Re: [time-nuts] How to accurately measure an oscillator's temperature.
The best way is to place the temperature sensor near the part or parts that are the most temperature sensitive. When dealing with something that is already in an oven, that may not be so easy. Didier KO4BB On April 23, 2014 9:37:29 PM CDT, Chris Albertson albertson.ch...@gmail.com wrote: I have both an OCXO and an FE-5680 Rb oscillator and I'd like to track their temperatures. What is the best why to measure? Maybe each has a different best method The OCXO is just a small steel can. Is measuring the steel can temperature the best why to go. Epoxy some kind of sensor to it? The Rb is mounded to a large heat sink and there is a fan. I want to control the fan so as to keep the Rb temperature constant. In both cases I tried using TMP36 three terminal sensors and just got noise. The reported temperature was up and down more than 2C.The fan controller just chases noise. BTW the fan based temperature control is effective. The FE5680 gets very warm in it's box but if I give the 12V fan even 8 volts the heat sink quickly cools. I want to throttle the fan to keep the Rb at constant temperature but the temperature data I'm getting is not very good. The problem I think is that any sensor I have is on the outside of the oscillator and is effected by cooling air What are others doing? What's the best kind of sensor. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Sent from my Motorola Droid Razr 4G LTE wireless tracker while I do other things. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How to accurately measure an oscillator's temperature.
Chris I am not sure if you want to measure temperature or control a fan. To measure there are many options depending on how much money you want to spend. To control I suggest either a LM 335 or a NTC resistor. I have worked extensively with both and for measuring I have now downsized to a YSI. Used to have a HP XTAL thermometer. Spend a lot of time and money on temperature control on Rb's and OCXO's all part of GPSDO's and have come to the conclusion on OCXO's a combination of thermal Isolation and thermal mass is the best solution and on Rb's fans. Spend a year playing with concepts on the FE5680 with all kind of fans and heat sinks and aluminum shapes till it hit me the answer was right in front of me. In my opinion a fan/heat pipe out of an old laptop is the cheapest and best solution, low cost, low noise, no special assemblies and easy to control. Use an aluminum plate as the interface or use the bottom plate directly and use one of the bottom screws to hold your sensor it is internally directly tied to the spine of the Rb. Wide variety available on ebay under CPU fan. Bert Kehren In a message dated 4/23/2014 10:38:11 P.M. Eastern Daylight Time, albertson.ch...@gmail.com writes: I have both an OCXO and an FE-5680 Rb oscillator and I'd like to track their temperatures. What is the best why to measure? Maybe each has a different best method The OCXO is just a small steel can. Is measuring the steel can temperature the best why to go. Epoxy some kind of sensor to it? The Rb is mounded to a large heat sink and there is a fan. I want to control the fan so as to keep the Rb temperature constant. In both cases I tried using TMP36 three terminal sensors and just got noise. The reported temperature was up and down more than 2C.The fan controller just chases noise. BTW the fan based temperature control is effective. The FE5680 gets very warm in it's box but if I give the 12V fan even 8 volts the heat sink quickly cools. I want to throttle the fan to keep the Rb at constant temperature but the temperature data I'm getting is not very good. The problem I think is that any sensor I have is on the outside of the oscillator and is effected by cooling air What are others doing? What's the best kind of sensor. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] How to accurately measure an oscillator's temperature.
I have both an OCXO and an FE-5680 Rb oscillator and I'd like to track their temperatures. What is the best why to measure? Maybe each has a different best method The OCXO is just a small steel can. Is measuring the steel can temperature the best why to go. Epoxy some kind of sensor to it? The Rb is mounded to a large heat sink and there is a fan. I want to control the fan so as to keep the Rb temperature constant. In both cases I tried using TMP36 three terminal sensors and just got noise. The reported temperature was up and down more than 2C.The fan controller just chases noise. BTW the fan based temperature control is effective. The FE5680 gets very warm in it's box but if I give the 12V fan even 8 volts the heat sink quickly cools. I want to throttle the fan to keep the Rb at constant temperature but the temperature data I'm getting is not very good. The problem I think is that any sensor I have is on the outside of the oscillator and is effected by cooling air What are others doing? What's the best kind of sensor. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] How to accurately measure an oscillator's temperature.
I'm unsure what temperature you wish to measure, but, assumng the OCXO has a proportional oven control, the input current is a good measure of the oc scillators ambient temp. Sam Shniper - Original Message - From: Chris Albertson albertson.ch...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wednesday, April 23, 2014 10:37:29 PM Subject: [time-nuts] How to accurately measure an oscillator's temperature. I have both an OCXO and an FE-5680 Rb oscillator and I'd like to track their temperatures. What is the best why to measure? Maybe each has a different best method The OCXO is just a small steel can. Is measuring the steel can temperature the best why to go. Epoxy some kind of sensor to it? The Rb is mounded to a large heat sink and there is a fan. I want to control the fan so as to keep the Rb temperature constant. In both cases I tried using TMP36 three terminal sensors and just got noise. The reported temperature was up and down more than 2C. The fan controller just chases noise. BTW the fan based temperature control is effective. The FE5680 gets very warm in it's box but if I give the 12V fan even 8 volts the heat sink quickly cools. I want to throttle the fan to keep the Rb at constant temperature but the temperature data I'm getting is not very good. The problem I think is that any sensor I have is on the outside of the oscillator and is effected by cooling air What are others doing? What's the best kind of sensor. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
