From: Magnus Danielson <[EMAIL PROTECTED]> Subject: [time-nuts] Z3801 saga Date: Wed, 26 Jul 2006 01:32:42 +0200 (CEST) Message-ID: <[EMAIL PROTECTED]>
> Fellow timenuts, > > The automation fell in my lap today. The Allan deviation plot show clear > evidence of CW modulation (traditional ripple). Turing over to frequency view > there it is. Actually, it has both varying amplitude and frequency. As > frequency lowers, so does the amplitude in frequency deviation. When it hits > around 450 mHz on the 10 MHz, the Z3801A goes into holdover. > > Now, it seems that there is some source of pumping up and down. I am > suspecting > something like the oven control pumping. The longer time it spends the longer > the temperature goes up and down and thus modulate the frequency more and > more. > > Somebody sitting there with the outer and inner oven control schematics. I've > only seen parts of the inner one. > > Does this ring a bell somewhere? Eh... forget THAT one. THAT was a result of a measuring mistake. Somewhere down the line I got into running the internal timebase which isn't fantastic as default, but I was beleiving I was running fancier... (Cs-beam vs. uncompensated crystal) Now it looks cooler. Much cooler. It still goes out of lock and it goes way out of range. Last time I looked it was dangerously close to the 1 us TI error limit at which time it goes into holdover and reallign itself. I'm a bit unhappy about that. Anyway, I keep it heated while I'm gone to see if things improve just by staying tuned. It's a pitty I can't receive more channels on this one, I have some 12 satelites above 10 degree threshold. Good signal on the 6 I'm tracking. Cheers, Magnus _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
