While you're at it, why not take this whole issue to
rfi@contesting.com? That's where the real mavens in this field hang out.
73, Pete N4ZR
The World Contest Station Database, updated daily at www.conteststations.com
The Reverse Beacon Network at http://reversebeacon.net, blog at
reversebeacon.blogspot.com,
spots at telnet.reversebeacon.net, port 7000
On 1/10/2011 8:54 PM, John Geiger wrote:
> Thanks for all of the replies and information so far. Here are some answers
> to questions people have asked me, plus some additional details about my
> station and TVI.
>
> The neighbor used to be on rabbit ears a few years ago and had TVI quite
> often from me. Never complained except for one time when the University of
> Oklahoma was playing in the national championship game-we live 60 miles from
> OU. I was on 30 meters at that time.
>
> SInce then they have gone on cable. She said the interference didn't occur
> very often now and wasn't concerned about it. Seems like she could live with
> it. DIdn't tell me not to operate or to do anything to my station. Almost
> seemed sorry that my daughter and her daughter brought it up to me. It did
> happen last night and I was on 6m at the time. I was on HF much of Saturday
> doing the NAQP. Didn't get any reports of TVI then. I tried to find out when
> else I was bothering her TV but she really didn't volunteer any information.
> She didn't say that it occurred on Saturday or was bad then or anything like
> that.
>
> The neighbors are on the same cable system we are. I have a TV in the shack
> about 5 feet from the rig, another in the living room about 15 feet from the
> shack, and a few others in the house. Did some testing today with the
> in-shack TV and the one in the living room.
>
> On 6 meters this afternoon on 6 meters it was shutting off the TV in the
> shack, and was causing some interference on the one in the living room. I
> had the 6 meter antenna going into an antenna switch so I could switch it
> between 2 different rigs. I bypassed this and ran the antenna's coax
> straight to the antenna tuner. This eliminated the turning off the shack TV
> and lessened interference in the living room.
>
> Later tonight I tried out the different HF bands on the TVs. On the living
> room TV HF caused some lines in the screen or other interference on the lower
> TV channels. The shack TV wasn't affected much but then it was on a higher
> TV channel. Just tried it on a lower channel and it was taking a beating.
> Lowering my power to 25 watts eliminated problems in the living room TV.
> Also eliminated the interference on the shack TV.
>
> So that is the current situation. I have a Drake Low Pass filter all
> antennas go thru, and the antenna tuner is grounded using 1/2 or 3/4 inch
> braid to a ground rod outside the shack. Don't have a connection to the rig,
> but then it is grounded thru the tuner anyways using the coax jumpers between
> the rig and the tuner. The antennas are a homebrew G5RV type dipole and a 3
> element yagi for 6m.
>
> 73s John AA5JG
> ----- Original Message -----
> From: Ron Notarius W3WN
> To: aa5jg@fidmail.com
> Sent: Monday, January 10, 2011 8:40 PM
> Subject: Re: [CQ-Contest] Power levels and TVI
>
>
> Before doing anything else, you need to find out exactly what's being
> affected. Otherwise, you may waste time and energy on the wrong solution,
> that is, "fixin' sumthin' dat ain't broke."
>
> How many TV's are affected?
> How old are they?
> Are they all on cable?
> Is the cable itself, how should I put this, uncompromised? (I can tell
> you from experience that, shall we say, creative cable splices can compromise
> the system and let leakage in)
>
> Does it happen on all HF bands, or only one?
> Does it happen on CW, SSB, RTTY/Digital, all?
>
> ...
>
> I know of a case of someone who had 4 TV's. one was a cheapie (at the
> time) portable on rabbit ears. It picked up everything, but of course, it
> was all the fault of the ham. None of the other sets, no other neighbors, no
> other electronics had a problem. When that set was put on cable, the problem
> disappeared.
>
> At my previous QTH, I found out the local cable company was blaming me for
> QRM to (then) cable channel "14". Turned out the problem was caused by a
> botched splice (no shielding!) at someone's house, when they tried to add
> extra rooms "on the cheap". Oh, and this house was located near the 140 '
> commercial tower that carried municipal communications, including the local
> VFD, and guess what they actually were picking up?
>
> If it's cable leakage, or an old cheap set in a plastic case (no
> shielding), reducing power may not cure the problem, especially considering
> the proximity. Worse, you may find that reducing power doesn't fix the
> actual problem, but forces you to compromise (by running lower power) which
> doesn't fix a bad install or a cheap set.
>
> Also, try a high pass filter on the feed of the set itself. Might not
> help if it's a shielding problem on the set itself (plastic case) but might
> help if it's the cable.
>
> And... get ahold of Ed W1RFI up at ARRL Hq and ask him for suggestions.
> He's forgotten more about RFI/EMI than I'll ever know!
>
> Good luck!
>
> 73, ron w3wn
>
> Jan 10, 2011 02:07:45 PM, aa5jg@fidmail.com wrote:
>
> I found out yesterday that I am having some occasional TVI with one of
> the
> neighbors. She is really cool about it but I don't know if it is also an
> issue with others in the neighborhood, plus I would like to be courteous
> about my operating as well. I am using a low pass filter, so I am
> assuming
> that the TV's front end is getting overloaded at times, as our houses are
> only a few feet apart and they have cable for TV instead of picking it up
> off the air. I am running 100 watts to a pretty much unity gain antenna.
> What power levels do others find works to reduce TV overloading? Would
> going to 25 watts make a big difference? Need to drop power further than
> that?
>
> 73s John AA5JG
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