said by qworster 
:It can use an omnidirectional antenna and a VERY narrow bandwidth radio centered on the middle of the TV channels it's scanning. Since the UHF DTV channels are sequentially allotted and exactly 6 mHz apart, this kind of radio is EASY to build! Remember, all it has to do is SENSE a carrier signal-and a 250,000 watt - 1 megawatt signal from atop a tower 500 feet or higher at that!
If a 25 year old Radio Shack scanner can do this-with low powered 2 way radio signals no less, then why can't a white space device?
Also remember, both FM and TV channels (stations) are allotted by the FCC to broadcast to specific markets. TV stations are only afforded protection within clearly defined service contours.
The fact that you might be able to pick them past these contours is irrelevant!
Disclaimer: I am a broadcast engineer with over 30 years experience. I understand REAL WORLD interference, as opposed to LAWYERSPEAK interference, which is usually shown to the FCC and/or Congress by the NAB along with a sizable cash payment!
First: Don't look at the "center" of the channel. ATSC broadcasts using 8VSB not COFDM, so the carrier is off-center. The device ought to look there. No more Audio carrier to hone in on anymore either.
