[Elecraft] Elecraft K3 interferes with IC-2820???

[Jim Brown]

On Tue,3/22/2016 4:50 AM, george allen wrote:
> RF is getting into your equipment.

While this is not the only possible cause, it's likely. Other possible 
causes include a bad piece of coax or bad DC wiring.

>   RF split cores on all leads into your 2820 should solve the problem.

If the problem is simple overload of the 2820, what is needed is NOT 
simply slipping a split core over the coax from the 2820, but rather 
multiple turns of the coax through a #31 or #43 Fair-Rite core. That 
could be a split core or a toroid. If it's a split core, five turns is a 
good start for 40-10M, one or two more if the problem is from 75M. If 
it's a toroid, I would start with 5 turns for 20-10, 7 turns for 40-15, 
10 turns for 80-20.

Also, think about antenna locations. Are the HF antennas and 2M antennas 
close together? Separating them a bit could help.  And the HF antennas 
should all have a multi-turn coax choke at their feedpoint (that is, up 
in the air).

RF interference is NOT solved by a connection to earth. RF interference 
CAN be solved or reduced by bonding together every piece of gear in the 
shack with short, fat copper. That combination of chassis DOES need a 
bond to all other grounds in the building, both for safety and for 
reduction of hum, buzz, and RFI.

And even though John said he had "checked" all the coax, a bad piece of 
coax (either the cable or the shield connections) should be suspected as 
a possible cause.

Study http://k9yc.com/GroundingAndAudio.pdf for lots of detail on this. 
And study k9yc.com/RFI-Ham.pdf for a tutorial on how RF gets into 
equipment, how ferrite chokes work, and how many turns on which ferrite 
cores to use for different situations.

73, Jim K9YC