reply to DavePR
Re: White Space Devices won't work
said by DavePR:I don't know about you but I wouldn't WANT it to propagate. I'd want it to be line-of-site. Like cellular, low-power TV, etc, it should cover a relatively small geographic area (whether it's WSD or WiMAX or WiFi or whatever). In that case, the frequency range used is pretty much moot. What's more, the lower frequencies are more susceptible to seasonal interference due to ducting and sporadic E-layer reflection (ask the CHP and other State Police depts which use frequencies below 50mc).
Bill Gates and Google will have to go elsewhere besides UHF 470-698 mHz. I suggest they try 54-72, 72-88 MHz. This propagates better than UHF anyway.
The higher the frequency, the easier it is to control the radiation and get "gain", shielding, and directivity, from a small antenna, and the less likely it is that a WS ISP in LA will get useless, wasteful, interference from a co- or adjacent-channel ISP in San Diego.
I don't know enough about these various systems from a technical standpoint to have an opinion, so I'm reading all the comments in this thread to learn a little. I do believe that we will need more Internet access as time goes on and I think that this will be necessary for a society that wishes to inform itself, enrich itself (I mean in $, not in poetry), and entertain itself. If the spectra left fallow by the Feb 2009 switch to DTV doesn't already have an anointed occupant(s), then why shouldn't engineers be experimenting with methods of connecting people's homes and businesses using it? If it IS already spoken for, then maybe those folks will, in turn, be abandoning other bands that can be used. All I can say for sure is that, when five-9's are desired, spectra below a couple hundred megahertz - minimum - are not ideal. They're fine for voice, even TV to some degree, but not, I don't think, for data (even with good error correction).
Thanks for the soapbox. I'll go back to absorbing your comments.
Phil Wells, AF6AV
San Diego, US