DTV rescan finds a number of numbers changes
Sun Jan 25 22:30:23 EST 2009
John Bolduc wrote:
> Channel 21 Concord NH ION, used to be
> 21-2 Ion 21-3 qubo 21-4 IonLife 21-5 Worship
> Actually on the channel designators used to show up, that is 21-2,
> with no label, i.e. Ion.
> Now the channels, in the same order, are renumbered 21-1, through
> 21-4. 21-5 still shows on my box as black, but the program guide for
> 21-5 is upto date for the Worhsip Channel.
> WDHD Boston I always used to scan 7-1, 7-2, and 42-5. 42-5 would
> alsways give an audio only indicator, with black screen.
> Now I am seeing 42-3 and 42-4, with same programming as 7-1 and 7-2.
Do you, by chance, have a Sony TV?
Here's my understanding of what's going on here: a DTV station sends out
two sets of data to tell a receiver what it's receiving. There's the
PSIP data that controls channel remapping (telling your TV, for
instance, that WHDH's main channel should be displayed as "7-1") - and
also something called PAT data, which indicates where each subchannel is
Certain receivers - Sony comes to mind, if only because I'm staring at
one right now - will display the PAT data if they can't receive or can't
interpret the PSIP data, or if there's no PSIP data available.
Case in point: my WXXI-DT transmits three "public" video streams on RF
channel 16, which are mapped by PSIP to 21.1, 21.2 and 21.3. But we also
have another datastream that carries audio to two of our FM transmitter
sites. There's no PSIP associated with it, because it's not really
intended for public consumption, and it doesn't appear at all on my
Zenith converter box or my Magnavox/Funai DVD recorder.
On the Sony, though, it appears as 16.7 (and sounds phenomenal, I might
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