Monday, September 07, 2009

GUEST COLUMN: Cleveland Digital TV

Long-time OMW reader Trip Ericson (RabbitEars) gives us his take on the local digital TV situation, including potential channel availability should one of the Cleveland market stations wish to make a channel move...particularly the alleged CBS affiliate currently stuck on RF digital channel 10...


Hello, all!

I'm Trip Ericson, the lunatic behind the website RabbitEars.Info, and I've penned this special guest feature on Ohio Media Watch to try to address some of the questions about WOIO and where they could move assuming they wanted to jump ship from channel 10.

This entire article will be written with the assumption that channel 31 is reserved for WJW, even though in reality, it's not. If WOIO was to take channel 31, then this article would apply to WJW just as well. Channel 31 is an open channel by all standards, and would solve the problem for one, but not both, of the VHF broadcasters in the market.

The big problem with all of this is that the FCC's interference rules are rather vicious. In the analog world, there were hard distance limits. If you were x miles away, your station fit. If you were x-1 miles away, your station did not fit. Very simple to understand and very logical.

In digital, the FCC requires a Longley-Rice interference study. The FCC rule is that your allotment cannot create more than 0.5% new interference to any one station. That is to say, you can cause 0.49% interference to station A, and 0.49% interference to station B, and still be within the rules.

The software to run these studies is made available on the FCC website but only runs on a specific computer system. Any other software to perform these studies costs many thousands of dollars, putting it out of the reach of many. I have a friend with access to some software to run these analyses, and had hoped to have him run some studies on WOIO for me, but as press time approaches, he has not been online since I decided to write this article.

Cleveland being where it is, so close to the Canadians, also makes this complicated. To start with, let's look at the Cleveland-area vacant allotments according to Canada:

03 1024' 9 kW ND
05 1027' 9 kW ND
25 994' 67 kW ND
31 (Ignored)


39 958' 200 kW ND

Shaker Heights:
19 1151' 151 kW ND

43 1105' 170 kW ND

A few of these can be tossed out right away. 3 and 5, obviously, would be worse than 10 is now, and thus are removed from the list. 43 is useless due to proximity to WGGN-42, which would almost certainly be way, WAY above 0.5% interference. A signal on 25 would be crippled by KDKA in Pittsburgh and thus unable to adequately cover the area. So this leaves us with channels 19 and 39.

Now, these are just channels that the Canadians have already negotiated with the United States; there's nothing preventing more channels from being negotiated. Let's pull in some other channels to run through that might look good at first glance:

14, 18, 21, 27, 44, 51

Most of these can be tossed out right away:

14 and 18: These two look very clean, until you read through FCC regulations and learn they are reserved for "land mobile." That is, they're used for two-way communication in Pittsburgh among public safety and other licensees. There's a hard spacing rule of 155 miles that Cleveland simply does not meet.

21 and 44: Adjacent channel issues to WFMJ and WNEO aside, which would probably toss these two out right away, spacing to WMYD and WWJ in Detroit probably would do it too. I would not expect either of these allotments to work out.

19 and 51: These frequencies, though promising, have adjacent channel problems. 19 would likely fail with regard to WFMJ-20, and 51 would certainly fail with respect to WEAO-50. Thus, these channels are not under consideration.

At this point, we now see that what started out as a pretty interesting list of channels under consideration, is now narrowed down to two possibilities: Channels 27 or 39. Let's analyze them.

Channel 27: On the adjacent channels, we find WVIZ-26 and WUAB-28, both of which are co-located and thus would not cause any issues. This leaves us with co-channel concerns. WBGU on 27 is probably far enough away that a minor directional null would safely protect it, though this should be checked with an interference study. The big problem is CKCO-DT-3 in Sarnia, which is allotted 994' 810 kW. Even with a WKYC-style directional pattern, I'm not sure that the Canadians would be willing to accept a channel 27 in Cleveland.

Channel 39: This one is more promising than channel 27. The adjacent channels are more than 100 miles away, which means that interference to them should be minimal. There's a Class A at 92 miles that could be an issue, but an interference study would be needed to determine how much of a problem it would be. WADL is both directional away from Cleveland, and on a short tower, and I suspect would not be a problem. Plus, channel 39 already existed as an allotment for WDLI, so the chances of it working are good. My question would be just how much power they could run on 39. It's possible that it wouldn't be enough to satisfy them.

Now, I was staring at it for a while, and I came up with another possibility that might actually be superior to either channel 27 or 39, but I'm not sure how much of a problem it will cause.

Channel 33 caught my eye because it was clean except for a single Canadian station at 76 miles. CICO-TV-59 (analog 59/digital 33) is only allotted 492' 4 kW ND (that's not a typo) on channel 33. I don't know a lot about Canadian allotments, but unless I missed something, it looks like the currently unbuilt CICO-TV-59 digital signal could be moved from channel 33 to channel 20. This would actually reduce interference that it would receive from adjacent channels.

Relocating CICO-TV-59 would then open up channel 33 for use in Cleveland. The only concern would be to CICO-TV-32 in Windsor, allotted 703' 350 kW ND. A slight directional pattern might protect it if it's even an issue. I wonder what the Canadians would say to this proposal, given that the vacant but agreed upon channel 31 allotment is also adjacent to it. Perhaps WOIO could trade the current channel 19 analog antenna to CICO-TV-59 to use on channel 20 digital, assuming it's usable for that.

It seems perfectly logical. I suppose that's why it would never happen.

Ultimately, after all that study and analysis, the most certain answer I can give is "I don't know."

Without the ability to run an interference study, channel 39 looks the best, but that's no guarantee that it works in a satisfactory manner. I would suspect that if WOIO wanted to get off of channel 10 bad enough and they were not in the Canadian border zone, they could make it work regardless, but the Canadians are an unknown.

Finally, I'd like to direct readers to a project I've been working on. I have been teaching myself PHP through coding a project for RabbitEars. I put it in public beta last week and it's currently called the "DX Tool." I plan to change that name, as it's misleading in that it's not just for DXers.

I would like to ask readers of Ohio Media Watch who use over the air to consider trying out the DX Tool. By doing this, the DX Tool allows for the inversion of the reception reports to form a coverage map based on real world reports.

Sign up and submit reception reports for your local stations and maybe we can fill in this map with data showing just how bad reception is for WOIO, plus reception issues for WJW or maybe other stations as well can be shown on their own respective maps.

Thank you to Ohio Media Watch for giving me the opportunity to write this essay. Continue the great work!


david5258 said...

I think that Youngstown falls within the 100 mile parameter, which would negate 21(wfmj/nbc), 27(wkbn/cbs) and 33(wytv/abc).

Ohio Media Watch said...

Remember, David, WFMJ is no longer on 21, WKBN is no longer on 27, and WYTV is no longer on 33.


The PSIP just fools you into thinking it's still 21, 27 and 33.


Don Guisinger said...

One thing not mentioned in the guest article is that WIVM has applied to put a digital signal on the air in Canton on 39. here's the application info. I have to plead ignorance here, but if WOIO wanted that channel after WDLI moves to 49, would they get preference to the channel since WOIO is a full strength signal?

Don Guisinger said...

One thing not mentioned in the guest article is that WIVM has applied to put a digital signal on the air in Canton on 39. here's the application info. I have to plead ignorance here, but if WOIO wanted that channel after WDLI moves to 49, would they get preference to the channel since WOIO is a full strength signal?

Trip said...

Yes, WIVM as a low-powered signal does not get any protection from the encroachment of full-powered signals. WOIO would get priority and WIVM would be required to find a new channel on which to operate.

Andrew said...

How can WDLI get a permit to use channel 49?? Wouldn't that cause problems for nearby WEAO on channel 50?

Trip said...

Adjacent channels are only a problem in digital if the transmitter is not co-located or nearly co-located. For example, in Cleveland, you had (until June 12) WBNX-30 and WJW-31, coming from the same tower farm. This is fine. However, if WBNX's transmitter had actually been down in Canton or something, it would have caused interference problems.

Mike said...

thanks for this update it was very helpful in understanding the issue.

david5258 said...

oa-just spent 3 weeks working in the youngstown market. when i took my breaks, the store tvs were set to wfmj dt 21.1, wkbn dt 27.1, wytvdt 33.1. my network showed up as 27.2, fox showed up as 27.3, fusion tv showed up as 49.1. if what you say is true, why doesn't the fcc mandate ID on the new number? i know a lot of changes have taken place over the summer.

Don Guisinger said...

Why should it be mandated to identify the RF channel assignment?

Assuming you're an average TV viewer, as long as your set-top box ATSC tuner is working correctly you wouldn't need to know the RF channel.

It doesn't really work in the station's advantage to promote their RF channel assignment. As far as viewers are concerned, they're still 21, 27, and 33. The stations have marketed themselves as channel ______ for years. Why change it now? Changing their branding now would only confuse viewers.

Let's also remember that cable and satellite viewers don't give a hoot if the actual RF signal isn't on channel 21 since their lineups weren't affected by the transition on June 12.

Andrew J said...

It makes me wonder whether WJW or WOIO really give a rats behind about their OTA coverage area. This considering the Cleveland area has a very high rate of cable/satellite TV viewership(supposedly). It seems to me that if WJW was serious then they would have filed for an STA for 31 right away like many other stations did after they discovered that high-VHF was not the golden pasture of great coverage with lower power that they hoped for.