[RFI] 160 meters RFI reduction using RF Choke on neighbors TV power cord

[Dale J.]

Don, 
Thanks for that bit of information.  I have one of those plasma things about 150 feet from the shack and even closer to my dipole.  I am going to see if my neighbor would be ok with a choke like you have on his plasma TV.  We tried one of those outlet strips with a filter but it did nothing so I thought the radiation was coming right from the screen of the TV.  This is very hopeful news you brought.  Again thanks for sharing your experience.

73
Dale, k9vuj


On 05, Dec 2013, at 20:28, Don Kirk <wd8dsb at gmail.com> wrote:

> I was asked to post the following info on rfi at contesting.com which I had
> also posted earlier today on the topband at contesting.com, so here it is.
> 
> Within the last few months I noticed a raspy signal on 1.824 Mhz 24 hours a
> day, 7 days a week.  My 3 pennant RX antennas indicated the noise was
> coming from a heading of approximately 135 degrees, and a large portable
> shielded loop placed in my yard indicated a signal heading of 124 degrees
> (reasonably close agreement).
> 
> I then set out on foot using a portable general coverage receiver and a
> shielded loop, and tracked the problem down to a neighbors plasma TV set
> that generated RFI regardless if it was on or off (signal first tracked
> down to the power companies feed on the side of the neighbors house).  The
> RFI completely disappeared when the TV power cord was unplugged.  Using
> Google Earth the neighbors house is located approximately 350 feet from my
> Pennants at a heading of 122 degrees (this house is not next door to my
> house, and it's actually located on an adjacent street to mine).
> 
> Yesterday my first attempt at eliminating the RFI turned out to be very
> rewarding.  I constructed a simple power cord RF choke for the TV using 14
> turns of a power cord on a 2.4" OD Fair-Rite #31 mix toroid core (based on
> the K9YC hams guide to RFI document).  The RFI at the neighbors house is
> considerably reduced using the choke on the TV power cord, and the RFI at
> my house appears nearly if not entirely gone.  I will try adding another
> choke in line with the first choke to see if additional reduction of RFI at
> my neighbors home can be achieved, but I certainly can live with the
> results of the single choke.  I will also purchase and try a commercial two
> stage power line filter on the neighbors TV to see how it compares with the
> simple toroid choke approach.
> 
> I tried to document the problem and cure in a video I've posted on
> youtube.  If interested the youtube link is :
> http://www.youtube.com/watch?v=mhJYCxJtFv0&feature=youtu.be
> 
> 73,
> Don (wd8dsb)
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