charts are updated every 14 days , nav databases are updated ever 28 days , you are responsible to have current charts and data

Las Vegas renumbered this year, Seattle has renumbered recently, its a regular thing. depending on where you are the magnetic variation can easily shift 0.5-1.0 deg / year. Usually the runway renumber happens when the mag heading shifts across the 5 deg boundary. most runways are built on ordinal true headings that are then converted to the nearest 10 deg magnetic equivalent for numbering. my local example is DEN - rwys 7/25 and 8/26 are currently both 82.1 mag with 8.4E mag var or 90 true. the mag var in DEN is changing 0.1 deg/yr W ( it was 9.6E in 2005 ). https://maps.ngdc.noaa.gov/vie... lets you look at the mag var over history

total loss of electrical power is the main reason - lose your generators and you have a limited time on battery only

here's one i found only the video processor is not defined linux/win I7 processor http://www.drs-ts.com/pdf/JV5%...

the third looks to have slid down the embankment but stopped short of the water

Contractors are preferred because when the contract is over the workers are not still on the government payroll. If they hire workers directly they would be covered by the civil service rules and be effectively employed for life no matter how bad they were. This shows up all the time when there is a need to change or slow down a program the contractors are in the news because of large layoffs.

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