[RFI] TV RFI better info

Kelly Johnson n6kj.kelly at gmail.com
Mon Jan 28 23:35:42 EST 2008

How close is the inverted V to the house and TV?  This is a pretty low
antenna and it's not directional so you're likely to get alot of RF
coming into the house with it.   Regardless, a well designed TV should
be unaffected at least at low power.  As a comparison, my 80 dipole
runs right over the top of my shack (and house) with the apex at 50
feet and the ends at about 25 or 30 feet.  I can run 1KW with no TVI
to the LCD TV inside the shack, however I get TVI (to the color) on
the TV in my living room while running only 50W.  This is clearly a
problem with a poorly designed TV.  I advise trying another TV.
Another thing you may want to try is to run the TV off a generator to
eliminate RF conducted through the power line.  You should power a VCR
or DVD player off the same generator so no input to the TV is
connected to the AC or long coax lines.

Does your TV have a sub-woofer.   Powered sub-woofers are notorious
for RFI problems.  If you have them, then you'll almost certainly need
ferrites on the speaker leads.  See the K9YC website.

Use a good Balun at the inverted V feedpoint to eliminate RF traveling
down the shield of the coax.  See the K9YC website.

On 1/28/08, rrath at charter.net <rrath at charter.net> wrote:
> Several of you have asked me to give more info. Here it is.
> I have the Yaesu FT 100, coax (not flat line) and the apex of the inverted V
> is about 40' and both ends are at about 9'. All radio equipment is gounded to
> a 12" long pc of copper pipe under my desk top. I am using 12 gauge
> stranded wire to the copper pipe. I am using 8 gauge solid copper to one 8'
> ground rod about 7' away, then the same pc of 8 gauge wire continues on
> about 5' more to a 4' ground.
> I have some TVI with out the amp on. The type of TVI is nothing to the
> picture and blaring distortion on the sound. This is with or with out the VCR
> turned on. The radio output is at 70 watts out.
> Now with the amp turned on and running between 300 to 400 watts SSB, the
> sound is just as bad and the picture had very bad horizontal lines.
> I have cable TV, no Digital, the TV is about 5 years old, has two built in
> speakers (but I think it is only mono sound - have no control for left or right
> on the speakers) and the VCR is less than 1 year old. I am using 75 ohm
> coax for all connections. I use no cable box.
> Need more info?
> Rod
> ps - K9YC, I am reading your web site. Thank you.
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