[Elecraft] K3: Now I've heard everything

[Kok Chen]

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