HD Radio Synchronization

[Carmine5]

Of course, some stations are abusing the multichannel SD scheme by putting 6 or more subchannels into the stream. LA's KVMD has a whopping nine subchannels of ethnic programming!

Why are additional sub-channels an 'abuse' when ATSC specifications allow for it? You may not like the programming or even the quality of the stream (although much of the quality problems stem from the original source).

If the ATSC standard allows for unlimited SD subchannels then that's my mistake. I thought they suggested no more than four. Anything more than four in my experience leads to really poor video quality. But I didn't have pristine feeds to compare them to.

In Northern Virginia, WNVC (displayed channel 30) has an apparent 10 SD channels, but it's a trick -- they use both channels 24 and 30 to do it. http://en.wikipedia.org/wiki/MHz_Networks

- Jonathan

Sure, that can be done. VHF stations whose digital signal is actually on a UHF channel use that strategy. It's accomplished in one of the PSIP tables. But there are also hardware multiplexers that will accommodate several sub-channels. The most I've seen from one multiplexer is eight SD subs.

c5