[RFI] TV RFI

Mon Jan 28 18:46:28 EST 2008

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
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