[time-nuts] Z3805A/58503A time receiver : 2 questions

Volker Esper ailer2 at t-online.de
Wed Feb 27 19:50:24 EST 2013


I just calculated the frequency offset. I count 5 crosses, while jumping 
down to 200 ns, I guess, 1 cross equals 10 min? So let's say the jump 
lasts 60 min (= T jump). When we want to calculate the frequency offset 
out of a phase jump, we have to differentiate the phase and we should 
achieve

delta f = delta phase / delta T
delta f = (delta t / T period) / T jump
delta f = (200ns / 100ns) / 60 min
delta f = 0,55 mHz (milli, not Mega!)

What precision / stability do you demand?

Volker


Am 28.02.2013 00:47, schrieb SAIDJACK at aol.com:
> Hello Claude,
>
> that gap is a classic crystal jump. It could be caused by the crystal
> changing frequency by itself, or by being hit with e.g. gamma particles etc.
> Could also have been instigated by vibration or shock to the unit.
>
> You should be seeing 6+ sats at all times though, your plot shows you
> sometimes seem to see 2 or 3 sats only? Maybe a better antenna position would
> help the stability of that unit.
>
> Nothing to worry about if it doesn't happen regularly. Enjoy,
>
> bye,
> Said
>
>
> In a message dated 2/27/2013 15:18:51 Pacific Standard Time,
> labtf1 at yahoo.fr writes:
>
> Hello,
>
> This is my first message here although I read this  list for a few weeks.
>
> I bought a Z3805A/58503A frequency  receiver  and I didn't notice on the
> pictures that the model number was  not  written on the front panel. It's not
> important but is there a reason  for that, if you know ?
> The item :  http://cgi.ebay.fr/ws/eBayISAPI.dll?ViewItem&item=251226027893
>
>
> I log some parameters of the receiver and today I notice a "gap"  in the
> frequency.
>
> Picture :  http://uppix.net/e/2/4/cf39ac772e5a69fc616f5cf30f208.png
>
> I have a  Rubidium and I measure it's frequency with a 5334B counter locked
> to the GPS,  and I can see the "gap" too  :
> http://uppix.net/f/b/a/d86c2737ad135264e4a2b78e503d5.png
> measurements  are with Gate Time of 10s, 60s and 100s,
>
>
> Do you know why this  happens and how to prevent this behaviour ?
>
> Thanks for yours advices
>
>
> Claude
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>
>    




More information about the time-nuts mailing list