They're advertised to cover all channels. Inside it is typcally a folded dipole curved into a circle. And a built-in preamplifer. The bigger versions often have a built-in rotator system.
They work about as badly as you might expect. They don't contain any magic.
Seems marketing can do magic to bring in money. People think "they wouldn't sell it if it didn't work".
About 3 years ago in a catalog I saw a crystal that you put in a microwave oven to take out the bad microwaves so your food tastes better. I wrote to the guy and told him that's ridiculous and he said he just sells the stuff. He didn't say they sold like hotcakes though.
Thanks for the info, I'll avoid it (I don't have a TV anyhow)
Thanks guys for all the info, thats a picture of my neighbhor's house. The house was sold recently and the new owner asked me if i knew anything about the antenna. Now i can tell him that he can take that eyesore off without any worries.
I haven't seen that one, only the small ones that would be no bigger than about .4m dia. A few years ago someone was demonstrating a yagi embedded in in Hi-K ceramic that allowed it to be shrunk by a significant amount. I haven't seen one on the market - must have been too expensive.
