[time-nuts] Thunderbolt reception problems

WarrenS warrensjmail-one at yahoo.com
Tue Nov 24 04:19:42 UTC 2009


Said 

Not bad at around + - 15 ns Peak over a day,


IF I got the scaling right it is about 2 hrs division  
AND there are around 3 hr cycles (10k sec) in the phase (along with lots of other stuff)
If it is the Tbolt which is likely, then it is due to some of the other things I warned about  like room temp cycling.
The Tbolt can get down to the 3 ns RMS range with care and luck.
Hate to have to say it cause I know you don't want to add yet more software BUT
If you want to know if it is the Tbolt, and how to fixed it. 
One the way to tell is to use Lady Heather and plot the phase error and Dac voltage at the same time as the PS10 phase difference.
If Lady heather shows about the same long term Phase noise then it's the Tbolt, If not its external.

If external, and if PS10 is a Stanford Research Systems Rubidium PSR 10 Osc then 
could be because the TC of the PSR10 is set to the wrong TC, It should be around 10K  sec.

Something to be aware of, but does not really change how or what you are doing here. 
Because you are using the same reference for both units (the GPS system), 
very low freq noise in the reference (GPS) which is much slower than either's TC will not be seen.  


>I was hoping for slightly better.  That is asking a lot,  
If you still feel that way, you should update the other Defaults also and use Mark's Lady heather to check for the other possible causes.

Have fun, 
ws

**********************

----- Original Message ----- 
From: SAIDJACK at aol.com 
To: time-nuts at febo.com ; warrensjmail-one at yahoo.com 
Sent: Monday, November 23, 2009 5:52 PM
Subject: Re: [time-nuts] Thunderbolt reception problems


Hi Warren, et. al,

here is a plot (about 20hrs long) of my PRS-10 (driven by a M12+) compared against my Thunderbolt both running from the same antenna feed. Comparison done on the 10MHz outputs, at maximum sample rate on my 5370B counter. Both units have been running for 6+ months now, the Thunderbolt has only been locked for a day+ though.

Standard deviation is 7.6ns, and the mean is 1.5ns. Peak to Peak is ~ -15ns to +19ns.

I was hoping for slightly better. Not sure who is the better of the two (yet).

Bye,
Said

In a message dated 11/23/2009 11:22:27 Pacific Standard Time, SAIDJACK at aol.com writes:
  Will post a drift plot sometime later today.

  bye,
  Said



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