Houston PBS 8.1 (only) stopped working with Windows Media Center

twegner

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Houston PBS 8.1 (only) stopped working with Windows Media Center

#1

Post by twegner » Tue Oct 01, 2019 4:46 am

I have used Windows Media Center (WMC) for many years, for the most part happily. That said, today I saw a bizarre problem. I feed my WMC box with an antenna signal from a high gain antenna on the roof. Today WMC gave me a message that it wasn't recording the PBS Newshour on KUHT 8.1 here in Houston because there was "no signal". All the other channels work fine. The weird thing is that there IS a signal. I also have the Hauppauge WinTV on the same Windows 7 box, and it works great with channel 8.1 with the very same signal. And I can switch my monitor, which is really a TV, into TV mode and it too receives channel 8.1 with the same signal just fine. Thinking maybe there was a problem with that Windows 7 HTPC box, I tried another old Windows 7 machine in another room that also has WMC on it and saw the very same symptoms: channel 8.1 has "no signal", all the other channels work with WMC, and WinTV on the same box works fine with channel 8.1.

I looked through the various WMC setup options, and saw that WMC thinks the channel 8.1 signal is strong. It's just that if you actually try to display TV from channel 8.1 that WMC says "no signal".

I'm wondering if either something got pushed out with the guide that messed up both instances of WMC for channel 8.1, or if something about the channel 8.1 signal actually changed that somehow affected WMC but not WinTV or my TV. I might call the station in the morning, but I doubt they will have much of an idea what I am talking about.

My short term fix is get WinTV to record the newshour, and use WMC for everything else. And while I hope the problem will magically go away, maybe the time has come to replace WMC with other software a bit sooner than I thought would be necessary.

If anyone has seen anything like this before, please let me know.

Tim

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StinkyImp

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#2

Post by StinkyImp » Tue Oct 01, 2019 2:50 pm

I have a channel (not PBS) that exhibits this same behavior. Occasionally I'll scan the airwaves with my TV (hooked directly to my antenna) to see what it captures. Then I'll go into WMC and do a scan and then verify it against what the TV captured. Then I just add the "missing" channels in WMC.

I did this yesterday and had a particular channel that just wouldn't cooperate.
  • Worked fine on the TV connected directly to the antenna.
  • Worked fine in WinTV using the same Hauppauge tuners that WMC uses.
  • Would NOT work in WMC. Tuner lit but showed "no signal" and had 100% strength.
I have no clue what could be causing it but I suspect it has something to do with the "assigned frequency" and I don't know how to determine the correct one. I found that my "problem" channel's frequency is UHF 599MHZ but that's not much good for assigning a two digit frequency in WMC.

Is there a regional/city listing of OTA channels somewhere that gives the WMC assigned frequency for each available channel?

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#3

Post by dmagerl » Tue Oct 01, 2019 3:48 pm

StinkyImp
You can go to rabbitears.info and find your metro area and then get the actual assigned physical channel from the listing. The US is in the middle of a frequency remap/repack so a lot of stations will be moving freqs if they havent already. That's indicated by a channel number-arrow-channel number in the listing. Meaning the old channel is moving to the new channel. 596-602 corresponds to channel 35.

twegner
It can indeed be something the station did to goof up the channel. There is something called PSIP (Program and System Information Protocol) that the station broadcasts and if the station made a change it and goofed it up, it could result in what you're experiencing. If so, nothing to do but call the station's engineering dept. and hope they listen to you. As to troubleshooting, the first thing I would do is manually add the station, thus manually bypassing the guide data, and see if the station comes in. If so, its Microsofts fault, not the station. It could also be environmental conditions causing the issue. We are just entering prime tropospheric skip season so it could be an interfering station, or it could be multipath, or it could be a bad something in your antenna system (unlikely since you mentioned a strong signal). It could also be WMCs fault. Go into the guide and right click the affected channel and then edit channel/edit sources. There should be a list of sources for the station and and their channel. There should be one source for each tuner you have. (It only lists the first 4 so if there's more you have to scroll the list.) Disable any you deem suspicious and see if that fixes it.

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#4

Post by twegner » Tue Oct 01, 2019 10:06 pm

StinkyImp - your situation matches mine EXACTLY. no luck yet. Haven't figured out what "assigned frequency" to enter yet, though I have found buckets of information about the station at rabbitears.info
dmagerl - I'm investigating all your suggestions (right clicking channel in guide, edit sources, etc.), haven't found anything yet.

Thanks to both of you for responding. Haven't called the station yet. From general web searchs, I see that we are not the first folks to have this problem.

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#5

Post by john z » Wed Oct 02, 2019 2:22 am

Same problem here in Houston, so you can rule out it being specific to your setup or signal. Much like you I haven't been successfully in figuring out what to do. I was considering trying to integrate WMC with EPG123 and see if something is different in their guide data that might drive the tuning???

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#6

Post by garyan2 » Wed Oct 02, 2019 3:10 am

You can use the EPG123 client to see what your tuner frequencies are for the channels in your guide. I have something a little similar in that being surrounded by mountains, we have different towers transmitting the same stations on different frequencies, but use the same logical channels. In my case, it is:

Code: Select all

Physical     Logical     Stations
9              9.1        KGUNDT
27             9.1        KGUNDT
As you can see, the logical channel is the same but the physical channels are different. My case is similar in that the broadcast on physical channel 27 is not very good in my location and I can get "no signal" alerts on it. I'm wondering if during your frequency moves, they are still transmitting on the old frequency just with no content. Are the subchannels working?

A scenario I don't like would be they are using a different codec and WMC can't handle it. A failure to decode would be translated as a "no signal" condition.
- Gary
Stomping out the Rovi disease, one media center at a time. http://epg123.garyan2.net

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#7

Post by Roginator » Wed Oct 02, 2019 10:11 am

I'm having a similar problem. My Recast shows the channels correctly, but WMC doesn't.

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#8

Post by dmagerl » Wed Oct 02, 2019 12:05 pm

If it is a frequency problem, manually adding it in with the correct frequency should fix the issue..

If that doesnt work, and if everyone with WMC in Houston is having the same problem, it points to a PSIP issue with the station.

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#9

Post by StinkyImp » Wed Oct 02, 2019 4:27 pm

Hi dmagerl and garyan2!

Thank you for your wisdom and guidance. As they say... a picture's worth a thousand words.

I've tried to set up 35.3 using frequency 15, 33, and 35. No luck. They all exhibit the same "no signal" phenomenon.

Rabbitears also indicates that the callsign hasn't changed since 2011.
garyan2 wrote:
Wed Oct 02, 2019 3:10 am
A scenario I don't like would be they are using a different codec and WMC can't handle it. A failure to decode would be translated as a "no signal" condition.
How would we find this out?

The tuner is picking up this signal in WinTV. Wouldn't it use the same codecs that WMC uses?

The only codec pack I've ever used is Shark007's. I'm currently running 64 bit v 8.3.3. His current version is 12.3.0. Maybe I need to update?

BREAKING NEWS!
I uninstalled WinTV and installed 8.5.37122 (May 2019) and had it do a rescan. 35.3 showed up perfectly again!
I looked at the properties, and lo and behold... it was on physical channel 12.

I set it up in WMC with an "assigned frequency" of 12 and it worked!

The only thing strange about it is... when I went in to set up the listings and check the tuner assignments I put it on "Show Preview" and it took a really long time to show up. By "long time" I mean probably a minute. When it did come in it showed a test screen with that high pitched squealing sound. It flashed the call sign a few times and then finally tuned the show that was on.

All's well that ends well!

Thanks for all your help! :)

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#10

Post by dmagerl » Wed Oct 02, 2019 7:03 pm

StinkyImp.
You have to be careful. A lot of stations out west, Phoenix included, use repeaters to get full coverage. In this instance 35.3 is rebroadcast as a subchannel on KPNX on physical channel 12 out of Mesa. You are probably out of range of KFPH ch 35. According to Rabbitears, ch 12 is at twice the height and twice the power.

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#11

Post by bobviolence » Wed Oct 02, 2019 7:22 pm

Same exact problem as OP ...

I've watched/recorded Houston OTA 8.1 KUHT for years on WMC 7 fed by a network HDHomerun with no issues. Few days ago, I noticed that scheduled recordings were failing due to no signal on 8.1 only. WMC shows 8.1 has 5 bars when checking signal strength, but when you tune to it, you get nothing (except the standard no signal message). On the same machine, I can watch 8.1 no problem with the HDHomerun software. I rescanned the channels in WMC just for kicks, but no help.

I have another WMC 7 box in the house, and it has the same issue.

I found this, but haven't had time to look into it (deals with PSIP, specifically post #2):

viewtopic.php?t=2257

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#12

Post by bobviolence » Wed Oct 02, 2019 10:07 pm

(I have no clue what I am doing when it comes to this stuff; I'm just following marching orders written by others)

So, as mentioned in the article above, I found these two items:

http://www.tsreader.com/purchase/purcha ... dlite.html

https://community.tablotv.com/t/tablo-f ... ds/9037/44

I see that piping 8.1 into TSReader, there is *NO VCT ENTRY* in the tree.

But using a working station (11.1), there is an expected VCT entry as the article discusses. Could this be the issue, since obviously the TSID values can't match if there isn't something to match it to from the PAT PID TSID value. Acronym soup for all!

(I'm too lazy to take screenshots, but my word is gold) ;)

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#13

Post by StinkyImp » Wed Oct 02, 2019 11:16 pm

dmagerl wrote:
Wed Oct 02, 2019 7:03 pm
You have to be careful... You are probably out of range of KFPH ch 35. According to Rabbitears, ch 12 is at twice the height and twice the power.
That's curious. Phoenix is a huge flat valley, hence the name "Valley of the Sun". The average elevation in the valley is between 1,100 and 1,200 feet. On the south end of the valley there's a mountain range named "South Mountain" that is home to all the transmission towers for TV, radio, emergency management, etc.

I can see this mountain and all the towers clearly from my house, which is approximately 20 miles away. The two towers are only 169 feet apart on South Mountain and are at around 2,500 to 2,600 feet in elevation.

At this distance, at my elevation, and with a clear line of site I should be able to pick up 35.3 but I can't.

Are you saying that the channel 12 rebroadcast is so much more powerful that it's "drowning out" the signal being broadcast from the channel 35 tower?

Is the channel 35 tower even broadcasting channel 35.3?

Like I said... curious. :think:

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#14

Post by dmagerl » Thu Oct 03, 2019 12:24 am

I can only say what I see on rabbitears.

It shows 35.3 on ch 35 KFPH and on ch 12 KPNX. I misread the height. ch12 is twice the height AGL but being on top of a mountain, thats insignificant. However, ch12 is twice the power.

I went back to rabbitears and looked at the info for ch35. It indicates that ch35 has changed over to ATSC 3.0 which explains why you cant receive it if true.

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#15

Post by StinkyImp » Thu Oct 03, 2019 1:28 am

dmagerl wrote:
Thu Oct 03, 2019 12:24 am
It indicates that ch35 has changed over to ATSC 3.0 which explains why you cant receive it if true.
Oh my goodness. One of my biggest fears is that ATSC 3.0 will make WMC7 unusable. I wonder if anyone will make an ATSC 3.0 tuner for WMC7?

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#16

Post by john z » Thu Oct 03, 2019 2:10 am

bobviolence wrote:
Wed Oct 02, 2019 10:07 pm
(I have no clue what I am doing when it comes to this stuff; I'm just following marching orders written by others)

So, as mentioned in the article above, I found these two items:

http://www.tsreader.com/purchase/purcha ... dlite.html

https://community.tablotv.com/t/tablo-f ... ds/9037/44

I see that piping 8.1 into TSReader, there is *NO VCT ENTRY* in the tree.

But using a working station (11.1), there is an expected VCT entry as the article discusses. Could this be the issue, since obviously the TSID values can't match if there isn't something to match it to from the PAT PID TSID value. Acronym soup for all!

(I'm too lazy to take screenshots, but my word is gold) ;)
It’s possible. Although if that is the issue it would seem like KUHT is the only entity that could resolve the issue.

I haven’t had any luck with other possible fixed. I’m using an HDHomeRun and I’ve updated firmware, played with guide entries, etc. HDHomeRun tunes the channel fine, so it’s a WMC specific issue.

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#17

Post by dmagerl » Thu Oct 03, 2019 12:14 pm

One thing you can do is to go to rabbitears.info and find the station in its listings. It has tsreader information for the station from 11/11/2013. (the icon right next to "pbs").

Its old but you could maybe compare today's data against 2013's data and see what differences there are. Then use that info when you approach the station.

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#18

Post by bobviolence » Thu Oct 03, 2019 2:48 pm

I emailed KUHT, and got a response:

-------------

I am no longer able to view your 8.1 digital broadcast on Windows Media Center, which relies on accurate PSIP data. Has this data been altered in the past week? (which is when the problem started).

Others in the Houston area are experiencing the same problem:

viewtopic.php?p=133070&sid=7a7705c29a1d ... 76#p133070

This question is probably best answered by one of your engineers.

You may respond to my email, or I can be reached at xxx-xxx-xxxx.

--------------

Thank you for contacting Houston Public Media.

We forwarded your comments to our engineer and we have been informed that the renewal licensing has not been updated at the station which has caused this error. We are currently looking to resolve this issue as we are in correspondence with the PSIP company to contact us with updates. We apologize for the inconvenience and anticipate to resolve this issue hopefully by the end of the week.

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#19

Post by twegner » Thu Oct 03, 2019 3:28 pm

Wow! Thanks to everyone who responded, what a great forum! I particularly appreciated responses that specifically corroborated problems with KUHT in Houston. But my most fervent thanks go to bobviolence, who did what I had not yet done, and contacted the station. So now we know that the station is aware of the problem, and has stated that the fix is imminent. Since KUHT has promised to fix the problem soon, and since I have succeeded in recording PBS on KUHT 8.1 using WinTV, I can hold out for a week or two if need be. There is nothing at all wrong with WinTV, it is a very solid and competent program, it just doesn't have Windows Media Center's schedule-based programming.

I realize I will sooner or later have to replace WMC. This experience has inspired me to to experiment with Plex or Kodi or MythTV or whatever sooner while Windows Media Center is still working, and not wait for WMC to fail. I have WMC working on both Windows 7 and Windows 8.1 on my HTPC, but the experience is less satisfactory on 8.1. On 8.1 WMC doesn't survive the HTPC going to sleep, I have to exit and restart WMC, a small annoyance, but I probably won't try to debug that problem.
I will report back when 8.1 magically cures itself.

Thanks again, I learned a lot from all the responses, even the ones not in Houston with slightly different problems.

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#20

Post by Mugsy » Sat Oct 05, 2019 2:26 pm

twegner wrote:
Tue Oct 01, 2019 4:46 am
I have used Windows Media Center (WMC) for many years, for the most part happily. That said, today I saw a bizarre problem. I feed my WMC box with an antenna signal from a high gain antenna on the roof. Today WMC gave me a message that it wasn't recording the PBS Newshour on KUHT 8.1 here in Houston because there was "no signal".
Hey Tim. I'm having the same issue. Here is what KUHT told me:

On October 1st, they "transitioned from Local Control in Houston, TX, to Joint Master Control in Syracuse, NY." But said the RF/transponder signal had not changed (from RF 8).

That seemed quite unlikely since a rescan on every other TV in my home (and with other software on the same PC) was suddenly able to "find" channel 8 (but there's no way to see what RF signal it's coming it from.) Even AntennaWeb.org says the frequency has not changed. :?

So I contacted KUHT again and they admitted there may be more to the issue than they first told me:

"[According to one of our engineers,] this is another problem they’ve been working on for much of this week. They expected to be done by now, but it’s looking like Monday."

So hopefully the issue will be resolved by then. I think the only "fix" without waiting would be to wipe your entire lineup (and scheduled recordings) and do a FULL scan. I'm not that desperate yet. ;)

BTW: The alternative TV viewer I used was "SageTV". Not as good as WMC, but the closest thing to it (and it's free.)

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