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Discussion Starter · #1 ·
I've got one for you...


I've been scanning the VHF TV bands for possible DX lately since our local VHF channels signed off (Except for those broadcasting digitally on 7, 10 and 12 locally.) I noticed a faint analog signal on ch 8, 11 and 13. Those are more or less empty channels near my home. In further investigation I saw Fox programming on 8 and ABC on 11. Remembering the Comcast channel line up in my area, I realized I was viewing a very faint, but detectable signal from somebody's Comcast drop line or an empty tap somewhere in the neighborhood. The signals haven't been strong enough to impact me.


I was curious to see how much of an impact you think 'leaky' cable service lines could cause to OTA reception in Urban areas? A lot of cable companies are keeping their 'lifeline' cable service of local channels in analog on channels 2-13. For those attempting to receive VHF DTV this could be an impact.


I should say, I've been Comcast free for over 4 years, and DTV via OTA only for closing in on two. In the interim I had Dish Network. So the Comcast signal isn't from anywhere in my home.
 

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It will be interesting to see what happens. Transmitter power for digital VHF is considerably lower than for analog. I wonder if the FCC took co-channel interference from leaky cable systems into consideration when setting maximum power levels. There are at least a few stations that went to VHF on the date of the digital cutover and very quickly filed emergency requests to change to UHF because their viewers were having problems. Much of this is likely due to people having the wrong antennas (UHF only) or using indoor antennas for which VHF reception is more problematic, particularly with the reduced power levels. Who knows what if any of it has to do with co-channel interference from cable leaks.
 

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Quote:
Originally Posted by Bozzmonster /forum/post/16984728


I've got one for you...


I've been scanning the VHF TV bands for possible DX lately since our local VHF channels signed off (Except for those broadcasting digitally on 7, 10 and 12 locally.) I noticed a faint analog signal on ch 8, 11 and 13. Those are more or less empty channels near my home. In further investigation I saw Fox programming on 8 and ABC on 11. Remembering the Comcast channel line up in my area, I realized I was viewing a very faint, but detectable signal from somebody's Comcast drop line or an empty tap somewhere in the neighborhood. The signals haven't been strong enough to impact me.


I was curious to see how much of an impact you think 'leaky' cable service lines could cause to OTA reception in Urban areas? A lot of cable companies are keeping their 'lifeline' cable service of local channels in analog on channels 2-13. For those attempting to receive VHF DTV this could be an impact.


I should say, I've been Comcast free for over 4 years, and DTV via OTA only for closing in on two. In the interim I had Dish Network. So the Comcast signal isn't from anywhere in my home.

Sounds to me like someone in your neighborhood has their cable service connected to an antenna that they are no longer using for tv reception. The RF from the cable system would then be transmitted OTA via the antenna.
 

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I had a problem once (back in the all analog days) with a cable system so leaky it interfered with several channels I wanted to get with the antenna. I would call but could not get any response as I was not a cable customer. I finally wrote a letter to their main office thanking them for broadcasting HBO for free to the entire neighborhood. They were out that week.
 

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i worked at a FM station that received a call from the FCC that we were transmitting on the wrong frequency. i checked the transmitter and found nothing wrong. the FCC called back and said they found the cable co had a leak. the cable co rebroadcast our signal a few khz from our frequency as normal. this was not the first time the cable co had a leak.

the fixed the leaks.

milt9
 

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Quote:
Originally Posted by arxaw /forum/post/16994113


bozzmonster, it may very well degrade your OTA VHF DTV reception. Leaks are a big no-no for cablecos. Most will come out and look for the source if you call them.

Better yet, find the phone number for the nearest FCC field office and call them instead. Works much faster.
 

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Discussion Starter · #8 ·
Well, no phone calls necessary. Checked today and no interference at all. I had seen a couple of Comcast trucks in the neighborhood since my post, so there may have been a local issue.


I think the culprit may have been nearby Comcast trunk line service box with a distribution amp. There's one right across the street. Looks like there was some movement around that (grass was disturbed, etc.)


In looking at rooftops around here, A LOT of people have switched to either DirecTV or Dish Network - my closest neighbors in proximity to me use one of the two. I wonder if that says anything?
 

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Back in the late 70s-early 80s in my neighborhood it was possible to receive a snowy but easily watchable signal from all cable channels 2-13 on a tv outdoors with rabbit ears. Even The Movie Channel (originally known as Star Channel, anyone else remember that?) on channel 7, blocked by traps on the line but "broadcast" over the air!
 
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