Whether operating in licensed or unlicensed bands, military radios must battle with noise and interference. The MM2 Series of 1.3-GHz military radios from FreeWave offer the flexibility of a board-level radio for installation into original-equipment-manufacturer (OEM) systems, but also the performance of a low-power radio that is capable of achieving communications over a clear line-of-sight range of 80 miles. The spread-spectrum radios measure only 2 x 2 x 0.3 in. (50.8 x 50.8 x 7.6 mm) and weigh only 0.74 oz (21 g), making them unobtrusive additions to a wide range of equipment and applications.

The compact, ITAR-controlled radios operate over a frequency range of 1350 to 1390 MHz, with an occupied bandwidth of 230 kHz. Transmit power can be set from 5 mW to 1 W. The radios rely on two-level Gaussian frequency-shift-keying (GFSK) modulation and offer from 1 to 112 user-selectable frequency-hopping channels from a total of 172 frequency-hopped channels. A total of 105 frequency-hopping patterns can be selected by the user (as many as 15 patterns per band), with a user capable of setting as many as seven frequency-hopping bands. The frequency agility results in data rates to 153.6 kb/s over a clear line-of-sight communication range of 80 miles.

The receiver portion of the MM2 radios achieves sensitivity of -106 dBm at a bit-error rate of 10-4. The receiver circuitry, which contributes to a total of 136 dB system gain for the MM2 radios, offers selectivity of -20 dB within 230 kHz of a (hopped) center frequency. The radios employ 32-b cyclic-redundancy-check (CRC) error correction, a proven method for ensuring the integrity of transmitted and received data even in noisy environments. In addition, a diagnostic port allows real-time local diagnostics and access to the radio setup menu for ease of programming. Diagnostic routines include adjustments to transmit current and signal level (in dBm). The radios are equipped with RS-232/485 or TTL interfaces for ease of connection to external computers.

The MM2 Series board-level radios (see figure) can run on power supplies of +8 to +30 VDC or +5 VDC. At +5 VDC, they draw only 1000 mA during transmit, 120 mA in receive mode, 30 mA in idle mode, and only 8 mA in sleep mode. When running on a +12-VDC supply, they draw 500 mA current in transmit mode, 75 mA in receive mode, 20 mA in idle mode, and 5 mA in sleep mode. On a +30-VDC supply, the board-level radios draw only 200 mA current during transmission, 40 mA current during reception, 9 mA current in idle mode, and only 2 mA current in sleep mode.

The compact radios are designed for an operating temperature range of -40 to +75°C. With their small size and light weight, the radios are ideal for providing secure, error-free communications in applications where space is at a premium, such as in unmanned aerial vehicles (UAVs), unmanned ground vehicles (UGVs), and other types of unmanned vehicles. The radios are also well suited for use in guided parachutes, as well as in sensor networks where small size and low power consumption are critical. These compact radios are built with many of the same features and to the same standards as the firm’s larger military and commercial radios, which have established a strong track record for high reliability in the field.

For applications where the MM2’s intended spectrum may be unavailable, the firm recently announced its GXM line of 2.4-GHz (2400 to 2483 MHz) radios measuring just 2.0 x 1.4 x 0.38 in. (50.8 x 36.0 x 9.6 mm) and weighing only 15 g. Designed as drop-in replacements for the MM2 radios, the GXM radios operate with transmit power levels from 10 to 500 mW (as an option, the power can be set for a maximum level of 100 mW). They can achieve an effective operating range of 20 miles at those frequencies.

Freewave Technologies, Inc.
1880 S. Flatiron Court, Suite F
Boulder, CO 80301
(866) 923-6168, (303) 381-9200 FAX: (303) 786-9948
e-mail: sales@freewave.com
www.freewave.com