[RFI] TV RFI

Mon Jan 28 18:59:51 EST 2008

I would start by trying another TV in the house.  I'll bet the problem
only occurs on one TV.  That is certainly true at my house.  I have 3
TVs in my house.  Two of them have NO TVI problems whatsoever even
when running 1 KW.  The 3rd TV experiences TVI when running as little
as 50W on 80m.  Nothing has been able to eliminate it on that TV.  I
have half a dozen toroids on the inputs and they knocked it down some,
but not completely.  If, on the other hand, you find TVI on multiple
TVs then I would suspect a poorly designed antenna system which is
allowing RF into the house.

On 1/28/08, dgsvetan at rockwellcollins.com <dgsvetan at rockwellcollins.com> wrote:
> David's comment #2 is VERY important.  After all, Rod admits that he got
> some TVI even before getting the amp.  Ergo, increasing the power level
> with all else being equal, the present situation is not unexpected.  Keep
> in mind that field drops off per the inverse of distance cubed in the near
> field, so moving the antennas farther up and/or away could make a
> substantial difference.  My suggestion would be to first try to get rid of
> however the TVI is manifesting itself while running barefoot.  If you
> still have problems while barefoot, there's not much point in cranking up
> the amp.
>
> K9YC also had a good point about describing the nature of the TVI in his
> posting.  The more Rod can describe it, the better.  There are many
> variables possible, so you need to start sorting them out and finding the
> weak points.  Yes, cable boxes themselves can be a problem.
>
> Best wishes.
>
> 73, Dale
> WA9ENA
>
>
>
>
>
> "Dan Violette" <danki6x at earthlink.net>
> Sent by: rfi-bounces at contesting.com
> 01/26/2008 04:36 PM
>
> To
> <rfi at contesting.com>
> cc
>
> Subject
> Re: [RFI] TV RFI
>
>
>
>
>
>
>  David knows what he is talking about.  Also try to narrow down.  Remove
> DVD, Cable box, etc. to see if problem goes away.  You can feed the cable
> line directly into the TV and check out the analog cable channels for RFI.
> My limited experience usually is that the attached boxes (VCR, DVD) are
> receiving the signal and feeding it into the TV.  If you see it just with
> the TV and cable line connected then you have problems.  If it goes away,
> you have less connections/equipment to worry about.
>
> Dan, KI6X
>
> -----Original Message-----
> From: rfi-bounces at contesting.com [mailto:rfi-bounces at contesting.com] On
> Behalf Of David Robbins K1TTT
> Sent: Saturday, January 26, 2008 11:14 AM
> To: rfi at contesting.com
> Subject: Re: [RFI] TV RFI
>
> If you have cable tv and have tvi your problem will not be solved with
> high
> pass filters or low pass filters.  Your problems is most likely one of:
>
> 1. VERY poor grounding resulting in extremely high currents in house power
> conductors... this is the ONLY one that you might be able to fix by doing
> something to the radio and grounding system.
> 2. The antenna is WAY too close to the house, nothing to do here but put
> up
> a higher tower or learn to like qrp.
> 3. The TV has a pin-1 or shielding problem... that is, it's the tv's fault
> that it is letting rf in through the power cord or directly through the
> case.  Try a power line filter, and also torroids on all the cables
> between
> the tv/cable/dvd/etc, if that doesn't work buy a new tv or wrap it in
> aluminum foil like mine is.
> 4. The cable system is leaky... either due to poor connections on the road
> end, or bad installations in the house.  Take off all the taps, splitters,
> extra boxes, dvd players, surround sound, etc.  check the crimp connectors
> to be sure their grounds are really connected, then try it with just one
> tv
> direct to the cable... if you still have problems get the cable company to
> check their connectors and grounds outside.
>
>
> David Robbins K1TTT
> e-mail: mailto:k1ttt at arrl.net
> web: http://www.k1ttt.net
> AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
>
>
> > -----Original Message-----
> > From: rfi-bounces at contesting.com [mailto:rfi-bounces at contesting.com]
> > On Behalf Of rrath at charter.net
> > Sent: Saturday, January 26, 2008 19:09
> > To: rfi at contesting.com
> > Subject: [RFI] TV RFI
> >
> > I am sure this topic has come up a lot, but I would like to put a
> > different spin on it.
> >
> > What brand / type are you using?
> >
> > Does it work (does your XYL or neighbors like the results)?
> >
> > Would you recommend it to a fellow Ham?
> >
> > Did you make your own?
> >
> > Would you share how you built it with the list?
> >
> > The reason for all these questions? I have TVI. I have to get rid of
> > it or not use the amp I bought. I get a little TVI with out the amp
> > and major TVI with it.
> > I have cable tv. I have my radio equipment grounded to a single pc of
> > copper pipe about 12 " long up under the desk, then an 8 gauge wire
> > from the pipe to an 8' and a 4' ground rods.
> >
> > I will be buying High Pass Filters this coming week. I have 4 good
> > neighbors that I like and want to be a good Ham to them. I bought the
> > amp to use not to look at. Thanks.
> >
> > Rod kc7vqr
> > _______________________________________________
> > RFI mailing list
> > RFI at contesting.com
> > http://lists.contesting.com/mailman/listinfo/rfi
>
>
>
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