Nope, it’s not because you lose the signal. It’s because the local television stations have failed to upgrade a critical piece of equipment in their signal path: the inserter. An inserter is the thing that allows TV stations to put their logo (“bug”) and little severe-weather map in the corner of your screen, and put a text crawl at the bottom of the screen. If the inserter isn’t upgraded to high-definition, guess what? Whenever they use it, it downgrades the picture to standard-definition.

Right now, there’s a severe thunderstorm watch for several counties in the area. So the evening news on channel 19 (which includes several tributes to Michael Jackson) is in standard definition. Any other programs that are on during the watch will also be downgraded. And it’s not just channel 19. I haven’t checked lately, but not long ago when I was watching David Letterman, the opening would pop down to standard def while the channel 31 logo appeared on the screen, then pop back up to high def when the bug disappeared.

My guess is that the TV engineers would really like to get one of these little babies, but the bean counters at corporate aren’t willing to shell out the bucks for it (they can run upwards of $8,000 — not an unusual price for broadcast equipment). So, all the benefits of the government-mandated conversion to HDTV go in the toilet whenever the station puts its logo on screen.

Hey, local TV stations: Buy an HD inserter already. Are you trying to drive your few remaining viewers away?