Military electronics systems often require an embedded radio to communicate voice or data to and from the system and a command post. But such radios must be small in size and low in power, especially for portable and tactical systems. Fortunately, the latest UHF and 1.3-GHz radios from FreeWave Technologies pack generous power into small footprints. The firm's new MM2-M13 and MM2-MU circuitcard radios feature both serial and Ethernet interfaces with operation at 1.3 GHz and UHF, respectively, and are ideal for applications in sensors, unmanned aerial vehicles (UAVs), and unmanned ground vehicles (UGVs). The board-level radios measure just 2 x 2 x 0.38 in. (50.8 x 50.8 x 9.7 mm) and weigh 0.74 oz (21 g).

The compact board-level radios (see figure) achieve maximum link throughput of 115.2 kb/s over a maximum 60-mile line-of-sight range (see table). They both use RS-232/485 communications protocols at rates of 1200 Baud to 230.4 kBaud. Both employ dynamic key substitution data encryption and minimize transmission errors through the use of 32-b cyclic redundancy check (CRC) error-correction code with automation retransmission.

The MM2-MU radio operates at UHF from 340 to 400 MHz. It transmits with output power levels from 5 mW to 2 W and occupies 230.4 kHz of bandwidth using two-level Gaussian frequencyshift- keying (GFSK) modulation. The receiver sensitivity is -107 dBm for a bit-error rate (BER) of 10-4, using a total system gain of 139 dB. The radio can operate on voltages of +8 to +32 VDC; a +5-VDC version is also available. The transmit current is 800 mA at +12 VDC and +320 mA at +32 VDC while the receiver current is 100 mA at +12 VDC and 50 mA at +32 VDC.

The MM2-M13 radio operates from 1350 to 1390 MHz with transmit power levels from 5 mW to 1 W. It has a line-ofsight range of 40 miles using two-level GFSK modulation, with an occupied bandwidth of 230 kHz. It provides as many as seven user-selectable frequencyhopping bands. The MM2-M13 radio features 15 frequency-hopping patterns per band with a total of 105 user-selecting hopping patterns. The receiver sensitivity is -106 dBm for a bit-error rate (BER) of 10-4, using a total system gain of 136 dB. As with the UHF radio, the 1.3-GHz unit operates on supply voltages of +8 to +32 VDC and optionally +5 VDC. The current consumption for transmit is 500 mA at +12 VDC and 200 mA at +30 VDC. The current draw for receive operation is 75 mA at +12 VDC and 40 mA at +30 VDC.

According to Harold Christopher, Product Manager for the MM2 radios, the new units were developed based on customer inputs: "Our customers told us they were looking for a small-form-factor radio with the performance of the larger FreeWave radios in the same 1.3-GHz and UHF government frequencies. Our customers wanted a radio that was robust and reliable enough to fly the whole mission while being compatible with existing, deployed systems."

Although the new board-level radios are small in size, they provide the same features and functions as the firm's fullsized military/government radios. The MM2-M13 family of radios is backward compatible with the firm's P series family of radios and the MM2-MU family is backward compatible with the company's F series wideband family of radios. This allows customers to replace their existing radios with a much smaller footprint in unmanned vehicles together with a standard size or enclosed radio at the base station or use the same base station with new UAVs.

The new board-level radios are ideal for control and monitoring of UAVs and UGVs as well as other unmanned military vehicles. They include a diagnostic port connector that helps quickly check transit current consumption and signal level in dBm. They are designed with noise immunity for superior performance in noise-congested environments. In addition, they can be equipped with time-division-multiple-access (TDMA) technology for improved robustness and security. FreeWave Technologies, 1880 Flatiron Court, Suite F, Boulder, CO 80301; (866) 923-6168, (303) 381- 9200, FAX: (303) 786-9948, E-mail sales@freewave.com, Internet: www.freewave.com.