look at the Gilderfluke (https://www.gilderfluke.com) playback systems. they are designed for this type of application. the SD-10 may be enough if your requirements are simple enough or the SD-25 can handle almost any requirement. designed to run on 12-24 V power , use SD cards for storage, 2 external switch inputs, line level audio outs.

I just looked in the Denver Area using the Spaectrum Bridge system, there is 1 white space frequency available for use, all the others are already blocked by existing TV usage. that single 6Mhz slot means that at least in the denver city area trying to make use of "White Space" for networking is basically useless. I would like to see a map of the US with the number of channels available per 10 sq. miles plotted across the country. I'm guessing that there will be lots of bandwidth available where there are low population densities and little bandwidth available where most of the population is located. .

there are no more NDB stations left in the USA and the FAA is working on turning off the VOR stations as soon as they finally get the WAAS GPS based nexgen navigation system working. The whole idea of the Nexgen Navigation system is to stop flying on airways defined by VORs and move to flying directly from point to point navigating by GPS only.. i predict a huge fight between the FAA and the FCC

actually the devices mush check the database at least daily, the TV station part is mostly unchanging, but the database also includes wireless mic users that are protected and those listing update daily. To be legal the TVBD must check the database for "today's" allowable frequencies. If the database can't be checked the TVBD must shut down till it can get a update from the database. see: http://www.fcc.gov/Daily_Releases/Daily_Business/2010/db0924/FCC-10-174A1.pdf pg 41

there is no "space" between the channels, each TV channel is 6 MHz and with digital TV uses all of the allocated 6MHz. the FCC allocates every other channel in a market, but the TVBD rules do not allow the use of the "empty" channel next to any allocated TV transmitter. In the major markets the "empty" channels are all allocated to stations in the next near by citys. you can look at the northeast coast area( BOS-DCA), the upper mid west(MKE-CHI), San Fran, Los Angeles, ... there is a broadcaster allocated on every channel from 7-51 in those areas which means within 50-70 miles of those citys TVBDs will be completely blocked from operating or if you are lucky ther might be 1 or 2 6 MHz channels to share with 1M other users

There are no "buffer" bands, analog TV used 2 carriers in the 6MHz channel and you could find some free space as long as you didn't mind the interference with either the audio or video. DTV uses all of the 6 MHz with almost no channel edge gap and is spread spectrum like wifi so there are no gaps to sneak into. In the major metropolitan areas the reality is there will be NO free channels for TVBDs. Which means that a lagre percentage of the US population will gain no benefit form the TVBD devices because they will have no channels to use them on.

At this point no one is making 400-700 Mhz hardware, and the required database for the fixed stations is not designed, much less in operation. Google and others have a working group that is working on a design spec for the database but they are not done and the FCC has not indicated if they will use the spec that Google etal come up with. Once a spec is approved then the database system has to be created and deployed before the first stations can be sold. I expect it will be 6 mo. to a year till the pieces are all in place to start the testing and manufacturing of white space networking hardware

Philly and Baltimore 2 ->38 3 ->26 6 stays 10->34 11 stays 12 stays 13 stays 17 stays 35 stays 45 ->46 57 ->32 60 ->9 (yes 9) 61 ->31 62 ->49 http://www.rabbitears.info/market.php

Every station was given a second frequency and could chose what to do with it in the long run. The answer is to contact your local stations and ask what their situation is. You can check the FCC license database which will show 2 DTV licenses for those stations that will switch from a temporary low power system to a permanent high power system.

one problem right now is many DTV signals are not being transmitted at their final full power because they are being sent from temporary transmitters and in many cases on different frequencies than then their final assignment. the stations will switch transmitters and frequencies when the switchover is made.So looking at DTV today does not necessarily tell what the signal will look like after the changeover.