Radio pulses from air showers at Mt. Chacaltaya

Abstract

Pulses from a helical antenna and from a broad-band log-periodic TV antenna were photographed when any of various trigger requirements were met. In order to use arrival directions to correlate radio pulses with air showers, the antennas were pointed away from the zenith. Results for arrival direction correlation are presented. Preliminary evidence that the radio pulse energy increases with decreasing frequency in the region 40–60 MHz is presented. In addition to triggering on air shower particles alone, we also successfully used a coincidence of radio pulses and shower particles as a trigger. Latest preliminary results obtained with the TV antenna indicate that radio pulses may not be polarized perpendicular to the earth's magnetic field.