[Elecraft] K3 Birdies

[Jim Brown]

On 6/3/2013 11:13 AM, Terry Schieler wrote:
> Replaced it with a Netgear and birdies are gone. Don't have the specific model number in front of me.

Could you please look it up and post it for us?  Mfrs who build stuff 
that's free of RF trash should be rewarded with our business, but many 
major mfrs make "good, better, best" products.

As to cleaning RF trash  with ferrite chokes -- to be effective, they 
must be "tuned" (by choosing the "right" mix and winding multiple turns) 
to be effective. Chokes can reduce ONLY the part of the trash radiated 
by the cable, but will have no effect on what is radiated directly by 
the equipment due to poor shielding and poor circuit layout.  If the 
cables are electrically long (longer than about 0.05 wavelength), chokes 
are needed at both ends, because the equipment on both ends can be a 
source of the trash. And don't forget the power supply cables, both on 
the low voltage side and on the 120V side.

"I tried some beads but they didn't work" usually means that the person 
doesn't understand how ferrite chokes work. Study 
http://k9yc.com/RFI-Ham.pdf

73, Jim K9YC