[time-nuts] Re: RAGA - was Re: Re: Low Phase Noise70 10 MHz bench signal source sought

[Andy Talbot]

I have encountered GPS active antennas that are unstable and oscillate,
especially when not mounted on a metal backing.    One even oscillated
occasionally when it did have a ground plane.   Because the ceramic patch
antenna is narrowband and has a high Q, the spurious oscillation is
relatively stable in frequency, and of course very close to 1575MHz where
patch resonates.
One such faulty antenna I had once jammed every other GPS receiver in the
house - although they were all the old 2nd generation type receivers of two
decades ago

Andy
www.g4jnt.com



On Sat, 2 Apr 2022 at 19:27, Lux, Jim <jim at luxfamily.com> wrote:

> I encountered a weird problem when I hooked up 4 OEM GPS modules to 4
> Beaglebones.. Side by side, they wouldn't all get GPS lock. It turns out
> the (unshielded) receivers radiate enough stuff to foul up adjacent
> receivers.   Move them several meters apart and no problems.  I didn't
> get around to seeing if there is some effect on the timing performance,
> even if they "get lock", but I'll bet there is.  A