[time-nuts] Thunderbolt no usable sats.

EWKehren at aol.com EWKehren at aol.com
Sun Jun 12 10:29:45 UTC 2011

the -12 VDC is also used by the  OCXO as tuning voltage!  Bert  Kehren
In a message dated 6/12/2011 6:05:01 A.M. Eastern Daylight Time,  
golgarfrincham at yahoo.com writes:

"I  bougth an Thunderbolt off E-bay some time ago, to use as 
reference for my  spectrum analyzer and signal generators.
I had it connected up with a  couple of power supplies and it 
worked as it should. Today I put together  an voltage inverter 
to get the -12V to the GPS in order to use it with an  single 
12V power supply."
The -12 requires  10 ma according to the manual but in reality 
probably draws about 2 ma so  loading shouldn't be a problem.
You didn't mention the 5 volt supply at  all. The +5 VDC should 
be able to supply at least 400 ma and the  +12  VDC 750 ma. 
Ripple and noise should be around 15 MV max for the +5  VDC
and 20 MV for the +/-12 VDC.

The -12 VDC is used for the RS-232  so if that was giving you 
the problem you wouldn't see anything on your  com port (note 
it will work at -7 VDC or so) and if the +5 VDC was off you  
wouldn't see anything on Lady Heather. The +12 VDC is for 
the  oven.  

If the unit was working before on the other supply, go  back to 
that supply and make sure it still works to see if it is your new  
supply setup or maybe you accidently fried something. If it 
works on  the old supply, connect the new supply and recheck 
all connections and  voltages both with a meter and a scope 
(or your spectrum analyser) to see  if there is anything unusual.
time-nuts  mailing list -- time-nuts at febo.com
To unsubscribe, go to  
and follow the  instructions there.

More information about the time-nuts mailing list