W5CUL escribió: > 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: [email protected] > 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 > I don´t find any info in the Flex Radio site regarding this frequency stability upgrade. I understand it is factory installed in new units and it could have warranty issues if it is done by the users. I´m planning to install a 100 Mhz OCXO I recently bougth, but I would like to take a look to the ECO. Since I already have a faulty Valpey Fisher module I don´t care about soldering to it (maybe the heat will repair the little SOB, HI). If anybody knows where is the info, please let me know.
-- 73 de Ignacio, EB4APL _______________________________________________ FlexRadio mailing list [email protected] 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
