Thanks all for the various replies, on and off list. John WA4WDL wrote: > Perhaps you should use only the leading edges for the > pulse-to-pulse interval measurement.
Yes, I'm just using the leading edge, turning it into a pulse using a couple of RC networks, slowing the rise and fall enough to give a nice shape for accurate locating of the centroid. Antonio CT1TE wrote: > I can send you the yesterday record of my GPS TBolt #2 against > DCF77, which apparently doesn't show any periodic phase > variation. Thanks for the offer. Hold on that, I'll assume for now that this slow cycle is not ionospheric. Rob Kimberley wrote: > I'm assuming your location is fixed, and you are tracking > sufficient SVs, Fixed. Maybe I can relocate the GPS antenna for a better view of the sky. Peter Vince wrote: > I don't believe that cyclic variability is GPS - I've not > noticed such a thing on any of the systems I monitor. Thanks, that's very helpful. Knowing that this is not normal behaviour for GPS timing means that I can set about tracking down a system fault. There are a few things I can think of to check. The cycle must correlate with something - soundcard rate, temperature, CPU clock, etc. It is pretty consistent, here is a bit more of MSF 60kHz and also DCF at 77.5kHz, http://abelian.org/vlf/live/pp100701msfc.png http://abelian.org/vlf/live/pp100701dcfc.png Thanks again, I'll report back when I find the problem. -- Paul Nicholson http://abelian.org -- _______________________________________________ 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.
