[time-nuts] Re: GPS Splitter for L1, GNSS, etc?

[Andy Talbot]

I once saw a design for a GPS antenna splitter that comprised a four-way
Wilkinson splitter on PCB microstrip, so had DC continuity between all
ports   At each output port was a capacitor to pass the RF, shunted by a
small diode.   That way any GPS receiver that put DC on its antenna port
would be isolated by the diodes  from all the other receivers.  The
receiver delivering the highest antenna supply voltage would  'win' and end
up supplying the active antenna via its diode in the splitter.

Andy
www.g4jnt.com



On Wed, 2 Jun 2021 at 10:14, shouldbe q931 <shouldbeq931 at gmail.com> wrote:

> On Wed, Jun 2, 2021 at 10:09 AM shouldbe q931 <shouldbeq931 at gmail.com>
> wrote:
> >
> > On Wed, Jun 2, 2021 at 5:21 AM W7SLS <w7sls.scott at gmail.com> wrote:
> > >
> > > Hello,
> > >
> > > Looking for group wisdom to avoid newbie mistakes with a GPS splitter.
> > >
> > > For context, I’m a home- not National- or University-Lab.
> > > That said, I have a non-zero budget.
> > >
> > > Today:
> > >         Antenna
> > >         1- CORS RTK GNSS Survey Antenna high gain measurement GNSS GPS
> GLONASS BDS <https://www.ebay.com/itm/253786590956>
> > >         2 - patch antenna - works really well with Time Hat, even a
> few meters way from window
> > >
> > >         Splitter
> > >         1 - Symmetricom 58536A
> > >
> > >         Devices
> > >         1 - Auction Site GPSDO
> > >         2 - Leo Bodnar GPSDO
> > >         3 - Time Hat <— wow!  a fan!
> > >         4 - (on the way) 2nd Time Hat
> > >
> > >         Site
> > >         - suburban, forest to the S, hill to the N
> > >
> > > Challenge:
> > >
> > >         Existing  splitter is L1 only (I think), which blocks the many
> newer GPS satellites.
> > >         With my compromised (for GPS) location, that’s not so good.
> > >
> > > I need / want a wider band GPS Splitter
> > >
> > >         1 - some posts talk about removing the bandpass filters in an
> existing splitter
> > >                 OK, but (a) it nukes any value of that splitter, and
> (b) those filters also eliminate other interference (yes?)
> > >
> > >         2 - new choices seem to be in the $1000 and way above, outside
> of my budget
> > >
> > >         3 - more interested in ‘ready to use’ than ‘have to add on
> bypasses' to power the antenna (e.g., Cable TV splitter)
> > >
> > >         3 - auction site has numerous options, but I’m not sure how to
> 'separate wheat from chaff’
> > >
> > >                 LOL, some of you may be the sellers :)
> > >
> > >                 several items $500+  <— more than I want to spend
> > >                 several items $30 -   <— I’d rather not get  aTV
> antenna splitter and a hobby to make it work
> > >
> > >                 324575653743  GPS Source S14 $175
> > >
> > >                 153359161105  GPS Antenna Splitter GPS/GLONASS L1
> GALILEO E1 BEIDOU B1- FedEx Fast Ship SV1AFN $120
> > >
> > >
> > > Thoughts?   Thanks for the group bandwidth.
> > >
> > > Scott W7SLS
> > >
> > > PS:  yes the Symmetricom 58536A will be for sale after I replace it.
> > > _______________________________________________
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> >
>
> And now for the complete email...
>
> One might consider something like 402528611114 combined with Bias Tee
> DC blocks such as 124130508678 for all bar one of the receivers, which
> is used to power the antenna.
>
> Not a one box solution, but very simple to put together with some SMA
> to SMA cables.
>
> Cheers
>
> Arne
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