[Elecraft] K2 Build # 653 SSB issues.

[Nigel (Nidge) Smith]

Hi All

I have in my possession a K2 with the following options.

KPA100, KSB2, K160RX, KNB2, KDSP2, .

I’m not the original builder of this example and the source of the original builder is a little vague.

So far I have done a complete reset of the radio, fine tuned the alignment of the bandpass filters
in the base, aligned the CW and SSB filters. As of yet I haven’t looked inside the KPA100 option, which
is mounted internally.

There are a few issues with this radio but the one I’m concentrating on at the moment is to do
with the SSB performance in conjunction with the KPA100. These can be seen below:

160m – Using the tune button produces 100Watts, SSB the radio folds back to about 5 Watts.

80m – All seems fine.

40m – When the power control is advanced to engage the KPA100 and the tx is peaked with a whistle the radio goes 
into self oscillation, no issues on CW.

30m – Display reads high current and the TX folds back to about 5 Watts.  No issues noted when the KPA100 is 
disengaged. 

20m -  All appears to be fine.

17m – Display reads high current and the TX folds back to about 5 Watts. No issues noted when the KPA100 is
disengaged.

15m – All appears to be OK

12m – All appears to be OK, max TX power is about 70Watts

10m – All appears to be OK, max TX power is about 65-70Watts.

There is an intermittent issue when stepping through the bands up to 15m/12m/10m  when there is no TX output
or receive. Switching the radio off and back on seems to cure this.

Any advice gratefully received.

Nidge (G0NIG)

IO93dv