In case you missed it.

[cactuswatcher]

A bill has just passed the US House of Representatives, which will require TV stations to broadcast in digital only beginning in February 2009. Which means that if you have an old style TV it will not receive anything over the air after that date. Congress is planning on offering vouchers to help purchase converters to keep our old sets running. But apparently the converters won't be free.

I have no idea where this is going to leave Canadians.

Comments

[atpo-onm.livejournal.com]

Actually, the broadcast frequencies are in the same range as with NTSC-- namely VHF and UHF. While I don't know if this plan has changed since it was first implemented, the original idea was:

1. Assign temporary new channel numbers for the digital stations. For example, in my area, the local PBS station transmits in analog on Ch. 33, and in digital on Ch. 36.

2a. After the changover (was 2007, now 2009, as mentioned previously) and all analog transmissions were ended, the original channels would be auctioned off for other uses.

2b. Or else, the stations would transmit digitally on the previous analog channel frequencies, and the temporary ones would be auctioned off.

(I'm still confused about the #2's, and have elected to not care either way.)

As to how to tell if a new TV has built-in digital tuning capabilities, look for the specifications to say "ATSC tuner included" or "equipped with NTSC/ATSC/QAM tuners".

NTSC = analog, the old system

ATSC = digital, the new system (also used by DirecTV & DISH Network)

QAM = digital cable system.

Yes, the cable folk have their own, and it's not compatible with ATSC. Cable companies will receive the original transmissions (in whatever form) and then convert them. For your TV to tune them, you will need either a box supplied by the cable company, or a TV with a QAM tuner. Fortunately, most current production TV's have all three tuners onboard.

One final note (yeah, right! ;-) about digital channels-- they can have "sub-channels", or channels within a channel. Digital is so efficient bandwidth-wise compared to analog that it is possible to fit as many as six channels in the space of one previous analog channel. The trade-off is in picture quality. Use all six at once, and you're about down to VHS tape quality. Do 3 and you're at DVD level. If you do full 1080i or 720p Hi-def, you get only one channel.

Some folks who already own HDTV's have noticed that the Hi-def doesn't always look like Hi-def, especially during the daytime. This is because the station "multi-casts" 2 or 3 channels at once. To do this, they have to compress or downconvert the Hi-def material in order to squeeze everything in.

Subchannels are denoted with a dash and a second number after the main channel number. For example, my PBS station has 36-1, 36-2 and 36-3 all running at once in the daytime.

[cactuswatcher.livejournal.com]

Thanks.

As far as I know the plan was to clear the really bandwidth-hungry lower VHF channel frequencies from the beginning. Then those frequencies would be sold for more efficient use for something else. (Which I think is why ABC dumped all of their lower-channel-numbered stations about a decade ago and reorganized with what had been independent stations in many markets. Whether that makes sense now or not I have no idea!)