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DTV Interference from CATV Trunk Amp?

post #1 of 10
1/29/11 at 4:43pm
Thread Starter 
There is a CATV trunk amplifier on a pole about 10 degrees off from the line of sight path to my local major market broadcast towers. If I use an analog tv and tune to cable channels I can get most of the local cable channels. When I say get, many of the catv channels come in with clear video and sound. I get snow on channels that are also occupied by OTA signal. I'm unable to get most of the OTA channels from my market area.

Is it possible that this amplifier is introducing noise on those channels? If so any advice on how to go about addressing this? Is it normal for such a device to be radiating this signal? I saw a similar thread here: http://www.avsforum.com/avs-vb/showthread.php?t=1170266 but the source wasn't specified. I'm pretty sure it's this catv trunk amp since when I rotate my antenna away the channels fade out.

Any help or experiences are greatly appreciated.
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post #2 of 10
1/29/11 at 5:31pm
If you are picking up cable channels using an antenna then the cable company has a major problem with signal leakage. Contact them and complain. If they don't fix it promptly, then file a complaint with the FCC - https://esupport.fcc.gov/ccmsforms/f...orm_type=2000E .
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post #3 of 10
1/30/11 at 5:20am
What coyote said. Call the cableco and tell them they have leakage and you're picking up cable chs over the air. Most companies will usually fix it promptly.
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post #4 of 10
1/30/11 at 6:11am
I had this same problem when I lived in a small town in New Mexico about 15 years ago. The cable company was actually a small outfit in another small town 60 miles away.
I wrote a tongue-in-cheek letter to the cable company thanking them for broadcasting cable to the entire neighborhood considering the poverty of many of the migrant workers. I stated that it was especially generous of them to provide HBO for free over the air.
They came out to fix the problem the next week
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post #5 of 10
1/30/11 at 10:06am
Thread Starter 
Is it possible/likely that noise from the amp is affecting reception of OTA channels?

I experimented and can only pick up 16 channels in analog from the amp. I get 10,13,23-25,65-73 which look like some of the analog channels from the standard cable lineup. Some channels, like cable 69 are snowy I assume due to an OTA channel on the same frequency (17). This is why I think it is interfering with OTA.

I'm also curious why I'm not getting all the analog channels from the amp, there is a lot missing in the vhf range. If 10 is bleeding out shouldn't the rest of them? Also I have a qam tuner but wasn't able to pick up any digital signal from the amp.

If the consensus is that it is interfering then I'll call the local cable company on Monday and see what they say.
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post #6 of 10
1/30/11 at 11:28am
Leakage may only involve certain channels. Call the cableco.
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post #7 of 10
1/30/11 at 12:00pm
Quote:
Originally Posted by zirkelad View Post

...I experimented and can only pick up 16 channels in analog from the amp. I get 10,13,23-25,65-73 which look like some of the analog channels from the standard cable lineup. ....

I can't explain 23-25, but if your analog tuner is on off-air or antenna, then it's AFC circuit will tune cable channels 65-73 when you choose UHF channels 16-24.
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post #8 of 10
1/30/11 at 8:19pm
Quote:


...I can't explain 23-25,

I can, 23 follows 13 in the frequency order of things.
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post #9 of 10
1/31/11 at 7:17am
Thread Starter 
I called the cable co and they said they would check out their equipment at the end of the week. We'll see what happens. I'm pleasantly surprised so far.

I'm still wondering if anyone has experienced, or heard of, a situation like this actually causing OTA stations to drop out. I guess I'll find out when they fix it.
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post #10 of 10
1/31/11 at 12:25pm
If there is radiation ("signal egress") from their equipment, it can easily cause problems with OTA. As far as "channels", Cable TV uses nearly the entire spectrum, and many of their channels are encrypted QAM, which can overlap the OTA channels in that spectrum. Their QAM signals would raise the apparent Noise Floor of the OTA signals.
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