[Elecraft] K2 mic gain super low on 20 meters

[Mark Newbold]

Hi all,

I acquired a secondhand K2/100 with KAT100 ATU a while back. The amp and ATU are in a separate 
enclosure. I have used it mostly for CW, but lately I have been using it for digital with a MicroHam 
DXP interface. When operating digital I keep an eye on the transmitter ALC level, where I expect to 
see 1 bar. I noticed recently that on 20 meters I can't get even 1 bar on the ALC meter, even 
turning the DXP's TX audio level up a lot. The RF output meter shows very low output power. No 
similar problem on 80, 40, 30 meters.

I plugged in a Heil Proset mic and observed the same behavior -- when I speak into the mic there is 
plenty of TX audio on 80 and 40 meters (too much in fact, even speaking very softly). On 20 meters I 
have to yell into the mic to get 1 bar of ALC.

This is with the output power set to 50 watts, Mic gain set to "2" (choices are "1", "2" and "3"), 
compression set to "1", ATU disabled (set to CAL).

Any ideas of why the mic gain would be super low on just one band?

--Mark K7NEW

-- 
Mark Newbold
Port Angeles, Washington, USA