Bjoern Thank you for the link I am able to change the frequency 4 Hz from - 2Hz ( 0V) to + 2 Hz (-12.2V) using pin 2. Reading the info that you got me probably explains the slot next to the connector, but I experience a much wider tuning range on pin 2 and John is right any positive voltage forward biases the diode cutting off oscillation. Will do some testing. Thanks again Bert In a message dated 8/10/2012 6:28:17 A.M. Eastern Daylight Time, b...@lysator.liu.se writes:
Bert, Good that you got the EFC working! But I would be a bit suspicious of needing -13V. It seems from: http://www.ece.gatech.edu/academic/courses/ece4007/08fall/ece4007l01/al4/dat asheets/symmetricon_oscillator_instructionsheet.pdf that the default EFC configuration is (0 to +10)V with a range of 4e-7 (2Hz). From the same document there are a lot of other EFC configurations, but none that goes outside of +-10V. My 1200 has about 3.5Hz tuning range on (0,10)V. Se attached jpg. I did not check behavior on negative EFC voltage. -- Björn > John, > that did the trick I can tune it with a negative voltage, minus 13 gives > me plus 2 Hz but this unit came out of a FTS 5000 and it had a positive > tuning voltage. > Bert > > > In a message dated 8/9/2012 9:13:29 P.M. Eastern Daylight Time, > jmi...@pop.net writes: > >> John >> Oven did reduce in current and I can not imagine that it would be that >> close with an overheated oven. At 0 V it is within .5 Hz of what they > normally >> are. Ground has no effect but even 0.8 V on pin 2 stops oscillation > > That's a suspicious-sounding voltage. Are you sure you're not > forward-biasing the varicap? Maybe some of these OCXOs were specified > for > use with negative EFC voltage. > > If so, then driving the diode with a negative voltage should raise the > operating frequency (which is what you want.) > > -- john, KE5FX > www.miles.io > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.