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CO-CHANNEL DIGITAL CHANNEL DISTANCES

One night I got bored and was drawing some maps of where the new channels would be.

I threw them up on a website. It's not much but you can kind of get an idea of the allocations for the new digital TV stations.

http://dtvallocations.com

Since I drew the maps it's only an approx of the city location.
 
tripinva said:
In Zone I it's 122 miles. In Zone II it's 139 miles. I detail spacing requirements on my site here:

http://www.rabbitears.info/faq.php#avail_channels

- Trip
Click to expand...

Less if the FCC allows it. KVVU-DT in Henderson/Las Vegas NV and KUSG-DT in St. George UT both broadcast from their final DTV facilities on channel 9, but are only 108 miles apart. While both stations' predicted grade B contours reach Mesquite NV, high mountains between St. George and Mesquite means that there probably isn't any signal overlap. Las Vegas stations do reach the higher-elevation outskirts of Mesquite. KUSG-DT puts its signal primarily to the north.

KVVU-DT contour
KUSG-DT contour
 
Well, for new stations, those are the requirements.

The FCC did allow some that are spaced quite a bit closer, especially in places where they had trouble packing all the stations in. I think KVVU/KUSG was a bad one considering how open the band is; if they allowed KVVU on 9 they should have moved KUSG elsewhere. But that's just me.

- Trip
 
I was surprised to see the two allocations so close, especially since the UHF dial is pretty well open in that area, and could have been used for KUSG. With Vegas stations on 15, 16, 21, 22, 29, 33, 39 and 40, and SW Utah stations (beside KUSG) on 14, 18 and 19, there was plenty of spectrum available.
 
Another channel 9 allocation I'm concerned about is in Indiana/Illinois. WNIN in Evansville, WILL in Urbana, and WISH in Indianapolis may have some interference. TIGER puts the WILL 54 dBu at the Indiana/Illinois line and the WISH contour 5 miles or so from that. WNIN has a fair bit of room according to the FCC TIGER map.
 
The FCC really had to pack some stations in. The spacing requirements are so small for exactly that reason, and they still end up broken in a lot of places.

My website has an automated tool to find what channels can be allocated in a given zip code or at a given set of coordinates, based on the FCC's spacing requirements. There are quite a few existing stations which fail the test.

- Trip
 
I can think of a few problems already. WCVB Boston is on CH 20, and WTXX Waterbury will also be on CH 20 post-transition, WFSB Hartford & WCBS NYC are both on CH 33 (how hard is it to get either one of these two down in hmm, the western shoreline area of CT? WEDY is supposed to return as DTV on CH 6, but WMNR 88.1 is a 10kW in Monroe and WESU also at 88.1 has a CP to go to 6kW from Middletown (albeit directional due to WMNR).

How many miles is it from WCVB to Rattlesnake MTN? and how many miles is it from Avon to the ESB? This is some pretty short spacing here.

Plus didn't WCVB also start interfering with new policeband radios in Washington D.C.? did that ever get resolved? and wasn't dumping channels 52+ part of the effort to free up space for public service so that this exact problem wouldn't happen (ok, so I haven't had time to keep up on all the news, time to enlighten me).
 
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