[Elecraft] Question on Alignment

[Vic Rosenthal]

Eddy Avila wrote:
> Curious.....I chose to ignore this recommendation and have left the 
> counter probe installed on my K2/KPA100....I've never noticed any 
> adverse affects but may be I'm missing something here? Its really really 
> convenient leaving the counter plugged in when I need to recheck the 
> filters...

The third harmonic of the BFO falls around 15 MHz, close enough so that 
some of it may pass through the 14 MHz output filter.  Leaving the probe 
in the BFO TP (yes, it's convenient!) radiates some BFO signal which may 
find its way to the output.  I listened to the 15 MHz spur on a second 
receiver with and without the probe connected and it was louder with the 
probe in place.  Elecraft feels that it is best to leave the probe out.

This is especially relevant if you follow your K2 with an external 
amplifier.  Remember that even if the spur is 50 db down at 10 watts, 
then it would be 30 db down at 1000 watts, which means that you would be 
radiating a 1 watt signal on 15 MHz!  So unless you have the equipment 
to measure the level of the spur, it's safest to leave the probe out.

Vic K2VCO