[time-nuts] Tbolt vs FE-5680A Startup

WarrenS warrensjmail-one at yahoo.com
Sat Dec 24 12:25:23 EST 2011

Chuck posted:
>without another high precision standard it is impossible to know for sure.

If you have a Tbolt running LadyHeather then You can use the GPS as the 
OTHER precision Freq/Phase standard to compare to.
With the antenna system set up well, the GPS phase error is around 10ns 
short and long term which can be used to show you what the TBolt's Osc is 
doing when it is locked or unlocked.

The  Tbolt can also be used as the precision TIC and GPS Reference osc 
directly to test an external 10 MHz osc, by modifying the TBolt to use the 
FE-5680A as its Oscillator.
The Tbolt and GPS can then be used to set and/or measure the Rb's freq with 
accuracy of around 1e-13 per day.

Attached is a LH's Tbolt plot measuring the phase error of a temperature 
compensated LPRO Rb as compared to the GPS over a 13 day test.


time-nuts] Tbolt vs FE-5680A Startup
Chuck Forsberg WA7KGX N2469R
Sat Dec 24 05:50:34 UTC 2011

This plot shows the phase difference between a Thunderbolt and FE-5680A
starting immediately after power up of both units.

At first the Rb is searching for lock, and the phase is all over the place.
The Rb locks at about 160 seconds.  The rest I assume is the Thunderbolt
warming up and getting its discipline sorted out, which is continuing.
Without another high precision standard it is impossible to know for sure.

Chuck Forsberg WA7KGX N2469R
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