Problem with a single channel

[bmac.to]

Everyone,

I am a Canadian which, among other things, means the analog to digital OTA conversion took place last night. This meant I had to turn off some analog channels and remap some digital ones. One of the digital channels that was remapped is exhibiting something I haven't seen before.

Many times when I select the channel in the guide, it will give me the "No Signal" warning. If I hit stop and reselect it, it always is able to tune it.

I have seen this occur when a channel is weak, but this channel is one the of the super strong ones (before and after the remap).

I have looked in the Help-Info section to see which tuner was chosen when it works, and when it doesnt, and during my tests it was always the same tuner.

Note that I am running SageTV 6.6 with two 2250s installed which are both connected to the same antenna (a total of 4 digital tuners).

I havent played with this much and I am hoping it is just something stupid I am missing ... does anybody have any ideas where I should look?

Thanks.

[panteragstk]

Originally Posted by bmac.to

Everyone,

I am a Canadian which, among other things, means the analog to digital OTA conversion took place last night. This meant I had to turn off some analog channels and remap some digital ones. One of the digital channels that was remapped is exhibiting something I haven't seen before.

Many times when I select the channel in the guide, it will give me the "No Signal" warning. If I hit stop and reselect it, it always is able to tune it.

I have seen this occur when a channel is weak, but this channel is one the of the super strong ones (before and after the remap).

I have looked in the Help-Info section to see which tuner was chosen when it works, and when it doesnt, and during my tests it was always the same tuner.

Note that I am running SageTV 6.6 with two 2250s installed which are both connected to the same antenna (a total of 4 digital tuners).

I havent played with this much and I am hoping it is just something stupid I am missing ... does anybody have any ideas where I should look?

Thanks.

I've had this happen and rescanning the channels fixed the problem.

[bmac.to]

Hmmm, perhaps deleting the .freq files would do it - or the section of the file that deals with this channel.

I scanned a long time ago but I havent rescanned for years - I just manually updated/added channels as I found out about them. A scan results in many cross-border channels that never get resolved by Sage very well ... the channel list almost has to be created by hand.

I never really figured out whether or not the .freq files have any value - are they the only files that get updated in a scan?

Thanks.

[panteragstk]

Originally Posted by bmac.to

Hmmm, perhaps deleting the .freq files would do it - or the section of the file that deals with this channel.

I scanned a long time ago but I havent rescanned for years - I just manually updated/added channels as I found out about them. A scan results in many cross-border channels that never get resolved by Sage very well ... the channel list almost has to be created by hand.

I never really figured out whether or not the .freq files have any value - are they the only files that get updated in a scan?

Thanks.

The frq files are what scanning finds. Deleting them and rescanning would be starting from scratch. Sounds like a good plan to me.

[bmac.to]

I played around last night without any great success. I removed the old frq files and performed a new scan ... the channel that has issues did get added to the frq file but got added differently than every other channel. At the end of each channel line in the frq file, all channels but this one had a label like

DTVxx.x

The bad channel actually had it's call letters instead. Plus, every channel except the bad one had "Major" set to 0, the bad channel had "Major" set to 9 (which happens to be it's channel).

One other strange thing, when I reviewed the autoscan results, it said that it was unable to tune this bad channel. This is strange since it added to the frq file - I thought only channels it could tune got added?

This autoscan did not end up fixing the problem - tuning this channel is still pretty flaky. However, I did notice that when it could not tune it, if I just waited a minute or so, it would eventually tune it. Due to this, I do not think Sage is trying to tune it wrong - either the tuner card is doing something strange or there is something weird in the way this channel is now being broadcast (incorrect PSIP for example).

I tried editing the frq file to make the channel look like all the other ones with no impact. I also tried renaming the channel so it had fake call letters to ensure it wasnt getting spoofed by some old setting for that channel somewhere.

Are there any registry settings or something that could be confusing the tuner card?

I will give it some time and then report back ... it is not as big an issue as I originally thought. When actively watching TV, trying to tune it a couple of times always fixes it, and if it is a recorded show, the worst that happens is the first minute gets dropped.

Thanks.

[panteragstk]

It really just sounds like the channel is weak and your tuners are having issues locking on to it. Try scanning in wintv or something to see what your results are.

[bmac.to]

Yeah, that matches the exact symptoms. I will try WinTV but if it is weak, something is strange as the TV that is connected to the same antenna, lists it as one of the top 3 strongest stations.

I will report back.

Thanks.

[texneus]

Three potential issues come to mind. Any of these could result in what you are seeing.

First, and probably more likely, is that you have a multipath problem. Most TV's will work with multipath pretty well. IME, most Pea Sea tuners on the other hand don't. Have you tried to move the antenna to a different location?

Second possibly is if the signal is too strong you could be over driving the tuner input. If you have 100% signal strength this could be the case.

Third possibility is the station itself is doing something odd with it's signal that resulted in it taking several seconds to lock. During the digital transition in the US there was one such station where I live and you could see the HDHR (with it's software) really struggle to lock onto the station for months. If you gave it enough time it would eventually lock after 15-30 seconds. None of the TVs were affected. I finally contacted Silicon Dust tech support about the issue, and they had me enable some logging. About a week later the signal magically resolved itself. I don't know if Silicon Dust contacted the station or what, but it got fixed, so I closed the ticket.

[gizmo3141]

Originally Posted by bmac.to

I played around last night without any great success. I removed the old frq files and performed a new scan ... the channel that has issues did get added to the frq file but got added differently than every other channel. At the end of each channel line in the frq file, all channels but this one had a label like

DTVxx.x

The bad channel actually had it's call letters instead. Plus, every channel except the bad one had "Major" set to 0, the bad channel had "Major" set to 9 (which happens to be it's channel).

One other strange thing, when I reviewed the autoscan results, it said that it was unable to tune this bad channel. This is strange since it added to the frq file - I thought only channels it could tune got added?

This autoscan did not end up fixing the problem - tuning this channel is still pretty flaky. However, I did notice that when it could not tune it, if I just waited a minute or so, it would eventually tune it. Due to this, I do not think Sage is trying to tune it wrong - either the tuner card is doing something strange or there is something weird in the way this channel is now being broadcast (incorrect PSIP for example).

I tried editing the frq file to make the channel look like all the other ones with no impact. I also tried renaming the channel so it had fake call letters to ensure it wasnt getting spoofed by some old setting for that channel somewhere.

Are there any registry settings or something that could be confusing the tuner card?

I will give it some time and then report back ... it is not as big an issue as I originally thought. When actively watching TV, trying to tune it a couple of times always fixes it, and if it is a recorded show, the worst that happens is the first minute gets dropped.

Thanks.

Channel 9-9-1 is VHF high, and also very weak @ 1.8kw. Compared to CBCDT or CIIIDT at more than 100kw.

What I'm saying here is that the 'no signal' indication may be accurate.

You need an antenna that is capable of receiving VHF channels 7-13, and because of the weak signal strength, you pretty much need direct line of sight.

I'm facing the wrong way here, and although I get CFTODT at 100%, there are data errors because I'm using a 4 bay UHF antenna and relying on a reflection.

Also, make sure you don't have any other channels in your .frq file that have a logical channel number of 9-1. Sage seems to start at the beginning of the .frq file and simply tune to the first listing it sees that is equal to 9-1, and that may not be the channel you're looking for. For instance 17-9-1 WSYRHD from Syracuse N.Y.

The only channels I have trouble getting now are 47-47-1 Omni and 9-9-1 CFTODT...I'm gonna modify the antenna and attach some rabbit ears on top of it in parallel. Then I might be able to get more channels in the 7-13 range.

Also, if you do have rabbit ears, position them horizontally and rotate them while previewing the channel in channel setup until the signal strength increases. Don't fully extend them, try maybe half way. The frequencies aren't as low as that. Maybe have them extended half way.

Although 9-9-1 is vhf, it is horizontally polarized like a uhf signal.

If your're wondering why OMNI and CTV are so hard to receive, just think about who owns them. Rogers and Bell respectively.

[bmac.to]

I have done some more experimenting with this. I think it comes down to something less controllable - multi-path/overload/etc as texneus suggested.

When I point my antenna away from the transmitter reducing the signal strength, it actually improves the situation. My tuning failure rate was quite high (75%) when I positioned the antenna to achieve the maximum signal strength for this channel - the failure dropped to 5% when I reduced the signal strength (cut it in half according to my TV's signal strength gauge).

The TV's tuner is just better at handling whatever is wrong than the Hauppauge 2250.

Regardless, if I am just patient, the 2250 eventually tunes the channel correctly (within 1 minute 100% of the time).

Note to gizmo3141, I added a VHF-HI antenna to my setup a couple of months ago in anticipation of the cut over - no issue with channel 9 (or the other VHF-HI stations in our area).

Thanks for everyone's help.