[Elecraft] RS232 Noise

[Mike Harris]

G'day,

Just in case anyone is interested.

Today I was investigating the effectiveness on a local 6m low level signal 
of the various combinations of NO PREAMP, K3 PREAMP ONLY, PR6 ONLY, K3 
PREAMP + PR6 in preparation for a 6m EME test.

All was as expected then I turned on the PC.  With the two preamps in line 
there was a 1-2 S-point increase in background noise (SSB bandwidth). 
This extra noise vanished when I removed the "RS232" cable from the K3. 
The cable is actually the one I made up for the K2.

Touching the shell of the connector to the K3 shell didn't restore the 
noise, only when actually inserting the pins did it come back.

No noise being carried on the two audio leads to/from the PC so no big 
deal the disconnect the RS232 during the moon run.

No further investigations to date.

Regards,

Mike VP8NO