Originally Posted by Sammer
If you look at the major markets (where the cell phone companies really want more TV Band spectrum) the broadcast radio and TV bands are probably closer to being full boxcars than any other spectrum.
It certainly looks that way on a spectrum analyzer, but that is the nature of DTV broadcasting (nearly all the 6MHz appears to be used, unlike analog).
In addition, looking at the bit-rate usage, only about 7% of bits went to null-packets for local stations when I collected data on 12/31/10 locally in LA. I certainly can't think of any other service that is actively using so much of its spectrum.
As for ham radio, I was surprised at how little the bands were used at first (especially 6m, 2m, 222 & 440), but there is a vast network of repeaters and portable transceivers that are ready for action in event of an emergency when most other forms of point-to-point communication available will fail.
225-400 typically look very quiet in CONUS, but the principal is the same. We don't want to be without these if we need them.
As for re-packing various land-mobile services into smaller allocations, that is happening to some extent:http://www.fcc.gov/pshs/public-safet...owbanding.html
On January 1, 2013, all public safety and business industrial land mobile radio systems operating in the 150-512 MHz radio bands must cease operating using 25 kHz efficiency technology, and begin operating using at least 12.5 kHz efficiency technology. This deadline is the result of an FCC effort that began almost two decades ago to ensure more efficient use of the spectrum and greater spectrum access for public safety and non-public safety users. Migration to 12.5 kHz efficiency technology (once referred to as Refarming, but now referred to as Narrowbanding) will allow the creation of additional channel capacity within the same radio spectrum, and support more users.
After January 1, 2013, licensees not operating at 12.5 KHz efficiency will be in violation of the Commission's rules and could be subject to FCC enforcement action, which may include admonishment, monetary fines, or loss of license.
At the core level, however, I just don't see how having longer range TV Band spectrum for point-to-point Mobile Broadband is practical, even if the entire remaining UHF TV band is "recovered." It's quite a bit more difficult to "stop" a signal around 550MHz from going too far vs. something around 2.5GHz. I'm sure many of us have seen the charts comparing the practical aspects of speed vs. range.
To truly get Broadband everywhere, we need SHF towers on every street corner or we need fiber to every home and business. Which is more practical?