[Elecraft] Making a K2/100 Cleaner

[Jim Brown]

In preparation for Field Day, I had occasion to set up my HP8590D 
last night and do comparative measurements of what my K2/100 and 
TS850 looked like 300 kHz away. I was surprised by the result. 

With both radios, I transmitted CW on 3515 kHz and looked to see what 
the SSB team would be contending with between 3750 and 4000 kHz. The 
TS850 was cleaner, by roughly 15 dB, than the K2/100. Transmitting on 
7025 and looking at 7150-7300, the TS850 was roughly 6 dB cleaner. 
Comparable tests on 14 MHz showed them pretty much even money. 

The K2 is s/n 3003. Several other hams built the various pieces of 
the K2/100, which I bought used, and their work looks quite clean. 
I've owned it for about a year and a half and been quite pleased with 
it. Both radios were matched to an indicated 1:1 VSWR using their own 
antenna tuners (the KAT100 with the K2), and working into the same 
antenna through a switch. This radio DOES have the key click mod. The 
K2/100 is >40" from the nearest power supply. 

So the question is, what can I be doing to get my K2/100 cleaner "in 
band?" Are there specific mods that are likely to accomplish this?  

And I recently bought an old-timer, s/n 301, identically equipped 
(K2/100, KAT100, K160RX, KNB2, KDSP). I'm currently troubleshooting 
an AGC problem in that radio, so it's apart on my bench and hasn't 
been tested in this way. Any suggestions for getting it as clean as 
possible?  

Jim Brown  K9YC