[time-nuts] Looking for information regarding Trimble 33429-00 microcentered GPS antenna.

Bob kb8tq kb8tq at n1k.org
Fri Jan 19 09:43:20 EST 2018


It is very much a 12V antenna. It also is a “50 db gain” antenna as well. 
Most of the timing gear is looking for 20 to 30 db less gain than that in 
an antenna. The good news is that you can run a really big splitter after
one to drive lots of stuff. The bad news is that you may still need attenuators.

Looking at the snow piles on my GPS antennas, I would not recommend using
the ground plane. It will significantly increase the load on the mount ….


> On Jan 18, 2018, at 1:39 PM, John Green <wpxs472 at gmail.com> wrote:
> I have been gone for a good while, but now that I am officially retired, I
> thought I would get back into the time/frequency hobby. I recently bought a
> Trimble 33429-00 antenna off eBay. I can't seem to find much on the
> internet about it. Google has not been my friend. First, I assume the
> "micro centered" refers to the phase center being located with precision.
> Mine was meant to be used with the ground plane, which did not come with
> it, so the marks indication the part to be pointed north are missing. It
> doesn't matter in my use since I won't be surveying anyway. Can someone
> tell me what voltage it takes? I decided that the Leica choke ring antenna
> I got a while back took 12 volts because the power input went to an 8 volt
> regulator, and I figured 12 volts should work ok. On this one, the power
> goes to a 2951 adjustable regulator, leaving me a bit in the dark. I will
> probably try hooking an adjustable power supply to it and slowly raising
> the voltage until the output of the regulator stabilizes. They seem to have
> made two versions of this antenna. One with groundplane, and one without.
> Since I will be feeding a GPSDO, would a groundplane be of benefit? In
> looking through the archives, it seems I have missed a lot of good
> discussions. Good to be back.
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