That makes sense. My inner oven is about 65C. I raised it to that just to get the DAC voltage close to 0v. I can raise it some more to get it between .1 and .9v.
I started to look for OCXO's but couldn't find one with the same part number as mine. Mine is 37265 and the others I found did not look like they had the same pinout. Does the tbolt accommodate other model OCXO's? It looks like the circuit board has extra through holes and I always wondered if it was for different OCXO models. Anyways I wanted to see if my homebuilt oven could match a commercial product. It was built from a 73 Amateur Radio magazine article over 10 years ago. Garren -----Original Message----- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Monday, February 25, 2013 2:11 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] Lady Heather numbers Hi A "typical" TBolt OCXO will settle out with a control voltage that's slightly positive (maybe 0.1 to 0.9V) rather than negative 0.7. Since the TBolt is rated to +70C, it's a good bet that the oven in the OCXO is running above 85C. Once things stabilize, you may want to bump your oven temperature up and see what it does to the frequency. Of course with TBolt OCXO's selling at auction for $20 you may or may not want to go to far with this. Bob -----Original Message----- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Garren Davis Sent: Monday, February 25, 2013 12:59 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Lady Heather numbers Thanks. I worry a little bit because my setup is not the normal thunderbolt running on the shelf or a rack. The oven for my oscillator is broken so I removed it from the circuit board and put it in a double oven with proportional controller that I built for a long ago project. The thunderbolt is in the outer oven running about 45C and the oscillator is in the inner oven running about 65C. The temperature rise on the display is probably the furnace in the house turning on this morning. I notice that the DAC voltage also rises and falls with the temperature change and wonder if that affects the oscillator in the inner oven. I'll let it run for the rest of the week and see what happens. Garren -----Original Message----- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Monday, February 25, 2013 9:35 AM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] Lady Heather numbers Hi Based on a very short display time, nothing looks seriously broken. I'd suggest running the OCXO calibration routine at some point. Everything is still warming up / settling out for the first week or two, so who knows where it will finish out at. Bob -----Original Message----- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Garren Davis Sent: Monday, February 25, 2013 12:00 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Lady Heather numbers Hi, I have been playing with my thunderbolt and Lady Heather over the weekend. I hope it's ok that I attached a screen dump of what I have. Can anyone comment on the picture. It's been running less than a day and I don't know if what I have would be considered good as far as accuracy and stability is concerned. Thanks. Garren ________________________________ This message and any attached documents contain information from QLogic Corporation or its wholly-owned subsidiaries that may be confidential. If you are not the intended recipient, you may not read, copy, distribute, or use this information. 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