Magnus But does anyone have comments on the meter approach HP suggested. I really need to understand whats semi normal for old tube.
I suspect I may be sitting near the noise floor of the system. As for the network analyzer I just happen to have a HP 8505 so may give this a try. Suspect I will see the fingers but very close to the noise floor. Regards Paul. On Tue, Oct 4, 2011 at 3:06 AM, Magnus Danielson <[email protected] > wrote: > On 04/10/11 04:56, paul swed wrote: > >> Hello to the group. >> Still working on the 5061 with a 5060 tube. Have home brewed a new CS oven >> controller thats appropriate to the 5060 tube and its working quite well. >> 2 >> op amps and a couple of transistors. It handles the 5060s higher current >> needs. Average current is 650 ma at 98 ohms for the thermistor. >> The zeeman frequency is still bothering me. Granted I may be dealing with >> a >> weak tube. >> But I can adjust the cfield and get the various peaks. But they are >> small. The normal HP meter is a 50 ua movement. Using a 25 ua larger >> scale >> meter to monitor the beam current results in, >> >> No modulation 8 ua >> Driving 42.82KC at +1dbm I actually see the meter drop to 7.5ua. >> Then adjusting the cfield to 20 ma I can see the middle peak at 8.5 ua >> maybe >> a little higher. >> >> Is this the peak? Or better question whats a normal old CBTs beam current >> and the peak expectation. >> I am wondering if I simply am way down at the edge of usability. >> I can adjust the ionizer and get a higher reading just unsure were to stop >> at. Burn something out perhaps like the ionizer is the risk. >> >> The other thing is that there is still a drift. You can see the system >> lock >> for about 3-5 minutes then slowly become unstable and slip 5ns. Depending >> on >> the zeeman peak used it goes right or left. The green op light stays on >> however so the slips awfully small. >> > > With a very small trick you can sweep your tube using a network analyzer > and a mixer. > > Take the Port 1 of your network analyzer and sweep around 12,6 MHz which > you insert in replacement of the synthesis frequency. Hook the 10 MHz of the > crystal to the network analyzer input for additional stability. Use the > detected signal (as amplified) and control a mixer which takes a bit of the > 12,6 MHz and feed that to Port 2 of the network analyzer. That way you > modulate the amplitude. > > Should give you an overview of the 7 peaks, there spreading and their > location. > > Note that this also works for spectrum analyzers having a sweep output, as > no phase is recovered this way anyway. > > Cheers, > Magnus > > ______________________________**_________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/** > mailman/listinfo/time-nuts<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> > and follow the instructions there. > _______________________________________________ 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.
