelite TV dishes. The specs are "close enough" that it will
work and they are inexpensive.
On Mon, Jul 30, 2012 at 8:41 AM, Chuck Harris cfharris@erols.com wrote:
On a window sill, my Motorola hockey pucks will get a useable satellite
every few minutes, for a few minutes. If the antenna is out in the yard,
it does much better, but all satellite signals are really low.
The system would like another 10 or 20db of gain... which is what the
Trimble bullet antenna would provide if it worked. The 50db Micro Pulse
antena should have been ideal... if it worked.... Sigh!
-Chuck Harris
Hal Murray wrote:
cfharris@erols.com said:
I suspect that I have just had the bad luck to buy two bad antennas, but
I
am naturally curious what happens when the sample set gets larger.
I have 2 TBolts using the small Motorola antenna from TAPR in a not-good
location. The sheet says 24 dB of gain. I have 6 or 9 or ?? feet of
RG-6.
They work as expected, that is they work, but not well. The holdover
logic
gets tested frequently and surveys take a long time. But they do work.
time-nuts mailing list -- time-nuts@febo.com
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and follow the instructions there.
--
Chris Albertson
Redondo Beach, California
Hi Azelio,
How would you use a network analyzer to test an active antenna
like these? I have the ANA, but I am not sure how to couple
the input to the antenna effectively.
-Chuck Harris
Azelio Boriani wrote:
Have you any other GPS unit to test your antennae? You can test GPS
antennae with a network analyzer or a spectrum analyzer with the tracking
generator... yes, first you have to find one.
On Mon, Jul 30, 2012 at 5:12 PM, Hal Murray hmurray@megapathdsl.net wrote:
cfharris@erols.com said:
I suspect that I have just had the bad luck to buy two bad antennas, but
I
am naturally curious what happens when the sample set gets larger.
I have 2 TBolts using the small Motorola antenna from TAPR in a not-good
location. The sheet says 24 dB of gain. I have 6 or 9 or ?? feet of RG-6.
They work as expected, that is they work, but not well. The holdover logic
gets tested frequently and surveys take a long time. But they do work.
--
These are my opinions. I hate spam.
On 7/30/2012 6:39 PM, Chris Albertson wrote:
I use one just like auction #180518378555. It is "only" 26dB but the
thing is very reliable. It is a helix antenna inside and the mounting
holes on the bottom line up with a standard iron pipe flange so
mounting is easy.
That's exactly the same antenna I use with my Thunderbolt.
It is mounted on top of the roof, with a 360 degrees view of the sky
and LH reports signal strengths usually in excess of 40 dBc.
About 25 meters of TV Sat cable.
73 Alberto I2PHD
I use a small power supply to feed the antenna (use a bias tee) and a DC
block for the analyzer input. I have made a quadrifilar helix for the
analyzer output. Set a suitable frequency range (1400-1700) and test. Yes,
I have (at work) an analyzer with the S-parameter test set, so that no
directional coupler and no problems, moreover I have new antennae to test
to make comparisons but the results are clearly visible and you can
recognize a defective antenna. Usually customers send in questionable
antennae and we can tell weather or not they are really unusable: lightning
is the killer.
On Mon, Jul 30, 2012 at 9:54 PM, Chuck Harris cfharris@erols.com wrote:
Hi Azelio,
How would you use a network analyzer to test an active antenna
like these? I have the ANA, but I am not sure how to couple
the input to the antenna effectively.
-Chuck Harris
Azelio Boriani wrote:
Have you any other GPS unit to test your antennae? You can test GPS
antennae with a network analyzer or a spectrum analyzer with the tracking
generator... yes, first you have to find one.
On Mon, Jul 30, 2012 at 5:12 PM, Hal Murray hmurray@megapathdsl.net
wrote:
cfharris@erols.com said:
I suspect that I have just had the bad luck to buy two bad antennas, but
I
am naturally curious what happens when the sample set gets larger.
I have 2 TBolts using the small Motorola antenna from TAPR in a not-good
location. The sheet says 24 dB of gain. I have 6 or 9 or ?? feet of
RG-6.
They work as expected, that is they work, but not well. The holdover
logic
gets tested frequently and surveys take a long time. But they do work.
--
These are my opinions. 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.
Hi:
What is the GPS bandwidth at 1575.42 MHz? For a band-pass filter /
amplifier would a Butterworth response be acceptable?
Thanks,
Ron
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Azelio Boriani
Sent: Monday, July 30, 2012 1:17 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Active antennas for a Thunderbolt...
I use a small power supply to feed the antenna (use a bias tee) and a DC
block for the analyzer input. I have made a quadrifilar helix for the
analyzer output. Set a suitable frequency range (1400-1700) and test.
Yes,
I have (at work) an analyzer with the S-parameter test set, so that no
directional coupler and no problems, moreover I have new antennae to
test
to make comparisons but the results are clearly visible and you can
recognize a defective antenna. Usually customers send in questionable
antennae and we can tell weather or not they are really unusable:
lightning
is the killer.
On Mon, Jul 30, 2012 at 9:54 PM, Chuck Harris cfharris@erols.com
wrote:
Hi Azelio,
How would you use a network analyzer to test an active antenna
like these? I have the ANA, but I am not sure how to couple
the input to the antenna effectively.
-Chuck Harris
Azelio Boriani wrote:
Have you any other GPS unit to test your antennae? You can test GPS
antennae with a network analyzer or a spectrum analyzer with the
tracking
generator... yes, first you have to find one.
On Mon, Jul 30, 2012 at 5:12 PM, Hal Murray hmurray@megapathdsl.net
wrote:
antennas, but
I
am naturally curious what happens when the sample set gets larger.
I have 2 TBolts using the small Motorola antenna from TAPR in a
not-good
location. The sheet says 24 dB of gain. I have 6 or 9 or ?? feet
of
RG-6.
They work as expected, that is they work, but not well. The
holdover
logic
gets tested frequently and surveys take a long time. But they do
work.
--
These are my opinions. 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.
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To unsubscribe, go to
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and follow the instructions there.
Ok, that's about what I thought you would do. Since it isn't in a
controlled antenna farm, you get a functionality test, with an approximate
example of the gain.
Thanks!
-Chuck Harris
OBTW, any luck fixing bad antennas?
Azelio Boriani wrote:
I use a small power supply to feed the antenna (use a bias tee) and a DC
block for the analyzer input. I have made a quadrifilar helix for the
analyzer output. Set a suitable frequency range (1400-1700) and test. Yes,
I have (at work) an analyzer with the S-parameter test set, so that no
directional coupler and no problems, moreover I have new antennae to test
to make comparisons but the results are clearly visible and you can
recognize a defective antenna. Usually customers send in questionable
antennae and we can tell weather or not they are really unusable: lightning
is the killer.
On Mon, Jul 30, 2012 at 9:54 PM, Chuck Harris cfharris@erols.com wrote:
Are you considering lumped components? At that frequency, you really need to be doing a stripline design. There are also COTS SAW filters.
I have this US Navy GPS active antenna with integral SAW filter, but never got around to using it due to the 4.3VDC spec. A separate power supply, DC insert and DC block is kind of clumsy.
I have considered a series diode to take 5V down to what the active antenna requires, but I don't know how well that would work.
-----Original Message-----
From: "Ron Ward" n6idlron@comcast.net
Sender: time-nuts-bounces@febo.com
Date: Mon, 30 Jul 2012 16:32:46
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] Active antennas for a Thunderbolt...
Hi:
What is the GPS bandwidth at 1575.42 MHz? For a band-pass filter /
amplifier would a Butterworth response be acceptable?
Thanks,
Ron
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Azelio Boriani
Sent: Monday, July 30, 2012 1:17 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Active antennas for a Thunderbolt...
I use a small power supply to feed the antenna (use a bias tee) and a DC
block for the analyzer input. I have made a quadrifilar helix for the
analyzer output. Set a suitable frequency range (1400-1700) and test.
Yes,
I have (at work) an analyzer with the S-parameter test set, so that no
directional coupler and no problems, moreover I have new antennae to
test
to make comparisons but the results are clearly visible and you can
recognize a defective antenna. Usually customers send in questionable
antennae and we can tell weather or not they are really unusable:
lightning
is the killer.
On Mon, Jul 30, 2012 at 9:54 PM, Chuck Harris cfharris@erols.com
wrote:
Hi Azelio,
How would you use a network analyzer to test an active antenna
like these? I have the ANA, but I am not sure how to couple
the input to the antenna effectively.
-Chuck Harris
Azelio Boriani wrote:
Have you any other GPS unit to test your antennae? You can test GPS
antennae with a network analyzer or a spectrum analyzer with the
tracking
generator... yes, first you have to find one.
On Mon, Jul 30, 2012 at 5:12 PM, Hal Murray hmurray@megapathdsl.net
wrote:
antennas, but
I
am naturally curious what happens when the sample set gets larger.
I have 2 TBolts using the small Motorola antenna from TAPR in a
not-good
location. The sheet says 24 dB of gain. I have 6 or 9 or ?? feet
of
RG-6.
They work as expected, that is they work, but not well. The
holdover
logic
gets tested frequently and surveys take a long time. But they do
work.
--
These are my opinions. 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.
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.