[Elecraft] Plasma TV Noise any ideas on how to filter it out.

[Jim Brown]

On 5/10/2011 7:49 PM, Jim Wiley wrote:
> You guys are aware, I suppose, that interference of this level and
> duration clearly qualifies as  the type of interference that merits
> direct FCC intervention.  File a complaint.

Absolutely. We are right and they are wrong.  If we "lay down," we have 
only ourselves to blame.

One suggestion though for suppressing the RF trash.  While I (so far) 
have no experience with Plasma TV RFI, MOST RF trash from electronic 
products, especially the stronger part of it)  is radiated as a common 
mode signal by wiring both inside and outside the product. We can't do 
anything about the wiring inside the product, but we can kill the RF 
current on the EXTERNAL cables that connect to it, like the power cable, 
the coax cable(s), and any audio and video cables.

To kill RF current on ANY cable, form a common mode choke by winding 
turns around a ferrite toroid (or clamp-on). 14 turns on a #31 2.4-in 
o.d. toroid is about right for 1-10 MHz, and 8 turns on a 1-in i.d. 
clamp-on.  For the higher HF bands (14-30 MHz), use 8 turns around the 
toroid (either #31 or #43 mix) and 5 turns through the clamp-on. Use a 
separate ferrite core for each choke. If you have trash on all the 
bands, use both chokes on each cable.

This may or may not help, and it certainly won't help the part of the 
trash radiated by internal wiring,  but if I had RFI from a plasma set, 
I sure would try it before throwing up my hands.

Lots of detail, including the technical explanations of why this works, 
is in

http://audiosystemsgroup.com/RFI-Ham.pdf

73, Jim Brown K9YC