Re: Digital is at full strength, but reception may improve on Feb. 17.

On Thu, 8 Jan 2009 12:42:54 -0800, dplatt@xxxxxxxxxxxx (Dave Platt)
wrote:


Does this mean that a standalone converter box, or my
I-forget-the-brand DVDR with HardDrive is capable of receiving the
same digitial station at different times on different frequencies??

Yes, although you might have to tell it to "scan for channels" again
after the switcheover on The Big Day.

Thanks. Your reminder will keep me from fainting that day.

Is this why it takes so long to tune in a digital channel?

Probably not.

Analog TV signals transmit a full frame of video 30 times a second
(two interlaced fields, at a 60-field-per-second rate). You can start
watching the signal as soon as the tuner gets the RF pathway set up.

Digital TV works differently. It doesn't send the complete picture
very frequently... typically only a few times a second. The other
(intermediate) frames are described during transmission in terms of
differences from the most recent complete frame... or sometimes in
terms of differences from the most recent complete frame and the
*next* complete frame (the one not yet actually transmitted). This
saves a lot of transmission bandwidth, which is part of how it's
possible to send a high-definition picture over the same amount of RF
bandwidth used to send a standard-definition analog signal.

What this means is that the TV set can't start displaying a meaningful
image until it has waited long enough to receive at least one, and
often two of the occasional "complete" frames. Depending on how the
station is choosing to encode its digital transmissions, this could
take a second or more.

But it takes 3, maybe 4 seconds to change from one channel to the
next. Even based on what you said, that seems bad. This is a
Philips DVDR and I think there are tuners that take longer.


Will tuning be quicker when it goes back to the traditional channel 9
frequency?

I'd tend to doubt that.

The Channel 9 man said that he thought I would have greater sucess
when they moved back to the VHF frequency. Is that because VHF
generally has longer range?

That might be part of it.

It might be that their "full power" UHF transmitter actually has lower
power output than their "full power" VHF transmitter.

It might be that their VHF antenna is better (higher gain, or in a
better location) than their UHF antenna.

OK, might be. So I don't have to ask the guy at the station. I guess
we'll find out in June!



.

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