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The Feds Vacate Airwaves
dada21 writes to tell us UPI is reporting that the government is getting ready to spend $936 million to move its radio communication to an obscure segment of the spectrum to make room for next-generation mobile tech. From the article: "'With 90 megahertz of additional spectrum, today's cellular carriers will be tomorrow's next-generation broadband providers,' Michael D. Gallagher, assistant secretary of commerce for communications and information, said in a statement."
I believe TFA says about US$2 billion, with some of it already sold. They also talk about selling more radio stations off, as well.
FTFA: They're going to auction off the 1710-1755 MHz spectrum in addition to the already planned 2110-2155 MHz spectrum.
UMTS: "The specific frequency bands originally defined by the UMTS standard are 1885-2025 MHz for uplink and 2110-2200 MHz for downlink."
Once again, we can't use the frequencies that the rest of the world uses, so we have to get "Americas" phones with different bands or wait for Nokia et al to release "6-band" (800, 900, 1800, 1900, Euro/Japan UMTS, Americas UMTS) phones. Goddammit!
1, 1, 2, 3, 5, 8, 13, 21 -- Mathematics is the Language of Nature.
The frequencies discussed in the article, 1710-1755 MHz and 2110-2155 MHz, can be found on the right side of the fifth bar.
The problem of emergency responder and public safety radio system (non)interoperability grows out of the history of growth of the systems.
In the beginning, each agency had one or a few dedicated frequencies for communcation. The fire department might have 3 channels labeled "Primary", "Secondary", and "Tactical". Each of those would correspond to a pair of frequencies known as a "repeater pair". One frequency is the "input" to the repeater, and the other, the "output". In "idle", each radio is listening to the "output" frequency. When a fireman transmits on the radio, it transmits on the "input". The repeater listens to the input constantly. When it senses someone transmitting on the input frequency, it fires up it's transmitter on the output frequency and passes the audio from the input receiver to the output transmitter.
(Not much has changed since then)
Each agency (police, fire, waste, roads & bridges, etc.) of a city, plus county(parish), state, and federal agengies was in direct administrative control over their frequencies (an therefore channels). The fire department would apply with the FCC for a license for 3 repeater pairs, and the FCC would say, you can use pairs X, Y, and Z at no more than P Watts of power. The FCC determined this by ensuring that pairs X, Y, and Z were not used elsewhere in a geographical proximity that would likely be breached by a transmitter at the fire department's location based on RF propogation models at the given frequencies and terrain.
Now, in a bigger sense, the FCC also defined the allocation of the RF spectrum for the entire radio electromagnetic radation spectrum. Not on an individual basis, but on a functional basis. Like, 150MHz - 158MHz is allocated for public safety use, and therefore frequency pairs in that "band" would be available for individual licensing to any public safety agency (police, fire, EMS, etc.) Great amounts of spectrum are currently allocated for "federal" use. Note that not all RF use is for voice communication. Some is set aside for radioastronomy: no licenses are given to allow transmitting there, so radioastronomers can be certain that if they listen in that band, there will be less human interference than if they just picked any arbitrary frequency band to monitor.
As the technology improved and became cheaper, it became possible to utilize higher and higher frequencies. As such, whenever a band seemed "crowded", and the FCC opened up a higher band for the same purpose, it opened up a wider band. Wider bands means the same number of available channelized frequencies in the pool could be wider, and therefore carry better sound quality. Alternatively, the same quality could result with a higher count of "channels" in a band.
Public safety and city maintenance radio systems used to operate around 30MHz and 50MHz (about 10meter and 6meter wavelenths). Those gave good range -- the radio energy from the repeater and mobile radios was not attenuated by the atmosphere too much. As the frequency increases, though, the attenuation (lessening) of the signal strength by the various components of the air increases. At the same time, there is less "other" RF energy floating around from such things as the sun and lightning in storms, so the end result was to have slightly increased power requirements on transmitters and vastly increased voice quality and vastly increased equipment maintainability. Much of RF engineering has to do with the real wavelength, so as you go shorter in wavelenth, some of your filtering hardware can get smaller and more compact.
Eventually, every little city had a dozen or so frequencies allocated to various agencies within. It was a very inefficient use of the scarce resource of RF spectrum. If the fire department of Podunk, WV had 3 frequencies allocated to it, no other agency within, say, 100 miles could be allocated those frequencies. And you have to realize also that an FM-modulated voice signal has a real "bandwidth", and so you had to space out the "channels" of available frequenc
As a licensed user of several of the WiFi channels I can transmit at 1500 watts over an entire city, if necessary to establish communication, and can interfere with any unlicensed WiFi routers on my channel with impunity. Not only that, if any of those routers are interfering with my signal, they are legally required to shut down or at least change channel.
Think that's unfair? The designers of WiFi were aware of those requirements when they first selected the frequencies. Luckily for all you unlicensed users of WiFi, most of us hams are nice guys who like WiFi for our own networks, and are excited about the availability of cheap hardware for using that part of the spectrum.
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the government controls 99% of the spectrum, useable and experimental, and this is the first time they have ever given back a single kilocycle of allocation. in the past, it has always been nonprofit, public safety, and commercial use that has been tagged for reallocations.
congratulations for finally stepping up to the plate, and many more for uncle selfish.
Actually that isn't true... check the chart at http://www.ntia.doc.gov/osmhome/allochrt.pdf
The vast majority of the spectrum is non-government exclusive or shared government/non-government. Only the sections with RED under them are government-exclusive allocations.
Natural != (nontoxic || beneficial)