If you live in the San Francisco Bay Area and have an HD over-the-air receiver, you may have run into problems in the last week if you tried to watch the Olympics in HD on NBC 11. Instead of getting a nice, crisp HD image of people moving quickly across the white stuff, you would have seen an unusually poor SD image of NBC weather on 11.1 and nothing on 11.2. Even worse, there was no crawl text along the bottom of the screen to explain the problem.
My wife did some searching on the Web and finally managed to track down the phone number of the newsdesk at the station. They explained that they had installed some new equipment just a week before and that this resulted in many HD receivers not being able to immediately lock onto the signal from the new equipment. If you dig around on their website, you can find the explanation there.
The fix is to force your HD OTA receiver to rememorize/reacquire KNTV’s digital channels at 11.1 and 11.2. If your receiver is like ours, it’s easiest to have it just reaquire all the channels.