Cincinnati, OH - HDTV - Page 109

WKRC-DT currently multicasting a SD subchannel with "precision doppler 12 radar" ....

Following is probably more than anyone wanted to know, but follows are my WKRC-DT observations concerning their recent signal improvements :

WKRC-DT Signal strenth:

Looks like signal strength wise, I'm getting about the same from WKRC-DT and WLWT-DT now here, which makes sense. The difference between 800KW ERP and 1000KW ERP is only a fraction of a db.

Compared to -43db for WKRC-DT/-45db for WLWT-DT when I checked it a couple of weeks back, I just checked it and can still just get perfect reception(~33% signal quality reading from this receiver) from either WKRC-DT/WLWT-DT with -45db attenuation added to feedline(includes an estimated ~2.5db loss from the ~65FT coax run).

So, it seems a couple of db "better" from WKRC-DT, but it is hard to actually say if there was any change in the noise floor(co-channel interference/any IM present etc) ....

I expect how much extra attenuation I can add between antenna+receiver and still be able to decode the signal involves a variety of factors, including signal strength and signal quality, receive antenna gain("supposedly" 16db on Ch 31 in this case according to manufactuer), preamp gain(29db in this case)/Noise figure, overall noise factor of receiving system(which should be right around ~3db(close to the preamp NF), the Receiver's AGC circut/etc/etc/etc .... Of course, ATSC specs say 15.9db SNR is required for perfect DTV reception, so at least that's somewhat of a "given", and that threshold should be close to the 33% signal quality reading on zenith receiver which is generally required for perfect DTV reception ...(a PSIP lock occurs at about 28~29%) ... And, that ~16db threshold SNR I'd think should also roughly equate to the 41dbu signal contour defined by FCC as a DTV stations coverage area(given a 10db receive antenna at 30FT AGL If I recall correctly, although FCC's contour prediction methodology doesn't take terrain into account) ....

Since I don't have any equipment such as spectrum analyzer, I can't vouch for how "accurate" my readings are, only that it should be fairly accurate in the sense that if I add an attenuator marked "10db attenuator", It should be actually attenuating signals passing through the coax by 10db, a 2 way splitter should be 3db insertion loss/etc/etc, an adustable RS attenuator(to max -20db) should be adding -20db attenuation of knob is fully clockwise/etc/etc .... It would of course be better, and probably produce a bit more accurate estimate of signal strength at this location to take out everything(especially the preamp) between the receiver+antenna except for the coax+a balun+then estimate the antenna's gain and subtract estimated feedline loss, however, as among other things that would also be very inconvienient since it would require removal of rotor, lowering of mast, getting my VHF antenna out of the way/etc/etc to remove mast mount preamp ...

Anyway, also It is taking -18db attenuation before signal quality readings from WKRC-DT start dropping any from 95~100% on Zenith HDV420 receiver.

WKRC-DT Signal Quality:

What has been a more noticable improvement is that prior to their improvements -- for about the past couple of years sometimes, the signal quality meter on Zenith receiver would only show a maximum of about 80%, and sometimes it would show about 80% for a few seconds when first tuning to the station, then afterwards it would go up to 95~100%, and sometimes it would show 95~100%, even when first tuning to WKRC-DT ..... I couldn't quite figure it out, my best guess was that it had to do with the signal being so strong along with what the receiver's AGC was doing. But, Now, it's allways a solid 95~100% so apparently the signal quality improvements at WKRC-DT did the trick.

BTW, With the DTC-100(which is currently out of commission, I can't check it currently), it would show between 76~82 most of the time, except prior to about two years ago, it was allways showing an "88" reading. It seems to like "88" for some reason, that's what it pretty much says for most ofl the Dayton/Cincy stations ... except WLWT-DT, which shows up as 90~94, and WRGT-DT also 90~94, and WCVN-DT usually "82" but sometimes 86~88 ....

possible WKRC-DT channel mask improvement? :

It's a little hard to say/tell but, on ch 32 using a analog, non-screen muting TV and looking at the "snow"(Snow from a strong DTV station appears as a sort of "big" horizontal snow on some analog TV's, either depending upon how AFT is implemented, or NTSC tuner which allows manual "fine tuning") it looks like WKRC-DT may have improved their channel mask a bit ... Can't really check anything on 30 in this regard, because of WRGT-DT 30 Dayton.

Attached is a series of screenshots to demonstrate(with antenna aimed at Cincinnati of course). At upper left shows the "snow" on Ch 32 if I have the tuner set at "-05" offset for ch 32. (Note -05 offset on this tuner seems to usually do the best job with weak signals on nearly all channels). As you can see, It's pretty much "clean" looking ordinary "snow"(The brighter white "band" 1/3 of the way down is a camera "shutter speed"/etc. "artifact") - probably mostly from noise in the front-end of receiver/preamp, but also somewhat from background radiation from the "universe"(you know, the dancing "ants") ... At upper right, shows the snow on Ch 32 with -08 offset on the NTSC tuner ... You probably can't tell much, if any difference via this screenshot, but if you could, in "real life" that was about what "-05" on Ch 32 looked like here before WKRC-DT made their improvements(The slight bit adjacent channel interference/"slop" was more evident when a actual NTSC signal from WLKY 32 Louisville is present).

So, It does seem to be a noticable improvment. The lower pic shows what WKRC-DT's "DT Snow" looks like via with a -17 offset on this NTSC tuner, tuned to ch 32(I wish I knew what the actual "center" freq. was, instead of just -17/etc). Note that with WLWT-DT, on ch 36 it looks pretty much the same with these same offsets, except that I'm currently(as is usually the case) getting a weak and somewhat unstable signal from WTVQ 36(analog), Lexington, which does looks quite "clean" with an offset of "-05" ...

Having come across very little info on it I have allways wondered, when working with strong signals what the 1st adjacent channel situation would be like for weak 1st adjacent channel signals(analog or DTV) if the signal modulation being used was COFDM instead of 8VSB ...

I do a lot of outdoor work, and, although I'm probably in the minority on this(well, maybe except for Hedrick) I'd actually like to have the radar up all the time(just more convienient for me to use the TV radar instead of the net, although the latter is fine too, and I've allways liked WKRC's radar better than the others), but only IF it didn't reduce HD PQ, including during bandwidth demanding programming ...

I know you are just doing it temporarily for testing purposes, but IF it is being considered on a more permanent basis ... if it could be setup with Stat Mux so HD allways gets the priority, to the point of the SD radar being able to drop all the way down to 0 bandwidth usage(without locking something up anyway) during those very short periods during HD sports/other bandwidth demanding sections of programming .... I think it would be great, and it seems to me, weather radar would be one of the very few applications where it wouldn't matter if the screen freezes for a second occasionally when HD needs everything ...

On the other hand, of course setting it up, and devoting what would essentially be your available "oppurtunitstic" bandwidth to a weather radar screen may not be exactly "econmically" wise .... Especially when we already have WCPO-DT doing a multicast SD weather service(with radar), with, apparently weather plus also soon to come from WLWT-DT .... But, don't worry, personally -- I still tune to Hedrick+crew when I want the Cincy weather forcast ...

This of course is local WCPO-DT issue, not a ABC Nat'l issue. When WKEF-DT actually is sending HD, it's easy to see not only the "jaggie free" aspect of ABC HD from WKEF-DT, but also quite apparent increased resolution/sharpness/etc(because, IMO, contrary to what we are getting from WCPO-DT since 8/04, it actually is true HD from WKEF-DT, with 1280x720 unique pixels in every frame).

WCPO engineering have told me they are going to do everything they can to get rid of the "jaggies" and have "pristine HD"(you know, how it used to be before their studio move last summer) by the time MNF HD football rolls around again ...

We'll see ...

Junk,

WDTN-DT's CE email address is listed on this page at WDTN site :

http://www.wdtn.com/index.cfm?action...ory&storyid=46

I noticed the email address for him as shown on the site is different than the one I have, perhaps that is why I have not received a response from him in a long time, although my emails never bounced back .... I can say however that in the past, he used to be very responsive to viewer inquiries/comments/etc ...

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I don't know why PSIP info isn't working from some of the stations, as all those seem to be working just fine, here. WBDT-DT Dayton is the only one currently(and for the past 9 days) which is not decodable with Zenith receiver here, I suspect because of a PSIP issue they are likely having. Channel remapping from VCT is also working properly from everyone(except WBDT-DT of course).

Just an idea, but you might want to try to "investigate" the possibility that your receiver/receiver's firmware may not be fully supporting A65b PSIP standard. I do know I think I've heard the internal Mits tuners are very good about "falling back" to using MPEG program info(and therefore still actually be able to decode the streams when it can't "figure out" the PSIP info the station is sending) .... And, I think I'd read that the earlier mits internal tuners weren't designed to support PSIP at all(obviously not the case with yours).

Personally, at this stage of the game I'm pretty happy as long as the A/V can be properly decoded on my end ... I surely don't care what channel # a station "shows up on"(I'd actually prefer turning VCT info "off" and using the actual RF channel # rather than the remapped channel # - too bad most receivers don't let you do this) ... Off air EPG info, and some of the other stuff from EIT/ETT certianly are a nice feature though ...

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Update: couple of other thoughts -- I'm sure you've already tried this, and I have no idea how your receiver model behaves in this regard -- but just in case -- Some receivers seem to require a channel rescan after a station changes certian values in their PSIP tables in order to see their PSIP info properly .. Especially if you haven't done a channel rescan in a while(which should clear out any "old stuff"), you might want to try it and see if it helps ...

Other than that, only other thing I could think of is some sort of "bug" that's specific to the PSIP setup at the station and your particular receiver model -- These such issues can be difficult, and may require cooperation and communication concerning the issue between station engineer and your hardware manufacturer ...

Let us know if/when it ever gets worked out and, if you find out what the solution was ...

Junk,

WDTN-DT did make a PSIP change around the time you lost them, along with the PID change(WXIX, and most other stations did PID change as well around that time) -- The MPEG program streams from WDTN-DT used to be:

50-2 - HD (PSIP remap to 2-1)
50-3 - SD (PSIP remap to 2-2)

Since Jan or so, that changed to:

50-3 - SD (PSIP remap to 2-2)
50-4 - HD (PSIP remap to 2-1)

So, the SD and HD "flipped" around if you have a receiver that's not using the PSIP VCT info.

Update: Oh yeah, another thing - WDTN also began sending EPG info via PSIP for their ANALOG station (2-0) around the time of their PID change. They are the only station in the area that seems to be doing this presently, although WCVN-DT used to do it for WCVN 54-0.

Also, yeah, receiver model specific PSIP issues with receiver's which depend upon proper PSIP from the station are a drag ....

On WBDT-DT, so you are seeing it remapped to Virtual Channel 26-1 instead of as 18-3, even if you have done a channel rescan since 5/13 ?

My DTC-100 is "in for repair", but has decoded them just fine(but only when I had PSIP turned off on it, I don't have that option on my Zenith receiver) when this has happened previously, and the Zenith Did not. WBDT-DT stopped decoding here on 5/13 when a line of storms moved through Dayton, this happened before 2 times, on 4/22 for about a week and a half until they fixed it, and for a week or so previously in the past 6 months or so, can't recall exactly when.

BTW, When it was working I've never seen Program guide info from WBDT-DT, I don't think they are sending any.

Thanks,

Was watching HD "Everwood" on WSTR-DT tonight, and during the program they inserted a promo for a WB 64 news story they are doing tonight at bottom of screen ... They did NOT drop from HD!

The only other time I've seen anything like this from a local station was the "WEBN" logo during HD Riverfest coverage from WKRC-DT in 2002+2003, and the UC HD games from WXIX-DT this year .. But, those of course involved HD production trucks ....

Way to go WSTR

Good news, thanks for the update.

nachoman91,

I'm afraid the Cincinnati stations coverage area reaches to a few miles or so North of I-70 .. Much farther than that and, due to the height of transmitting antennas the main limiting factor for reliable VHF/UHF reception(Curvature of the Earth) is going to get in the way.

With a hi-gain directional antenna setup mast mount preamp and mounted as high as you can get it, you might be able to pull in the Dayton Stations if you are going to be say -- Celina/St. Marys area or South (Lima+Ft. Wayne are also a possibility from Celina/St Marys) ... ... North of that, Ft. Wayne/Lima and maybe Toledo area might be worth a shot OTA ...

You won't be able to get the Cincinnati stations via satellite(DBS LIL via E* or D*), I'd guess you'll probably be in Either Dayton or Ft Wayne DMA and therefore would be eligible for those stations via LIL (analog, no sat service currently carries DTV/HD locals).

I do believe however TW Western OH(I think they might call it TW SW Ohio now) serves much of that area all the way North to Lima. For instance, a poster in Lima in Dayton thread once indicated via TW, he was getting digital/HD stations out of Dayton, Toledo, and perhaps Columbus as well if I recall correctly.

You might want to search the local Threads for Dayton/Lima, and Ft. Wayne for more info.

Hope this helps.

That is funny ... Their E* surely does often seem to have "rain fade" problems ...

They do have a Construction permit from FCC to move to channel 36 -- its possible that might have something to do with it ...

See the ch 36 listing for W61DE here: http://www.fcc.gov/fcc-bin/tvq?state...&slon2=&size=9