Dave, This sounds feasible since the thermistor upgrade is based on keeping a constant temperature for the crystal, thus stabilizing the crystal output. Since the thermistor dissipates energy into heat, the more energy applied, the more heat it will dissipate. The reverse holds true when less energy is applied. As the temperature fluctuates, the output of the crystal will do the same. If you have a power supply that has large tolerances in its output, and you calibrate the SDR-1000 during one usage, on the second usage the power supply may not be producing the same voltage. As the thermistor heats up to a different temperature than before, this will throw off the first calibration. I have taken up the practice of calibrating my SDR-1000 to WWV during each use, giving it about 20 minutes to stabilize prior to performing the procedure.
Mike W5CUL -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Dave & Nancy Ridge Sent: Wednesday, November 15, 2006 8:24 PM To: FlexRadio@flex-radio.biz Subject: [Flexradio] SDR Frequency Stability The FlexRadio SDR is a great radio when it comes to measuring frequency down to the Hertz! I have the optional thermistor upgrade. I noticed by accident that if you change the 12 volt DC supply voltage to the SDR just a little, (i.e. .1 volt) the radio will move in frequency by 10's of hertz. This raises the question that if the DC supply voltage regulation is not within .01 +/- volts or better in stability, the frequency change/stability will always be a problem. Am I missing something? Dave, W9DR -------------- next part -------------- An HTML attachment was scrubbed... URL: /pipermail/flexradio_flex-radio.biz/attachments/20061115/8960b097/attachment .html _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
