[time-nuts] WTB: GPS Antenna Splitter

Dave M dgminala at mediacombb.net
Wed Oct 8 11:22:27 EDT 2014

Thanks, Tim,
I have wondered about the available antenna current from GPSDO units, but 
haven't been able to find a spec on any of them, or at least, the GPS units 
that I have. I have an HP Z3801A and a Nortel GPSTM NTBW50AA. Have you (or 
anyone) any information on typical available antenna current, or alarm 
conditions for antenna overcurrent?  I know the Nortel unit spec says that 
it can survive a shorted antenna/cable without damage, but no info on alarms 
or current limits.  My guess is that the unit won't see any satellites and 
will just go into holdover.
The Z3801A must have an active antenna connected (no passive antennas 
allowed), but no specs in the manual on antenna current limits.
I guess I could substitute an active load (transistor or FET) for the 
antenna so I can vary the current drawn, and see what alarms pop up.

Thanks for more info,
Dave M

Tim Shoppa wrote:
> At the very low end, a F-cable splitter for like Cable TV will likely
> (*) get the job done. Many of us are already using RG-6 type cable
> for the GPS antenna run anyway.
> (*) Some GPS units may get confused if they have active sensing on the
> antenna preamp current and this goes out of tolerance.

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