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Author Topic: Neighbor notices when I'm transmitting  (Read 19379 times)
KB2HSH
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« on: October 21, 2013, 05:52:56 AM »

Good morning, everyone.  I've been a ham for 25 years, and this is a first for me.  When I was married and had my station in my home, I never had a problem with TVI.  But since moving into an apartment and using a compromise antenna (43' loop fed with 450-ohm ladder line and tuned with an MFJ-941E) my neighbor finally figured out what has been "messing with his TV".  This weekend, during the JARTS RTTY Contest, he knocked on my door to let me know that I was distorting his picture on his TV (an old, analog/tube model).  We all have cable in the complex, BTW.

Is it due to the fact that this antenna is non-resonant?  I have been reading up on the PAR EF series...perhaps THAT will help?  Anyone have any input???  I certainly don't want to give up now.

John KB2HSH
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WX7G
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« Reply #1 on: October 21, 2013, 08:08:29 AM »

No, I don't think the TVI is due to your antenna being non-resonant. Some possible solutions (there are more) are:

1. Stop transmitting
2. Reduce transmitter power
3. Buy the neighbor a new TV
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K1CJS
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« Reply #2 on: October 21, 2013, 10:18:27 AM »

You may all have cable, but the quality of the patch cables (between the cable box, accessories and TV) may have a lot to do with it.  Ask your neighbor if you could look at his TV connections.  Chances are that you'll find a low quality patch cable somewhere--the patch cables that came with VCRs are notoriously low quality.  Cable company cables are both 100% shielded and double shielded, while the low quality patch cables are little better than cable shaped twinlead--leakage in AND out all too easily.  

If the cables between the cable box and the TV aren't cable TV quality cables, offer to give him some better quality patch cables.  Sometimes, if you go to the cable TV office and ask, they'll be happy to supply you with some short patch cables--for free.  If those short junk cables are replaced, your neighbor will probably get a better picture too.

It may still be the TV, but replacing those low quality cables may solve the problem--it did for me!  73!
« Last Edit: October 21, 2013, 10:21:54 AM by K1CJS » Logged
N4NYY
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« Reply #3 on: October 21, 2013, 03:36:41 PM »

No, I don't think the TVI is due to your antenna being non-resonant. Some possible solutions (there are more) are:

1. Stop transmitting
2. Reduce transmitter power
3. Buy the neighbor a new TV

I am going to have to agree with #3. It may be the cheapest solution.
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WB8VLC
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« Reply #4 on: October 21, 2013, 09:30:19 PM »

But test any new TV at your neighbors apartment before you tell him he can have it if u go this route. I have seen new TV's that are no better at handling rfi than older analog ones and if this is a typical apt CATV install the chances of having multiple open 75 ohm cables coming off of a splitter with frayed shields Is a real possibility.
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W7KB
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« Reply #5 on: October 21, 2013, 09:52:09 PM »

Post a DO NOT DISTURB sign on your door and don't answer it while operating.
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KB2HSH
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« Reply #6 on: October 22, 2013, 05:21:53 AM »

You may all have cable, but the quality of the patch cables (between the cable box, accessories and TV) may have a lot to do with it.  Ask your neighbor if you could look at his TV connections.  Chances are that you'll find a low quality patch cable somewhere--the patch cables that came with VCRs are notoriously low quality.  Cable company cables are both 100% shielded and double shielded, while the low quality patch cables are little better than cable shaped twinlead--leakage in AND out all too easily.   

If the cables between the cable box and the TV aren't cable TV quality cables, offer to give him some better quality patch cables.  Sometimes, if you go to the cable TV office and ask, they'll be happy to supply you with some short patch cables--for free.  If those short junk cables are replaced, your neighbor will probably get a better picture too.

It may still be the TV, but replacing those low quality cables may solve the problem--it did for me!  73!

Distinct possibility...he has the cheap "dollar store" push-on type F-connectors.

TNX!
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K5LXP
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« Reply #7 on: October 22, 2013, 06:24:18 AM »

Another point of ingress could be the power cord or any accessory cabling like for speakers or composite video.

If the neighbor is agreeable you can go through the process of establishing the baseline interference levels for the bands there's an issue, then go through the process of checking/changing cables, adding ferrites, etc.  Good bet he'll tell you to bugger off and it's your problem, in that case you can decide how important to you it is to be on good terms with that neighbor.

In confined areas it can be tough to get enough isolation from incident RF.  The solutions may take multiple actions - change/move the amateur antenna, add ferrites to cables, bypass equipment inputs, re-route cabling and even adding shielding if possible.  It's a lot of work and sometimes expense, so pick that battle carefully.

Mark K5LXP
Albuquerque, NM
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K1CJS
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« Reply #8 on: October 22, 2013, 10:09:29 AM »

You may all have cable, but the quality of the patch cables....

Distinct possibility...he has the cheap "dollar store" push-on type F-connectors.

TNX!

Offer to get him good patch cables, and explain to him that you run a licensed amateur radio station and have tested it to ensure you're within your legal limits.  (Yeah, it may be bull--but he doesn't have to know that.)  Explain to him that replacing those cables is probably the only way he can have a good clear, interference free picture--maybe better than he has now.  Be nice and maybe he'll give in and try it.

Good luck and 73!
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K8YS
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« Reply #9 on: October 22, 2013, 12:25:42 PM »

cable is leaking, letting RF in, and if it gets in, it gets out. Listen on the common cable TV channels, especially 145.250. If you hear a signal there, chances are good that the able is in violation. You might have a leg to stand on if the cable is leaking more than allowed.
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WX7G
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« Reply #10 on: October 22, 2013, 12:48:41 PM »

The QTH is an apartment and not a house. That changes the rules.
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KD0REQ
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« Reply #11 on: October 24, 2013, 08:29:28 AM »

WAN (Worked All NTSC) is an easy cert to get.  sloppy, no shielding, long internal leads.  if the cable is not leaking, cheapest fix is a Wally World special tabletop LCD set.  but test it in the shack before bringing it over.
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KB2HSH
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« Reply #12 on: October 28, 2013, 05:57:23 AM »

Well...firstly, I'd like to thank EVERYONE for their input.

I started off by taking WX7G's advice and opened up the TS-120 and reduced the final output power by adjusting VR3.  Now the Kenwood is more like a TS-120V.  After having been a lifelong QRPer, this is the first rig that I've had in my 25 years that is capable of this much power.  After lowering it to 10 watts, I transmitted a RTTY signal on a few bands, and my neighbor couldn't see or observe anything.

But the TWIST to this story came yesterday when after I returned home from a 5 mile run (rig not even ON...and only a lamp and my refrigerator running) and my neighbor asking me if I was (quote) "electrocuting myself next door".  I asked him what that was supposed to mean...I had been RUNNING.

I entered his apartment...and sure enough...TV wiped out, and LOUD buzzing emitting from his cheap laptop/desktop speakers.

When he realized that I had been gone, he apologized...but it makes me seriously wonder now WHERE the interference is coming from.  Now he DID hear my call come through his speakers a few times yesterday when I was working a few DX stations on 10, but I have received NUMEROUS emails from other hams that have installed PAR/LNR End-Fedz and had the TVI/RFI problems "disappear".  Mine will be installed this week.

I have a warehouse shelf filled with the snap-together ferrite chokes.  I think I may bring some to my neighbor and try them on his leads to see if it helps.

And...even my girlfriend was on the same page with buying him a new TV if it persisted.

John KB2HSH
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WX7G
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« Reply #13 on: October 28, 2013, 08:14:03 AM »

Before filtering I would attempt source suppression. That's finding the RFI source and fixing it.
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KB2HSH
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« Reply #14 on: October 28, 2013, 08:16:07 AM »

Before filtering I would attempt source suppression. That's finding the RFI source and fixing it.

Stellar idea.  I'm really wanting to know what is causing this in his stuff...but not mine.
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