I have one of the prototypes of that unit, together with the DX Antenna DTA-5000:http://www.dxantenna.co.jp/english/p...a/dta5000.html
The antenna is a pair of crossed dipoles, together with a solid-state routing matrix, which feeds different combinations of the four antenna elements to a preamp. The preamp has several gain settings, and has bandpass filters for the major TV bands (VHF-Low, VHF-High, and UHF).
The power and control signals are multiplexed on to the single coax, using a little interface box that sits behind the receiver.
When you scan the STB, it goes to channel 2, tries all combinations of antenna "directions" (it can create 16 possible azimuths by electronically switching the elements), and then...if it sees something resembling a DTV signal...it fine tunes the filters, azimuth, and preamp gain for the best signal. This is done using signal strength and signal "Q" (Quality, using the error correction signals within the STB), and the settings are then stored in the STB. Then, it tries channel 3, and so on.
Most of the newer chipsets for DTV have the interface capability, but this is only one of a couple of boxes I have seen that implement it. The NTIA specs, for the "subsidized" converters allow it to be used.
I think it's pretty slick. I hope more manufacturers start implementing it.
BTW, if you can find them, the DTA-5000 sells for about $80-100, street-price.