[time-nuts] Re: Tbolt

[Bob kb8tq]

Hi

If you manually set the DAC with the commands LH nicely provides 
(LH is the *best* thing about these TBolts !!!) you will find it runs from
-5 to +5V. The OCXO should tune linearly over that range ( all of mine
do). 

If you take a saw to the typical TBolt OCXO, you likely will find 
a 10 MHz SC cut crystal in a single oven. The design changed over 
the many years they were supplied. One date coded 1997 is not going
to be the same as one date coded 2005.

On any OCXO, to see if it’s using a doubler, just hook up a spectrum 
analyzer to the OCXO output. You *will* see the sub-harmonic. Much
quicker / easier than tearing the thing to pieces. 

Bob

> On Jul 22, 2021, at 5:00 AM, Dave B via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> On 22/07/2021 08:30, time-nuts-request at lists.febo.com wrote:
>> Message: 1
>> One more comment on the Vectron OCXO. My Tbolt shows a tuning voltage of +0.4 Volt and has 3.6 Hz per Volt. Assuming the OCXO was sold to Trimble with 0 V and my unit has at least 12 years on it (4380 days) aging is 3.29 E-11 per day. Not bad for an  OCXO.                                                                                                                                  Bert Kehren
> 
> ------------------------------------------------------------------------
> 
> Hi.
> 
> According to Lady Heather, My T'bolt sits with it's DAC at about 0.2V   I always wonder about that.
> 
> From the above comment, is the DAC output (and VCXO input I guess) bipolar, as in can range +- some amount from 0V?
> 
> I've not seen any schematics for them, so in honesty haven't a clue what it's likely range is, good bad or indifferent.
> 
> I did email TVB direct about the possibility of sourcing another one or two of them, but as he said (and I guessed) he was swamped with responses.
> 
> I use mine mainly as a frequency reference, powered on 24/7
> 
> Regards to All.
> 
> Dave G8KBV (In the UK as far as I can tell.)
> 
> 
> -- 
> Created on and sent from a Unix like PC running and using free and open source software:
> 
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com -- To unsubscribe send an email to time-nuts-leave at lists.febo.com
> To unsubscribe, go to and follow the instructions there.