Thunderstorm Signals at Very-high Frequency and Ultra-high Frequency

Abstract

WHILE signals from distant very-high and ultra-high frequency transmitters were being monitored on June 26, 1954, a thunderstorm occurred in the region of the receivers. The transmitters, which operated at 49, 91, 173 and 492 Mc./s., were some two hundred miles from the receiving site. Fig. 1 shows a portion of the signal amplitude records obtained during the storm. The speed of response of the receivers was limited by one half-second time constant of the recorders. A single five-element Yagi antenna was used with each of the 49, 91 and 173 Mc./s. receivers, and a twelve-foot paraboloid reflector antenna was used with the 492 Mc./s. receiver. All antennæ were horizontally polarized and were directed towards the transmitters.