On Thu, Apr 23, 2015 at 12:33 AM, Bob Camp <[email protected]> wrote: > Hi > > Looking at that screen shot, something is *very* wrong with your GPS > reception. Your GPS > is 10X worse than it should be.
You're right. The interference from the nearby Oncore UT+ seems to have been the problem. Since I moved the antennas further apart the signal strength for satellites in view of the Tbolt is 35-45 dBc and it can routinely view 6-7 satellites simultaneously -- this is essentially the same performance as when the Oncore is powered off and the antenna removed, so I'm happy. After moving the antennas further apart and doing a standard 2000-point site survey the 100-200ns phase offset spikes that occurred when satellites were added/removed from the solution dropped to 5-10ns. The oscillator offset also decreased. I'm now doing a longer precision survey to hopefully smooth those out more and get a better average position over a few satellite orbits. > I would bet that the amp on the “Oncore” antenna is oscillating. It may do it > intermittently. The frequency may swing back and forth through the GPS band. > It > may be the source of your GPS problem. Interesting. I have a second identical Oncore UT+ and antenna and will do some more tests to see if one of them is just being noisy, if it's a fault of the Oncore module itself, or the antenna. Many thanks to everyone on the list for the insight and assistance. Cheers! -Pete -- Pete Stephenson _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
