[Elecraft] K2/100 Flat topping on 30m?

[kc4kgu@ENTERZONE.NET]

On Wed, 30 Oct 2002, Stuart Rohre wrote:

> OK, I took it you were talking SSB speech bandwidth signal, not the narrow
> transmission on SSB resulting from PSK 31 modulation.  (31 Hz or so)
> 
> I could see that it should not at narrow modulating frequencies.  Should be
> well centered in the filter on PSK31.  Interesting, are levels optimized?
> Locally our club station took a couple of sessions to set up the Audio
> interface levels from sound card to radio mike input.
> Stuart K5KVH


Stuart,

It's been a while since I ran any digital modes on the K2 but, the flat
topping I'm seeing on the scope isn't caused by overdriving the AF
input.  You will note that with the SAME AF drive at lower requested RF
levels, there is no flat topping.  I also just confirmed that I can cause
the same flat topping using the Heil MH2 microphone, the same mic I use
99% of the time when I use the K2.

This only occurs on 30m and at greater than 8w in QRP mode or greater than
50w in QRO mode.

73 de John - KC4KGU
K2/100 #2490