Is it common in many areas to have co-channeling?

miguelaqui

SatelliteGuys Pro
Original poster
Oct 14, 2004
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Where I live I can, for the most part , receive 3 DMA's , Roanoke ,VA, Raleigh, NC, and Greensboro, NC.

Many times , I cannot get Roanoke FOX because Raleigh NBC also broadcasts on 17.

There is a county in VA, Halifax , that is in the Roanoke DMA and the neighboring country in NC, Person, is in the Raleigh DMA.

Charlotte NC and Raleigh NC have channels that share a frequency also.

I am sure that many of you understand that when there is co-channeling , there is no channel at many times.

Is this common? I remember the FCC used to be very strict on full power TV stations and interfering with each other. Maybe they have stopped caring so much because most people watch cable or satellite .
 
Where I live I can, for the most part , receive 3 DMA's , Roanoke ,VA, Raleigh, NC, and Greensboro, NC.

Many times , I cannot get Roanoke FOX because Raleigh NBC also broadcasts on 17.

There is a county in VA, Halifax , that is in the Roanoke DMA and the neighboring country in NC, Person, is in the Raleigh DMA.

Charlotte NC and Raleigh NC have channels that share a frequency also.

I am sure that many of you understand that when there is co-channeling , there is no channel at many times.

Is this common? I remember the FCC used to be very strict on full power TV stations and interfering with each other. Maybe they have stopped caring so much because most people watch cable or satellite .
How about being specific, at least give a zip code. Besides ch. 17 are there others?
 
I don't know if it's common or not, but it happens to me here on channel 5. Superb signal but no picture because of two channels sharing the same freq. If the weather is lousy, then I lose the farther away station and the closer one comes in great.
 
Is this common? I remember the FCC used to be very strict on full power TV stations and interfering with each other. Maybe they have stopped caring so much because most people watch cable or satellite .

The FCC does have guidelines still but you have to remember a few things from analog to digital
-analog traveled further
-analog had 68 channels available whereas digital has (for most part) 45 (7-51)...yes some stations are on 2-6 but they are mainly in the western US. SO there is less room.

There is a county in VA, Halifax , that is in the Roanoke DMA and the neighboring country in NC, Person, is in the Raleigh DMA.
umm ok. Here in MN one county (Beltrami) is in the Minneapolis DMA (which is technically 200 miles away) whereas the county to the west is in the Fargo, ND market and the county to the East is in Duluth, MN market (90 miles away)

Alot of it has to do with the atmosphere and what your setup is. If you are further out from the "main" area then yes you can get more stations. But looking at rabbitears site there are only a couple stations that even have the same RF station

Using the 17 example according to the FCC maps the signals dont cross
17 Raleigh
http://www.rabbitears.info/contour.php?appid=1316485&map=Y
17 Roanoke
http://www.rabbitears.info/contour.php?appid=1316833&map=Y

Once you get to the fringe yes there may be some overlap depending on the weather
 
Up here in the high country we have a good deal of co channel overlapping.That's to be expected when you get signals from multiple markets.
 
Where I live I can, for the most part , receive 3 DMA's , Roanoke ,VA, Raleigh, NC, and Greensboro, NC. Many times , I cannot get Roanoke FOX because Raleigh NBC also broadcasts on 17. There is a county in VA, Halifax , that is in the Roanoke DMA and the neighboring country in NC, Person, is in the Raleigh DMA.

If Media-General had wanted to spend the money, they could have put WNCN on channel 45, but they probably didn't want to put up a new antenna for that channel given a perfectly good channel 17 antenna was already up there. Fortunately, most viewers can see WSLS for NBC and WWCW or WRAZ for Fox. It also works out that, because of the terrain, WFXR tends to be pretty solid in most of its coverage area, while WNCN tends to get stomped on by WFXR in the northern parts of its coverage area. My parents have only rarely had WFXR taken out by WNCN. Much more common is WPXR wiped out by WUNP.

Charlotte NC and Raleigh NC have channels that share a frequency also.

Only two real cases. WCCB/WRDC on 27 were assigned that way by the FCC, assuming the two would be using less power than they are now using. (WCCB at 86.5 kW instead of 1000 kW, WRDC at 226.3 kW instead of 725 kW.) WTVI/WTVD on 11 came about because WTVI was assigned to 24 and would have received a lot of interference from WBTV on 23. There really wasn't a better option available for WTVI, and being a struggling non-commercial broadcaster that needed to save money and not have to rebuild after the transition.

I am sure that many of you understand that when there is co-channeling , there is no channel at many times.

Is this common? I remember the FCC used to be very strict on full power TV stations and interfering with each other. Maybe they have stopped caring so much because most people watch cable or satellite .

It's somewhat common. The worst one, in my opinion, is WFSB and WCBS both on channel 33. Good luck watching CBS from either one half-way between the two of them.

The rules used to be distance-based, but if that had been kept during the transition, stations never would have been able to go digital. There wouldn't be enough channels to assign every station a second channel to go digital while keeping the distance rules, even taking into account that digital doesn't have interference issues except for the co- and adjacent-channel cases, whereas analog could have interference as far as plus or minus 15 channels. I don't necessarily agree with the method that was chosen (and I work for the FCC), but hard distance rules weren't the right answer.

In my opinion, some of the worst cases are:

WFSB/WCBS on 33
WNYW/WMCN/WDPB on 44
WCVB/WCCT on 20
WFXT/WTIC/WPXN/WPPX/WSWB on 31
WMPT/WTXF on 42
WITF/WTTG on 36
WFME/WUVP/WMPB on 29
WUNP/WFPX/WPXR on 36 (I've been to a place where you can turn the antenna one way, see WPXR, then turn it the other way and see WUNP.)
WJZY/WZRB/WCSC on 47
WPGX/WALA on 9
WOIO/CFPL on 10
WFFT/WLNS on 36
WFWA/WKAR on 40
WGN/WMTV/WHOI/WXMI on 19
WSNS/WLLA on 45
KSNW/KOTV on 45
KFWD/KCEN on 9
KHOU/KVCT on 11
KSCI/KUSI on 18

There are probably many more that could be problematic, of course.

- Trip
 
A good directional antenna could help eliminate pickup from the backside of your antenna.

If your avatar is any indication, it looks like you have an Antennas Direct 91-XG that should have a fairly high front to back ratio.
 
A good directional antenna could help eliminate pickup from the yesbackside of your antenna.

If your avatar is any indication, it looks like you have


an Antennas Direct 91-XG that should have a fairly high front to back ratio.
I do have a the 91 -Xg and the largest low and high chef that ups would ship. Wbra PBS out of Roanoke is on 3 , WSET from Lynchburg is on 13 and WTVD is on 11 from Raleigh. Wncn only messes with my WFXR during troop, but it messes with my brother all the time because he lives on the side of a mountain and can get all the Raleigh channels all the time, but wncn will.mess with wfxr just enough to make it unviewable...his solution was just to.watch WGHP for Fox.
 
When I asked an engineer at WBRA, which broadcasts on 3, he told me that some stations may have to move to low vhf; this was his response as to why they were on 3 and did not try to either purchase channel 24, which is now dead, or try to stay on 15, their original analog frequency.
Channel reuse will probably get even worse as the FCC tries to free up channels to be converted to cellular.
 
Most name brand antennas have a Polar Plot you can use it to aim the antenna to receive the signals you want and null out the interfering signals. Horizontal stacking can also be used to reduce co-channel interference. No it isn't as simple as throwing a fringe antenna up on a tower but if you want to learn what you are doing it can be successful.
 
When I asked an engineer at WBRA, which broadcasts on 3, he told me that some stations may have to move to low vhf; this was his response as to why they were on 3 and did not try to either purchase channel 24, which is now dead, or try to stay on 15, their original analog frequency.

They're on 3 because management liked the power bill. The engineer there around 2007 tried to push management to get off of channel 3 but they wouldn't budge. He works elsewhere now. The engineer there now is a good guy, too.

And they aren't doing too fantastically financially; as you may know, they turned off the transmitters for WMSY and WSBN last year. As such, I doubt they could have afforded to buy channel 24. Channel 15 was not an option due to WRPX in Rocky Mount, NC.

- Trip
 
Had they used 15, they still would be further away from the channel in Rockey Mount NC than wfxr and wncn are now. I hardly ever get that channel from Rocky Mount. I honestly get wncn more often than I do that 15 (47 virtual). I was unaware that they had turned off the other channels. It sort if stinks that they are using 3 because Roanoke did not have an analog low vhf channel, so.many rooftops were high vhf combined to UHF.
They're on 3 because management liked the power bill. The engineer there around 2007 tried to push management to get off of channel 3 but they wouldn't budge. He works elsewhere now. The engineer there now is a good guy, too.

And they aren't doing too fantastically financially; as you may know, they turned off the transmitters for WMSY and WSBN last year. As such, I doubt they could have afforded to buy channel 24. Channel 15 was not an option due to WRPX in Rocky Mount, NC.

- Trip
 
How bad do you think it will get when the 600 MHz auction comes up? I know a majority of the Detroit channels broadcast in that range.

I think that the big 4 will move down and the rest will get a channel or two and put all their programming on sub channels.
 
Had they used 15, they still would be further away from the channel in Rockey Mount NC than wfxr and wncn are now.

WFXR to WNCN: 138 miles
WBRA to WRPX: 132 miles

The real problem is what I mentioned earlier about WFXR. Due to terrain, WFXR is pretty solid, but WNCN gets stepped on. Since WFXR was on 17 (in digital) first, WNCN effectively "volunteered" to have that interference in its coverage area in order to keep channel 17. If it had been the other way around, WFXR would not have been approved to use 17 because it would cause too much interference to WNCN.

WBRA could not have kept channel 15 because WRPX was there first, and would have received too much interference from WBRA on 15. The only channel I found that would have worked for WBRA would have been 16, and even that only would have worked if they had a directional antenna that nulled power to the west (limiting power toward Blacksburg) due to WKHA on 16 in Hazard, KY.

At one point, WBRA had petitioned to move to channel 26, but it would have been directional in such a way that it would have limited power toward Lynchburg and Danville to protect WRLH in Richmond. They decided to increase power and go omni on 3 instead, which did help my parents' signal level by about 6 dB, so it doesn't vanish for hours at a time anymore.

I hardly ever get that channel from Rocky Mount. I honestly get wncn more often than I do that 15 (47 virtual). I was unaware that they had turned off the other channels. It sort if stinks that they are using 3 because Roanoke did not have an analog low vhf channel, so.many rooftops were high vhf combined to UHF.

Yeah, I took phone calls on transition day at WDBJ and there were a number of people who had high-VHF only antennas on their roofs. They would scan in, but not actually decode, WBRA on 3, and get nothing else.

- Trip
 
The San Francisco and Sacramento/Stockton, CA transmitter sites are separated by 62 miles. I'm in San Francisco, and two stations that I used to receive from Sacramento are no longer available due to local low power stations, so, apparently, they aren't protecting nearby markets. KCRA 3 (RF 35) from Sacramento is blocked by KGO 7 (RF 35 translator) and KTXL 40 from Sacramento is blocked by low power KMMC 40.

Larry
SF
 

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