9160 Red Branch Road • Columbia, MD 21045 W: 410-884-0500 • F: 410-884-0536 White Paper on “High Antennas for Radio Communications” (HARC) Any aerostat can become a tall antenna tower for radio comms over long distances and rugged terrain. Deploy HARC for tactical, emergency and disaster recovery communications. January 2010 • • • This White Paper may be exported • • • White Paper on “High Antennas for Radio Communications” (HARC) January 2010 Page 2 of 6 1. FORAX-HARC Overview The FORAX-HARC system enables persistent, inexpensive wide-area radio communications using aerostats. This White Paper explains how the lightweight FORAX-HARC™ payload enables any aerostat to become, in effect, a tall antenna tower for radio communications over long distances and rugged terrain. The FORAX-HARC payload is used for: • Tactical communications • Emergency communications • Disaster recovery communications. Commanders can communicate out to the aerostat’s visual horizon and talk over terrain and down into valleys that are otherwise denied line-of-sight communications. Radio relay links can operate with the radios safely in the operations center; only the antennas are on the high-flying aerostat. Syntonics’ FORAX™ (Fiber Optic Remote Antenna eXtension) RF-over-fiber communication technology connects distant antennas to their radios using optical fibers. FORAX transports RF signals over distances up to ~100-km if necessary. FORAX has been installed around the world in mission-critical 24x7 operations since 2005. FORAX-HARC enables almost any radio operating at VHF/UHF/cellular frequencies to take advantage of High Antennas for Radio Communications (HARC). Multiple radios on the ground share one optical fiber in the tether to connect to their antennas on the aerostat via a lightweight electronics payload. The FORAX-HARC system has two major components: • A ground-based Radio Interface Unit (RIU) is collocated with the radios in an operations center. An optical fiber runs from the RIU to the AIU via the aerostat’s tether. • A lightweight Antenna Interface Unit (AIU) is installed on the aerostat along with lightweight antennas, also supplied by Syntonics Several FORAX-HARC systems were delivered to the Army and deployed forward in 2009. Long-range VHF (SINCGARS, 30-88 MHz) communications using a FORAX-HARC system were successfully demonstrated at the Yuma Proving Grounds, AZ in October 2007 on the PTDS aerostat. VHF and UHF (EPLRS, 420-450 MHz) communications were demonstrated at Fort Dix, NJ in June/July 2009. High UHF data rates were successfully demonstrated at Fort Carson, CO in October 2009 on a RAID aerostat (shown above) and again at Camp Dawson, WV in December 2009. White Paper on “High Antennas for Radio Communications” (HARC) January 2010 Page 3 of 6 1.1. General FORAX Features and Benefits FORAX RF-over-fiber communication systems enable users to position their radios without regard to the antenna location. For example: • FORAX connects antennas on an aerostat to multiple radios on the ground. • FORAX moves highly visible, emanating antennas — “aiming stakes” for an enemy — away from the command post (CP), reducing radiating emissions and enhancing the electronic covertness and survivability of the CP. • FORAX connects distant antennas to radios inside a Secure Compartmented Information Facility (SCIF), penetrating the SCIF perimeter with benign optical fibers. FORAX changes communications doctrine as it relates to radio/antenna separation. FORAX allows antenna to be positioned away from the command post and, where applicable, to be moved off “Radio Hill.” This decreases risk to personnel and costly equipment, decreases time for CP set-up, and lowers maintenance reaction time. It also lets users position their antennas where they want them, without the current short tether of a coaxial cable. FORAX can play a vital role in Operations Centers of all sizes and in other tactical and air traffic control programs. Initially developed for the U.S. Special Operations Command, features and benefits of this RF-over-fiber technology include: Feature Benefit Long Connections » Radio and its antenna can be located up to 10 km apart using single mode fiber; Easy Routing » RF signals are carried on lightweight, flexible, rugged, optical cables » Multiple radios can be carried on a single fiber optic cable » Geographic diversity in RF signal routing becomes easy » FORAX™ products handle all modulations including HF, SINCGARS, HAVE- All frequencies, all modulations EMP/EMI Immunity greater distances are possible. QUICK, UHF MILSATCOM, EPLRS, VHF and UHF LOS » Lightning, electromagnetic pulses, or RF interference cannot propagate over, or » 1.2. influence the signals on, optical fiber cables Radio equipment is opto-isolated from antenna Specific FORAX-HARC Features and Benefits FORAX-HARC technology was first developed for the U.S. Army’s Persistent Threat Detection System (PTDS). In brief: • High antennas improve line-of-sight (LOS) radio coverage by enabling long distance communications and communications relay over mountainous terrain or down into congested urban areas. Using lightweight antennas installed in a specific configuration on the aerostat, multi-radio problems with co-site interference are avoided. • Aerostats can inexpensively carry high antennas. Aerostats provide a tall, quasipermanent radio tower. Aerostats are unmanned platform with relatively low acquisition and operating costs as compared to other operational approaches to providing wide-area LOS communications. White Paper on “High Antennas for Radio Communications” (HARC) January 2010 Page 4 of 6 • FORAX-HARC connects multiple ground-based radios to high antennas on the aerostat via a single optical fiber in the aerostat’s tether. Leaving the radios on the ground enables immediate access for radio maintenance and crypto key loading. All radio controls are at the User’s fingertips. A number of six-radio FORAX-HARC-PTDS systems, each handling four SINCGARS and two EPLRS radios, have been delivered to the U.S. Army. • Figure 1-1 presents a notional system diagram of the FORAX-HARC-PTDS system. The Radio Interface Unit (RIU) is located within 1-km of the aerostat’s mooring platform and connected by a tactical optical fiber cable supplied by Syntonics. • Figure 1-2 shows the same system’s Radio Interface Unit (RIU) in its military-grade shock-mount transit case with UPS, supplied by Syntonics. • Figure 1-3 shows the lightweight FORAX-HARC-PTDS Antenna Interface Unit (AIU) that flies on the aerostat connected to multi-element antennas. Figure 1-1. Notional system diagram of FORAX-HARC-PTDS system White Paper on “High Antennas for Radio Communications” (HARC) January 2010 Page 5 of 6 PTDS configuration with HARC RIU (left) in transit case with UPS, all supplied by Syntonics. The RIU is connected to four SINCGARS radios during a field demonstration. Figure 1-2. PTDS RIU Front view of modules Rear view of modules with cables installed Figure 1-3. Lightweight PTDS AIU 1.3. Conclusion Any aerostat can become a tall antenna tower for radio comms over long distances and rugged terrain. Communication and communication relay links can operate with the radios safely in the operations center; only the antennas are on the high-flying aerostat. With a lightweight FORAX-HARC payload, an aerostat can be used for tactical communications, emergency communications and disaster recovery, and military exercises. Using HARC, commanders can communicate out to the aerostat’s visual horizon and talk down into “urban canyons” and valleys that are otherwise denied line-of-sight ground communications.