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Victoria University Antarctic Research Expedition Science and Logistics Reports 1981-82: VUWAE 26

NARRATIVE:

NARRATIVE:

The field work began with a helicopter inspection of the telemetry transmitters by Stan Whitfield and Jon Prosser on 26 October 1981. At Hoopers Shoulder and Abbotts Peak, the equipment was working and intact, except for the guy wires on the antenna mast. The turnbuckles had unscrewed in the wind - sometimes completely. The Gel/cell batteries measured 14V, even when the solar panels were shielded from the sun. At the summit, the antenna cable was broken, and the ventilation pipe to the buried battery box was tilted ominously. The transmitter was not working. The protective polythene film had been stripped off the infrasonic microphone and the aperture was blocked with snow.

In the period 10-30 November, the USARP party serviced the Abbott and Hooper stations, retrieved and overhauled the summit transmitter, installed new permanent telemetry seismographs at "Bomb" and "Terror" (Fig. 1), and installed a temporary telemetry seismograph near Bird Hut for the purpose of recording the large seismic explosions fired in McMurdo Sound on 23 and 27 November by Lyle McGinnis. I assisted in recording the 23 November explosions before ascending to the fang with the Event 4 party on 24 November.

Between 28 November and 13 December, I operated a tape seismograph at the hut (from 1217 NZST, 29 Nov.); rebuilt the old infrasonic microphone, reinstalled it at the Winch Site, and connected it to the monitor speaker in the hut (from 2300 NZST, 30 Nov.); reinstalled the telemetry transmitter to give seismic recordings at Scott Base (from noon, 2 Dec); installed the new infrasonic microphone (consisting of 2 Philips 8 inch Hi Z speakers mounted on opposite sides of a 0.05m chipboard box and connected in parallel so as to reduce seismic response) on the main crater floor (3 Dec.); located and repaired 4 breaks in the loop and renewed 350m of damaged wire, and (with Pat Tinnelly) surveyed the position of the loop around the crater rim (5 Dec.); rebuilt the infrasonic preamp/VC (1020 Hz), and installed it, together with the new Geotech model 45.50/46.22 preamp/VCO (1360 Hz) for the loop, in the transmitter box at the summit (noon, 6 Dec.); and made trial electromagnetic transmissions from a 100W audio signal generator and portable loop from the edge of the summit plateau to the main loop (8 Dec.).

Problems encountered in carryout out the work were moisture damage to the old infrasonic microphone and the preamp/VCOs; the persistent drifting of the infrasonic VCO (1020 Hz) out of its frequency range due to an unexpected failure of the main battery; the tendency for the induction loop to become unburied and the insulation to crack off exposed wire; and the majority decision by the N.Z. party to leave the mountain earlier than planned as a combined group with the U.S. party. In fact the helicopter problem delayed this and we descended on 13 December.

The Japanese party were based at McMurdo for their entire period from 23 November to early January. They began by deploying their "DAR" slow speed tape seismographs on the flanks of Erebus. While these were recording (≧ 20 days), the party played back the telemetry tapes as they finished recording at Scott Base, and made continuous slow speed index recordings and high speed recordings of selected events on a visicorder. Photocopies were made for distribution to all collaborating scientists. All DAR seismographs page 17 were then retrieved for return to Japan. The Citizen quartz clock with the Sony UFR data recorder at Scott Base, which had hardly tolerated the ionosondes, was replaced with a new TCG-1000B clock made by the Eikura Transmitting Co. Also a 4 channel pen recorder was installed temporarily at Scott Base to allow real time monitoring of 4 telemetry channels in addition to the permanently installed San-ei Sokki monitoring recorder.