[time-nuts] how to feed multiple GPS receivers ?

[Brooke Clarke]

Hi Arne:

Here's some info on one:
https://prc68.com/I/4GPS.shtml

-- 
Have Fun,

Brooke Clarke
https://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
axioms:
1. The extent to which you can fix or improve something will be limited by how well you understand how it works.
2. Everybody, with no exceptions, holds false beliefs.

-------- Original Message --------
> Hi Bob,  and others that responded off list.
>
> On Mon, Feb 25, 2019 at 2:15 PM Bob kb8tq <kb8tq at n1k.org> wrote:
>> Hi
>>
>> On a GPS distribution system the issue of 75 vs 50 ohm cable is pretty
> much a
>> non-issue. A lot of people have run 75 ohms (like Trimble on the TBolt)
> and had
>> no problems from this.
> This is what I thought, thanks for the confirmation.
>
>> The “TV” splitters are generally spec’d to 2 GHz, so well beyond GPS
> frequencies.
>> Again, it should not be an issue. There are also cheap multi-port
> splitters on the
>> auction sites.
> Some hints on what to search for would be appreciated.
>
>> DC blocks *are* a good idea. DC loads may or may not be needed. It’s a
> try it and see
>> sort of thing. Some have been known to simply drop a 50 ohm load on one
> port of a
>> 8 way splitter and let that be the DC load. You *can* run into issues
> doing this ….
>> (one device feeds 12V and another is a 3.3V feed …. smoke results …).
> Cable TV
>> DC blocks are dirt cheap ….
> Some DC blocks have been ordered.
>
>> Ideally you want the antenna as high as you can get it. In an urban area
> with various
>> constraints, that may or may not be very high. Coax losses plus splitter
> losses should
>> be considered when designing something like this. An amplifier ahead of
> the splitter
>> is not at all unusual.
> To begin with I'm just going to use one of the "puck" antennas in the
> window that it is currently in, at which point I'm expecting to discover
> that the loss through the TV splitter means that more gain will be
> required, or a lower loss splitter.
>
>> With the arrival of world of low cost multi-band GPS devices … put up a
> multi-band
>> antenna. At the very least L1 / L2 (including Glonass coverage). Ideally
> L1 / L2 / L5.
>> Much easier to do it right the first time.
> The longer term plan is to get a L1/L2 (and possibly L5) antenna and roof
> mount it, but stage one is just to get the same feed to the different
> receivers.
>
>> Bob
> While I'm moderately good at fitting most connectors onto cables, making a
> wilkinson splitter PCB or managing to cut coax to exactly the right length
> do make on out of co-ax its a little bit beyond what I can get away with in
> the workshop kitchen.
>
> Cheers
>
> Arne
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