MINIATURE HIGH-POWER IMPULSE TRANSMITTER FOR RADIO-ECHO SOUNDING

We have developed a miniature high-power impulse transmitter for radio -echo sounding of glaciers. It features two synchronous second break-d own pulse generators operating in a differential configuration. Specif ications include bipolar 550 V pulses having rise times less than 2 ns , 512 Hz repetition rate, 180 mA at 10-14 V d.c. operating power, 5 mA standby current and maximum dimension of 12 cm. Because of its small size and low power consumption, the transmitter is suitable for back-p ortable systems and for towed arrays. The transmitter first saw servic e in 1990 on Trapridge Glacier, Yukon Territory. Subsequent copies hav e been used on Agassiz Ice Cap, Northwest Territories, Bering Glacier, Alaska and elsewhere. To date, the maximum ice thickness measured usi ng this transmitter is 825 m, on temperate Bering Glacier.