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post #12271 of 12285 Unread Today, 12:15 AM
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I wrote:
I saw it earlier this week when watching "The Voice" via Dish Network. Switched to OTA 11.1 and it's there, too. I think KNTV is the source of the problem! Something there is intermittent.
Bobby replied:
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Originally Posted by bobby94928 View Post
Larry, I know you also have Comcast. How does it look there? Comcast is fiber fed direct to the POP.
Good point! I don't watch KNTV that often, but I do watch "The Voice" every week. The next time I see pixelation on KNTV on Dish or OTA, I'll check my Comcast feed to see what it looks like there. I haven't noticed any problems with the Comcast KNTV feed so far.

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post #12272 of 12285 Unread Today, 01:24 AM
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I was just surfing the channels and signals tonight are the strongest I've seen in a long time. It's good to see some signs of action in getting the more distant stations.

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post #12273 of 12285 Unread Today, 07:10 AM
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Quote:
Originally Posted by PeninsulaMark View Post
Unplugging the AC from the AMP ----> SNR = 24. Plugging AC in -----> 25.5 . Have three TV's attached to the AMP.

Explanation for 11.1 now at 25 after being 32-33 for weeks ?

I don't know exactly what's going with your setup but your signals are so strong that you can still receive stations through the amp with it powered off by leakage alone. This is telling you that the amp isn't necessary and you may be better off without it.

As far as KNTV is concerned it sounds like you need to start calling KNTV.

Chuck
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post #12274 of 12285 Unread Today, 07:37 AM
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Now that there is a consensus that KNTV is having a problem, the symptoms sound like their transmitter is the issue. I've seen pixelation problems many times on low power stations. Many of us have seen it on KFTY and K03HY.

My observation is that if the link is the problem, then you see pixelation but the SNR is stable. I've actually seen messages on KMMD that say "weak signal" when the link is bad. OTOH, if you see pixelation and the SNR is unstable then there's a transmitter problem. From Mark's report the problem seems to be with their transmitter.

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post #12275 of 12285 Unread Today, 08:36 AM
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Sounds like until KNTV pulls the plug out of their @@@ and looks into what the cause may be, we're stuck with this problem for awhile
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post #12276 of 12285 Unread Today, 10:28 AM
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Quote:
Originally Posted by dr1394 View Post
MPEG-2 bit-stream errors are pretty interesting. Exactly where they occur can make a big difference in the visual severity of the impairment. In my simulated example, I stacked the deck to make it more severe.

First, I chose an I-frame (also called a key-frame) that was right after a scene change. Then I flipped a bit that caused the decoder to realize that the bit-stream no longer makes sense. However, in MPEG-2 there is a resynchronization point at the first macroblock for each macroblock row (that is, the left hand side of the image).

Here's what that I-frame looks like. The error is in macroblock row 28 and column 27. The decoder gives up at column 40 (there are 1088/16 = 68 rows and 1920/16 = 120 columns). Since the decoder gave up, the orange video you see on that macroblock row is what's leftover in the frame buffer from a previous frame (in this case, since it's at a scene change, it's obviously different). The decoder resynchronizes on the next macroblock row.
Again, much thanks, those two posts have explained what many of us have seen on and off for years in a very easy to understand and informative fashion. If you need a second career you should try your hand at education!
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post #12277 of 12285 Unread Today, 10:33 AM
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Quote:
Originally Posted by Otto Pylot View Post

Watching Grimm now and there are sill some sporadic issues. Hopefully a KNBC engineer is reading this. The issues we are seeing now seem to be more audio related than pq.
As an FYI for research on this problem, I watched Grimm on KNTV via Comcast last night and there were zero problems. I have several other KNTV recordings I haven't had a chance to watch yet but when I do I'll report back, but it does seem as if the fiber feed to Comcast is problem free.
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post #12278 of 12285 Unread Today, 10:55 AM
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Quote:
Originally Posted by Keenan View Post
As an FYI for research on this problem, I watched Grimm on KNTV via Comcast last night and there were zero problems. I have several other KNTV recordings I haven't had a chance to watch yet but when I do I'll report back, but it does seem as if the fiber feed to Comcast is problem free.
So, it seems we have isolated the issue to the station to the transmitter, feed or transmitter itself....

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post #12279 of 12285 Unread Today, 10:58 AM
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Quote:
Originally Posted by bobby94928 View Post
So, it seems we have isolated the issue to the station to the transmitter, feed or transmitter itself....
It seems that way, I also have DirecTV but they get a fiber feed from KNTV as well so that option is of no help.
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post #12280 of 12285 Unread Today, 11:09 AM
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I left my TV on KCSO this morning with the diagnostic screen enabled to see when K03HY went off. That occurred around 10:45 am when the KCSO SNR jumped from near the cliff to 30 dB. That would indicate that K03HY was about 15 dB weaker than KCSO. I added 20 dB attenuation and KCSO was still SNR 28 dB so I'm expecting KTVJ to be about that strong with an SNR of 28 dB when it comes on the air. KTVJ should be 3 dB stronger than K03HY was based on antenna patterns.

Chuck

Edit: KTVJ is already on the air. It is SNR 24 dB here because it has a 10 dB downward slope to the signal from low to high frequency. I wasn't expecting to see that. That effectively makes it 25 dB weaker than KCSO.

Edit: Added analyzer image showing KFTY, KCSO and KTVJ.
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post #12281 of 12285 Unread Today, 11:43 AM
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It sure didn't take Keith long to get KTVJ on the air after turning off K03HY.

The channel 4 signal, virtual 12, is not quite as strong here as the channel 3 signal was. It's coming in at 19 dB SNR vs 21 dB SNR off the side of my 10 element VHF antenna pointed toward Walnut Grove.

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post #12282 of 12285 Unread Today, 12:44 PM
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KNTV is finally coming in here. Five seconds after I tuned it in I saw a glitch in the picture. I brought up the diagnostic screen and the SNR was 21 dB so the glitch was not caused by a weak signal. I watched the hockey game for 15 minutes and saw at least another half dozen picture/sound breakups. The SNR never budged, not even 0.1 dB. From this end it looks like a link problem.

I shot off an e-mail to Doug Lung about this since he contacted the KNTV engineers about the K15CU call sign issue very fast. Maybe that will get some action.

Chuck

Edit: The KNTV glitches continue so I watched a bit of the game on KCRA and then on KSBW. No problems.

Last edited by Calaveras; Today at 01:38 PM.
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post #12283 of 12285 Unread Today, 01:24 PM
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If that doesn't do something nothing will!

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post #12284 of 12285 Unread Today, 01:51 PM
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K15cud

[QUOTE=

I shot off an e-mail to Doug Lung about this since he contacted the KNTV engineers about the K15CU call sign issue very fast. Maybe that will get some action.
.[/QUOTE]

Maybe you could get him to fix the K15CUD (Cozi TV) guide info. It is off by 3 hours. It should be the same as 11-2. Thanks.

Dave
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post #12285 of 12285 Unread Today, 02:19 PM
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Quote:
Originally Posted by PGDave View Post
Maybe you could get him to fix the K15CUD (Cozi TV) guide info. It is off by 3 hours. It should be the same as 11-2. Thanks.

Dave

I heard back from Doug and he said they're going to have an engineer visiting KNTV soon to go through the transmitter to optimize the transmitted SNR. Further he said he'll have station personnel check into this problem using TS Reader. Sounds to me like no one has looked at it yet.

I passed along your K15CU schedule issue.

Chuck
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