RFI from neighbors new cable install TV possible.

[Retroradio]

Edit: some more research has indicated this its possible... Now to figure out how to proceed.

A local now has a burst of static every 4-5 seconds on Channels 1-40.
He has swapped out radios, check his setup etc..He did the search in his neighborhood and narrowed it down to a house. The neighbour was very co-operative.
Using a AM portable (music) radio the neighbor found the interference apparently coming from the newly installed cable. He disconnected the cable and it stopped.

I have never heard of anything like this.
Is this possible?

 

[W9WSS]

Cable TV feeds interferes with VHF Ham frequencies. Most notorious for 145.250 MHz.

 

[Retroradio]

Great info!
I found a good article online and was looking a harmonics etc...
The local just did a live test ( he was on the phone with the neighbor) and had them unplug from the cable box...the interference went away and returned when it was hooked back up.

 

[dlwtrunked]

Cable TV feeds interferes with VHF Ham frequencies. Most notorious for 145.250 MHz.

Only if the cable TV is an old analog system. 145.25 MHz is one of the old system analog video frequencies. I always found it a benefit as I could find the audio FM for that channel on (adding 4.5 MHz) 149.75 MHz. Ofcourse it sounded rather crappy with the receiver having really a too narrow bandwidth for the wider TV audio. Adding and subtracting multiple of 6 MHz from these will find the other channels if one still has an old analog cable system but I thought these had disappeared.

 

[Retroradio]

So the question now is weather its the new cable or the router box...
Have been looking for the Industry Canada regulations on this and no luck. Interesting topic as I’m learning something...lol

 

[mmckenna]

Ideally the cable company should resolve this. While I'm not familiar with the rules in Canada, in the USA the cable companies are responsible for resolving interference issues.

It may take some work, but have the customer contact their cable provider and open a ticket.

 

[a417]

disconnecting the cable from the box, or disconnecting the power from the box solved it?

 

[RFI-EMI-GUY]

Many times the cable is not properly bonded to the utility ground. That should be checked.

 

[prcguy]

Yes, do this and also disconnect any other cables to and from the box or modem to try and isolate the thing causing noise. Once you find the culprit and since its affecting CB frequencies I would get an FT-240-61 ferrite core and wrap 12 turns of the cable TV coax through the core right at the cable modem or box that had the most affect when you disconnected it. That will kill any RFI flowing from the box down the coax to the pole or wherever it comes from. It could also be the power supply in the cable box or modem and if so the same ferrite and number of turns on the power cable should fix that.

If its a completely new cable install then it could actually be the TV set making the noise and the cable system is simply the antenna thats radiating it to the neighbors TV. Plasma TVs are notorious for making RFI so keep an open mind when looking for the noise source.

There are many different types and mixes of ferrite and for it to work you must have the right mix and number of turns for the target frequency range. The 61 mix and 12 turns on a FT-240 size core will give maximum attenuation in the CB band.

disconnecting the cable from the box, or disconnecting the power from the box solved it?

 

[iMONITOR]

I wonder of the new Cable TV customer is using one of those audio/video rebroadcasting devices (27 MHz?) to a second TV rather than ordering a second cable box.

 

[Retroradio]

disconnecting the cable from the box, or disconnecting the power from the box solved it?

Disconnected the cable from the box

 

[a417]

I wonder of the new Cable TV customer is using one of those audio/video rebroadcasting devices (27 MHz?) to a second TV rather than ordering a second cable box.

Which one is in the 27 MHz range?

 

[iMONITOR]

Which one is in the 27 MHz range?

I had one back about 20 years ago that was. I might still have it down in the basement. I check later. I also had a computer mouse that was 27MHz.

 

[iMONITOR]

I had one back about 20 years ago that was. I might still have it down in the basement. I check later. About 10 years ago I also had one that was 900MHz. I also had a computer mouse that was 27MHz.

 

[a417]

I had one back about 20 years ago that was. I might still have it down in the basement. I check later. I also had a computer mouse that was 27MHz.

It's ok, you don't have to.
I don't think that was it TBH, as it was a new cable installation per the OP, and I don't think any reputable cable company would do that. They'd probably find ways to tell them it was incompatible with their hardware and force the customer to buy more hardware.

 

[iMONITOR]

It's ok, you don't have to.
I don't think that was it TBH, as it was a new cable installation per the OP, and I don't think any reputable cable company would do that. They'd probably find ways to tell them it was incompatible with their hardware and force the customer to buy more hardware.

I wouldn't think the cable company would provide it, I thought possibly the home owner.

 

[a417]

I wouldn't think the cable company would provide it, I thought possibly the home owner.

The neighbour was very co-operative.

...and probably would have offered up this tidbit, if he had done it.

 

[merlin]

Possible, just not likely. I would look to another source for the interference.
The lowest frequency found on cable is 54 Mhz. Now it is possible an upstream frequency is to blame, That can be between 5 and 42 Mhz. Any detectable leakage is a bad connection. Try a typical FM pocket radio as a sniffer.
Section 4 in the linked document details the technicals of troubleshooting subscriber cable.

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwi8iJ7-7NTuAhVZCs0KHShqA58QFjAFegQIHRAC&url=https%3A%2F%2Fwww.commscope.com%2Fglobalassets%2Fdigizuite%2F1695-cable-technician-pocket-guide.pdf&usg=AOvVaw2YGcgl4kJ_uqBUVfIZ2UP2

 

[Retroradio]

Possible, just not likely. I would look to another source for the interference.
The lowest frequency found on cable is 54 Mhz. Now it is possible an upstream frequency is to blame, That can be between 5 and 42 Mhz. Any detectable leakage is a bad connection. Try a typical FM pocket radio as a sniffer.
Section 4 in the linked document details the technicals of troubleshooting subscriber cable.

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwi8iJ7-7NTuAhVZCs0KHShqA58QFjAFegQIHRAC&url=https%3A%2F%2Fwww.commscope.com%2Fglobalassets%2Fdigizuite%2F1695-cable-technician-pocket-guide.pdf&usg=AOvVaw2YGcgl4kJ_uqBUVfIZ2UP2

I thought it wasn’t possible due to the frequency range and leakage specs...However when the cable is unplugged from the standard issue box the RFI goes away. Thereby the issue is there. I figured it had to be an upstream feed like a time sync etc... I am not a cable guy just a radio nut....lol

I am suspecting cable leakage. However the dichotomy is this....Is the RFI from the cable box as it gets active when the cable is plugged in or is it the cable? I am now in a Shrodingers’ cat scenario...

Also there is no rebrodcast device. The TV has not been on so it is eliminated. I am going to let my fellow radio enthusiast know the info so far.

Thanks all so far to the excellent advice. Lots of knowledgeable people here.

 

[vagrant]

It is the power supply either in the cable box, or the wall wart. I had a wonky wall wart for a Nokia phone that provided RFI like that. As it was in my home, and quite strong, I could not choke it. I would plug it in while sleeping. A replacement wall wart or cable box will probably solve it.