Thread: Radio spectrum availability
06-07-2000, 10:59 PM #1SteveR502Firehouse.com Guest
Radio spectrum availability
Any thoughts on spectrum issues such as 700mHz coming in a few years, maybe use 138-144mHz for inter-agency disaster work, 220Mhz for public safety, 476mHz from Television band?
We're choked out here in Chicagoland looking for relief from the zoo in the 150mHz band. All 800mHz frqs are in use in this area.
A/C Steve Rauter
Lisle-Woodridge Fire District
08-11-2000, 06:24 PM #2scc911Firehouse.com Guest
Pardon the extended time to reply (better late than never), but there are some options.
700 MHz remains an indefinite. If you have been following the PSWN (www.pswn.gov), many areas still have this spectrum assigned to TV broadcasters and their requirement to vacate is contingent upon consumers accepting HDTV. With the prices now in the mid 4 digits and competitive NTSC large-screen TVs in the several hundred $ range, HDTV is just a high-end toy. So, who knows?
You're fortunate enough to be an SMSA with UHF T-Band channels (we don't have that here and the FCC assigned HDTV on what *used to be* open T-Band channels making a waiver impossible). In the New York City SMSA, they are fractioning T-Band to 11.25 kHz bandwidth. This may be something that can be done there. With controlled ERPs, you can get by with minimal interference. Also, interstitial frequencies below NPSPAC 800 channels may be feasible if you can convince your frequency advisor and obtain a waiver from the FCC. A lot of older equipment with mnemonic charts for programming within the present channel mask may have some trouble accepting these. There was also no plan to narrowband 851 - 866 MHz, so the impression given was that it was "safe" from refarming. Now, only if iDEN fit into the emission mask...
The NTIA has just opened 40 channels (20 in the 162 - 174 range and 20 in the 406 - 420 range) partially for law enforcement (10 per band) and partially for interoperability (10 per band) in both CAI digital and 11.25 kHz widths. A special license with the endorsement of a sponsoring federal agency is necessary, but with the focus on WMD this is easily done if you have an integrated response plan. We're watching to see whether Wisconsin's 138 MHz trunked system using freqs borrowed from DoD is worthwhile. Many of the newer radios can accept a flash with trunking protocol. There are some pretty stringent rules requiring concurrence from everyone on VHF and UHF if you intend to plop a trunked system on the frequencies your co-channel neighbors are licensed for.
Despite available freqs, 220 just hasn't been a hot seller. Most of the stuff there is ACSB and ACSB derived technologies. Not very good marketing and not much variety in equipment or infrastructure configuration, but you probably have a lot of spectrum options there.
Finally, if you don't mind the occasional band opening, low band seems to be wide open in the midwest. The problem is that it can be very easy to receive mobiles from the northeast or from Texas under the right conditions.
Some of the things happening south of you near St. Louis are VHF narrowbanding (complete with splatter from adjacent channels), short spacing within safe harbor tables (low power/ low height/ lots of transmitters) and a lot of interservice sharing or creative pooling (police departments on what used to be tow truck frequencies).
Steve Makky, Sr., ENP
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