Pocket Communications
FROM SACKS TO SHIRTS, ANTENNAS BECOME MORE MOBILE.
When military commanders stress the need for effective communication, they’re not only referring to being a good listener, but also to battlefield communications. Miscommunication between warfighters can occur during the fog of war, much to the dismay of commanders from all services.
Effective communications on-the-move has been a goal of military planners for years. Now, antennas have been developed that are small enough to fit into a rucksack or to be worn on a soldier’s shoulder. This means that more effective, immediate, onthe- move communication is now possible.
Ball Aerospace & Technologies Corp., Boulder, Colo., has worked with the military for years developing and manufacturing advanced antenna and radio frequency (RF) communication subsystems. “We have probably the largest stand-alone antenna group in the country,” said Dean Paschen, chief technologist for the antenna group at Ball Aerospace. The company worked with USSOCOM to develop two backpack-sized antennas, the AN0624A Rucksack Antenna and the AN0647A Stuff-sack Antenna.
Constructed from synthetic foam and weighing less than two pounds, the AN0624A is one of the smallest and lightest UHF tactical antennas on the market, according to Paschen. The AN0624A is discreetly designed to look like a stadium cushion seat.
“Our most difficult challenge was to keep the weight light and to keep it compressible,” said Paschen. He explained that the antenna could be carried by airborne soldiers while dropping into a remote location. “USSOCOM personnel stressed that the antenna had to be light and easy to handle,” said Paschen.
The AN0624A is designed for low datarate communications, line-of-sight communications, and monitoring command and control links while on the move. As far as ruggedness, Paschen, while not able to provide a specific example, has it on good authority that the antennas made by Ball Aerospace can be shot and still keep functioning.
The AN0647A Stuff-sack Antenna is equally rugged. It is constructed from lightweight synthetic foam and conductive fabric and encased in a weatherproof/ breathable Gore-Tex outer shell, according to Paschen. “It also has a valve like an air mattress and can be inflated and deflated. The support structure is composed of shock-cord, tent-pole technology, typically used with lightweight, rugged backpacking equipment,” said Paschen. “These materials allow the antenna and its support structure to be stowed in a small, 12-inch by 3-inch diameter stuffsack.” The total weight of the antenna, support structure and stuffsack is less than two pounds.
The original version of the AN0647A was so small that it could literally be blown away on a windy day. “We built a newer version that’s perforated and suspended it without the foam inside, so it won’t blow away,” explained Paschen. “And the bag that contains the antenna is stitched to it so the bag won’t blow away either.”
The AN0647A is sized for high data-rate communications and the stuffsack antennas can be combined to increase gain.
Ball Aerospace also has delivered prototypes of wearable antennas, according to Paschen. One is the MTX—Mini-Transmitter Antenna for Blue Force tracking and another is for the Enhanced Position Locater Reporting System (EPLRS). At five inches long and an inch-by-inch square, both antennas attach to the soldier’s loadbearing harness. “The baseplate of the antenna is made of the same type of aluminum that’s used for finger implants, making the antenna very malleable,” said Paschen.
The Communications-Electronics Research, Development and Engineering Center (CERDEC), Space and Terrestrial Communications Directorate’s Antenna and Ancillaries Branch Army Technology Objective (ATO), Fort Monmouth, N.J., currently has five body-wearable antennas (BWAs) under contract.
“Two promising systems are those recently developed by MegaWave Corporation and BAE Systems,” according to a CERDEC representative. These antennas are designed to operate wideband in the 225-2,500 megahertz (mHz) range, “which supports Soldier Radio Waveform, which is the JTRS waveform for the dismounted soldier.”
“Initially we worked with the 30-88 mHz (VHF) to support the SINCGARS radio, but the lower in frequency the larger the antenna, which required rather exotic techniques to configure the antennas to electronically appear larger,” explained the CERDEC representative. So, the ATO focus has been on the 225-2,500 mHz range.
“The antennas are designed to fit the Future Force Warrior (FFW) ensemble,” said Marshall Cross, chairman and vice president of research and development for the Boylston, Mass.-based MegaWave Corp. Several factors about the ensemble presented a challenge for the MegaWave team. “First, the armor plates on the ensemble are very stiff and aren’t friendly to radio waves,” said Cross. Then, there is the fact that FFW ensemble is chock-full of various systems and equipment. “What with the computer, navigator pouch, water-pack and health-monitoring system and more on the ensemble, there’s no real good place to put an antenna,” said Cross.
“Our idea was to use the plates to help the performance of the antenna.” MegaWave designed a thin pouch for the ensemble that has thin mesh in it. “It turns the plate into a counterpoise—which is like a ground,” said Cross. “We did the same with the back plate—making it into an endload—which increases the effectiveness of the antenna.”
A wire that connects the two pouches is placed on a shoulder strap which keeps the wire at least one inch from the soldier’s body.
“It radiates as well as something you’d hold up to your head,” said Cross. The MegaWave and BAE Systems BWA’s were tested recently at the Command, Control, Communications, Computer, Intelligence, Surveillance and Reconnaissance (C4ISR) On-the-Move Experimentation demonstration at Fort Dix, N.J., and both antennas performed well, achieving good range, according to the CERDEC representative.
“The antenna has approximately a 1 kilometer (km) range when the operator is standing in the open and approximately one-half km when the operator is prone,” said Cross. He anticipates that the antenna will be fielded in 2010.
“The most successful designs incorporated the soldier’s ensemble into the design—exploiting the properties of the ceramics plates and equipment to add to its wideband performance,” said the CERDEC representative.
“Ideally, you want equal power, no matter what direction or position the soldier is in,” said John Pedersen, engineering project manager for BAE Systems, with U.S. headquarters in Rockville, Md. He continued, “So, we put one antenna on either side of the soldier, thinking that would make for the least interference from other systems.”
The two torso-mounted radiators are connected by an RF splitter that is not much different from a splitter on a TV, according to Pedersen.
Saying that the antenna is lightweight is somewhat of an understatement, as it’s made of a conductive type of cloth. “Upon further implementation of the antenna, it will be sewn into the soldier’s vest,” said Pedersen. Obviously, this antenna is very flexible. “The antenna should be basically invisible as far as the soldier feeling any effects from it,” said Pedersen. An added plus is that the cloth is very inexpensive.
“We’re also doing a re-design called Soldier Radio which uses the same principles as our torso-mounted antenna, but this one is worn off the shoulder. We’re hoping for increased range,” said Pederson.
While CERDEC, ATO and their industry partners continue their advanced antenna research and development, the military can rely on an antenna technology that is 100 years old—high frequency. “HF has a long link. If there is a disaster anywhere in the country, officials can take a 5-pound HF antenna, put it on a stick and they’d be able to talk to D.C.,” said Bill Whittington, vice-president of sales, C&S Antennas, Inc., Sterling, Va.
“HF radio is no longer somewhere between the art of black magic and pure luck,” said Whittington. The post-1990 family of 2 to 30 mHz radios with digital signal processing and automatic link establishment (ALE), teamed with the correct type of antennas, allow for accurate communication 95 to 98 percent of the time, according to Whittington. ALE, when activated between two radios or all the radios in a net, goes out and finds the best working frequency, analyzes its strength, remembers it, and goes automatically to that frequency when one calls that station.
The C&S FANLITE LFH Manportable Theater Range Antenna has been in service with all branches of the military for over 15 years. This extremely strong broadband NVIS-designed antenna operates in the 2- 30 mHz range, requires no tuner, is completely omnidirectional and will contact everything within a 2,300 mile circle of the sending radio, according to Whittington. The FANLITE can be reconfigured into a directional mode (sloping vee) to reach 3,000-5,000 miles, and is easily erected by one or two men in a short period of time.
Whittington points out that, “VHF and UHF won’t work once you get behind mountains or there are too many obstructions, but HF can be used.” He added, “Satellite bandwidth is crowded and expensive. In a firefight you can’t wait in line until your turn.”
C&S also makes a small, 5-pound backpack NVIS antenna, the MTA-xl, which can be configured to frequency or tuned with a coupler. The MTA-xl is small enough to be hidden. “The radio comes awake, signs in, picks up traffic, sends out traffic and goes back to sleep,” said Whittington. “It’s hard to locate because HF is omnidirectional. You almost have to trip over it to find it and if someone does find it, it’s password protected.”
Antenna development has made great advances, and the specialists at CERDEC anticipate further advances in the future. More technologies are being looked at such as meta-materials and nanocomposites to achieve similar BWAs while retaining similar antenna characteristics.
“CERDEC will continue to use our expertise in antenna research to seek out, find and refine this technology to support our nation’s forces and equip the warfighter.”
Small veteran-owned consortiums such as Victory Mil, located in the Space Coast, Fla., are providing special operation forces with innovative, lightweight, and “pocketsized” solutions for satellite communications on-the-move. Products such as the VTCS-9000 and VTCS-4000 are improving SATCOM links at affordable prices.
The Victory Mil VTCS-9000 is a rollup type antenna designed for low profile applications. “Communicators wanted an invisible UHF TACSAT antenna designed to replace the obvious X-wing profile when mounted on civilian vehicles; in relatively short time we developed and deployed this unit to the field.” said inventor and consortium co-founder Frank Vassallo.
In addition to providing quick turnaround, custom RF and antenna solutions, Victory Mil offers a portable lightweight miniature UHF SATCOM low noise amplifier. The VTCS 4000 works with the Harris 117F radio and any SATCOM antenna improving weak signals during receive mode.
According to Gary Beckert, consortium co-founder, “As former Marines, Victory Mil founders understand the need for lightweight gear, and the importance of making our solutions affordable down to the squad level. We know that satellite communications are critical to survival in combat and technology innovations priced in the thousands of dollars just make it harder to get it to the individual soldier.” ♦