622 OTA tuner gone nutty

[M Sparks]

I turned on my only OTA digital channel worth watching the other morning (NBC) and it's gone black, even though the signal strength was in the 90s. Later in the day when it was still out, I did a front panel reset...nothing. I ran the channel scan to see if any of the other channels (which I had deleted) were coming in. One indie channel that just broadcasts a blue line popped back up even though the signal strength is in the low 60s. It didn't find the Telefutura station that normally comes in well. (Those are the only three on the air here- neat, huh!)

I deleted all the channels and searched again- this time only the worthless blue line was detected. If I try to manually add the NBC station, the signal strength was still good, but it can not be added.

Since the NBC and Telefutura DT stations are on a different mountain than the other station, I thought the problem might be at the transmitters. But I'm friends with the engineer at the NBC station, and he says both channels are up and running fine. I'm also picking up the analog versions perfectly. (I had to run a cable to my VCR, since that's the only analog tuner I have left.)

Anybody have any ideas? Should I do an "unplug it for a while" type reset on the 622? We did have a monster storm recently, but the analog picture is as good as it gets, so the antenna seems to be OK.

 

[boy921]

Sounds like the station is having problems with the data in the signal. Did a yellow warning screen appear with the black screen (applicable to the 622)? Generally one does pop up and if the help button is selected in the yellow screen it tells you of signal loss and to call the station. Sounds like the station or stations are having a PSIP/MUX data corruption and they need to perform a reset of the equipment to restore the proper data to the signal. BTW the engineers at the station are clueless usually about this problem as they don't see it. They usually think it is your equipment.

 

[M Sparks]

No, like I said, the signal was there...no yellow pop-up.

I did notice something else last night. When you add channels manually, there is a little indicator of what channel it is supposed to be mapped to. When I tune to UHF 32 (the channel with the blue line), the indicator says Channel 9. When I tune to 22 (the channel I want), it says Channel 0. (Should say 2.)

As for the spanish station, I'm not getting a signal at all when I manually tune it- I don't really care, but I should be as it's on the air.

I know that at the station, they monitor the digital off air with an old DirecTV receiver. It lists the channel as 22-1, not 02-1. So it's possible that the channel mapping data is screwed up, but they can't tell because their system doesn't use it.

There are literally only a handful of people watching this digital signal. I used to work at this station and I'm friends with the engineers. I am their troubleshooting watchdog. One time, they had an audio channel out of phase that was causing the sound to shift to the rear speakers. The head engineer called me from the transmitter a few days later and played "better or worse" with me while swapping cables around. I'll ask him to reset, but unfortunately it will have to wait until next time he goes up to the transmitter.

The other possibility is that my UHF elements were screwed up in the hailstorm. I am getting one analog UHF channel- it doesn't look so great, but it never did to begin with. But again, I shouldn't be picking up the "blue line"channel if that were the case.

 

[boy921]

No, like I said, the signal was there...no yellow pop-up.

When I tune to 22 (the channel I want), it says Channel 0. (Should say 2.)

This is the proof that there is corruption in the data stream! The data stream is corrupted if it is only showing, "0." Not all receivers react well with corrupted data. Here, I at first, had to plead with the stations to do a reboot, they did and the signal was back.

I know that at the station, they monitor the digital off air with an old DirecTV receiver. It lists the channel as 22-1, not 02-1. So it's possible that the channel mapping data is screwed up, but they can't tell because their system doesn't use it.

Yes, it is screwed up. If not by a random power fluctuation then by a software issue if they recently updated their software. This is more proof that there is a data corruption problem. They need to do a reboot of the MUX/PSIP equipment.

There are literally only a handful of people watching this digital signal. I used to work at this station and I'm friends with the engineers. I am their troubleshooting watchdog. One time, they had an audio channel out of phase that was causing the sound to shift to the rear speakers. The head engineer called me from the transmitter a few days later and played "better or worse" with me while swapping cables around. I'll ask him to reset, but unfortunately it will have to wait until next time he goes up to the transmitter.

This is excellent. Since you know them and are friends they will gladly reboot for you and then you will get the channel back, they will know that they can't see the problem and if they are progressive like the engineers in my DMA, they will make a protocol to frequently reboot to keep the data clean. Here they have full time employees at the transmitters, but usually the PSIP/MUXing equipment is at the site where the engineers generally work and the mixed signal is sent to the transmitter.

The other possibility is that my UHF elements were screwed up in the hailstorm. I am getting one analog UHF channel- it doesn't look so great, but it never did to begin with. But again, I shouldn't be picking up the "blue line"channel if that were the case.

No this is not the problem.