Radio communications improve services on forest lands Communications system designers with radio frequency and funding limitations find ways to deliver the best possible coverage. Often, interagency communications requirements lead to using VHF highband c
Workers in the nation’s forests carry out duties as commonplace as insect control, as dangerous as fighting fires and as vital as saving lives. Without adequate radio communications, their daily tasks would cost more, fighting fires would be more perilous and it might be impossible to respond to emergencies fast enough.
“We have aircraft that fly every day during the winter fire season,” said David Campbell, a forester in Louisiana. “The pilot looks for smoke, and when he finds smoke, he radios the dispatcher in Natchitoches to give the location. The dispatcher calls whatever unit is in the area and sends it to the fire.”
When a fire is burning, the plane circles the fire and tells foresters where the fire has jumped the fire lines. At times, information from the pilot is critical. “On one particularly bad fire, the crew that fought on the fire line didn’t know it, but the fire was crowning trees ahead of them and advancing on them quickly,” Campbell said. “The pilot told them to get out of there, and that warning saved their lives and the equipment for sure.”
Campbell is with the South Natchitoches forestry unit. “The Natchitoches office covers four parishes for District 6 of the state forestry service, including Sabine, Red River, Desoto and Natchitoches,” he said. “We use radios on a daily basis for communications. We have radios on fire plows and tractors. We have hand-held radios to use to communicate with one another while fighting fires.”
The forestry units use radios on a routine basis to report weather conditions and fires to the office in Woodworth. “With these reports,” Campbell explained, “the central office can keep up with all of Louisiana’s fire districts and record the information. For example, all of the parishes report daily rainfall.”
Campbell added that his hand-held radio gives him a sense of security. “If I go into the timber, I carry my hand-held radio,” he said. “If something happened to me, I could call someone. It’s definitely a safety factor.”
Oregon floods Radios commissioned for the forestry service are not used only to fight fires that blaze when rainfall is light and the timber is dry. For example, they were called into use in Columbia County, OR, during 1995’s spring floods that affected 355 square miles of territory. “We used our radio system for coordinating Red Cross efforts,” said Clare Wren, communications manager for the Oregon Department of Forestry. “We helped the Red Cross as it assisted people in getting their homes cleaned up.”
The state’s forestry radio communications network also supports search and rescue efforts in combination with the Air National Guard, U.S. Forest Service and search-and-rescue organizations.
Even though Oregon’s network of 44 repeaters designed for forestry communications supports other activities, its principle purpose is to help with the suppression of fires during the active season from June to September.
Asked what new technologies or features he would like to see offered by radio equipment manufacturers, Wren said, “We try not to let technology rule us. Instead, we want to define how we need to do business 10 years into the future and to foresee what technologies will be necessary.”
Examples of technologies that are expected to be useful include automatic vehicle location (AVL) equipment combined with Global Positioning System (GPS) hardware to provide accurate position information about heavy equipment used during fire suppression. Wren also said that a mobile data capability for mobile-to-mobile and mobile-to-base communications would be helpful.
Cellular and satellite The forestry department is equipping certain outlying units with cellular telephones. “The cellular phones make possible long-distance communication as well as a more secure method of communication compared to open-air radio,” Wren explained. “Also, the department has entered into pilot program with American Mobile Satellite to test 10 mobile units in western Oregon to see what coverage we have in that hilly territory.” The state police are already taking part in the pilot program, which is expected to last 90 to 120 days. After the forestry department joins the program, Oregon’s military department will run a test, too.
“The satellite communications will be press-to-talk,” Wren said. “You can make a group call to talk with everyone within the group. The forestry department will have its own group. To call an individual unit, you access the satellite and call an identification number, and the unit at the other end rings like a telephone.”
Wren described cellular phones and satellite communications as extra tools, but he does not foresee them as replacing existing radio systems. Foresters work in remote areas not likely to be served by cellular systems that are built to reach populated areas and areas with vehicular traffic. Satellite communications may not reach into all locations where a view of the sky is obscured.
At present, the VHF highband carries all of Oregon’s forestry radio communications. “We are on the verge of obtaining UHF,” Wren explained, “but we are not there yet. We have about 44 repeaters statewide on six frequency pairs. The system includes mobiles, portables, base stations and repeaters. We use a portion of the Oregon Department of Transportation’s 6GHz analog microwave systems to control our mountaintop repeaters.”
The repeater system is not linked. Instead, it is divided into 13 districts. Each district has its own frequency pair. A given district has from one to five repeaters, depending on the district’s size and terrain. Although all of a district’s repeaters are on the same frequency, each repeater uses a different subaudible tone control frequency.
“All repeaters in a district hear all of the radios,” Wren said, “but they only key up when the proper tone is selected.”
This configuration can lead to co-channel interference. For example, a radio used on a 6,000-foot mountain can place a strong signal on all repeater input frequencies for 100 miles. The radio might block other signals from the other repeater’s input, but no interference would be heard because the subaudible tone control would keep the other repeater silent.
“We have lived with this type of interference for years,” Wren said. “We are waiting optimistically for FCC to free up new interstitial channels so we can license on 7.5kHz splits in highband. That will solve many of our co-channel interference problems within districts and between districts.”
One relatively new project for the forestry department is centralized dispatching. The dispatching function for as many as five districts is being combined with dispatching for the U.S. Forest Service and the Bureau of Land Management to use one dispatching location.
As is done in Louisiana, the Oregon forestry department uses aircraft, including a Cessna 414 and a Part Navia equipped for aerial photography. Radio equipment on the aircraft can communicate with the U.S. Forest Service and other agencies besides the state forestry department. This capability is useful when the aircraft are used for insect and bear surveys in cooperation with other agencies.
Besides his work with the state of Oregon, Wren is involved with national spectrum allocation matters in his role as president of the Forestry-Conservation Communications Association (FCCA). FCCA has been actively involved in subcommittees of the Public Safety Wireless Advisory Group (PSWAG), a committee with a mandate from Congress to formulate radio spectrum needs for public safety through 2010.
South Dakota When it comes to spectrum allocations, “Everything is in kind of a turmoil,” said Les Childers, a technician with South Dakota State Radio Communications, the agency that oversees radio communications for the state, including forestry communications. Blocks of VHF and UHF land mobile frequencies assigned for specific purposes, such as forestry communications, are subject to refarming, which may mean frequency reassignments for other purposes and with new technical and regulatory requirements. “We don’t know what will happen to those blocks, whether they will be left for government use or auctioned. What we would like to see is that when frequencies are split [creating more channels], frequencies for forestry, local government and police use stay in that group.”
Childers explained that funds for upgrading radio communications systems tend to be more available during a short period following particularly destructive fires. For example, in 1986, lightning ignited a fire–the Galena Park fire–that burned about 18,000 acres in Custer State Park in the Black Hills. A plan had been drawn up during 1985 and 1986 to reconfigure the radio system using 70 channels and including the existing communications resources of local fire, Civil Defense, law enforcement, state forestry and federal forestry agencies. After the fire, funds were made available to acquire equipment for the state forestry department, and the operating plan was developed.
Before the channel plan, Childers said, there were a lot of problems during a fire in the Flint Hills and other burns in the Black Hills. “Communications were rather nonexistent,” he said. “The current system was built in response to that. Rather than reinvent the wheel, we used what was there.”
The plan is based on the original equipment bought for forestry use in that area during the period following the Galena Park fire. The channels are divided into 12-channel banks that fit 48-channel portables. The first bank is dedicated to state agencies, the second to fire line repeaters, the third to local agencies and the fourth to federal agencies.
Although the system uses five repeater sites with another two yet to be installed, Childers said that interference problems are minimal.
Asked what he would like to add to the system, Childers said he would like to have a microwave system dedicated for forestry department use to link repeaters sites together. At present three sites are linked with microwave, and the rest are operating with control stations. “The advantage with microwave is direct linking,” he explained. Control stations cannot always cover such great distances because of terrain shielding, which makes linking with control stations difficult.
The microwave system was nearly achieved. “With one phase of the project, a $950,000 appropriation was supposed to be made for the dedicated microwave system to cover Black Hills,” Childers said. “It didn’t come about. All that was funded was a $3,500 study with maps, and actual construction fell by the wayside. Usually, the situation is that, if there is a fire, everyone wants to address the problems quickly, and then they forget.”
Along with the microwave system, Childers would like to add more mountaintop base stations and repeater sites, and he would interconnect the system with the public switched telephone network for mobile phone calls. The system currently relies on local telephone cooperatives’ equipment and programmable radios with Touch-Tone pads. These radios are dedicated for telephone calls.
Although the communications manager is largely satisfied with the system’s coverage, he would like to have better coverage in some areas. “The Black Hills is mountainous terrain–not good for radio coverage,” Childers said. “Without a high number of repeaters, coverage can be sporadic.”
To improve portable radio coverage, the forestry department uses portable fire line repeaters and 450MHz links. “We situate them where we can link back into the microwave system,” Childers said. “We can have communications right back to the emergency operations center where all the staging is done.”
Successful forestry radio communications takes various forms depending on the expanse of territory to be covered and how many agencies cooperate in providing services to that territory. The safety of life and property, as well as the efficient performance of routine tasks, is improved with the right communications system.