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Interference Between Distant TV Frequencies?

Norfolk-Virginia Beach-Newport News have channels 2 (WUND-TV, with it's new COL of Edenton, NC), 3 (WTKR, Norfolk) and 4 (WSKY, Manteo) in the same market, though I think they keep the 65-mile separation from each other. Also, in the next-door Greenville-Washington-New Bern market, channels 7 (WITN, Washington), 8 (WFXI, MOrehead City) and 9(WNCT, Greenville) share the market, though WFXI is dropped in on the far eastern edge of the market on a rather short tower (~800 feet) (7 & 9 share a 2,000-foot tower at least 65 miles away from WFXI)

> > I often wonder how it works in the Duluth area.
> >
> > I used to visit Hibbing and clearly got Channels 10, and
> 13.
> > WIRT, Hibbing is a translator of WDIO In Duluth.
> >
> > Recently Channel 6 opened up a full power translator on
> > Channel 11. (Channel 11 wa originally assinged to Int'l
> > Falls but moved to Chisholm, a few miles from Hibbing.)
> >
> > I wonder if Channel 10 and 11 interfere with each other in
>
> > Hibbing? I realize the transmitter must be located north
> of
> > Chisholm, but considering how clear Channel 10 comes into
> > Hibbing, I wonder
>
> Realize that just because a station is clear doesn't mean
> it's strong. The opposite is true also. Before WFXR-DT
> signed on channel 17, I used to get WNCN-17 out of Raleigh
> all the time. Now I only get it during tropo. And WFXR-DT
> is only at about 3 kW (out of a possible 400 kW). Likewise,
> I can't get WPXR-38 analog clearly, but I can't make it go
> away either (except when WUVC-DT 38 is coming in via tropo).
>
>
> VHF stations have to be 65 miles apart adjacent. KRII-11
> and WDIO-10 meet that requirement (else they wouldn't be
> there). I assume the only place they have interference is
> about half-way between, and there it doesn't matter since
> WIRT-13 and KBJR-6 should be receivable should 10 and 11
> harm each other. If KDLH wanted to put a channel 9 (I don't
> know if that would work, but it's an example) in Hibbing or
> Chisholm or Virginia or any of those towns, it too would be
> safe. If their channel 9 was harmed by WDSE-8 in Duluth,
> people could tune to KDLH-3. If WDSE-8 was not watchable
> due to their channel 9, watch WRPT-DT 31.
>
> Now the market I've always wondered about was Monroe, LA/El
> Dorado, AR. They have KTVE-10 as their NBC and KAQY-11 as
> their ABC. IN THE SAME MARKET (they do make the 65-mile
> separation). Though to be fair, the southern half of the
> market can probably get NBC from KALB-5 in Alexandria.
>
> - Trip
>
 
Re: How does Birmingham/Anniston have so many stations close together?

> True that Cleburne County is in the Atlanta DMA. But if
> you go to zap2it and look at the channel lineup for Charter
> Communications in Heflin, you'll find that it carries only
> WXIA, WTBS, and WGCL. By contrast, it carries WBRC, WVTM,
> WTTO, and WJSU from Birmingham/Anniston. Is there a
> possibility
> that WBRC and WJSU want their Atlanta Fox and ABC
> counterparts
> kept off that particular cable system?

I would find that strange in the case of WBRC/WAGA, since they're both Fox O&Os.

Allbritton keeping WSB off is possible, but it isn't the simplest explanation.

Anniston/Gadsden was once a separate market. Cleburne County was part of it at the time, as far as I know. WJSU and WBRC (via translator) probably just already had their feeds in place. WSB and WAGA would have waived must-carry because running a microwave feed to Heflin wasn't cost-effective.

Odd that they show the "i" national satellite feed rather than WPXA or WPXH and don't carry UPN at all, but Charter-Heflin's whole lineup seems strange (albeit better than Coosa Cable's by far. I wouldn't have upgraded to digital if Speed Channel and G4 had been available on analog basic here)
 
> > I have a question.
> >
> > I talked to an engineer at a TV station near me who
> informed
> > me that the reason their station could not move any closer
>
> > is due to channels 24 and 38 not being to co-exist. In
> > addition, reading a thread on the Phoenix TV board, K53GF
> > did a study and decided against channel 19 because of too
> > much interference from KTVW-33.
>
> > Does anyone have a list of all the frequencies that cannot
>
> > peacefully co-exist? I'm certain there's a list at the
> FCC
> > site somewhere (why wouldn't there be?) but I can't find
> it.
> >
> >
> > - Trip
> >
>
> Here's the table of no-no's from CFR 47.698. It lists
> channels where interference can happen. Channel 24 can put
> a sound image on Channel 38 and vice-versa. Same goes for
> Chs. 19 and 33. It's a plain-text file.
>
> Here is a pdf file of the same data.
>


So how does the Philly area get away with UPN 57 and Telemundo on 65? They both seem to come in clear in Cherry Hill (my point of reference) as well.
 
> So how does the Philly area get away with UPN 57 and
> Telemundo on 65? They both seem to come in clear in Cherry
> Hill (my point of reference) as well.

Univision on 65.

And both are from the same tower farm.

- Trip<P ID="signature">______________
Visit my website, www.rabbitears.info! It's eventually going to be your one resource for television info! Digital television, histories, and technical information for the entire USA from one source!</P>
 
> > So how does the Philly area get away with UPN 57 and
> > Telemundo on 65? They both seem to come in clear in Cherry
>
> > Hill (my point of reference) as well.
>
> Univision on 65.
>
> And both are from the same tower farm.
>
> - Trip
>

Right. I confused it with 62.
 
> Norfolk-Virginia Beach-Newport News have channels 2
> (WUND-TV, with it's new COL of Edenton, NC), 3 (WTKR,
> Norfolk) and 4 (WSKY, Manteo) in the same market, though I
> think they keep the 65-mile separation from each other.
> Also, in the next-door Greenville-Washington-New Bern
> market, channels 7 (WITN, Washington), 8 (WFXI, MOrehead
> City) and 9(WNCT, Greenville) share the market, though WFXI
> is dropped in on the far eastern edge of the market on a
> rather short tower (~800 feet) (7 & 9 share a 2,000-foot
> tower at least 65 miles away from WFXI)
>
> > >
> > >
> >
> > >
> > Realize that just because a station is clear doesn't mean
> > it's strong. The opposite is true also. Before WFXR-DT
> > signed on channel 17, I used to get WNCN-17 out of Raleigh
>
> > all the time. Now I only get it during tropo. And
> WFXR-DT
> > is only at about 3 kW (out of a possible 400 kW).
> Likewise,
> > I can't get WPXR-38 analog clearly, but I can't make it go
>
> > away either (except when WUVC-DT 38 is coming in via
> tropo).
> >
> >
> > VHF stations have to be 65 miles apart adjacent. KRII-11
> > and WDIO-10 meet that requirement (else they wouldn't be
> > there). I assume the only place they have interference is
>
> > about half-way between, and there it doesn't matter since
> > WIRT-13 and KBJR-6 should be receivable should 10 and 11
> > harm each other. If KDLH wanted to put a channel 9 (I
> don't
> > know if that would work, but it's an example) in Hibbing
> or
> > Chisholm or Virginia or any of those towns, it too would
> be
> > safe. If their channel 9 was harmed by WDSE-8 in Duluth,
> > people could tune to KDLH-3. If WDSE-8 was not watchable
> > due to their channel 9, watch WRPT-DT 31.
> >
> >
> > I've lived where I could get WDBJ/7 Roanoke, VA; and
WGHP/8 High Point, NC, off the air. Both came in equally
clearly, but then again, we're talking about roughly 100
miles between the two.

What can get unintentionally funny is when you're between
two stations on the same channel. This same area where WDBJ
and WGHP come in equally well is between WRAL Raleigh and
WCYB Bristol/Kingsport/Johnson City, both on Channel 5.
I'll never forget one night, when WRAL was still an ABC affiliate
(it's CBS now), they were running Peter Jennings at 7 PM, while
WCYB had Family Feud. I was seeing Jennings' face but
hearing Richard Dawson's voice. That absolutely blew my mind.
> >
> >
>
 
> > Well, I've not seen a market where there was a 3 and a 4,
> > and I have seen a market with 6 and a 7, or a 5 and a 6.
> But
> > this could just be luck of the draw...
>
> Channels 4 & 5 are not adjacent. Neither are 6 & 7 or 13 &
> 14. They don't pose a problem being located in the same
> city.

Unless I am wrong. You actually meant to say that channels 4 and 5 are adjacent, didn't you?

-John L.
 
> > > Well, I've not seen a market where there was a 3 and a
> 4,
> > > and I have seen a market with 6 and a 7, or a 5 and a 6.
>
> > But
> > > this could just be luck of the draw...
> >
> > Channels 4 & 5 are not adjacent. Neither are 6 & 7 or 13
> &
> > 14. They don't pose a problem being located in the same
> > city.
>
> Unless I am wrong. You actually meant to say that channels
> 4 and 5 are adjacent, didn't you?
>
> -John

I have never seen both a 5 and a 6 in the same market. 4 & 5 can be
together in a market because there is a little frequency space between
those channels. Ditto for 6 & 7(FM and all that are between those two
channels) and 13 & 14(13 is VHF, but 14 is UHF).

Markets with both 4 & 5:
New York, Los Angeles, Dallas-Ft. Worth, Nashville, Seattle, San Francisco,
Oklahoma City, St. Louis, Boston, Washington DC, and countless others.

Both 6 & 7 markets:
Miami, Omaha, Denver, Spokane, Wichita Falls TX/Lawton OK, and others
I can't remember.

Both 13 & 14:
Houston, El Paso, Minot ND, Salt Lake City, Oklahoma City, etc.
 
> Unless I am wrong. You actually meant to say that channels
> 4 and 5 are adjacent, didn't you?
>
> -John L.

Nope. Channels 4 and 5 are not adjacent. There is a 4 MHz gap (72-76 MHz) between them, which is the reason both channels can be in the same city.
 
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