Now is a great time to invest in a wireless technology solution. Three major issues must be addressed before a company commits to a wireless field service system — coverage, cost, and contingency.

Let’s start with the basics of wireless communications. There are four major components to a wireless field service system:

1. A wireless network over which data, not voice, is sent between the field technicians and (typically) dispatchers;

2. The portable computer used by the technician in the field, with a modem that transmits and receives wireless data;

3. Software running on a host machine and also on the portable computer, providing both the business functionality and network and operating system services; and

4. The Internet, which provides access to anyone anywhere with the proper authorization.

Wireless data coverage

This article addresses the first component, the wireless network, starting with the coverage question. It’s the right question to ask first, because if your technicians are “out of coverage” most of the time, you may as well stick to paper and a pager, like your technicians have today.

Back in the late 1980s, when IBM established the first large wireless field service system, they had to set up their own national system of communications towers, to the tune of hundreds of millions of dollars.

Ten years later, the story is vastly different. Major communications companies have invested those hundreds of millions, even billions of dollars, to provide wireless data systems available to even the smallest user. Coverage by commercial systems exceeds 90% in the major metropolitan areas, with 100% coverage when satellite options are added.

“The highly reliable nationwide BellSouth Intelligent Wireless Network (IWN) currently covers more than 93% of the urban U.S. business population and we are aggressively expanding wireless coverage,” said Lew Blumstein, vice president of industry marketing for BellSouth Wireless Data, a subsidiary of BellSouth Corp.

“We are adding approximately one base station per day and expect to be at 2,000 base stations by the end of the year.”

There are two alternative technologies that can meet the needs of field service systems—packet data radio systems, which allow two-way wireless communications using radio frequency, and cellular sometimes digital packet data (CDPD) systems, which use voice networks.

Two giants of wireless data communication, RAM Mobile Data and American Mobile Ardis, compete head-to-head in the RF market with nationwide coverage. A patchwork of telephone companies offer regionally based CDPD systems, with the larger ones, such as ATT Wireless, often offering a nationwide view to the user.

The major carriers all offer coverage maps which can be viewed on the company websites, and based on locations as specific as ZIP Plus 4. Chances are that your sites are in range, therefore the coverage of each carrier in your geography is a major criterion, though not the sole one, in selecting the carrier you are trusting with your wireless data.

The more sophisticated field service software will allow you to mix and match wireless carriers, giving you flexibility in coverage and in price negotiation.

Coverage maps don’t tell the entire story, and you’ll want your system supplier to explain their coverage in detail. Among the factors which can influence coverage are:

• The specific handheld PC and modem you select; this can make more of a difference than many people suspect. Final coverage testing should always be with the portable computer you have selected.

• In- or out-of-building use; radio signals are degraded as they pass through walls, and places deep in buildings can suffer sever degradation of coverage. Some carriers provide better in-building coverage than others do, so again a consultation and testing are in order.

• Variations in terrain; Kansas — love that flat land. The hills of San Diego — better use the best portable computers and wireless carrier you can find. Radio signals generally travel in straight lines, so natural or man-made obstacles, such as the high-rise maze of New York City, may result in spotty coverage.

Cost of data

Communication systems are largely a function of fixed cost. Therefore, the more users, the lower the cost. Wireless voice systems have seen their subscriber base increase from two million to more than 60 million from 1988 to 1998.

The average monthly bill has dropped by more than half, from $95 to $40 during that same period, even as the number of minutes used has increased dramatically. Wireless data is on a similar trajectory.

“Field service companies can expect to pay between $30 and $50 a month per portable computer using the cost-efficient, nationwide BellSouth Intelligent Wireless Network,” added Lew Blumstein.

Per-user prices were about double that just a few years ago.

Many hvac companies considering the move to wireless data may recoup the wireless data cost easily by reducing or eliminating their cell phone or Nextel® subscriptions, which are often in a similar price range or even higher.

Eliminating the wait time until the technician and dispatcher both free up, and also reducing the “chat factor” of voice systems, combine for a net gain in productivity and reduction in cost.

Contingency planning

What if your technician is out of coverage? System workarounds include:

• Dispatching the information needed by the technician before he or she travels to an out-of-range location;

• Using a phone line at the out-of-coverage site to send and receive information; and

• Changing location slightly, maybe as simple as moving to a window, to get back in coverage.

“I’ve been using FieldCentrix [a wireless field service system] in the San Diego area since October 1998,” said Dennis Maestri, senior hvac technician with Mesa Energy Systems. “There are a lot of hills here, and although I’m usually in coverage, it’s not always the case.

“The handheld PC stores a tremendous amount of information, so as long as my work-orders have already been sent by dispatch I can still access all the jobsite and equipment history, and enter my updates as I do the work. Once I’m back in range the software automatically sends and receives information that has been stored.

“Once we switch to the ruggedized Itronix T5200 HPC, from a consumer-class device, we instantly got much better coverage, even into Mexico. That was a surprise, because we thought the network coverage was weak before using the Itronix units, but actually it was the other HPCs that were a problem. And, I like being able to just plug a phone jack right into my unit when I need an update and the wireless coverage is poor.”

Wireless communications systems have a lot to offer hvac contracting companies. However, to make the best decision for your company, it is wise to consider coverage, cost, and contingency planning.