[Elecraft] Running high power

[Jim Brown]

On 11/22/2022 2:36 PM, Al Lorona wrote:
> 1/ interfered with FM broadcast radio.
> 
> 2/ caused the internet to drop out every time I keyed up on the lower bands.
> 
> Am I the only one? Those of you who run high power all the time... how do you deal with these annoyances?

Both are caused by lousy design of the equipment. Band-aids are SERIOUS 
common mode chokes on every wire connected to the victim. Follow 
guidelines for HF transmitting chokes for the bands involved, winding 
each individual cable through a #31 2.4-in i.d. toroid. Those wires are 
receiving antennas coupling RF into that badly designed stuff, and 
chokes kill RF current on them.

http://k9yc.com/2018Cookbook.pdf

3/4-in and 1-in i.d. #31 clamp-ons can work with 4-5 turns, but they 
MUST be wound in sequence around the core. See the photo on page 10 in
http://k9yc.com/KillingReceiveNoise.pdf

As Vic has noted, use a serious choke at the feedpoint of every antenna, 
use only coax-fed antennas, matched to the feedline resonant on the 
bands where they are used, using that same Cookbook as a guide. Try to 
locate antennas as far as practical from victim equipment. An end-fed 
antenna, vertical or otherwise, ending in the shack is a recipe for RFI 
to equipment. ALWAYS provide a serious counterpoise for any end-fed 
antenna. If you don't, that antenna will use everything in your home as 
a counterpoise, causing RFI.

In summary, take antennas seriously, -- their design, their location, 
chokes at the feedpoint, bonding in the shack. Avoiding the problems you 
describe is nothing more or less good engineering practice.

Also, some cable/DSL modems are notorious for RFI susceptibility. W8JI 
solved a problem by complaining to the vendor, who gave him a 
replacement. This usually requires taking the complaint up one or more 
levels.

73, Jim K9YC