220MHz: The enigma
The 220MHz band showed so much promise when it was first authorized by the FCC. But interest in the 220MHz band, along with a lot of other current technology, is relatively low.
Motorola has announced that it will introduce 12.5kHz-channel equipment for 220MHz use. Although that should spark interest, the company’s plan is not a long-term answer. Because the band is segmented into slivers of non-contiguous, 5kHz-wide channels, Motorola’s plan requires an inordinate number of contiguous slivers to fit its 12.5kHz-channel bandwidth requirements.
Once enough 5kHz channels are put together (three or more), spectrum efficiency decreases more than 60%. The answer is either a consolidation of the 220MHz band or the development of a digital format, such as IDEN, that could use 5kHz-wide channels. The contiguous nationwide and E Block channels could accommodate 12.5kHz-wide signals, but, once again, with a substantial loss of efficiency. Didn’t the promise of spectrum efficiency prompt the FCC to structure the band as it did?
Problems associated with using the 220MHz band have been many and varied. Two of the three initial narrowband voice equipment manufacturers — Securicor Wireless, Uniden America and SEA — have dropped 220MHz. Bizcom USA, the company that bought the rights to make SEA’s former 220MHz equipment, is seeking financing to restart the manufacturing that SEA suspended for lack of funds.
Survey the real customers
Neither Uniden, SEA nor Securicor Wireless understood the reality and workings of the SMR industry. All three seemed to think that they knew more of what the operators wanted than the operators themselves. Not one of the three bothered to survey their real customers, so it is little wonder that we find ourselves in the present state of affairs.
The 220MHz products continue to be merely adequate, while UHF and VHF FM product engineering benefits from what was learned at 800MHz before the arrival of Nextel.
For example, when Kenwood Communications entered the 800MHz LTR equipment race, the company’s research was methodical. Kenwood representatives visited dealer after dealer in an effort to understand the needs of the SMR operators. They didn’t assume that they had the answers, as they first wanted to actually hear the questions. As a result of those efforts, Kenwood developed a superior 800MHz product that has sold extremely well, and whose features are now prevalent in every trunking radio that the company makes.
The 220MHz band offers SMR operators the opportunity to revive dependable and inexpensive dispatch service that once existed at 800MHz before Nextel. A fact that seems to be overlooked by most dealers is that 220MHz operation resembles 800MHz operation in offering a valuable feature — exclusivity.
The same cannot be said of the UHF or VHF bands because there is no guarantee that an operator in those bands would not have to contend with co-channel users and the resulting interference that would surely occur eventually. Granted, there are only 2MHz of spectrum at 220MHz, but even with this bandwidth limitation, the market potential remains significant.
5kHz: A great opportunity
The manufacturer that develops a 5kHz digital product for the band would have a tremendous market position. As an operator with a considerable number of SEA 220MHz systems in place, I can speak from experience that amplitude-companded, single-sideband works, and in fact it works well. It has its peculiarities, but then again, so does everything else, including digital.
Developing digital equipment for these 5kHz channels would be a daunting task, but if a relative flyweight such as SEA could develop 5kHz equipment, certainly a super heavyweight such as a Kenwood or a Motorola should be able to do considerably better.
Imagine IDEN, or a similar digital product at 220MHz, with a feature such as the Nextel direct connect. It need not have wireless telephone capability; two-way radio dispatch is enough. Excuse my enthusiasm, but how significant would that be for an operator? Should we call it FleetLink, or perhaps NextLink?
Better yet, who cares what it is called, as long as a forward-thinking company has the good business sense to develop it?
Adler is the owner of PCS Communications, a radio equipment dealership and SMR operator with commercial mobile radio systems in the Philadelphia, Baltimore and Atlantic City, NJ, areas.
