Most public safety radio users are aware of the impending change from “wideband” channels to “narrowband” channels, and federal radio users in many cases have already made the change (federal radio frequencies and operating modes are regulated by the NTIA, while all other radio users are regulated by the FCC). The topic has had much confusion, and it is a complex issue, in part because of schedules and deadlines that have shifted but also because of the “phased” nature of the transition.
 

Why The Change?

The motivation is to increase the number of “channels” and thus users on the various public safety frequencies in the VHF and UHF bands (the other public safety bands, such as 800 MHz and 700 MHz have always been narrowband). The wideband radios operate on 25 KHz wide channels, and the narrowband radios operate on 12.5 KHz wide channels, roughly half the size of the wideband channel. In general, this is a good thing, as there has been tremendous pressure for more operating channels for more than a decade, as population and operational areas of public safety agencies have grown.

The new channel plan for narrowband in VHF is a bit different than UHF, given the many decades of legacy licenses in VHF, but the overall effect is the same.

However it is important to note that any given licensee, such as a county sheriff or city fire department, will not directly benefit from the conversion to narrowband. Surrendering their 25 KHz channel will not give them the right to use two of the new 12.5 KHz channels. In fact, technically most licensees will be modifying their existing license to reflect the narrowband operating mode (and for a period of time, also retaining their ability to continue operating older radio equipment in wideband mode), not canceling their old license and receiving a new one. But we digress…

So what is the motivation for an agency to switch? Frankly, there is none. This is an unfunded mandate, required by FCC (and NTIA) rules. The ensuing controversy because of the unfunded mandate is one of the reasons why the schedule, time-table and interpretation of the rules has shifted and evolved over the past several years. But experts agree that the end of the old wideband mode for public safety is now in sight…
 

When Do I Switch?

The short answer is “soon” -- by 2008 ideally.

The schedule can be confusing, but summarized: it is not possible to modify old wideband equipment (wideband has been used since the 1940’s) to operate in narrowband mode, and all of the radios must be “forklift” replaced. This transition has been in progress for several years now, and can be measured by the many perfectly good wideband-only radios on sale at eBay at a fraction of their original cost. The FCC has set 2008 (after several resets) as the last date that a radio manufacturer can sell a radio capable of transmitting on wideband; and all new radios purchased today already offer both wide- and narrow-band modes in the radio (as mandated).

While operation in narrowband mode will not be mandated for 6 more years (2012) it will be effectively mandated by 2008.  Why? Because agencies will not be able to purchase any type of new portable or mobile radio capable of wideband after 2008, and since most agencies are prohibited by procurement rules from buying used equipment, they will effectively be forced into narrowband.

We generally advise our clients to plan a move to narrowband immediately, both because of the mandate but also for interoperability. But wait, there’s more…

The Big Issue With Narrowband

Many agencies do not realize that if they approach their wideband to narrowband forklift replacement without systems design, they will experience degradation of their coverage area. Because of technical constraints, a narrowband analog transmitter using the same antenna and power output as the wideband analog transmitter it replaces, will decrease in coverage area roughly 20% to 30%. For agencies already battling challenging terrain to provide full radio coverage in their OA, this is not good news.

The traditional solution to this type of problem is to install additional high-point repeaters and/or remote bases, incurring not only the cost of the new tower (or a new lease on an existing tower) but also the FCC/NTIA frequency coordination process which will consume months of time. Again, another reason to immediately begin planning for narrowband if you haven’t started already.

National Interop can provide analysis and design or we can recommend a consulting firm, but we strongly recommend analysis of this issue at the first opportunity. Well-informed is well-prepared.

A Ray of Hope: P25 Digital

Although we weren’t originally fans of the P25 digital mode (also called Project 25 and APCO P25), we are now. Among other advantages, operating in P25 digital mode on a narrowband channel can restore some and sometimes even all of the geographic coverage lost in the wideband to narrowband transition.

As is always true with projecting radio RF coverage, the adage “your mileage may vary” is always cautioned. Please contact us, or a qualified professional consulting firm, to review your specific situation, geography and existing licenses to assess whether P25 digital operating mode will help your transition to narrowband. Early experience is promising, but not a guarantee.

See also our other comments on P25 digital.

An Emerging Alternative?

Two of the leading public safety radio manufacturers, Kenwood and Icom, have announced an “ultra-narrowband” technology that uses just 6.25 KHz per channel, which is half again the size of the mandated 12.5 KHz narrowband technology. Unlike the broadly available narrowband technology, the ultra-narrowband technology is digital only (no analog mode is offered) and it is only available from two manufacturers (virtually every manufacturer offers the 12.5 KHz analog technology).

However we believe the technology may well become an attractive alternative despite the two constraints because the FCC has indicated that current licensees with wideband channels can amend their license to create as many as four ultra-narrowband 6.25 KHz channels from each existing 25 KHz wideband channel (in certain situations; your mileage will vary).

This is the first time that additional spectrum has been made available to current public safety licensees without any significant cost. And the cost of these digital radios, even at introduction (the most expensive price of a radio is when it is first introduced) is below the cost of current P25 digital radios. So despite the existence of only two manufacturers, it appears that cost will be lower than normally expected, not higher.

There are many unknowns about the radios, we in fact have not used them ourselves or placed them at our customers for in-depth testing. Base stations and repeaters are not yet available (or certified by the FCC), and there is not yet a P25 compatibility mode on 12.5 KHz narrowband, which we believe is necessary to preserve the momentum of all public safety radios interoperable in P25 mode. So it is too soon to begin designing systems with the ultra-narrowband technology for public safety, but we recommend keeping a close eye on this technology as a great opportunity to add frequencies for public safety users.

If you are a non-public safety user, contact us, as you may not need P25 compatibility mode and could immediately benefit from additional channels.

>> Request more information on this solution