[time-nuts] Thunderbolt oven / non-stable operating temperature

Bob Camp lists at rtty.us
Wed Dec 12 13:55:58 UTC 2012


The later TBolt OCXO's have temperature performance similar to an HP10811.


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Mark Sims
Sent: Tuesday, December 11, 2012 9:36 PM
To: time-nuts at febo.com
Subject: [time-nuts] Thunderbolt oven / non-stable operating temperature

Although the Trimble oscillator has superb phase noise performance,  it has
TERRIBLE temperature sensitivity.  It appears to be a single oven
oscillator,  not a double oven.   The PWM'ed fan temperature control
implemented in Lady Heather effectively makes the unit a double oven.  Also,
by stabilizing the temperature of the rest of the tbolt electronics and
power supply (if included in the temperature controlled box) you get
additional performance out of the unit.   Some testing indicates that a
temperature stabilized tbolt/power supply can improve the performance by an
order of magnitude (around 30% of that is due to issues outside of the
oscillator can).

And yes,  Lady Heather can control the Tbolt DAC.   There is a PID
controller in there for controlling the DAC (based upon the 1PPS error
signal,  if I remember correctly...  it could be the OSC error signal).

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