[time-nuts] Trimble Thunderbolt setup optimization and addinga10811 OCXO

[SAIDJACK at aol.com]

Hi Tom,
 
>Two questions - Will the internal TI value still be updated  against
>GPS in this case (as it is with the TBolt)?


No, unfortunately not.
 
There is another (better?) command to manually put the Fury/FireFly units  
into holdover mode:
 
   SYNChronisation:HOLDover:INITiate
 
To get out of manual holdover, use:
 
   SYNChronisation:HOLDover:RECovery:INITiate
 
Pretty obscure commands, I forgot about these.
 
>And, is there also a mode where you just freeze the DAC, that  is,
>holdover without any compensation (no drift or temp  corrections).
>This being a trick to temporarily maximize short-term  stability, a
>way to most closely resemble a standalone free-running  OCXO.


This can be done in two ways:
 
1) set both tempco and aging to 0.0, and disable the GPS. This will lock  
the DAC in place.
 
2) turn on the unit, wait ~10 seconds, then enable the reset via jumper.  
This will lock the Coarsedac into place, and disable the fine-dac. Absolute  
frequency will be off a bit due to the disabled fine-dac.
 
Option 2) will disable the CPU, and will reduce any noise that the CPU  etc 
generates, and thus may be a more Time-nutty way of checking the OCXO just  
by itself.

Hope that helps,
bye,
Said