On Jul 12, 2010, at 7/12 10:25 AM, Wes Stewart wrote: > I haven't gotten very far with this because 1) the IMD is apparently > temperature sensitive and drifts, becoming a moving target
For what its worth, when I ran close-spaced IMD measurements (*very* closed spaced -- the BPSK31 idle tone :-), I did not notice much drifting in IMD values once I got the "ALC" meter up to 4 to 5 bars. The transmit IMD will vary a little (I saw 2 dB) depending on the input drive, even while maintaining a constant 5 bars on the "ALC" meter. But the reading was stable as long as I kept the drive stable. Also, are you systematically tapping the signal from the dummy load? If you are just using a short pickup wire on the antenna port of the SQR-IQ, you could be seeing other artifacts. I had used Elecraft's directional coupler kit (no one should be without one :-) plus oodles of attenuation to directly feed the measurement receiver. 73 Chen, W7AY ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
