[time-nuts] Z3801A - notes on the hp58533a GPSDO

Didier Juges didier at cox.net
Fri Jan 12 20:10:43 EST 2007


David I. Emery wrote:
> 	As for performance, I am curious myself.   Certainly the
> Thunderbolt is better documented in respect to performance, but whether
> in fact it actually IS a lot better when GPS locked is something I'd
> like to know.   Its firmware does seem to supply a lot more data about
> the quality of the lock than then 58540A does - that box is basically a
> simple power up and forget box for applications where tweaking for
> ultimate timing or frequency performance isn't needed.
>
>   
The Thunderbolt I have (1999 vintage) has older firmware (2.2 I believe, 
the current is 3.0), which actually offers much more control than 
current firmware. Trimble found out a lot of people were messing their 
Thunderbolts by changing settings they should have left alone. The newer 
units also have slightly different hardware, so the software is 
different also to accommodate the hardware. Therefore, there would be no 
point in trying to upgrade the firmware on an older Thunderbolt.

The 58540A does have a few LEDs on the unit's front panel to indicate 
status, and it would have been nice to have the same on the TB, but I am 
going to put a small uC and a 2x15 LCD to display the TB status without 
having to plug it in the computer.

Finally, a small switching step-up converter to make it run 
uninterrupted from a 12V battery will finish the job.

Didier KO4BB




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