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Can Anyone Explain This To Me?

landtuna

landtuna

I have a 2-year old Magnavox 39" flat screen in my kitchen (wall mounted) that every once in a while will suddenly display this black panel. It happens mostly on my local CBS affiliate and usually within a minute of bringing up that channel (KPHO-5, RF 17 I think) although I have seen it infrequently on other stations. I have OTA service through a rooftop antenna.

This example has a message line but most of the time that top text line is just jibberish or symbols which mean nothing. I have two other HDTV's and have never experienced this on either one of those nor have I ever seen it on any analog TV (converter boxed or normal).

I can get rid of it easily enough by pressing the 'menu' button on the remote but otherwise it stays on screen permanently.

Ideas?
 

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Contact Magnavox. Either that or do a rescan. Failing that, see if KPHO knows anything since it's their frequency. (Their RF is indeed 17.)
 
Ccook55 said:
Contact Magnavox. Either that or do a rescan. Failing that, see if KPHO knows anything since it's their frequency. (Their RF is indeed 17.)
Click to expand...

Rescans do not change operation and Magnavox says it is a broadcaster issue (but didn't comment beyond that). I submitted the example to KPHO but have not received an answer.
 
Based on the screenshot, I think you should check the TV's closed captioning settings. From the looks of it, it is set to TEXT, which takes up more of the screen. See if the closed captioning is set to OFF. Hope this helps.
 
Mastaclocksetta said:
Based on the screenshot, I think you should check the TV's closed captioning settings. From the looks of it, it is set to TEXT, which takes up more of the screen. See if the closed captioning is set to OFF. Hope this helps.
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What they said; turn off analog captions and switch to digital captions. The text closed caption channel sometimes comes on unexpectedly if you have it on analog mode and most of the time it just shows that blank screen. It's a remnant of when only a few broadcasters (ABC and TBS mainly) tried to create an English-like Ceefax service using the CC standard but failed. At least in digital mode you can switch the background to translucent or off entirely so it doesn't show up at all like that.
 
AHA! I didn't go far enough into the closed captioning instructions. This particular model has about a dozen different settings divided up into Digital and Analog. The Digital setting was indeed turned off (and it never occurred to me that anyone would be using the Analog settings since the digital conversion) but the Analog was set to something called T-4 which is not covered in my manual. Apparently that is the default for whatever reason.

Anyway, turned all captioning off and will monitor to see if event happens again.

Thanks much for all the responses. This has bugged me for the two years I have had this set.
 
I don't know if it's the same with digital but I know that the text window could turn on during live news or sports broadcasts with nothing but a blank screen or garbage on analog sets.

Concerning how ABC and TBS tried to start a text service, at one time I had a tape of National Lampoon's Christmas Vacation from the early 90's when it was on ABC that had the text window available. All that was listed was ABC's schedule for the night. I never found anything else like that on any other tapes I've had.
 
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What they said; turn off analog captions and switch to digital captions. The text closed caption channel sometimes comes on unexpectedly if you have it on analog mode and most of the time it just shows that blank screen. It's a remnant of when only a few broadcasters (ABC and TBS mainly) tried to create a Ceefax-like service using the CC standard but failed.
Click to expand...

^- This. Actually "the big black box that does nothing" used a variation of the system used for regular captioning but they were NOT identical.

I remember in the late 90s and early 2000s, bringing up T3 (?) mode and seeing URLs, scheduling information and other related stuff in that box. It was apparently for the benefit of Web-TV users, as part of its now long obsolete "interactive TV" gimmick. What you're seeing is probably a remnant of that system.
 
Oh by the way, if you have any old video tapes of network programming recorded off of ABC and (I think) PBS in the mid to late 1980s (crainbebo?), play one with the decoder set to text data channel 1 or 2. Also try closed-caption data channel 2.

tuna--

When your black box showed up on KPHO, were they on the network feed or was it local origination?
 
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Darth_vader said:
tuna--

When your black box showed up on KPHO, were they on the network feed or was it local origination?
Click to expand...

It seems to happen most commonly during the evening network news but it has happened during syndicated shows as well (just not very often).
 
It could possibly still happen on live sports as well. I've wondered if it might have something to do with either the captioning being live or possibly something to do with when a teleprompter is used on a live broadcast as in news or possibly sports.
 
Apparently the teletext modes can be used to send other data besides human-readable text. It's possible that the supposedly "garbage text" people sometimes report seeing in their big black boxes that do nothing, under favourable reception conditions, are (encoded?) binary data for some reason -- for example a "push-out" firmware update for TV station equipment. Probably something for devices designed to receive the network feed, or a leased one-way low-bitrate data link, but the data are being allowed to leak out onto the local signal.

If anybody has an ATSC box that can pass EIA608 data *and* an NTSC computer tuner board with line-in, and software that can perform signal analysis (I have neither), one could use it to monitor the caption/text/XDS tracks in the VBI for anything interesting/funny like that.
 
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