Mark Sounds like the same problem I had when I had the AMU set TOO high. ( I don't think it can be set with LH, Need Tboltmon to change it) I have not seen the condition that you describe where the Tbolt will switch satellites just because it has found a better one. (I don't think that happens) Mine will hold all eight and will not release any unless the signal level goes below the AMU setting. I do not know of any other way that will causes a satellite to switch out in only a few minutes when tracking under 8.
When I had the AMU set too high, and the signal level was right at the bounty, then the satellites would tend to toggle in and out as you described. The solution for me was to set the AMU to one so that the Tbolt did not release a satellite once it got it, and I also raised the elevation mask so that it did not pick up the satellite until the satellite got higher and stronger in the sky. In my location which sounds similar to yours, with Elevation set high and the AMU set low it no longer toggles. As you said the worse thing for noise is when the Tbolt toggles the satellites in and out. This is much worse than holding a low level noisy signal. My unit works fine now with the TC set to 750+ seconds when there is ANY signal at least in the high 20s, which is always the case at my location. The High TC setting of 500+ and a damping setting of 0.7 (and Dac gain set correct) greatly helps in reducing the noise cause by satellites switching. ws ****************** Mark Sims said: I have considerable experience operating Thunderbolts in less than optimum conditions (my house is in an urban jungle, surrounded by Jurassic trees and nasty multipath monsters). Lady Heather defaults to the dBc setting since that seems to be the most understandable and better defined system. Signal levels above 40 are very good. There seems to be little to be gained with signals above 40. Above 35 are OK-ish. From 32-35 are usable, if you are not too picky about your system. Below 32 are just plain craptastic and pretty much unusable. The most problematic and intractable source of Tbolt output errors seem to be the result of satellite constellation changes as the unit constantly switches between satellites in an effort to track the "best" available satellites. If you plot the satellite count and DAC voltage (and along with the PPS error estimate) you will see that the DAC voltage changes with every satellite constellation change. This causes the oscillator to change frequency. The better your signal levels, the less reason the unit has to switch tracked satellites and the better will be your oscillator and PPS outputs. The Tbolt firmware supplies few tools for minimizing its annoying habit of tracking the supposedly "best" satellites of any given instant. At my location, I am doing real good if the tracked satellite constellation stays fixed for over a minute... _______________________________________________ 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.
