1. Old fashioned off-air antennas have always come and gone with their signal. When it's going into an HD receiver, does it make the picture perfectly clear, or does it still fade in and out?
For the most part, digital reception is either you get it or you don't. It's much like satellite dish reception, in that a correctly tuned antenna will give you a perfect stable picture, whereas if it's not pointed correctly (or not an adequate antenna for your location), you either won't get a picture, or it will have lots of sound and video dropouts. As you see in those
screenshots, the HDTV Tivo does have a point-antenna screen to aid in orienting the off-air antenna.
With digital off-air broadcasts, the ghosting, sparklies, interference, and other related artifacts you'd see on analog local channels are a thing of the past.
2. Do you recommend an antenna to use?
This all depends on how far you are from the transmitters. The
AntennaWeb will tell you how many miles away you are. A top performance UHF antenna for HDTV locals reception will cost in the
$25 range, although it won't be very pleasing to the eye. Aesthetically pleasing antennas typically cost more, but tend to offer less performance.
The Winegard Squareshooter is a popular antenna for <35 miles, as it represents a good compromise between performance and aesthetics (looks). You can see some pictures of it
right here. It is available in two models, one without a preamp (
$99), and one with a preamp to enhance signal strength (
$149).
Voom has a lot more HD channels, but most of those channels are upconverted programming, not true HD material. Most of the programming is the same stuff that's broadcasting on the SD channel, just upconverted to HD.
This is not true. VOOM offers 35+ HDTV channels with native HD content. Some content is video sourced, like from a HDTV camera (as often seen on Hdnet), and other content is converted from film (as seen on HBO). That said, much of VOOM's exclusive content is repeated on a regular basis -- for example, on their RAVE HDTV music video channel, they typically have one new concert in HDTV with DD5.1 every Friday, but most of the other concerts and music videos shown throughout the week are repeated.
That said, TNT-HD is a rather pathetic channel so far, and has shown only limited material in HD, aside from the NBA Western Conference Finals, the
Salem's Lot series, and a few movies.