Can Ham radio interfere with OTA TV reception? Yes. - AVS Forum
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post #1 of 27 Old 10-17-2011, 10:29 AM - Thread Starter
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Can Hamm radios interfere with OTA TV antennas receptions? My neighbor has a hamm radio and it see that when ever he goes on it my TV antenna goes on the fritz. Picture gets pix-elated and lags. Not sure if the hamm has anything to do with it or if its just a coincidence.
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post #2 of 27 Old 10-17-2011, 11:07 AM
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Yes.

I don't know how you know when he's "on"... but, best bet is to speak with him, test and have him resolve his issue(s). It's his responsibility.
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post #3 of 27 Old 10-17-2011, 11:48 AM
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Ask him politely about the problems. Most Hams are glad to help.

You'll need to work out a time to do some tests, having him transmit while you watch the effects on different channels.
It might help to keep a log for a few days, noting what time the problems occur, and what channels are affected....that will help determine whether it's something like HF ("shortwave") band signals, maybe coming in through the power cord, or something like two-meter (VHF) signals, maybe overloading your tuner. He'll be able to tell if you had trouble while he was talking to somebody locally (on 2-Meters) or across the country (on his HF rig). That helps narrow things down.

Often, a small filter on your TV, or ferrite core on the power cord will fix things. Those would. legally, be your responsibility, but many Hams will have something available to give you, if you're being a good sport about it.

If his transmitter is putting out some odd-frequency spurious emissions, he'll need to put a (big) filter on his stuff, and that's entirely his responsibility.

Most cities have a Ham Club, with folks he can call on to help out. These Volunteer Coordinators have extensive experience with interference control.

If it turns out to be something else besides Ham Radio, your Ham neighbor can help you locate the problem's source....things like electrical problems, computer-generated interference, etc.

Ken English, Sr. Engineer, KSL-TV.
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post #4 of 27 Old 10-17-2011, 11:50 AM
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Absolutely!

A Ham next door to my parents house not only interferes with their TV reception at times, but can turn touch lamps on and off!
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post #5 of 27 Old 10-17-2011, 12:06 PM
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Quote:
Originally Posted by kenglish View Post

Often, a small filter on your TV, or ferrite core on the power cord will fix things. Those would. legally, be your responsibility, but many Hams will have something available to give you, if you're being a good sport about it.

If his transmitter is putting out some odd-frequency spurious emissions, he'll need to put a (big) filter on his stuff, and that's entirely his responsibility.

I could be wrong, but "legally" (FCC regulations?), interference either:
1) should not occur
2) and if it does, it's the operator's responsibility to address/resolve.

Either way, the key is to hopefully have a calm discussion. Try to understand the issues, test and isolate the possible source of the issues and fix the issue(s).

Last resort if he/she doesn't want to help/admit... contact the FCC.
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post #6 of 27 Old 10-17-2011, 01:28 PM
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The vast majority of cases where a Consumer Electronics device is having interference issues with licensed (and PROPERLY OPERATED) transmitting equipment, is due to the CE device.

These are usually due to the fact that the device is being used in a "non-typical" environment (closer to a transmitter than it was designed for), or is being operated in a manner different than it was designed for (things like, odd peripheral devices, extra long cables or non-standard cables, etc).
Most manufacturers will try to help, often supplying filters or other parts necessary to eliminate the interference. It's actually cheaper for them to "fix" individual instances of RFI, than to build all their products to a "bullet-proof" level.

If (and only if) the transmitter is operating properly and legally, then the fault lies with the device being interfered with.

This all comes from my contacts with the FCC, and some years spent chasing interference myself.

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post #7 of 27 Old 10-17-2011, 01:48 PM
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Quote:
Originally Posted by kenglish View Post

If (and only if) the transmitter is operating properly and legally, then the fault lies with the device being interfered with.

Totally agree.
The reality is that many radio operators "heat up" their power/transmitters and make modifications that are not FCC compliant.

If everyone was compliant, you wouldn't have to spend years to chase interference yourself.
With the advent of cable/satellite/FiOS, complaints have subsided over the years.

My point is that a "cool approach", testing and compromise could be an easy resolution. Most radio operators:
1) want to continue transmitting
2) will usually be helpful
3) like the challenge to resolve RF issues
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post #8 of 27 Old 10-17-2011, 02:32 PM
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Topic title edited.

'Better Living Through Modern, Expensive, Electronic Devices'

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post #9 of 27 Old 10-17-2011, 03:16 PM
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Quote:
Originally Posted by Ratman View Post

Totally agree.
The reality is that many radio operators "heat up" their power/transmitters and make modifications that are not FCC compliant.

If everyone was compliant, you wouldn't have to spend years to chase interference yourself.
With the advent of cable/satellite/FiOS, complaints have subsided over the years.

My point is that a "cool approach", testing and compromise could be an easy resolution. Most radio operators:
1) want to continue transmitting
2) will usually be helpful
3) like the challenge to resolve RF issues

I agree completely on the "cool approach".

BTW, the years of "chasing interference" include doing it for viewers, Cable companies, and even being recommended by the FCC.
(Now, if I could just go after a few scofflaws that are our station's clients, without getting them upset, I could fix the rest of my own neighborhood issues.)

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post #10 of 27 Old 10-17-2011, 03:42 PM
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Well, if the FCC recommends you as the RF interference chaser, they should have the necessary tools to resolve your neighborhood problems and return the favor. No one will divulge the undercover operation.
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post #11 of 27 Old 10-18-2011, 07:42 AM
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I think a bulldozer would help my neighborhood.
The mall is currently being renovated, and I'm HOPING they remove all those old neon sign transformers while they are at it (they've been doing construction all night long, all summer now).

If not, we'll just have to wait for them to catch fire, like the last few have done.
Plasma TV sets and tanning beds are next on the list.

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post #12 of 27 Old 10-18-2011, 10:28 AM - Thread Starter
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Thanks for all the reply's and i did figure that yes was the answer. I can tell he is on because i can hear him loud and clear from my sub woofer, so when he started to talk i noticed the OTA broadcast getting choppy and digitally pixelated. I have asked him before about it and he said he would only go on after midnight when i was asleep but he has not kept his end of the bargain by any means at all. In fact after we had the conversation he was on in less then 20minutes. The easy fix for me was just to unplug the sub woofer because he seemed to only be on for about 20-30 minutes at a time once or twice a day. In that case i could live with out the sub for a TV show or part of movie but now im planning to switch over to OTA completely and have no cable, so that is much bigger of a problem since its going to effect the screen image and also the audio. I would love to just correct it on my end with a filter or something but i actually have already posted about this HAMM interference in the past and basically was told there is not much that can be done if he is transmitting at a high illegal level.
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post #13 of 27 Old 10-18-2011, 12:26 PM
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If he doesn't want to "play nice"... contact the FCC.

If he isn't compliant to FCC regulations, you shouldn't have to buy/do anything.
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post #14 of 27 Old 10-18-2011, 12:53 PM
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It would be nice to know what kind of frequencies he is on....if he is on HF or VHF, especially.

I've heard lots of complaints concerning subwoofers, due to the fact that most are just a plastic or wooden box, with a circuit board for the electronics (amp, crossover, etc) sitting inside it...basically, "floating" in the electrical field, with no shielding (visualize it like, everything that's non-metal is clear plastic).

If it's coming in via HF band (below 30, or 50, MHz or so), winding the power cord and the audio cables, individually, through a toroid or ferrite core that's the correct chemical "mix" for that range of frequencies might do the trick. That's assuming the cable(s) are acting as an antenna to his signals.

If the interference is coupled directly to the circuits through the air, then the best bet might be to try and re-position the sub (maybe to the other side of the screen, a few feet away) , or see if you can block the signal with a piece of metal or foil...at least temporarily, as an experiment. Sometimes, a roll of metal "window screen" and some clips to keep the edges folded together, can be a great troubleshooting tool.

One thing I'd wonder though....when you disconnect all the cables (power and audio) from the subwoofer, does the TV interference go away? If so, it's just being channeled to the TV and other equipment, via the wires from the sub. So, fixing the subwoofer end of things would do it.

If I remember correctly (I'm at work, my stuff is at home), something like the FT-240-J works with most power cords, and the FT-140A-J will handle a couple of audio cables with RCA plugs on them, here:

https://www.amidoncorp.com/items/21

Look at the drawing of the "Choke Balun" here, for how to wrap the cables:
http://www.ce3rkw.net23.net/antena_vertical_hf.htm

The J-series core material is good over much of the HF Ham Radio band, up to about 20 MHz. If he's a CB'er, he's on 28-29 MHz, and you'd need something higher, like the 43-series. You'll find that many of the readily-available ferrites, from places like Radio Shack, are that material, and start at about 20-25 MHz, soaking up interference to about 250 MHz, which includes the VHF Ham Bands like "2-meters".

Also, keep the lengths of excess cable to a minimum. Either use shorter ones, or at least coil up the extra length in a small bundle.

BTW, if the interference is coming in via the TV antenna cable (which would be proven by disconnecting all the other cables from it, except power and the antenna), looping the antenna cable through a core 2 or 3 turns/passes, right near where it plugs in to the TV, may help. That keeps his radio's RF off the shell of the tuner module, and off the TV's circuit board. A core on the power cord is likely to be necessary, too.

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post #15 of 27 Old 10-18-2011, 01:48 PM
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If subwoofer is the only "problem", oftentimes, a good shielded coax cable (RG6) between the receiver and sub will help.

If you have "problems" with using an antenna and only have interference at "specific" times that you can correlate to the Ham operator's x-mission times, start a time log for reference.

You can try to apply all the suggestions and spend a few $$ and time only to find it doesn't resolve anything.

Take your best shot and prepare for frustration.
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post #16 of 27 Old 10-18-2011, 02:09 PM
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I'm not an expert on RFI by any means, but this thread is now going more on opinion rather than fact in my view. Yeah, that statement sounds oxymoronic I know.

First off. Yes, contact the radio amateur (sounds like you've already done so). Most amateurs want to make sure his/her transmissions are not causing problems with neighbors and, being neighborly, will want to try anything within reason the mitigate the interference (TVI). Being cool about it is key. Please take steps kenglish suggested. If EITHER of you get nasty about it then nothing good will come of it. The solution often is installing something on the device being interfered with. More on that shortly.

Where in th RF spectrum is he transmitting when your TVI occurs? Is he on HF (below 30 MHz) VHF (51, 146 or 223 MHz) or UHF (420 MHz and up). Where he's transmitting can be an important clue.My guess that if you can understand what your neighbor is saying on the air on your woofer he's probably in FM mode on VHF or UHF. Your woofer wire wound around a toroid core a certain number of times should do the trick as far as the audio is concerned.

Again, as kenglish said, the overwhelming majority TVI complaints can be traced to the consumer (part 15) device. This includes TV's radios and cordless phones. Also, Where is your antenna in relation to his? Can you move your antenna as far away as possible from his? Having the best cable feeding your TV from the antenna is a must also. If you're going to be "cutting the cord" you could use the CATV line once you have service disconnected. Either way you will need cable with a lot of shielding. Make sure you have good solid connections on either end. Bad connections and inadaquate shielding can result in interference leaking into your system. In short, make sure you've done all you can do on your end. On the other hand, there could be grounding issues, bad connections, and as kenglish mentioned, spurious emissions that the amateur can easily fix on his end.

As far as "illegal" power is concerned..... with a few exeptions, most stations in the amateur service in the US is licensed up to 1500 watts PEP.... BUT.... common amateur practice is to use the minimum power necessary to achieve the desired communication. This is even spelled out in Part 97 (amateur regs). If your neighbor is on VHF/UHF he probably already is running only a few watts unless he's accessing a distant repeater. Even working satellites require only a few watts. On the other extreme, working moonbounce is another story altogether.

Work with him. Accept that you will probably need filters and/or toroid cores installed on your end. If he's not an expert in TVI/RFI either, I'm sure he can find someone who can help him out. If the amateur is not cooperating, you can take further steps. My next step would be contacting the American Radio Relay League (ARRL) in Connecticut. They should be able to hook you up with someone to help. The FCC can help by imposing restrictions on him if nothing can be accomplished otherwise. Those restrictions can be quiet times and/or power output. Please, PLEASE let that be the last resort.

Remember, amateur radio is more than a hobby, IT IS A SERVICE. By that, I mean your local and state management agency even the federal government as well as national organizations like the Red Cross rely on amateurs to provide emergency backup communications during emergencies/diasters. If the times you want him quiet is during traffic and emergency nets, he should be even more interested in mitigating the problem. Just like first responders, we have to practice our skills too.

Another source on RFI/TVI is a book that the ARRL offers written By Ed Hare W1RFI. Before his passing ( I think he passed away a few years ago), he was THE authority on RFI issues like yours.

Good luck to the both of you. I'd be interested in hearing about the results.

I see kenglish added another post while I was composing this post. By all means listen to the engineer!

Steve KC4JGC
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post #17 of 27 Old 10-18-2011, 02:19 PM
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To add...
Don't get me wrong. Ham/CB operators can provide a wonderful/lifesaving service in times of emergency.

OTOH, if they do not comply to FCC rules during times of "non-emergency" and are not willing to work and resolve with the complaintant, there's a problem.
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post #18 of 27 Old 10-18-2011, 02:56 PM - Thread Starter
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The issue with picking up his radio is in the amp on the sub its self, even with the sub cable disconnected to the receiver it still comes through. I have to actually unplug the power cable from the wall that goes to the sub amp to stop the noise from his radio. So I'm assuming that my house's electric wiring is what is picking it up and then passing it through the subs amp. I even opened up the sub and lined the interior and wires in aluminum foil and it didn't make any difference, im guessing because its coming in on the electric wire that is not shielded. So in my case i think the big issue is that he is obviously broadcasting at a level that is too high. I'm just wondering if any one else is having these issues around me since i live on a densely populated block in a major city.
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post #19 of 27 Old 10-18-2011, 03:23 PM
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Is the the sub your only problem or is the OTA reception a problem too?

1) aluminum foil won't do a darned thing to block RF.
2) it's probably not your electrical wiring (romex).

"I'm just wondering if any one else is having these issues around me since i live on a densely populated block in a major city"

Talk to your neighbors and see if they have issues.
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post #20 of 27 Old 10-18-2011, 03:55 PM
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Leave the subwoofer plugged in (power), and disconnect all the other (audio, etc) cables from it...right at the subwoofer.

If you still hear him, it's either "conducted" interference, coming thru the power cord and electrical wiring, or it's "radiated" interference, meaning it is getting in through the cabinet and on to the circuit board.
Unplugging the power would kill the sound either way, so it won't tell you much.

If it's only heard when you re-connect the audio cables, then it may be using them as an RF antenna (and the audio is being demodulated by the amplifier's semiconductors) , or it may be coming in as already-demodulated audio, from somewhere else (like a DD receiver, or the TV itself), which would indicate that that item is at fault.

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post #21 of 27 Old 10-18-2011, 03:58 PM
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Quote:
Originally Posted by nofronts View Post

The issue with picking up his radio is in the amp on the sub its self, even with the sub cable disconnected to the receiver it still comes through. I have to actually unplug the power cable from the wall that goes to the sub amp to stop the noise from his radio.

Now you're getting somewhere! What you have here is conducted interference. There are two types of conducted interference, differential mode and common mode. What you have in your case appears to be differential mode. Basically, the AC wire is acting as an antenna, it's length resonant to your neighbor's operating frequency. It could be only the wire from the outlet to your sub OR....

Quote:


....my house's electric wiring is what is picking it up and then passing it through the subs amp.

Right.

Quote:


So in my case i think the big issue is that he is obviously broadcasting at a level that is too high.

Not nesessarily the case.. Being that close to you his transmissions can get in with as little as 1 watt.

Now that you've narrowed it down, head on down to the electronics shop and purchase an AC line filter. Once you bring it home, you may need to play with turns and such for best results.

Ken at KSL, what do you think?

To Ratman: While you're right on the cooperation issue, never assume he's running illegally. What's important first: Is he running a "clean station" (i.e., good cables and connections, good grounding, etc)? That goes a LONG way to convincing the FCC to get involved. Once that question is answered beyond a doubt, then the next step can be taken. With todays electronics (and the lack of shielding), interference can and will happen. That's why part 15 devices have the labeling that says the "device must not create interference but must accept any interference" it recieves. No one needs to have a neighborhood feuds started because "it must be his problem". Feuds like this can spiral out of control to the point of the community passing laws against radio operation (which such laws are violating federal law PRB-1).

My point is: Do what you can do on your end before raising an unnecessary ruckus.

Ken, I see you've posted again during my composing! Great advice!

Steve KC4JGC
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post #22 of 27 Old 10-18-2011, 04:38 PM
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Quote:
Originally Posted by KC4JGC View Post

To Ratman: While you're right on the cooperation issue, never assume he's running illegally.

Spoken like a responsible operator.
IMO (and I could be wrong), if he is not willing to cooperate and/or provide assistance, it raises an eyebrow.
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post #23 of 27 Old 10-18-2011, 04:52 PM
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Quote:
Originally Posted by Ratman View Post

1) aluminum foil won't do a darned thing to block RF.

You mean my aluminum foil helmet doesn't work?
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post #24 of 27 Old 10-18-2011, 05:17 PM
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Only for x-missions from ET's or other voices you may hear.
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post #25 of 27 Old 10-18-2011, 05:42 PM
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Oh, good!

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post #26 of 27 Old 10-19-2011, 08:17 AM
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Those run-of-the-mill power line filters will help if the interference is above about 25-30 MHz, but if it's HF (below 30 MHz), they may not be very effective. That's where a low-frequency ferrite core is better.

Also, just coiling the excess power cord tightly (maybe 5-10 loops, about 4" in diameter, like a big donut) can help some....maybe enough to see if it's starting to help.

If there's a junk shop nearby, see if they have the ferrite bar that was used in the antenna of old AM radios (tube sets, like in the 50's), and wrap the cord tightly in a spiral on that. Those are usually a low-frequency material. But, a couple of ferrite cores might be better.

The whole idea of all of this though, is to isolate down to what individual item/items are where the interference is getting in to the whole system. I'd guess the subwoofer, and the tuner of the TV, both.
Are there other components in the system, like receivers, preamps, DVD, etc, that are hooked together?

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post #27 of 27 Old 10-20-2011, 09:47 AM - Thread Starter
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I do not plan on contacting the FCC about this since its not a major issue. My system is only disturbed like 2-3 times a week for like 20-30 minutes.

I want to try to block the signal, and more so for the OTA antenna for TV broad casts since i can live with out the sub for a few minutes but not having the TV can be a bigger deal like if its the end of a close foot ball game or some thing.

I will start with AC line filter's and ferit bars and such to see how it goes but not sure it will do much on the RG-6 co axle cable.

My system is as follows...
HTPC, cable box, and Nintendo wii all go into the receiver through HDMI. Then they are passed through to the TV with one HDMI cable.
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