[Elecraft] RFI With KPA500 Full Output on 40m

[Jim Brown]

On 3/18/2012 12:08 AM, Vic K2VCO wrote:
> I would start with the phone line and the power
> supply. Remember, at 40 meters you need to as many turns as you can get around the cores.
> Just passing the wire through a bead won't do it.

Security systems are notoriously awful for RFI.  Vic has given you good 
advice, but I would also consider RF bypass caps on any cables going to 
external sensors (if there are any) that are simply carrying dry switch 
contacts. Even better, if you can, replace any parallel wire cables with 
twisted pair.  0.01uF or 0.0047 uF would be good values to use.

73, Jim K9YC