One factor that affects IMD is power supply voltage variation under load. The standard PS cable that comes with the K3 drops several tenths of a volt at max power. Add that to power supply regulation and internal voltage drop in the K.
On my unit, the voltage reading on the K3 display goes from 13.5V to 12.4V when I press the key on CW. (100W, 14 MHz) I could easily see that being the limiting factor in transmit IMD performance on SSB. Al N1AL On Mon, 2009-01-26 at 10:19, Julian, G4ILO wrote: > > Gregory Fischer wrote: > > > > Not doubting your TX IMD report in PSK. But I typically see ~-32dB IMD > > when > > checking PSK at 50W. > > > You are probably right to doubt it. Such a difference made me try a test > again, on a different band. I got a different set of results. Probably it is > better to use a dummy load when testing the TX. The IMD Meter is designed to > be used off-air (hence when TXing into an antenna) but it would appear that > other factors can affect the readings. This needs further investigation. > > ----- > Julian, G4ILO. K2 #392 K3 #222. > http://www.g4ilo.com/ G4ILO's Shack http://www.ham-directory.com/ Ham > Directory http://www.g4ilo.com/kcomm.html KComm for Elecraft K2 and K3 _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
