[time-nuts] FTS 1200

bg at lysator.liu.se bg at lysator.liu.se
Fri Aug 10 06:27:13 EDT 2012


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/datasheets/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,
> jmiles at 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 at 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 at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: fts1200.jpg
Type: image/jpeg
Size: 33011 bytes
Desc: not available
URL: <http://lists.febo.com/pipermail/time-nuts_lists.febo.com/attachments/20120810/08fb51aa/attachment.jpg>


More information about the time-nuts mailing list