Empathy List Archives

D

donandarline@gmail.com

Sat, Mar 31, 2018 3:58 PM

I found a supplier for high quality GPS antennas at a very reasonable price.
PCTEL GPSL1-TMG-SPI-40NCB.
They have other ones too.
I bought one and it works great.
New in the box, never opened.
The only thing wrong was the 4 base mounting screws were too short (no big deal).
They are on Ebay # 282851759313.
$48.00 shipped.
Thanks,
Don W9BHI

Sent from Mail for Windows 10

I found a supplier for high quality GPS antennas at a very reasonable price. PCTEL GPSL1-TMG-SPI-40NCB. They have other ones too. I bought one and it works great. New in the box, never opened. The only thing wrong was the 4 base mounting screws were too short (no big deal). They are on Ebay # 282851759313. $48.00 shipped. Thanks, Don W9BHI Sent from Mail for Windows 10

C

cfo

Sun, Apr 1, 2018 6:36 AM

On Sat, 31 Mar 2018 10:58:19 -0500, donandarline-Re5JQEeQqe8AvxtiuMwx3w
wrote:

I found a supplier for high quality GPS antennas at a very reasonable
price. PCTEL GPSL1-TMG-SPI-40NCB.

*** SNIP ***

I had one of those on 25m cable, and it worked fine on a Tbolt , until
i got an active antenna splitter that also had some gain.
Then i had to replace it w. a 26dB version of same type, else the
"Jackson Lite" was loosing sync.

What i mean here, is that you can get too much gain too.

Btw: Good price.

CFO
Denmark

On Sat, 31 Mar 2018 10:58:19 -0500, donandarline-Re5JQEeQqe8AvxtiuMwx3w wrote: > I found a supplier for high quality GPS antennas at a very reasonable > price. PCTEL GPSL1-TMG-SPI-40NCB. *** SNIP *** I had one of those on 25m cable, and it worked fine on a Tbolt , until i got an active antenna splitter that also had some gain. Then i had to replace it w. a 26dB version of same type, else the "Jackson Lite" was loosing sync. What i mean here, is that you can get too much gain too. Btw: Good price. CFO Denmark

BK

Bob kb8tq

Sun, Apr 1, 2018 1:42 PM

Hi

Indeed, it is very easy to put to much gain in front of a timing GNSS receiver. These
beasts are trying to dig out a signal that you can’t even see with a spectrum analyzer.
It’s way to far below the noise floor to detect that way. They optimize things pretty
tightly to get that done (and to hit a price target ….). Put to much gain in front of
them and they get unhappy.

Making this even more crazy, the survey industry standard antenna does have
a lot of gain. Survey receivers need way more gain in front of them than timing
receivers. Put a survey antenna directly on a timing device and trouble will likely be the
outcome. Equally, a survey instrument probably will not be happy with a timing
receiver.

Why all this nonsense? As far as I can tell, it goes back to how the very early L1 / L2
survey boxes were designed back in the 1980’s and early 1990’s. They made a
basic decision to put a lot of gain at the antenna. Motorola came along with their
GPS modules later on. They made a very different decision about how to distribute
the gain. There are very good arguments on both sides for why they did it this way.
The bottom line is still - you need to match things up …

Bob

On Apr 1, 2018, at 2:36 AM, cfo xnews5@luna.dyndns.dk wrote:

On Sat, 31 Mar 2018 10:58:19 -0500, donandarline-Re5JQEeQqe8AvxtiuMwx3w
wrote:

I found a supplier for high quality GPS antennas at a very reasonable
price. PCTEL GPSL1-TMG-SPI-40NCB.

*** SNIP ***

I had one of those on 25m cable, and it worked fine on a Tbolt , until
i got an active antenna splitter that also had some gain.
Then i had to replace it w. a 26dB version of same type, else the
"Jackson Lite" was loosing sync.

What i mean here, is that you can get too much gain too.

Btw: Good price.

CFO
Denmark

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 Indeed, it is *very* easy to put to much gain in front of a timing GNSS receiver. These beasts are trying to dig out a signal that you can’t even see with a spectrum analyzer. It’s way to far below the noise floor to detect that way. They optimize things pretty tightly to get that done (and to hit a price target ….). Put to much gain in front of them and they get unhappy. Making this even more crazy, the survey industry standard antenna *does* have a lot of gain. Survey receivers need way more gain in front of them than timing receivers. Put a survey antenna directly on a timing device and trouble will likely be the outcome. Equally, a survey instrument probably will not be happy with a timing receiver. Why all this nonsense? As far as I can tell, it goes back to how the very early L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. They made a basic decision to put a lot of gain at the antenna. Motorola came along with their GPS modules later on. They made a *very* different decision about how to distribute the gain. There are very good arguments on both sides for why they did it this way. The bottom line is still - you need to match things up … Bob > On Apr 1, 2018, at 2:36 AM, cfo <xnews5@luna.dyndns.dk> wrote: > > On Sat, 31 Mar 2018 10:58:19 -0500, donandarline-Re5JQEeQqe8AvxtiuMwx3w > wrote: > >> I found a supplier for high quality GPS antennas at a very reasonable >> price. PCTEL GPSL1-TMG-SPI-40NCB. > > *** SNIP *** > > I had one of those on 25m cable, and it worked fine on a Tbolt , until > i got an active antenna splitter that also had some gain. > Then i had to replace it w. a 26dB version of same type, else the > "Jackson Lite" was loosing sync. > > What i mean here, is that you can get too much gain too. > > Btw: Good price. > > CFO > Denmark > > _______________________________________________ > 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.

DC

David C. Partridge

Sun, Apr 1, 2018 8:21 PM

Or use a choke ring survey antenna and an attenuator :)

Dave

-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Bob kb8tq
Sent: 01 April 2018 14:43
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS ANTENNA

Hi

Indeed, it is very easy to put to much gain in front of a timing GNSS receiver. These beasts are trying to dig out a signal that you can’t even see with a spectrum analyzer.
It’s way to far below the noise floor to detect that way. They optimize things pretty tightly to get that done (and to hit a price target ….). Put to much gain in front of them and they get unhappy.

Making this even more crazy, the survey industry standard antenna does have a lot of gain. Survey receivers need way more gain in front of them than timing receivers. Put a survey antenna directly on a timing device and trouble will likely be the outcome. Equally, a survey instrument probably will not be happy with a timing receiver.

Why all this nonsense? As far as I can tell, it goes back to how the very early L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. They made a basic decision to put a lot of gain at the antenna. Motorola came along with their GPS modules later on. They made a very different decision about how to distribute the gain. There are very good arguments on both sides for why they did it this way.
The bottom line is still - you need to match things up …

Bob

On Apr 1, 2018, at 2:36 AM, cfo xnews5@luna.dyndns.dk wrote:

On Sat, 31 Mar 2018 10:58:19 -0500,
donandarline-Re5JQEeQqe8AvxtiuMwx3w
wrote:

I found a supplier for high quality GPS antennas at a very reasonable
price. PCTEL GPSL1-TMG-SPI-40NCB.

*** SNIP ***

I had one of those on 25m cable, and it worked fine on a Tbolt , until
i got an active antenna splitter that also had some gain.
Then i had to replace it w. a 26dB version of same type, else the
"Jackson Lite" was loosing sync.

What i mean here, is that you can get too much gain too.

Btw: Good price.

CFO
Denmark

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.

Or use a choke ring survey antenna and an attenuator :) Dave -----Original Message----- From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Bob kb8tq Sent: 01 April 2018 14:43 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] GPS ANTENNA Hi Indeed, it is *very* easy to put to much gain in front of a timing GNSS receiver. These beasts are trying to dig out a signal that you can’t even see with a spectrum analyzer. It’s way to far below the noise floor to detect that way. They optimize things pretty tightly to get that done (and to hit a price target ….). Put to much gain in front of them and they get unhappy. Making this even more crazy, the survey industry standard antenna *does* have a lot of gain. Survey receivers need way more gain in front of them than timing receivers. Put a survey antenna directly on a timing device and trouble will likely be the outcome. Equally, a survey instrument probably will not be happy with a timing receiver. Why all this nonsense? As far as I can tell, it goes back to how the very early L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. They made a basic decision to put a lot of gain at the antenna. Motorola came along with their GPS modules later on. They made a *very* different decision about how to distribute the gain. There are very good arguments on both sides for why they did it this way. The bottom line is still - you need to match things up … Bob > On Apr 1, 2018, at 2:36 AM, cfo <xnews5@luna.dyndns.dk> wrote: > > On Sat, 31 Mar 2018 10:58:19 -0500, > donandarline-Re5JQEeQqe8AvxtiuMwx3w > wrote: > >> I found a supplier for high quality GPS antennas at a very reasonable >> price. PCTEL GPSL1-TMG-SPI-40NCB. > > *** SNIP *** > > I had one of those on 25m cable, and it worked fine on a Tbolt , until > i got an active antenna splitter that also had some gain. > Then i had to replace it w. a 26dB version of same type, else the > "Jackson Lite" was loosing sync. > > What i mean here, is that you can get too much gain too. > > Btw: Good price. > > CFO > Denmark > > _______________________________________________ > 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.

AB

Azelio Boriani

Sun, Apr 1, 2018 10:29 PM

An unusual attenuator with a DC pass.

On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge
david.partridge@perdrix.co.uk wrote:

Or use a choke ring survey antenna and an attenuator :)

Dave

-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Bob kb8tq
Sent: 01 April 2018 14:43
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS ANTENNA

Hi

Indeed, it is very easy to put to much gain in front of a timing GNSS receiver. These beasts are trying to dig out a signal that you can’t even see with a spectrum analyzer.
It’s way to far below the noise floor to detect that way. They optimize things pretty tightly to get that done (and to hit a price target ….). Put to much gain in front of them and they get unhappy.

Making this even more crazy, the survey industry standard antenna does have a lot of gain. Survey receivers need way more gain in front of them than timing receivers. Put a survey antenna directly on a timing device and trouble will likely be the outcome. Equally, a survey instrument probably will not be happy with a timing receiver.

Why all this nonsense? As far as I can tell, it goes back to how the very early L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. They made a basic decision to put a lot of gain at the antenna. Motorola came along with their GPS modules later on. They made a very different decision about how to distribute the gain. There are very good arguments on both sides for why they did it this way.
The bottom line is still - you need to match things up …

Bob

On Apr 1, 2018, at 2:36 AM, cfo xnews5@luna.dyndns.dk wrote:

On Sat, 31 Mar 2018 10:58:19 -0500,
donandarline-Re5JQEeQqe8AvxtiuMwx3w
wrote:

I found a supplier for high quality GPS antennas at a very reasonable
price. PCTEL GPSL1-TMG-SPI-40NCB.

*** SNIP ***

I had one of those on 25m cable, and it worked fine on a Tbolt , until
i got an active antenna splitter that also had some gain.
Then i had to replace it w. a 26dB version of same type, else the
"Jackson Lite" was loosing sync.

What i mean here, is that you can get too much gain too.

Btw: Good price.

CFO
Denmark

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.

An unusual attenuator with a DC pass. On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge <david.partridge@perdrix.co.uk> wrote: > Or use a choke ring survey antenna and an attenuator :) > > Dave > > -----Original Message----- > From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Bob kb8tq > Sent: 01 April 2018 14:43 > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] GPS ANTENNA > > Hi > > Indeed, it is *very* easy to put to much gain in front of a timing GNSS receiver. These beasts are trying to dig out a signal that you can’t even see with a spectrum analyzer. > It’s way to far below the noise floor to detect that way. They optimize things pretty tightly to get that done (and to hit a price target ….). Put to much gain in front of them and they get unhappy. > > Making this even more crazy, the survey industry standard antenna *does* have a lot of gain. Survey receivers need way more gain in front of them than timing receivers. Put a survey antenna directly on a timing device and trouble will likely be the outcome. Equally, a survey instrument probably will not be happy with a timing receiver. > > Why all this nonsense? As far as I can tell, it goes back to how the very early L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. They made a basic decision to put a lot of gain at the antenna. Motorola came along with their GPS modules later on. They made a *very* different decision about how to distribute the gain. There are very good arguments on both sides for why they did it this way. > The bottom line is still - you need to match things up … > > Bob > >> On Apr 1, 2018, at 2:36 AM, cfo <xnews5@luna.dyndns.dk> wrote: >> >> On Sat, 31 Mar 2018 10:58:19 -0500, >> donandarline-Re5JQEeQqe8AvxtiuMwx3w >> wrote: >> >>> I found a supplier for high quality GPS antennas at a very reasonable >>> price. PCTEL GPSL1-TMG-SPI-40NCB. >> >> *** SNIP *** >> >> I had one of those on 25m cable, and it worked fine on a Tbolt , until >> i got an active antenna splitter that also had some gain. >> Then i had to replace it w. a 26dB version of same type, else the >> "Jackson Lite" was loosing sync. >> >> What i mean here, is that you can get too much gain too. >> >> Btw: Good price. >> >> CFO >> Denmark >> >> _______________________________________________ >> 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.

J

jimlux

Mon, Apr 2, 2018 12:11 AM

On 4/1/18 3:29 PM, Azelio Boriani wrote:

An unusual attenuator with a DC pass.

A few feet of RG-174 (or any 0.1" diameter coax) would probably work.

On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge
david.partridge@perdrix.co.uk wrote:

Or use a choke ring survey antenna and an attenuator :)

Dave

-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Bob kb8tq
Sent: 01 April 2018 14:43
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS ANTENNA

Hi

Indeed, it is very easy to put to much gain in front of a timing GNSS receiver. These beasts are trying to dig out a signal that you can’t even see with a spectrum analyzer.
It’s way to far below the noise floor to detect that way. They optimize things pretty tightly to get that done (and to hit a price target ….). Put to much gain in front of them and they get unhappy.

Making this even more crazy, the survey industry standard antenna does have a lot of gain. Survey receivers need way more gain in front of them than timing receivers. Put a survey antenna directly on a timing device and trouble will likely be the outcome. Equally, a survey instrument probably will not be happy with a timing receiver.

Why all this nonsense? As far as I can tell, it goes back to how the very early L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. They made a basic decision to put a lot of gain at the antenna. Motorola came along with their GPS modules later on. They made a very different decision about how to distribute the gain. There are very good arguments on both sides for why they did it this way.
The bottom line is still - you need to match things up …

Bob

On Apr 1, 2018, at 2:36 AM, cfo xnews5@luna.dyndns.dk wrote:

On Sat, 31 Mar 2018 10:58:19 -0500,
donandarline-Re5JQEeQqe8AvxtiuMwx3w
wrote:

I found a supplier for high quality GPS antennas at a very reasonable
price. PCTEL GPSL1-TMG-SPI-40NCB.

*** SNIP ***

I had one of those on 25m cable, and it worked fine on a Tbolt , until
i got an active antenna splitter that also had some gain.
Then i had to replace it w. a 26dB version of same type, else the
"Jackson Lite" was loosing sync.

What i mean here, is that you can get too much gain too.

Btw: Good price.

CFO
Denmark

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.

On 4/1/18 3:29 PM, Azelio Boriani wrote: > An unusual attenuator with a DC pass. > A few feet of RG-174 (or any 0.1" diameter coax) would probably work. > On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge > <david.partridge@perdrix.co.uk> wrote: >> Or use a choke ring survey antenna and an attenuator :) >> >> Dave >> >> -----Original Message----- >> From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Bob kb8tq >> Sent: 01 April 2018 14:43 >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] GPS ANTENNA >> >> Hi >> >> Indeed, it is *very* easy to put to much gain in front of a timing GNSS receiver. These beasts are trying to dig out a signal that you can’t even see with a spectrum analyzer. >> It’s way to far below the noise floor to detect that way. They optimize things pretty tightly to get that done (and to hit a price target ….). Put to much gain in front of them and they get unhappy. >> >> Making this even more crazy, the survey industry standard antenna *does* have a lot of gain. Survey receivers need way more gain in front of them than timing receivers. Put a survey antenna directly on a timing device and trouble will likely be the outcome. Equally, a survey instrument probably will not be happy with a timing receiver. >> >> Why all this nonsense? As far as I can tell, it goes back to how the very early L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. They made a basic decision to put a lot of gain at the antenna. Motorola came along with their GPS modules later on. They made a *very* different decision about how to distribute the gain. There are very good arguments on both sides for why they did it this way. >> The bottom line is still - you need to match things up … >> >> Bob >> >>> On Apr 1, 2018, at 2:36 AM, cfo <xnews5@luna.dyndns.dk> wrote: >>> >>> On Sat, 31 Mar 2018 10:58:19 -0500, >>> donandarline-Re5JQEeQqe8AvxtiuMwx3w >>> wrote: >>> >>>> I found a supplier for high quality GPS antennas at a very reasonable >>>> price. PCTEL GPSL1-TMG-SPI-40NCB. >>> >>> *** SNIP *** >>> >>> I had one of those on 25m cable, and it worked fine on a Tbolt , until >>> i got an active antenna splitter that also had some gain. >>> Then i had to replace it w. a 26dB version of same type, else the >>> "Jackson Lite" was loosing sync. >>> >>> What i mean here, is that you can get too much gain too. >>> >>> Btw: Good price. >>> >>> CFO >>> Denmark >>> >>> _______________________________________________ >>> 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. > _______________________________________________ > 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. >

BK

Bob kb8tq

Mon, Apr 2, 2018 12:16 AM

Hi

They are indeed a bit unusual. Generally you do a DC block and bias tee ahead of the
attenuator. For a “self contained” approach, a second block and bias tee pulls the DC
of the GPSDO side of the attenuator. My preference has been to just run the bias tee
with an external DC source.

Bob

On Apr 1, 2018, at 6:29 PM, Azelio Boriani azelio.boriani@gmail.com wrote:

An unusual attenuator with a DC pass.

On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge
david.partridge@perdrix.co.uk wrote:

Or use a choke ring survey antenna and an attenuator :)

Dave

-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Bob kb8tq
Sent: 01 April 2018 14:43
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS ANTENNA

Hi

Indeed, it is very easy to put to much gain in front of a timing GNSS receiver. These beasts are trying to dig out a signal that you can’t even see with a spectrum analyzer.
It’s way to far below the noise floor to detect that way. They optimize things pretty tightly to get that done (and to hit a price target ….). Put to much gain in front of them and they get unhappy.

Making this even more crazy, the survey industry standard antenna does have a lot of gain. Survey receivers need way more gain in front of them than timing receivers. Put a survey antenna directly on a timing device and trouble will likely be the outcome. Equally, a survey instrument probably will not be happy with a timing receiver.

Why all this nonsense? As far as I can tell, it goes back to how the very early L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. They made a basic decision to put a lot of gain at the antenna. Motorola came along with their GPS modules later on. They made a very different decision about how to distribute the gain. There are very good arguments on both sides for why they did it this way.
The bottom line is still - you need to match things up …

Bob

On Apr 1, 2018, at 2:36 AM, cfo xnews5@luna.dyndns.dk wrote:

On Sat, 31 Mar 2018 10:58:19 -0500,
donandarline-Re5JQEeQqe8AvxtiuMwx3w
wrote:

I found a supplier for high quality GPS antennas at a very reasonable
price. PCTEL GPSL1-TMG-SPI-40NCB.

*** SNIP ***

I had one of those on 25m cable, and it worked fine on a Tbolt , until
i got an active antenna splitter that also had some gain.
Then i had to replace it w. a 26dB version of same type, else the
"Jackson Lite" was loosing sync.

What i mean here, is that you can get too much gain too.

Btw: Good price.

CFO
Denmark

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and follow the instructions there.

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Hi They are indeed a bit unusual. Generally you do a DC block and bias tee ahead of the attenuator. For a “self contained” approach, a second block and bias tee pulls the DC of the GPSDO side of the attenuator. My preference has been to just run the bias tee with an external DC source. Bob > On Apr 1, 2018, at 6:29 PM, Azelio Boriani <azelio.boriani@gmail.com> wrote: > > An unusual attenuator with a DC pass. > > On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge > <david.partridge@perdrix.co.uk> wrote: >> Or use a choke ring survey antenna and an attenuator :) >> >> Dave >> >> -----Original Message----- >> From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Bob kb8tq >> Sent: 01 April 2018 14:43 >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] GPS ANTENNA >> >> Hi >> >> Indeed, it is *very* easy to put to much gain in front of a timing GNSS receiver. These beasts are trying to dig out a signal that you can’t even see with a spectrum analyzer. >> It’s way to far below the noise floor to detect that way. They optimize things pretty tightly to get that done (and to hit a price target ….). Put to much gain in front of them and they get unhappy. >> >> Making this even more crazy, the survey industry standard antenna *does* have a lot of gain. Survey receivers need way more gain in front of them than timing receivers. Put a survey antenna directly on a timing device and trouble will likely be the outcome. Equally, a survey instrument probably will not be happy with a timing receiver. >> >> Why all this nonsense? As far as I can tell, it goes back to how the very early L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. They made a basic decision to put a lot of gain at the antenna. Motorola came along with their GPS modules later on. They made a *very* different decision about how to distribute the gain. There are very good arguments on both sides for why they did it this way. >> The bottom line is still - you need to match things up … >> >> Bob >> >>> On Apr 1, 2018, at 2:36 AM, cfo <xnews5@luna.dyndns.dk> wrote: >>> >>> On Sat, 31 Mar 2018 10:58:19 -0500, >>> donandarline-Re5JQEeQqe8AvxtiuMwx3w >>> wrote: >>> >>>> I found a supplier for high quality GPS antennas at a very reasonable >>>> price. PCTEL GPSL1-TMG-SPI-40NCB. >>> >>> *** SNIP *** >>> >>> I had one of those on 25m cable, and it worked fine on a Tbolt , until >>> i got an active antenna splitter that also had some gain. >>> Then i had to replace it w. a 26dB version of same type, else the >>> "Jackson Lite" was loosing sync. >>> >>> What i mean here, is that you can get too much gain too. >>> >>> Btw: Good price. >>> >>> CFO >>> Denmark >>> >>> _______________________________________________ >>> 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. > _______________________________________________ > 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.

BG

Bruce Griffiths

Mon, Apr 2, 2018 1:21 AM

Just use a standard attenuator between a pair of bias T's with their dc ports connected together.

Bruce

 On 02 April 2018 at 10:29 Azelio Boriani <azelio.boriani@gmail.com> wrote:

 An unusual attenuator with a DC pass.

 On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge

 <david.partridge@perdrix.co.uk> wrote:

     Or use a choke ring survey antenna and an attenuator :)

     Dave

     -----Original Message-----
     From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Bob kb8tq
     Sent: 01 April 2018 14:43
     To: Discussion of precise time and frequency measurement
     Subject: Re: [time-nuts] GPS ANTENNA

     Hi

     Indeed, it is *very* easy to put to much gain in front of a timing GNSS receiver. These beasts are trying to dig out a signal that you can’t even see with a spectrum analyzer.
     It’s way to far below the noise floor to detect that way. They optimize things pretty tightly to get that done (and to hit a price target ….). Put to much gain in front of them and they get unhappy.

     Making this even more crazy, the survey industry standard antenna *does* have a lot of gain. Survey receivers need way more gain in front of them than timing receivers. Put a survey antenna directly on a timing device and trouble will likely be the outcome. Equally, a survey instrument probably will not be happy with a timing receiver.

     Why all this nonsense? As far as I can tell, it goes back to how the very early L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. They made a basic decision to put a lot of gain at the antenna. Motorola came along with their GPS modules later on. They made a *very* different decision about how to distribute the gain. There are very good arguments on both sides for why they did it this way.
     The bottom line is still - you need to match things up …

     Bob

         On Apr 1, 2018, at 2:36 AM, cfo <xnews5@luna.dyndns.dk> wrote:

         On Sat, 31 Mar 2018 10:58:19 -0500,
         donandarline-Re5JQEeQqe8AvxtiuMwx3w
         wrote:

             I found a supplier for high quality GPS antennas at a very reasonable
             price. PCTEL GPSL1-TMG-SPI-40NCB.

         *** SNIP ***

         I had one of those on 25m cable, and it worked fine on a Tbolt , until
         i got an active antenna splitter that also had some gain.
         Then i had to replace it w. a 26dB version of same type, else the
         "Jackson Lite" was loosing sync.

         What i mean here, is that you can get too much gain too.

         Btw: Good price.

         CFO
         Denmark

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         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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Just use a standard attenuator between a pair of bias T's with their dc ports connected together. Bruce > > On 02 April 2018 at 10:29 Azelio Boriani <azelio.boriani@gmail.com> wrote: > > An unusual attenuator with a DC pass. > > On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge > > <david.partridge@perdrix.co.uk> wrote: > > > > > > Or use a choke ring survey antenna and an attenuator :) > > > > Dave > > > > -----Original Message----- > > From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Bob kb8tq > > Sent: 01 April 2018 14:43 > > To: Discussion of precise time and frequency measurement > > Subject: Re: [time-nuts] GPS ANTENNA > > > > Hi > > > > Indeed, it is *very* easy to put to much gain in front of a timing GNSS receiver. These beasts are trying to dig out a signal that you can’t even see with a spectrum analyzer. > > It’s way to far below the noise floor to detect that way. They optimize things pretty tightly to get that done (and to hit a price target ….). Put to much gain in front of them and they get unhappy. > > > > Making this even more crazy, the survey industry standard antenna *does* have a lot of gain. Survey receivers need way more gain in front of them than timing receivers. Put a survey antenna directly on a timing device and trouble will likely be the outcome. Equally, a survey instrument probably will not be happy with a timing receiver. > > > > Why all this nonsense? As far as I can tell, it goes back to how the very early L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. They made a basic decision to put a lot of gain at the antenna. Motorola came along with their GPS modules later on. They made a *very* different decision about how to distribute the gain. There are very good arguments on both sides for why they did it this way. > > The bottom line is still - you need to match things up … > > > > Bob > > > > > > > > > > On Apr 1, 2018, at 2:36 AM, cfo <xnews5@luna.dyndns.dk> wrote: > > > > > > On Sat, 31 Mar 2018 10:58:19 -0500, > > > donandarline-Re5JQEeQqe8AvxtiuMwx3w > > > wrote: > > > > > > > > > > > > > > I found a supplier for high quality GPS antennas at a very reasonable > > > > price. PCTEL GPSL1-TMG-SPI-40NCB. > > > > > > > > > > > > > > *** SNIP *** > > > > > > I had one of those on 25m cable, and it worked fine on a Tbolt , until > > > i got an active antenna splitter that also had some gain. > > > Then i had to replace it w. a 26dB version of same type, else the > > > "Jackson Lite" was loosing sync. > > > > > > What i mean here, is that you can get too much gain too. > > > > > > Btw: Good price. > > > > > > CFO > > > Denmark > > > > > > _______________________________________________ > > > 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. > > > > _______________________________________________ > > 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. > > > > >

DC

David C. Partridge

Mon, Apr 2, 2018 1:43 AM

just use a bias tee to feed in the antenna volts :)

-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Azelio Boriani
Sent: 01 April 2018 23:29
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS ANTENNA

An unusual attenuator with a DC pass.

On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge david.partridge@perdrix.co.uk wrote:

Or use a choke ring survey antenna and an attenuator :)

Dave

-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Bob
kb8tq
Sent: 01 April 2018 14:43
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS ANTENNA

Hi

Indeed, it is very easy to put to much gain in front of a timing GNSS receiver. These beasts are trying to dig out a signal that you can’t even see with a spectrum analyzer.
It’s way to far below the noise floor to detect that way. They optimize things pretty tightly to get that done (and to hit a price target ….). Put to much gain in front of them and they get unhappy.

Making this even more crazy, the survey industry standard antenna does have a lot of gain. Survey receivers need way more gain in front of them than timing receivers. Put a survey antenna directly on a timing device and trouble will likely be the outcome. Equally, a survey instrument probably will not be happy with a timing receiver.

Why all this nonsense? As far as I can tell, it goes back to how the very early L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. They made a basic decision to put a lot of gain at the antenna. Motorola came along with their GPS modules later on. They made a very different decision about how to distribute the gain. There are very good arguments on both sides for why they did it this way.
The bottom line is still - you need to match things up …

Bob

On Apr 1, 2018, at 2:36 AM, cfo xnews5@luna.dyndns.dk wrote:

On Sat, 31 Mar 2018 10:58:19 -0500,
donandarline-Re5JQEeQqe8AvxtiuMwx3w
wrote:

I found a supplier for high quality GPS antennas at a very
reasonable price. PCTEL GPSL1-TMG-SPI-40NCB.

*** SNIP ***

I had one of those on 25m cable, and it worked fine on a Tbolt ,
until i got an active antenna splitter that also had some gain.
Then i had to replace it w. a 26dB version of same type, else the
"Jackson Lite" was loosing sync.

What i mean here, is that you can get too much gain too.

Btw: Good price.

CFO
Denmark

time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
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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.

just use a bias tee to feed in the antenna volts :) -----Original Message----- From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Azelio Boriani Sent: 01 April 2018 23:29 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] GPS ANTENNA An unusual attenuator with a DC pass. On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge <david.partridge@perdrix.co.uk> wrote: > Or use a choke ring survey antenna and an attenuator :) > > Dave > > -----Original Message----- > From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Bob > kb8tq > Sent: 01 April 2018 14:43 > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] GPS ANTENNA > > Hi > > Indeed, it is *very* easy to put to much gain in front of a timing GNSS receiver. These beasts are trying to dig out a signal that you can’t even see with a spectrum analyzer. > It’s way to far below the noise floor to detect that way. They optimize things pretty tightly to get that done (and to hit a price target ….). Put to much gain in front of them and they get unhappy. > > Making this even more crazy, the survey industry standard antenna *does* have a lot of gain. Survey receivers need way more gain in front of them than timing receivers. Put a survey antenna directly on a timing device and trouble will likely be the outcome. Equally, a survey instrument probably will not be happy with a timing receiver. > > Why all this nonsense? As far as I can tell, it goes back to how the very early L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. They made a basic decision to put a lot of gain at the antenna. Motorola came along with their GPS modules later on. They made a *very* different decision about how to distribute the gain. There are very good arguments on both sides for why they did it this way. > The bottom line is still - you need to match things up … > > Bob > >> On Apr 1, 2018, at 2:36 AM, cfo <xnews5@luna.dyndns.dk> wrote: >> >> On Sat, 31 Mar 2018 10:58:19 -0500, >> donandarline-Re5JQEeQqe8AvxtiuMwx3w >> wrote: >> >>> I found a supplier for high quality GPS antennas at a very >>> reasonable price. PCTEL GPSL1-TMG-SPI-40NCB. >> >> *** SNIP *** >> >> I had one of those on 25m cable, and it worked fine on a Tbolt , >> until i got an active antenna splitter that also had some gain. >> Then i had to replace it w. a 26dB version of same type, else the >> "Jackson Lite" was loosing sync. >> >> What i mean here, is that you can get too much gain too. >> >> Btw: Good price. >> >> CFO >> Denmark >> >> _______________________________________________ >> 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. _______________________________________________ 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.

B

Björn

Mon, Apr 2, 2018 7:32 AM

Or find an Arra “level set” variable attenuator. 3844 and 3854 models can often be found cheaply, have dc-pass and attenuate at both L1 and L2.

/Björn

Sent from my iPhone

On 2 Apr 2018, at 03:43, David C. Partridge david.partridge@perdrix.co.uk wrote:

just use a bias tee to feed in the antenna volts :)

-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Azelio Boriani
Sent: 01 April 2018 23:29
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS ANTENNA

An unusual attenuator with a DC pass.

On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge david.partridge@perdrix.co.uk wrote:
Or use a choke ring survey antenna and an attenuator :)

Dave

-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Bob
kb8tq
Sent: 01 April 2018 14:43
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS ANTENNA

Hi

Indeed, it is very easy to put to much gain in front of a timing GNSS receiver. These beasts are trying to dig out a signal that you can’t even see with a spectrum analyzer.
It’s way to far below the noise floor to detect that way. They optimize things pretty tightly to get that done (and to hit a price target ….). Put to much gain in front of them and they get unhappy.

Making this even more crazy, the survey industry standard antenna does have a lot of gain. Survey receivers need way more gain in front of them than timing receivers. Put a survey antenna directly on a timing device and trouble will likely be the outcome. Equally, a survey instrument probably will not be happy with a timing receiver.

Why all this nonsense? As far as I can tell, it goes back to how the very early L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. They made a basic decision to put a lot of gain at the antenna. Motorola came along with their GPS modules later on. They made a very different decision about how to distribute the gain. There are very good arguments on both sides for why they did it this way.
The bottom line is still - you need to match things up …

Bob

On Apr 1, 2018, at 2:36 AM, cfo xnews5@luna.dyndns.dk wrote:

On Sat, 31 Mar 2018 10:58:19 -0500,
donandarline-Re5JQEeQqe8AvxtiuMwx3w
wrote:

I found a supplier for high quality GPS antennas at a very
reasonable price. PCTEL GPSL1-TMG-SPI-40NCB.

*** SNIP ***

I had one of those on 25m cable, and it worked fine on a Tbolt ,
until i got an active antenna splitter that also had some gain.
Then i had to replace it w. a 26dB version of same type, else the
"Jackson Lite" was loosing sync.

What i mean here, is that you can get too much gain too.

Btw: Good price.

CFO
Denmark

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and follow the instructions there.

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To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Or find an Arra “level set” variable attenuator. 3844 and 3854 models can often be found cheaply, have dc-pass and attenuate at both L1 and L2. /Björn Sent from my iPhone > On 2 Apr 2018, at 03:43, David C. Partridge <david.partridge@perdrix.co.uk> wrote: > > just use a bias tee to feed in the antenna volts :) > > -----Original Message----- > From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Azelio Boriani > Sent: 01 April 2018 23:29 > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] GPS ANTENNA > > An unusual attenuator with a DC pass. > >> On Sun, Apr 1, 2018 at 10:21 PM, David C. Partridge <david.partridge@perdrix.co.uk> wrote: >> Or use a choke ring survey antenna and an attenuator :) >> >> Dave >> >> -----Original Message----- >> From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Bob >> kb8tq >> Sent: 01 April 2018 14:43 >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] GPS ANTENNA >> >> Hi >> >> Indeed, it is *very* easy to put to much gain in front of a timing GNSS receiver. These beasts are trying to dig out a signal that you can’t even see with a spectrum analyzer. >> It’s way to far below the noise floor to detect that way. They optimize things pretty tightly to get that done (and to hit a price target ….). Put to much gain in front of them and they get unhappy. >> >> Making this even more crazy, the survey industry standard antenna *does* have a lot of gain. Survey receivers need way more gain in front of them than timing receivers. Put a survey antenna directly on a timing device and trouble will likely be the outcome. Equally, a survey instrument probably will not be happy with a timing receiver. >> >> Why all this nonsense? As far as I can tell, it goes back to how the very early L1 / L2 survey boxes were designed back in the 1980’s and early 1990’s. They made a basic decision to put a lot of gain at the antenna. Motorola came along with their GPS modules later on. They made a *very* different decision about how to distribute the gain. There are very good arguments on both sides for why they did it this way. >> The bottom line is still - you need to match things up … >> >> Bob >> >>> On Apr 1, 2018, at 2:36 AM, cfo <xnews5@luna.dyndns.dk> wrote: >>> >>> On Sat, 31 Mar 2018 10:58:19 -0500, >>> donandarline-Re5JQEeQqe8AvxtiuMwx3w >>> wrote: >>> >>>> I found a supplier for high quality GPS antennas at a very >>>> reasonable price. PCTEL GPSL1-TMG-SPI-40NCB. >>> >>> *** SNIP *** >>> >>> I had one of those on 25m cable, and it worked fine on a Tbolt , >>> until i got an active antenna splitter that also had some gain. >>> Then i had to replace it w. a 26dB version of same type, else the >>> "Jackson Lite" was loosing sync. >>> >>> What i mean here, is that you can get too much gain too. >>> >>> Btw: Good price. >>> >>> CFO >>> Denmark >>> >>> _______________________________________________ >>> 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. > _______________________________________________ > 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.

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GPS ANTENNA