Pete Pyeatt said:
It drops back to analog after a certain distance? I have so much to learn!
Yes. Once your radio's software can no longer decode the HD signal, it will drop to the analog signal if one is available.
Also, why does the HD2 go silent when I get outside the listening range of an HD Radio station? Why don't I hear static on an HD2?
An HD2 will go silent because your radio has nothing to fall back on after you get out of its range. That's also part of why you don't hear static on an HD2. HD Radio is digital; you either get the signal or you don't. When you get it, it's clear. When you can't get a strong enough signal to decode, you get complete silence. It's not unlike what happens with digital TV. Snowy pictures are a thing of the past now. Some people who used to put up with a snowy signal get a completely clear picture while others get absolutely nothing.
When I'm listening to KBPAHD2, when I get south of New Braunfels, the station will go silent, then go back to programming, then back and forth from silent to programming until my radio puts up the message "HD2 Off." Why don't I hear static like on an analog station?
See above. When you get out of range of the HD signal, it's gone. This is referred to as the "cliff effect." It's perfect until you're out of range, and, then, poof, it disappears. When you're listening to an HD1, you won't notice it as much because you'll automatically get the analog signal after you can no longer decode the digital signal. When you listen to 103.5 HD2 and it's going back and forth from silent to programming, you're getting digital's version of "picket fencing." The signal is getting weaker, but you can still decode it in some parts better than others. Much like with analog signals, a variety of factors can affect digital listening. The digital signals, however, show a more pronounced difference because it's all or nothing.
ETA: I forgot to ask, what is a "legacy" HD Radio transmitter and why can't it be upgraded to 5 or 10 percent on a maximum power Class C station?
A legacy HD Radio transmitter is an older HD Radio transmitter built before the FCC allowed the increase in power and before the technology evolved to allow even more HD streams. As for why it can't be upgraded beyond roughly 1,000 watts, it was simply designed that way, probably for many different reasons. The following are just my theories:
You build according to what you need today. You'll never see a 1,000,000 watt FM transmitter because there's simply no need to build a higher cost transmitter that no one can use. No one knew the FCC would decide HD Radio would be allowed to operate above 1% power. So, there was no need to build a stronger HD Radio transmitter. In fact, there was probably a lot of incentive not to build one because of how many stations run unattended. Simply put, you can get away with less transmitter monitoring if the transmitter can't exceed your station's maximum power!
Also, keep in mind that HD Radio was initially an experimental system. Again, no one is going to spend a ton on a transmitter they might not be able to use for more than a few years. This meant transmitter manufacturers would build those transmitters as cheaply as possible, too. The cheaper the equipment, the less you can do with it. There was no incentive at all to invest a bunch of money into an HD Radio transmitter when broadcasters didn't want to spend much money on it.
