[time-nuts] Using Thunderbolt to Discipline FE 5680A?

WarrenS warrensjmail-one at yahoo.com
Thu Dec 22 14:44:56 EST 2011


What you may of seen was how to use a TBolt to discipline a LPRO Rb.
There are several time nut posting on how to do that in a very simple and 
high performance way.

You should be able to do something similar using the FE-5680A.
The basic way I've done it is to:
Modify a Thunderbolt (preferable one with a poor Osc) to use the LPRO's 10 
MHz as it's ref osc, and bring out the Tbolt's Dac thru a 1K ohm.

For the LPRO, I added a 12K 1% resistor to the high side of its "C" field 
winding, making a low sensitivity EFC input, and connected that to the 
Tbolt's 1K Dac out resistor.
Then by using an 'Extended' Time constant and damping factor setting on the 
Tbolt, you can set the control loop to anything you want up to many days.
Depending how good the Rb's temp-co is and how much you allow it's 
uncompensated temperature to change,
I found that an extended Time constants from 5K sec to 24 hrs worked best 
for the LPRO.


----- Original Message ----- 
From: "Frederick Bray"
Sent: Thursday, December 22, 2011 8:50 AM
Subject: [time-nuts] Using Thunderbolt to Discipline FE 5680A?

> Has anyone successfully used a Thunderbolt to discipline a FE-5680A?
> I thought I saw a posting or site where someone disabled the 10 MHz 
> oscillator on the Thunderbolt and used the Thunderbolt to discipline the 
> FE-5680A.  However, I can't find it now.
> Thanks.
> Fred

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