Rick Thanks. But I am far simpler than that. I am trying to get the 10811 back to 10 Mhz its -45Hz. In the long thread above I go into the troubleshooting details so far. Because a crystal simply can't go this bad. :-) I hope not at least. Regards Paul.
On Fri, Jul 26, 2013 at 1:38 PM, Rick Karlquist <[email protected]>wrote: > Ed Palmer wrote: > > Hi Paul, > > > > Did you see this page that talks about tweaking the 10811 oven > controller? > > > > http://www.realhamradio.com/z3801a-turning-point.htm > > > > Ed > > > > Although this article anecdotally claims success, it overlooks > a number of important issues. First of all, a large proportion > of 10811 crystals DO NOT HAVE A TURNOVER. They merely have a > very low TC around 82 degrees. It is ALWAYS 82 degrees for these > crystals. The crystals that do, technically, have a turnover, > still have very low TC even if the oven is slightly off the turnover. > Secondly, the tempco of the electronics, specifically > the selected 2N5179 oscillator transistor, is a significant player. > The thermal gain, if properly adjusted, is around 1000 at the > crystal, but is much less at the oscillator transistor. It may > very well be the dominant factor in overall oscillator tempco. > Possibly, if you have a crystal with a turnover, you should > deliberately operate off the turnover at a point where the crystal > drift cancels the drift of the electronics. > If you want to tweak a 10811, you should also tweak the thermal > gain by custom adjustment of the heat balancing resistors for > the heater transistors. This has to be done by converting the > oscillator to mode B and then converting it back to mode C > afterwards. > > Rick Karlquist N6RK > > _______________________________________________ > 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. > _______________________________________________ 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.
