[Elecraft] KXPA100 SSB Distortion

[Don Wilhelm]

Ray,

Do you have a dummy load and another receiver?  If so, connect the dummy 
load to the KXPA100 and put a short antenna wire on the other receiver.
Transmit, and adjust the distance between the dummy load and the other 
receiver "antenna" to produce an S-9 signal.
Does the KXPA100 produce a distorted signal?
If not, then look carefully at your antenna system - the likely problem 
is RF-in-the-shack.

OTOH, if the KXPA100 output is distorted working into the dummy load, 
you should contact support at elecarft.com with those facts.

One thing that can cause some distortion is low power supply voltage to 
the KXPA100.  That voltage should be at least 13.8 volts during receive 
and drop to no less than 13.2 during transmit at 100 watts.  Low voltage 
during transmit can cause increase IMD (distortion).

73,
Don W3FPR

On 4/23/2018 11:32 AM, Ray W2RS via Elecraft wrote:
> 
> My KXPA100 transmits distorted audio on SSB, but works normally on CW and RTTY.  With 100 watts output, drain current is 11.7 A and supply voltage is 13.1 V, down from 13.7 V on receive.  My power supply is a pre-MFJ Astron RS-35A.
>