Cable interference

[dhett]

cable channels 15 and 18 will now be open as well. (What is the over the air equivalent of these channels?) It's strange

These two channels are not used by over-the-air TV. Cable channel 15 is (probably) 126-132MHz which is used by aircraft, and channel 18 is 144-150MHz which is for the most part the 2-meter ham band. (148-150 is military) There usually isn't much problem with interference *to* cable reception on these channels. Interference *from* cable *to* amateurs is often pretty severe; the channel 18 carrier frequency of 145.25MHz has been defacto reallocated from ham radio to cable TV as the interference makes legitimate use frequently impossible.

Interference *from* cable *to* aircraft is usually stomped on pretty quickly by the FCC(grin)!

That's news to me. Cox doesn't seem to have any problems using channels 15 and 18. Both are in use in Phoenix.

 

[Morgan Wick]

cable channels 15 and 18 will now be open as well. (What is the over the air equivalent of these channels?) It's strange

These two channels are not used by over-the-air TV. Cable channel 15 is (probably) 126-132MHz which is used by aircraft, and channel 18 is 144-150MHz which is for the most part the 2-meter ham band. (148-150 is military) There usually isn't much problem with interference *to* cable reception on these channels. Interference *from* cable *to* amateurs is often pretty severe; the channel 18 carrier frequency of 145.25MHz has been defacto reallocated from ham radio to cable TV as the interference makes legitimate use frequently impossible.

Interference *from* cable *to* aircraft is usually stomped on pretty quickly by the FCC(grin)!

That's news to me. Cox doesn't seem to have any problems using channels 15 and 18. Both are in use in Phoenix.

Jackson may be a hub for ham radio (I'm purely speculating tho).

 

[Garrett]

Thanks all for the advice and comments. I called Comcast and told them the situation about and they said "they would look into it". :

I have four TVs in my house, one connected to the digital cable box and it has no interference as expected on any channel; however, the other three, which aren't connected to any digital cable boxes including the one I tried watching AMC on have the same interference issue...one even seems to be having problems with getting VHF stations, although I think we've had that TV since at least 1987...

Genius,
I'm surprised nobody mentioned this yet but, make sure you have all new equipment from the cable company and/or newer TV's. Here's why...

Back when I had Cox, I was having similar troubles. I noticed that only one TV, my RCA XL-100 from 1988, which has a sharp picture most of the time, was getting 88.1 over Cable channel 6. After several visits from Cox cable, I learned that 1) Insulated cable is absolutely importortant. Use the highest grade (but this has already been mentioned)
2) As electronics fatigue, capacitors and transisters wear out, and this causes them to be less able to tune. In the old days of Tube sets, you could sometimes re-tune a TV set so that it still recieved stations on the correct frequency, but this is harder to do with modern electronics that are pretty much fixed. Just being tiny bit off can cause a TV to not be able to decipher between a 5.9 and 6.1 analogue channel. That's why some TVs in your house work fine and others may not. Same may be true for VCRs or older Cable Boxes. Another solutions (although more expensive) would be to go digital. But keep in mind, this is where the insulated cable comes in, becuase if there is even the slightest loss of singal in the line, digital won't pick up, because it's receiving data: either it gets it or it doesn't.

Sorry if some of this has been mentioned already, but I hope that helps.

 

[genius]

cable channels 15 and 18 will now be open as well. (What is the over the air equivalent of these channels?) It's strange

These two channels are not used by over-the-air TV. Cable channel 15 is (probably) 126-132MHz which is used by aircraft, and channel 18 is 144-150MHz which is for the most part the 2-meter ham band. (148-150 is military) There usually isn't much problem with interference *to* cable reception on these channels. Interference *from* cable *to* amateurs is often pretty severe; the channel 18 carrier frequency of 145.25MHz has been defacto reallocated from ham radio to cable TV as the interference makes legitimate use frequently impossible.

Interference *from* cable *to* aircraft is usually stomped on pretty quickly by the FCC(grin)!

That's news to me. Cox doesn't seem to have any problems using channels 15 and 18. Both are in use in Phoenix.

I'm not sure what they are trying to imply. Of course channels 15 and 18 can be over the air...they're both somewhere in the range of 470–500 MHz. He does say that cable channels 15 and 18 are in the range he's talking about, which is true but again his post is confusing.

Genius,
I'm surprised nobody mentioned this yet but, make sure you have all new equipment from the cable company and/or newer TV's. Here's why...

Back when I had Cox, I was having similar troubles. I noticed that only one TV, my RCA XL-100 from 1988, which has a sharp picture most of the time, was getting 88.1 over Cable channel 6. After several visits from Cox cable, I learned that 1) Insulated cable is absolutely importortant. Use the highest grade (but this has already been mentioned)
2) As electronics fatigue, capacitors and transisters wear out, and this causes them to be less able to tune. In the old days of Tube sets, you could sometimes re-tune a TV set so that it still recieved stations on the correct frequency, but this is harder to do with modern electronics that are pretty much fixed. Just being tiny bit off can cause a TV to not be able to decipher between a 5.9 and 6.1 analogue channel. That's why some TVs in your house work fine and others may not. Same may be true for VCRs or older Cable Boxes. Another solutions (although more expensive) would be to go digital. But keep in mind, this is where the insulated cable comes in, becuase if there is even the slightest loss of singal in the line, digital won't pick up, because it's receiving data: either it gets it or it doesn't.

Sorry if some of this has been mentioned already, but I hope that helps.

Thanks Garrett, I will check into this when I get a chance. On the TV I mentioned that is from the late 80s it appears that Channel 14 has pretty much taken it over.

 

[anotherguyTN]

What I meant in my comments on cable channels 15 and 18 was that they have been used by Charter in Jackson for years (Carrying TNT and USA) but after the realignment of channels next week they will be empty. I won't say that there isn't any ham activity here, but I don't know of any big amount. What doesn't make sense to me is that 15, 18, and 75 are being left open when there is no problem with an interfering channel, but 67 and 70 have real possibilities of interference in some areas from OTA channels 16 and 19, but they will have stations on them.

 

[MarcB]

Lucky COMCAST subscribers in Central CT have virtually interference free cable. Just minor inteference from OTA channel 3. Cable 3 is CN8. Minor interference on QVC Channel 70, which is bleed over from OTA channel 18. No channels are on 69, 71, or 75. Minor Interference on Leased Access 96.

 

[genius]

What I meant in my comments on cable channels 15 and 18 was that they have been used by Charter in Jackson for years (Carrying TNT and USA) but after the realignment of channels next week they will be empty. I won't say that there isn't any ham activity here, but I don't know of any big amount. What doesn't make sense to me is that 15, 18, and 75 are being left open when there is no problem with an interfering channel, but 67 and 70 have real possibilities of interference in some areas from OTA channels 16 and 19, but they will have stations on them.

I completely understand your comments, it was w9wi's who left me somewhat befuddled. And your right about channel 19 interfering on channel 70...our CW station is channel 19 and before they extended the grid and put a network on ch. 70 you could flip to channel 70 and get ch. 19 very clearly.

 

[w9wi]

That's news to me. Cox doesn't seem to have any problems using channels 15 and 18. Both are in use in Phoenix.

Cable channels 15 and 18 are on frequencies that are not used for over-the-air broadcasts. Obviously cable channels 15 and 18 exist, and obviously over-the-air channels 15 and 18 exist. But they are on different frequencies, and there is no over-the-air TV channel that corresponds to cable channel 15 or 18.

 

[Morgan Wick]

That's news to me. Cox doesn't seem to have any problems using channels 15 and 18. Both are in use in Phoenix.

Cable channels 15 and 18 are on frequencies that are not used for over-the-air broadcasts. Obviously cable channels 15 and 18 exist, and obviously over-the-air channels 15 and 18 exist. But they are on different frequencies, and there is no over-the-air TV channel that corresponds to cable channel 15 or 18.

This clarifies a weak point in your original post, but it's a bit confusing in its own right because I'm not sure what the post you quoted has to do with it.

 

[dhett]

That's news to me. Cox doesn't seem to have any problems using channels 15 and 18. Both are in use in Phoenix.

Cable channels 15 and 18 are on frequencies that are not used for over-the-air broadcasts. Obviously cable channels 15 and 18 exist, and obviously over-the-air channels 15 and 18 exist. But they are on different frequencies, and there is no over-the-air TV channel that corresponds to cable channel 15 or 18.

Channel 15 is a local OTA channel here - KNXV, the ABC affiliate - and I pick it up on channel 66, so that doesn't seem to be right, either. Channel 18 is a local OTA in Tucson, and I'm pretty sure I can get it on channel 69.

 

[Morgan Wick]

That's news to me. Cox doesn't seem to have any problems using channels 15 and 18. Both are in use in Phoenix.

Cable channels 15 and 18 are on frequencies that are not used for over-the-air broadcasts. Obviously cable channels 15 and 18 exist, and obviously over-the-air channels 15 and 18 exist. But they are on different frequencies, and there is no over-the-air TV channel that corresponds to cable channel 15 or 18.

Channel 15 is a local OTA channel here - KNXV, the ABC affiliate - and I pick it up on channel 66, so that doesn't seem to be right, either. Channel 18 is a local OTA in Tucson, and I'm pretty sure I can get it on channel 69.

Seems to match up with the cable-TV translations provided by another thread.

 

[dhett]

Ahhhhhhh - never mind.

I have Doug turned around - he's right. Broadcast ch 15 is CATV ch 66. There is no corresponding broadcast TV channel for CATV ch 15.