Hi Joe, It is good that they are that stable, but what is the phase noise like? If a ham across town is using them for WSPR and QRSS they are most probably OK in that regard, but not all DDS modules are. Best 73's Nic VK2KXN / VK5ZAT
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Joseph Gray Sent: Sunday, 21 July 2013 2:04 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] DDS module I have a few of those $5 AD9850 DDS modules from China. I'm going to use one to replace a crystal in a transmitter. I attached it to a TI MSP430 Launchpad and programmed a fixed frequency. Just out of curiosity, I wanted to see how stable this thing is. Using cellophane tape, I put a few pieces of foam around the oscillator can. Then I hooked it up to my HP counter, which is locked to my GPSDO. I'm not logging, but I have kept an eye on the setup for well over 24 hours now. So far, the frequency has held to within 0.01-0.08 of the programmed value. The house thermostat is set at 75 F, but this room gets somewhat warmer due to the equipment in it. Also, this room gets the morning sun. Considering the cost, I am impressed with how well this little module works and how stable it is. There is an Amateur in town who has been using several of these modules to drive WSPR and QRSS transmitters. He has done up a poor man's oven to keep his transmitters on frequency. Joe Gray W5JG _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
