[time-nuts] GPS splitter

Bob kb8tq kb8tq at n1k.org
Sun Jun 18 12:35:38 EDT 2017


It also depends a bit on weather the original designer anticipated odd things happening on
the antenna circuit. The answer to that one is …. errr …. not always. Some designs have the
antenna supply tacked straight into a bulk regulator that feeds a bunch of stuff. Other designs 
have an indépendant regulator for the antenna. Even with the independant regulator, one needs
to know how much that regulator “likes” an over voltage on the output.


> On Jun 18, 2017, at 11:56 AM, Magnus Danielson <magnus at rubidium.dyndns.org> wrote:
> Hi,
> On 06/18/2017 05:37 PM, Bob kb8tq wrote:
>> Hi
>>> On Jun 18, 2017, at 11:17 AM, David J Taylor <david-taylor at blueyonder.co.uk> wrote:
>>> "David J Taylor" <david-taylor at blueyonder.co.uk> wrote:
>>>> .. or a ready-made, and smaller item:
>>>> http://www.ebay.co.uk/itm/1GHz-3GHz-2-4GHz-Power-Splitter-Combiner-2-Way-SMA-/141740586696
>>>> I use this successfully for 1.09 GHz ADS-B splitting.
>>> Please be aware that this is a Wilkinson splitter and thus has a DC
>>> path connecting all three ports. You will need to add a DC block
>>> at one of the receivers.
>>> Attila Kinali
>>> =======================================
>>> In practice, what would happen if you didn't have the block?
>>> Say with two identical receivers?
>> As long as they both are powered up, noting much. If one looses power, it *might* try to power
>> up the other one via the antenna feed. With most receivers, even that would likely just be an
>> odd occurrence / no damage caused. The fear is that you have a receiver that *would* be damaged
>> by the back feed. With eight receivers into a coupler, there *could* be quite a bit of current available.
> As you power up, there can be a bit of a rush-in power.
> Lack of isolation can cause antenna power detection to be confused.
> Two driving one antenna => too little current => judged as unconnected.
> One driving antenna and other GPS => too much current => judged as short circuit.
> If you have different voltages, it might be bad for the low-voltage device.
> Cheers,
> Magnus
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

More information about the time-nuts mailing list