[time-nuts] Re: GPS antenna distribution???
The companies "GPS Source" and "GPS Networking" make so-called "networked" splitters which have very high isolation between ports and which, as a bonus, do not require unused outputs to be terminated. How does this work? The incoming signal is amplified by roughly 25 dB, then split several ways through a Wilkinson divider or equivalent. Each of the splitter outputs then passes through an attenuator of roughly 15 dB on the way to its output jack. This provides > 40 dB isolation between ports (15 dB + 15 dB + whatever the Wilkinson divider gives) and 30 dB broadband termination for the ports of the divider even if the output port jack is left open. The amplifier gain is typically adjusted so that the overall gain from input to output is around 3 dB, to compensate for typical cable loss from a roof-mounted antenna. Splitters from these companies show up frequently on auction sites, occasionally at attractive prices. The nice thing is that all the optional features including the "networked" option seem to be implemented by loading different components on the same PCB. If you can read microstrip circuitry and solder 0805 parts, you can change an "amplified" splitter into a "networked" splitter, tweak the overall gain, add or remove DC blocks, and so forth. Cheers! --Stu ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: GPS antenna distribution???
A resistive splitter has essentially no useful port-to-port isolation, in
addition to the
excess splitting loss problem. For this reason, resistive splitters are
usually used
only when very broad frequency ("DC to daylight") coverage is needed.
Many RF splitters are of the Wilkinson variety, or some variant thereof.
In principal
these have good isolation between the output ports over some useful
frequency
range, *but if and only if the source impedance well matched to Zo*. This
last point
is often overlooked, which is unfortunate because many sources are in fact
rather
poorly matched.
So if the system need includes good isolation between output ports of a
splitter, it
is best to sprinkle the system with amplifiers and attenuators, which if
properly
chosen and configured will provide excellent isolation between output ports
regardless.
Dana
On Tue, Jun 29, 2021 at 7:45 AM Bob kb8tq wrote:
> Hi
>
> Pretty much *any* splitter will have issues with outputs being
> un-terminated.
> Resistive splitters are really no worse that others. The problem that they
> have
> is 6db of loss per split rather than 3db.
>
> The Symmetricom units are not immune to this. They have a single amplifier
> that
> drives a splitter.
>
> A “DC output” module or receiver normally will be quite happy running into
> a
> blocking capacitor. The dirt cheap ebay parts seem to do fine. It is rare
> to find
> a device that refuses to work this way. The “why” is that basement crazies
> aren’t
> the only ones to run splitters …..
>
> Bob
>
> > On Jun 29, 2021, at 2:16 AM, Julien Goodwin
> wrote:
> >
> > I keep forgetting to do a thread about this.
> >
> > I recently (er, perhaps a year ago) picked up a Microlab unit, and was
> > very disappointed, notably the output simply isn't built to handle being
> > plugged into units that provide antenna power, with each port ending up
> > having a DC path to ground (at 200 ohm, so not too terrible, but it's
> > still not great). Plus being a simple resistive splitter it's not ideal
> > if all outputs aren't terminated.
> >
> > Luckily the Sysmocom unit mentioned elsewhere is fine with this (up to
> > 12v because I specifically talked to them about this exact issue when
> > they were working on it).
> >
> > On 27/6/21 1:49 pm, lstosk...@cox.net wrote:
> >> I seem to have an gathering of GPS antenna on my window ledge. I seem
> to have missed info on building a splitter/amp to take one signal and
> distribute it. Quick reference? N0UU
> >> ___
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> >>
> > ___
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[time-nuts] Re: GPS antenna distribution???
Hi Pretty much *any* splitter will have issues with outputs being un-terminated. Resistive splitters are really no worse that others. The problem that they have is 6db of loss per split rather than 3db. The Symmetricom units are not immune to this. They have a single amplifier that drives a splitter. A “DC output” module or receiver normally will be quite happy running into a blocking capacitor. The dirt cheap ebay parts seem to do fine. It is rare to find a device that refuses to work this way. The “why” is that basement crazies aren’t the only ones to run splitters ….. Bob > On Jun 29, 2021, at 2:16 AM, Julien Goodwin > wrote: > > I keep forgetting to do a thread about this. > > I recently (er, perhaps a year ago) picked up a Microlab unit, and was > very disappointed, notably the output simply isn't built to handle being > plugged into units that provide antenna power, with each port ending up > having a DC path to ground (at 200 ohm, so not too terrible, but it's > still not great). Plus being a simple resistive splitter it's not ideal > if all outputs aren't terminated. > > Luckily the Sysmocom unit mentioned elsewhere is fine with this (up to > 12v because I specifically talked to them about this exact issue when > they were working on it). > > On 27/6/21 1:49 pm, lstosk...@cox.net wrote: >> I seem to have an gathering of GPS antenna on my window ledge. I seem to >> have missed info on building a splitter/amp to take one signal and >> distribute it. Quick reference? N0UU >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an >> email to time-nuts-le...@lists.febo.com >> To unsubscribe, go to and follow the instructions there. >> > ___ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an > email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: GPS antenna distribution???
I keep forgetting to do a thread about this. I recently (er, perhaps a year ago) picked up a Microlab unit, and was very disappointed, notably the output simply isn't built to handle being plugged into units that provide antenna power, with each port ending up having a DC path to ground (at 200 ohm, so not too terrible, but it's still not great). Plus being a simple resistive splitter it's not ideal if all outputs aren't terminated. Luckily the Sysmocom unit mentioned elsewhere is fine with this (up to 12v because I specifically talked to them about this exact issue when they were working on it). On 27/6/21 1:49 pm, lstosk...@cox.net wrote: > I seem to have an gathering of GPS antenna on my window ledge. I seem to > have missed info on building a splitter/amp to take one signal and distribute > it. Quick reference? N0UU > ___ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an > email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: GPS antenna distribution?
On 28/06/2021 21:56, lstosk...@cox.net wrote: Thanks guys. Opened a lot of things to think of. Makes me wonder how I get any results from a north facing window with the UV coating! Will work out something. N0UU Maybe an antenna in the loft might produce better results? Check it with your (Android) phone/tablet which can display the signal strengths. You could consider using something which sticks to the outside of the window if the attenuation is too great? Cable through a small hole, or where the window opens? 73, David GM8ARV -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: GPS antenna distribution?
Or, it could be that the UV coating is really a multi-layer dielectric coating, not metal at all, in which case it would have negligible impact on L-band signals. Dana On Mon, Jun 28, 2021 at 6:17 PM Dana Whitlow wrote: > Could be that north-facing window/reflector is actually helping you a bit > with signals > from the south coming through the house. Stranger things have happened ... > > Dana > > > On Mon, Jun 28, 2021 at 4:03 PM wrote: > >> Thanks guys. Opened a lot of things to think of. Makes me wonder how I >> get any results from a north facing window with the UV coating! Will work >> out something. N0UU >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe >> send an email to time-nuts-le...@lists.febo.com >> To unsubscribe, go to and follow the instructions there. >> > ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: GPS antenna distribution?
Could be that north-facing window/reflector is actually helping you a bit with signals from the south coming through the house. Stranger things have happened ... Dana On Mon, Jun 28, 2021 at 4:03 PM wrote: > Thanks guys. Opened a lot of things to think of. Makes me wonder how I > get any results from a north facing window with the UV coating! Will work > out something. N0UU > ___ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send > an email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: GPS antenna distribution???
Hi One significant thing to consider: How many GNSS bands do you want / need / wish to cover? A while back, you would be fine just grabbing GPS and Glonass on one band. These days widening things out to two or three bands may make sense. There are an ever increasing number of devices that both do multi GNSS ( GPS / Glonass / Galileo / Compas ….) and multi band. Why does this all matter? The “cellular” amplifiers have relatively narrow band filter is in them. There is zero chance of them doing multi band. They also do a poor job of handling GPS and Glonass. The somewhat wider L1 amps might do Glonass and GPS. They aren’t going to get you the other bands. Other bands are what get you better correction for ionosphere. That’s a big deal. Bob > On Jun 26, 2021, at 11:49 PM, lstosk...@cox.net wrote: > > I seem to have an gathering of GPS antenna on my window ledge. I seem to > have missed info on building a splitter/amp to take one signal and distribute > it. Quick reference? N0UU > ___ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an > email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: GPS antenna distribution???
I have a couple of these and they work wonderfully well: https://timemachinescorp.com/product/4-way-gps-splitter/ They also have an option that you can power with an external supply, which is a nice feature if you need it. John Original Message Subject: [time-nuts] Re: GPS antenna distribution??? Date: 2021-06-27 6:50 pm From: djl To: Discussion of precise time and frequency measurement 4-port: ttps://www.sv1afn.com/en/gnss-gps/-7.html 99euro I have one works fine Don On 2021-06-27 15:06, Georg Sauthoff wrote: Hello, On Sat, Jun 26, 2021 at 11:49:26PM -0400, lstosk...@cox.net wrote: I seem to have an gathering of GPS antenna on my window ledge. I seem to have missed info on building a splitter/amp to take one signal and distribute it. Quick reference? N0UU Sysmocom has a 16-channel GPS antenna splitter: https://sysmocom.de/products/lab/gps-spl16/index.html Best regards Georg ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: GPS antenna distribution???
4-port: ttps://www.sv1afn.com/en/gnss-gps/-7.html 99euro I have one works fine Don On 2021-06-27 15:06, Georg Sauthoff wrote: Hello, On Sat, Jun 26, 2021 at 11:49:26PM -0400, lstosk...@cox.net wrote: I seem to have an gathering of GPS antenna on my window ledge. I seem to have missed info on building a splitter/amp to take one signal and distribute it. Quick reference? N0UU Sysmocom has a 16-channel GPS antenna splitter: https://sysmocom.de/products/lab/gps-spl16/index.html Best regards Georg ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there. -- The whole world is a straight man. -- Dr. Don Latham AJ7LL PO Box 404, Frenchtown, MT, 59834 VOX: 406-626-4304 ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: GPS antenna distribution???
Hello, On Sat, Jun 26, 2021 at 11:49:26PM -0400, lstosk...@cox.net wrote: > I seem to have an gathering of GPS antenna on my window ledge. I seem > to have missed info on building a splitter/amp to take one signal and > distribute it. Quick reference? N0UU Sysmocom has a 16-channel GPS antenna splitter: https://sysmocom.de/products/lab/gps-spl16/index.html Best regards Georg ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: GPS antenna distribution???
Hi It’s well worth getting an antenna into a good location before you play with splitters. Things like the amount of gain needed may change as coax runs get longer. Bob > On Jun 26, 2021, at 11:49 PM, lstosk...@cox.net wrote: > > I seem to have an gathering of GPS antenna on my window ledge. I seem to > have missed info on building a splitter/amp to take one signal and distribute > it. Quick reference? N0UU > ___ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an > email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: GPS antenna distribution???
Sending something like this to google ”gps splitter site:febo.com” is a good start to search the archives. /Björn Sent from my iPhone > On 27 Jun 2021, at 06:47, wb...@gci.net wrote: > > A DuckDuckGo or Goggle searco on "gps antenna split" will give you more than > you want to know > - Original Message - > From: lstosk...@cox.net > To: time-nuts@lists.febo.com > Sent: Sat, 26 Jun 2021 23:49:26 -0400 (EDT) > Subject: [time-nuts] GPS antenna distribution??? > > I seem to have an gathering of GPS antenna on my window ledge. I seem to > have missed info on building a splitter/amp to take one signal and distribute > it. Quick reference? N0UU > ___ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an > email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. > ___ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an > email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: GPS antenna distribution???
A DuckDuckGo or Goggle searco on "gps antenna split" will give you more than you want to know - Original Message - From: lstosk...@cox.net To: time-nuts@lists.febo.com Sent: Sat, 26 Jun 2021 23:49:26 -0400 (EDT) Subject: [time-nuts] GPS antenna distribution??? I seem to have an gathering of GPS antenna on my window ledge. I seem to have missed info on building a splitter/amp to take one signal and distribute it. Quick reference? N0UU ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
