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KC9OKV
02-07-2009, 07:08 AM
I went on 2meters recently and was talking to my friend on a local repeater (145.190Mhz) when my neighbors called. They said they heard my voice on their TV. But they were watching CABLE TV. So i'm not sure what to do. I was wonder if anyone had any ideas?:confused:

W6ECE
02-07-2009, 07:15 AM
Ask them if they have a license to listen to you and if not they better turn off their TV!

N5RLR
02-07-2009, 10:55 AM
Interesting.

If your neighbors heard you clearly, obviously their TV was demodulating your FM transmission. Were you told upon which channel(s) you were heard?

Firstly, I'd suspect a less-than-optimum interface at a coaxial connection [theirs]; probably a shield that isn't making the contact that it should. Also, your signal could be entering through an unused port on a splitter or distribution amplifier, if so equipped.

Secondly, I'd suspect the classic deficiency(ies) of the typical mass-produced television set. I.e., the things aren't designed to exclude moderate-to-strong radio signals in close proximity. What few additional components that could have been built in to filter extraneous radio signals, aren't, to save cost.

Regarding your transmit frequency, which would have been 144.590 MHz [-600 KHz from 145.190]...this falls within the lower end of the luminance portion of CATV Channel 18, toward the opposite end of the channel from the audio subcarrier.

* * * * * * * * * * * * * * * * * * * *

http://cnyack.homestead.com/files/modulation/ntsc.gif

* * * * * * * * * * * * * * * * * * * *

CATV 18 runs from 144 to 150 MHz. Picture carrier is 145.250, with audio at 149.750. Under normal circumstances, 144.590 shouldn't be heard on a set tuned to Cable 18.

Hope this helps. :D

[Anyone, feel free to confirm/correct the above, written after a long night of work :p]

WD4CHP
02-07-2009, 12:31 PM
Contact the cable company.

A friend of mine (WB4LPX sk) had this problem and it was a leaky line amplifier on the cable.

K8YZK
02-07-2009, 01:07 PM
Contact the cable company.

A friend of mine (WB4LPX sk) had this problem and it was a leaky line amplifier on the cable.


I agree contact the cable company, but can your friend hear any interference from the cable on his radio?

Worked for one(cable com) years ago, and talking to the chief engineer and about leaking cables. He started to bad mouth hams for interference to the system, I looked at him and said per the FCC it is the companies responsibility to fix the leak especially if it is causing interfernce to the ham. He said screw hams, and I said oh really, that I was a ham and I will let the management know his opinions and the FCC at the same time.

Got to love COMCAST (NOT)

N8FGB
02-07-2009, 03:10 PM
Ya, call the cable company. They will tell your neighbor you are CB'er with an ilegal amp. I had a head tech once tell me I was the one leaking. I showed my license and sais i was licensed to leak, not him.
Rich

W2IBC
02-07-2009, 03:18 PM
Ya, call the cable company. They will tell your neighbor you are CB'er with an ilegal amp. I had a head tech once tell me I was the one leaking. I showed my license and sais i was licensed to leak, not him.
Rich

it is amusing how to the cable comps everything "interference" is a cb'er with a illegal amp. that must be in there book somewhere..

K8ERV
02-07-2009, 03:18 PM
I showed my license and sais i was licensed to leak,


I'll show mine to my xyl when I don't make it to the potty in time. Which is often.

TOM K8ERV Montrose Colo

KC9ECI
02-07-2009, 04:09 PM
I bet they were watching cable ch 18. I had the same problem. I called the cable company and they sent a guy out the next day. He found a bad connector on the pole end of the drop. The cable was also old and weathered so he replaced the length of the drop and that took care of the problem.

KC9OKV
02-07-2009, 05:03 PM
Well my neighbors heard me on a few channels.....but they never looked to see what channel because they were wonder what's with the voice in their TV. After they relized it was mine they called and they said they only saw channel 52 because they were distracted by my voice.

KC6TOA
02-07-2009, 05:41 PM
ARRL has an interesting writeup on the issue.
http://www.arrl.org/tis/info/HTML/catvi/catvi-leakage.html

Another item of interest is that if your CATV provider runs on the channels 14, 15, 16 (not UHF) then its operating on the 108-137MHz airband. This operation requires the annual flyover to verify leakage compliance.
I suspect many cable operators avoid CH14, 15 and 16 for this reason.

Cable channels 24 to 53 fall within the 225-400MHz air band, and have similar leakage limits.
A handheld scanner could be used to make a rough measurement of their leakage there.

WB7DMX
02-07-2009, 05:54 PM
what I did:

if your getting inro the cable, then the cable is interfering with you.

set your reciver to 145.250 and walk or drive around the area and make notes of the signal strength at differant locations, the carrier your picking up is signal leaking from the cable, write a letter to the FCC complaining of the interferance, or reply to them if you were sent a letter, give the details of the signal strength at several locations and the name and address of the cable co's main office,

what the FCC will then do is give the cable Co. 10 days to correct the problem or loose there frainsice to operate,
belive me, doing this will bring fast action in correction of the problem.and the FCC is on your side in the matter.

I been there and done that.

K8YZK
02-07-2009, 06:00 PM
I'll show mine to my xyl when I don't make it to the potty in time. Which is often.

TOM K8ERV Montrose Colo

Depends would take of that problem..

KB1PVQ
02-07-2009, 11:12 PM
If you are inclined to help your niebor out, then I would suggest that you disconnect the cable at the affected television and then make a transmission to see if the problem still exists. If it does, then there is probably an issue with the televisions tuner shielding. If the problem goes away then your niebor should seek help fron the cable provider. They should be more than happy to repair the ingress to the cable plant. I am a cable technician and this is standard procedure in my system and hopefully yours as well.:)

KC9OKV
02-08-2009, 12:56 AM
Ok i have done some testing and found that it was my neighbors TV that is receiving the signal. Now i am in an akward position because my neighbor isn't going to buy a new TV and i am out of ideas to help him.:o

KB1PVQ
02-08-2009, 01:12 AM
Please see PM

KA5S
02-08-2009, 12:06 PM
Ok i have done some testing and found that it was my neighbors TV that is receiving the signal. Now i am in an akward position because my neighbor isn't going to buy a new TV and i am out of ideas to help him.:o

Any other TV's getting it? See, if you can show that your transmissions are not picked up on other sets, you have some evidence you are not liable for the interference. I am not a lawyer, etc.

Should we drive by and chew the rag for you until he buys another TV?

Heh!


Cortland
KA5S

W2IBC
02-08-2009, 01:30 PM
Ok i have done some testing and found that it was my neighbors TV that is receiving the signal. Now i am in an akward position because my neighbor isn't going to buy a new TV and i am out of ideas to help him.:o

well, I guess your neighbor is just #### out of luck isn't he

W9MAV
02-08-2009, 04:57 PM
well, I guess your neighbor is just #### out of luck isn't he

Hahahahahahaha!!!!

Oh man thats funny!!:D:D:D

KQ9J
02-08-2009, 05:45 PM
Ok i have done some testing and found that it was my neighbors TV that is receiving the signal. Now i am in an akward position because my neighbor isn't going to buy a new TV and i am out of ideas to help him.:o

Just for giggles...how did you test it? Did you disconnect the coax directly at the back of the TV or was there another place you took it off like on a splitter or converter box? Disconnect it at the TV and make sure no other cables are going to the tv if it has other coax inputs, audio/video inputs, etc. Maybe try terminating the coax input to the TV with a 75 ohm terminator.

The point of all this is that the cable from headend to the drop to the TV should be a CLOSED system. The TV may be "copying" you 5-9 but wouldn't be if the cable system didn't have a leak and was supplying a good (minimum 0 dbmV) signal.

If you already did all these things then good luck.

N1JBS
02-08-2009, 05:56 PM
I have benn there and done that.

I will suggest you contact the ARRL for help. I did and the result was good.
When the cable company would not even talk to me, I then contacted John Hennesey (sk). He put me thru to a person in Maryland and all of the sudden I was a "good guy". He explained to the person in charge that leaks were a problem of the cable company and Amateur Radio has a primary allocation.

I had to find all of the leaks, but they fixed them within days.
My trick: watch the signal on 2 meters (145.250) and 220 (223.250) at the same time. The 2 meter signal will peak and then the 220 signal will peak when you are closer.

Hope this helps

n1jbs

N8EKT
02-08-2009, 06:10 PM
MOST problems are due to poor shielding and or weak cable signal.

ALL coax and jumpers MUST be RG-6.

And cable signal is REQUIRED to be at least 0 Db level.

But most taps will be well above that.

Other than that, there is nothing you can do.

Most decent cable companies abandoned channel 14 because of aircraft interference and many either don't use 18 or they put programming on it most won't watch to address the problem.

KQ9J
02-08-2009, 06:12 PM
MOST problems are due to poor shielding and or weak cable signal.

ALL coax and jumpers MUST be RG-6.

And cable signal is REQUIRED to be at least 0 Db level.

But most taps will be well above that.

Other than that, there is nothing you can do.

Most decent cable companies abandoned channel 14 because of aircraft interference and many either don't use 18 or they put programming on it most won't watch to address the problem.

Hopefully he doesn't live next to the only guy in town that actually watches the Knitting and Crocheting channel :)

N5PVL
02-08-2009, 06:31 PM
I had the same problem here at my home. - We live way out in the sticks, so neighbors are not an issue.

My daughter was most upset, though!

I moved my antenna to the side of the house that was furtherest from the cable drop, and tried a new pole that was 20 ft. instead of 10 ft tall.

That fixed it.

Good luck, try moving the antenna around, or maybe a different antenna. If you are using an omni and generally only use one repeater, try a beam. Then see if you can get by with less power.

Lots of things to try, give it a shot, why not? Moving the antenna 20-30 feet may seem trivial, but remember that we are dealing with the inverse-square law here. - Sometimes just a little does a lot!

KC9OKV
02-08-2009, 11:21 PM
Dang this was turning out to be a popular thread...but for now the problem has been fixed. Thanks for all the tips and ideas.:D

W4HAY
02-09-2009, 01:32 AM
The cable company I once used in my pre-satellite days was very happy when I reported that my neighbor complained of inteference. Neighbor got into trouble big time because of an illegal tap!

Illegal "drops" were a big problem before fiber optics displaced the old systems. The cable providers got very aggressive about enforcement.

AC3P
02-09-2009, 01:33 AM
What was the fix?

73

Frank AC3P

W1RFI
02-09-2009, 03:02 AM
ARRL has an interesting writeup on the issue.
http://www.arrl.org/tis/info/HTML/catvi/catvi-leakage.html
A more comprehensive page of information is at:

http://www.arrl.org/tis/info/HTML/catvi/index.html

This was written by me for Communications Technology, the journal of the Society of Cable Telecommunications Engineers. I chose to submit it there instead of publishing it in QST because the journal is well-known to the cable industry and its information is trusted.

In reading the thread, here are a few fast-take observations.

When interference to cable TV happens, especially if is just to Channel 18 analog from 2 meters, there is clearly leakage. What is not known is whether the leakage is in the cable system, and thus the cable operator's responsibility, or whether it is leakage directly into cable-ready equipment. The cable company is not required to fix that. In fact, they are generally prohibited from doing anything to modify customer-owned equipment.

If the leakage is into the cable plant, Sec. 76.605 of the FCC rules governing cable applies; the cable company is required to deliver a specific signal-to-noise and signal-to-coherent disturbance ratio to their customers. If you are leaking in, an FM signal would be a coherent disturbance and the cable company would be required to fix it.

Of course, the finger pointing could begin, but there is a simple diagnositic test. Have the cable company demonstrate satisfactory performance with one of their converter boxes. If the system works, then their plant is not leaking. The TV is the source of the leak and because it is no longer tuned to Channel 18, the interference is gone. This has also demonstrated that the problem is something in the TV and the fact that it works well on the cable equipment also shows that your station is not at fault.

If it is the cable system, do contact your cable company. Print the CT article from the ARRL web site (fair use as far as I am concerend) and give them an opportunity to resolve it.

If you do get some of the attitudes I have seen posted here, contact Mike Gruber in the ARRL Lab. Mike first make sure you have read ARRL's material and tried to work it out with the cable company, but once it is apparent that a cable operator is not willing or able to address the interference, Mike will send information about the case to Ron Hranac, N0IVN. Ron is ARRL's liaison to the SCTE and he is well known to the senior technical people at the major cable companies. Often, a phone call to them from Ron is sufficient to ensure that local repair person with a 'tude about ham radio is given an opportunity to learn new things.

Ed Hare, W1RFI

W1RFI
02-09-2009, 11:19 AM
Hopefully he doesn't live next to the only guy in town that actually watches the Knitting and Crocheting channel :)
I don't know if they ever changed it, but when I went on a local RFI call, the Cox system in Newington had American Movie Classics on channel 18. Many retired folks enjoy the old movies days and evenings, so it was a recipe for complaints.

Ed, W1RFI

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