Ah. The problem is not that I am gullible, it's that I didn't understand what was being said. I thought my non-HD cable TV was going to stop working.

Or you get it intermittently perfect or not at all, with occasional bright green blocks...

that's called "perfect"
 

HDTV, NTSC and even FM radio are radio signals. Antennas are tuned to radio frequencies with little concern for that signal content.

But digital TV signals are picky. To appreciate the problem, consider a TV with a ghost image. IOW a signal is received directly AND another signal is received by being reflected. Same signal arrives twice - at slightly different times.

So what does the digital TV do? It has two copies of digital information combined in one signal. Which should it use? How does it know which signal to reject? To a TV, the image and its ghost are one digital signal - now confused.

To rush to HDTV, the US decided to implement a first option available - 8-VSB - so as to protect Zenith, the only remaining US TV manufacturer. It was a decision based in politics - not in engineering. As a result, the US standard is different and inferior to standards (COFDM) used in Europe, Japan, Australia, etc. The US standard is less resilient to ghosting meaning that US TV will not operate properly even in moving vehicles.

See the Sinclair Broadcasting lawsuit as a last ditch attempt to implement better standards found elsewhere. Their tests in Baltimore revealed reception of COFDM was better than 8-VSB at two sites and that reception difficulties were due to the presence of strong static signal reflections, or "multipath."

Now for your antenna. HDTV uses the same UHF frequencies of analog TV. An HDTV antenna is simply a better (high gain) UHF antenna to reject more ghosts and to get a stronger signal. High gain means the antenna is more directional. More elements (crossbars) on an antenna create a narrower (higher gain) reception angle.

Ghosting is even why interior antennas don't work well with digital TV. Even the phenomenal bowtie antenna is not very directional - is poor at rejecting ghosts.

So how do you know if a signal is defective? In analog TV, you could see both ghosting and little white dots indicating noise - a loss of signal. But digital TV either compensates for that ghosting or noise, OR you have a stopped image. If signal is lost too long, then it appears as no broadcaster on that frequency (channel).

Cable companies are just licking their chops. Many consumers will give up early on their antenna and finally conceded to more expensive digital cable service.

Current antennas are tuned both to VHF and UHF frequencies. VHF frequencies will be assigned to other services (ie cell phones) in a few years. It was to happen long ago. But HDTV sales were not sufficient. Currently Best Buy and Circuit City are throwing TVs out the door in a price war. Large numbers of new TVs suggests the shutdown of VHF TV channels will occur in 2009. Meanwhile, Zenith is now a foreign manufacturer.

IOW, while analog TV is available, then use that TV to get a good UHF antenna - no ghosts and no little white spots. Then your antenna will be ready for HDTV.

Thanks for your reply. I don't fully understand what it all means, but it sounds like I should buy a conversion box and just wait to see if my current antenna works. If it doesn't, then I'll figure it out at that time.

I've currently got a pretty good situation. Both Washington D.C. stations and Baltimore MD stations are in basically the same line of sight from my Arlington VA house. With my (pretty damn old) roof antenna, I pick up about 8 channels clearly, and another 5-8 channels with static. That's more than enough for me. If high gain means a narrower reception angle, then I imagine I'll lose some staions that I currently get, because the transmitters aren't lined up perfectly.

I won't be too happy if this conversion means I'll lose channels that I'm currently getting.

Higher gain means those other 5-8 stations get received and means no ghosts. Reread the post. Narrower reception angle means the ghost (reflected from another direction) is ignored. Higher gain means getting a new antenna so that ghosts are eliminated.

So your question is whether that current antenna has sufficient gain. Generally, antennas for both VHF and UHF do not have better gain found by 'UHF only' antennas.

An important point - or how to get ready: NTSC (analog) TV must receive UHF stations without ghosts or white dots (static). If not, now is the easy time to get it right. Wait for later and the task becomes difficult and probably more expensive.

Only UHF stations received by the current antenna clearly will be ones located where your HDTV stations will be received. UHF - means channels 14 and higher. When your channel five moves (maybe) to channel 36, well, if the neighbor UHF stations (maybe 20, 26, or 32) are not being received, then you also lose channel 5 when it moves to 36. If you are not getting UHF stations from that location, now is the time to fix it. Again, (and noted in the previous post) now is when to get a working HDTV antenna because only now will you see what you do and do not have; have enough information to fix or improve the reception. When conventional TV (NTSC) goes away, then spend and spend again until something works. When NTSC goes away, you lose the ability to see what needs correcting.

OK. Thanks. I guess I'll figure this out sooner rather than later. (I've never given any of this any thought before, so I'm pretty clueless. I just plugged the antenna cable into my tv when we moved into this place ten years ago and was pleased with the great reception we got.)

I believe that there is also some sort of proposed government program to provide digital receiver/converters to people who can't buy afford to buy one (yes, TV welfare).

Your existing analogue TV will become obsolete, in a sense, but the acquisition of a HD recever/converter will let you continue using your existing analogue device. You just won't be seeing things in HD/digital. And, of course, this really only applies to those viewing TV over the air (OTA) anyway, although I'm not real sure what cable/sat providers are going to do to HD programming to make it viewable on such devices. Anyone know if these settop boxes downconvert HD to regular NTSC?

That converter was part of the original plan. These converter boxes would only cost $100 or $200 and be available for both OTA and cable. Prices ended up higher. So high that it is almost worthwhile spending more on a new TV.

Gee, what a coincidence.

I have certain strange opinions about things. One of them is that if you're on welfare, you shouldn't be paying for cable (or buying crack, but that's another thread). They can't exist without TV, so what's going to be done about this?

Hey, did you hear? The End Times Are Upon Us. Now TV is a "right" - but <insert rant about our actual rights eroding, without complaint> . . .
Why the "charity" here to make sure people can get the TV they "need"? Makes you think TV is just a vehicle for immersing the collective mindset into a vat of toxic corporate values. Nah...that's too far-fetched. I'm sure there is some other reason for this :::crickets chirping:::

If I read all of tw's infopost correctly, and thats a maybe for sure. Lotta info for the day after Xmas brain. I have two options - either buy a digital tv or get a converter box which will coincidentally amount to about the same cost. Is that right? Cuz I just bought a tv last week which takes about 3 seconds to switch between channels. Since it is going back anyway, what am I looking for in this new - new tv I'm now getting?

The converter box will be cheaper. But value per dollar does not compete considering the advantages of DTV and especially if that NTSC TV is too many years old. A new DTV would be a better value per dollar especially with prices falling so quickly and other features. DTV will still cost more. To be worthwhile, a converter box had to cost maybe $150.

I have not seen those converters priced; only read that their actual costs ended up being many times higher.

OK well I have this Magnavox POS back in the box with complete wrapping and all the other crap they sent me. I think I'm just gonna do a little research on which brands are better than others and so on. I have till mid Jan. Thanks for the info.