[Elecraft] Nasty spurs on RX with new KPA500

[Gary NC3Z]

Connecting the RX directly to the antenna and the spurs are not there, 
the spurs are coming from the KPA500, and only when the KPA500 is 
connected to a radio (happens on all my radios connected to the KPA). 
Have tried the amp on 220 and 120, same issue. The KPA500 can be 
connected to a dummy load at the RF Out, and RF In to the RX and the 
spurs are there. With out a doubt they are being generated in the KPA500 
when the LCD backlight is on, and these are healthy spurs.

I have spent hours taking the thing apart and putting back with the same 
results. Tripled checked all assembly with no luck. But I am 100% 
positive it is directly related to the LCD backlighting. This is a very 
weird issue!

Gary Mitchelson
NC3Z/4 Pamlico County, NC FM15
NC AHIMT COML
SHARES NCS997
NC Deputy Auxcomm Coordinator - Statewide
www.mitchelson.org

On 3/9/2019 09:45, Andy Durbin wrote:
> Nothing heard or seen on 10 m with my kit built KPA500.
>
> I'd suggest disconnecting the RX from the KPA500 and connecting it directly to the antenna.   Does the problem go away?
> If not, connect the RX directly to the dummy load.  Does the problem go away?
> If not,  disconnect everything else from the KPA500 except the power cord.  Does the problem go away?
> If not, connect the KPA500 to an outlet on a different circuit.  Does the problem go away?
>
> Hopefully, one of these steps will give some information on the source of the problem.
>
> 73,
> Andy, k3wyc
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