LMR systems in the military

Military establishments worldwide use a large variety of specialized radio systems that operate on bands ranging from extremely low frequencies (ELF) all the way to super high frequencies (SHF). These bands are used for tactical, data, SATCOM and other specialized types of communications. Given the tremendous number of radio types and the frequency range open for military communications, why does the U.S. military purchase and use land mobile radio systems? How does this use affect the local users near large installations? How can support businesses profit from this situation?

The U.S. Armed Forces, which I will refer to collectively as the “military” regardless of branch, is careful to distinguish among types of communications. This distinction is often called the “mission.” What is the focus of “tactical” and “logistics” communication missions? Tactical communications equipment can generally be classified as those combat systems that must be able to operate in the same unforgiving combat environment as the soldier, sailor or Marine. These MIL-SPEC tactical systems are expensive but well worth the value they offer. They typically carry Army/Navy (AN/) nomenclatures, such as “AN/PRC-104.” I have fired up tactical “backpack” HF radios that had been cold-soaked for more than 24 hours in temperatures well below 2408. Despite the cold, the radio could communicate with inbound aircraft hundreds of miles away (aircraft carrying my food, water, ammo and spares, which is why I still think the money is well-invested). However, these impressive radios are expensive, and not everyone in the military operates in a harsh combat environment.

In a less demanding environment, someone had to load and fuel that same aircraft, an activity that requires close coordination for safety and efficiency. These “logistic” communications are carried out in the same environment as that in which LMR business users perform their daily tasks. There is no need for super-rugged tactical combat systems.

Another factor to consider is cost. The tactical radios mentioned previously cost more than $8,000 apiece in large numbers (batteries extra), depending on climate. LMR systems, thanks to competition and economy of scale, have much lower purchase prices. The military routinely uses LMR systems for appropriate logistics activities.

Competing for frequencies Most military users operate on the government portion of the spectrum, both VHF and UHF. Rarely do they compete with local businesses for spectrum. Although the radio systems use the same bands, they do not share the same frequency set. The opportunity is present for co-channel interference. I have found military users cooperative in resolving interference issues. As a plus, they may bring sophisticated test or direction-finding (DF) equipment into play to quickly find, then solve the problem.

While at Nellis Air Force Base, near Las Vegas, I ran a large air-traffic control maintenance facility. One day, an AM radio station’s signal showed up in the middle of the passband of our primary air-to-ground receiver. A second receiver placed online showed the same problem. I quickly built and added a filter to the system feed while we sorted out the problem. (See “Use Coaxial Filters to Reduce Interference,” MRT Public Safety Supplement, August 1993, page 12.) The culprit was intermod distortion (IMD), caused by a new, off-frequency, paging transmitter in the middle of town mixing within the victim receiver. The offending transmitter was quickly located with sophisticated military DF equipment.

When a military installation uses LMR systems, it generally uses many units. In the previous example, that installation had more than 800 LMR portables and more than 200 LMR mobile sets supported by multiple repeaters and base stations. If you compare such an installation to a city, then you can see where the same functions would apply: police, fire, and civil engineering for power production and transmission. In fact, because military installations often have support agreements with local communities for firefighting, they try to ensure their communications systems are as compatible as possible with the local civilian jurisdiction.

The military uses other systems with traditional LMR frequencies. These may be remote control, area security, SCADA and other specialized systems found in industrial activity. These systems may represent both potential problems and business opportunities. (See “RF and remote control,” page 30.)

Potential service customer Almost all military installations that use LMR systems outsource the maintenance and installation of these systems. Military radio maintenance technicians move between bases and tend to focus on the systems they would maintain in a combat situation. Cross-training for the incredible variety of installed systems found around the world would beprohibitively expensive.

Civilian service centers can tap into this potential market. Installation and maintenance contracts are normally awarded under a competitive bid process. The Federal Acquisition Regulations (FAR) and Defense Acquisition Regulations (DAR) are the guidelines used for this process. These contracts are advertised for bid in the Commerce Business Daily, a federal government publication. The Commerce Business Daily is also available online at www.gpo.ucop.edu/search/cbd.html, or cbdnet.gpo.gov/index.html for the government version. Use the supplied search engines to search for the key words “LMR” or “maintenance contract.” The military also supports a “Procurement Technical Assistance Center” (PTAC) in towns near the larger installations. Check with your local chamber of commerce to see if one is available. If not, see your local Small Business Administration office.

A word of warning: Before you bid on, or accept, any federal contracts, be sure you fully understand all of their vendor/contractor requirements. Talk to someone who has a current contract, or contact the small business office at your local installation procurement unit. Understanding contract requirements is important. For example, the requirements for vendor “certification” (a drug-free workplace, use of recycled paper, etc.) run some 23 pages in the FAR alone. If you are willing to meet these requirements, winning a contract can bring several years of steady work-if your performance is satisfactory.

The military makes use of “Contractor-Off-the-Shelf Systems,” or COTS. One good example is the REMOTEC “Andros” remote-controlled bomb removal robot that is used by the 716th Explosive Ordinance Disposal (EOD) Detachment team at Ft. Richardson, Alaska. The EOD team members can perform the same sets of tasks that are performed by a metropolitan police bomb disposal unit. The Andros is normally used to remove unexploded homemade bombs, a dangerous but necessary job.

The robot (see photos, pages 18-21) is remotely controlled by an RF link set that provides both command for motor control and video for steering the unit. Wire or fiber-optic cable, which would work in an urban setting, will snag on the obstructions typically found in an unimproved area. The robot RF link offers a potential for interference but the members of the 716th EOD team have had no reported problems to date.

All of Alaska is the responsibility of this EOD team (because most Alaskan jurisdictions are lucky to have a full-time police force, let alone a highly trained explosives squad). Short-range, interteam communication is via Motorola “Talkabout” FRS radio sets. This inexpensive and practical solution works well in Alaska. The team also uses regular LMR sets from GE as part of the trunked system found on the post. Operating on the 406MHz government band, these portable radios offer a cost-effective solution for the large area that makes up Ft. Richardson. For work in the Pacific Rim, the team has MIL-SPEC SINCGARS radio sets available for use as well.

Thanks to Capt. Green (USA) and the brave men and women of the 716th Ordinance Company (EOD) for their help and patience in answering questions. I would like to acknowledge the professional work of Staff Sgt. William Johnston in demonstrating the radios used by the team and thank Staff Sgt. John Phipps for the high-speed robot road test. NOTE: Mention of specific brand names or types of radio systems or sets is not an endorsement by the U.S. Army or the government.

Contributing Editor Koehler has more than 30 years of experience in radio, telephony and computer electronics. He has been teaching part time at the University of Alaska, Anchorage, for the past four years. His email address is [email protected]. Radios used in combat situations are often shelved during peacetime in favor of more traditional VHF systems, which can also be used for remote control operations.