[time-nuts] GPS antenna splitter recommendation? (John Ackermann N8UR)

[N1BUG]

I was lucky. I was looking for a GPS splitter a few months ago. Since I 
wasn't in a big hurry I had the luxury of time to hunt. I picked up a 
GPS Networking LNFA1X4-N for under $50. File that success under even a 
blind squirrel sometimes finds an acorn. It is an active splitter that 
provides just enough gain to overcome the splitter losses. It can accept 
DC power for itself and for pass through to an active GPS antenna from 
any of the four receiver ports without back feeding voltage to receivers 
on other ports.

I was concerned that this splitter and my Symmetricom 58532A antenna 
wouldn't operate if all of my receivers were 3.3V but both seem to work 
perfectly well with either 3.3V or 5V.

Paul, N1BUG


On 4/30/20 1:37 PM, biwa at att.net wrote:
> I use splitters for broadcast satellite stuffs all the time.  My
> preference is for splitters that have diodes so that all receivers
> can provide LNB power and at the same time not back-feed any of the
> other receivers. That way, if any of the receivers fails, any of the
> remaining receivers can provide LNB power to keep the system up and
> operating. I would want my GPS system to operate the same way.
> 
> However, here in my home shoppe I have two DATUM 9300-53054 receivers
> running 24-7, and on UPS.  They are each on their own antenna.
> 
> Burt, K6OQK
> 
> On April 30, 2020 10:11:55 AM PDT, Chris Quayle <syseng at gfsys.co.uk>
> wrote:
>> On 04/30/20 17:00, time-nuts-request at lists.febo.com wrote:
>>> Re: GPS antenna splitter recommendation? (John Ackermann N8UR)
>> 
>> Usually a lurker here, but a couple of points. The best splitters
>> are those designed for the task, such as the HP or symmetricom 4
>> way boxes seen from time to time on Ebay, though typically
>> expensive.
>> 
>> There are various issues:
>> 
>> 1) The gps receiver will throw a fault if the antenna dc load is 
>> missing, though a simple fixed resistor load takes care of that.
>> 
>> 2) The commercial units provide low noise gain to make up for the 
>> loss in a passive output splitter.
>> 
>> 3) Typically, only one of the receiver ports is specified to
>> provide the antenna power and also internal preamp power, with dc
>> isolation for the rest.
>> 
>> Can't see that a passive splitter would be an ideal solution
>> without serious hackery, when you could build one using the cheap
>> uhf amp gain block pcb's widely available now...
>> 
>> Regards,
>> 
>> Chris