Frequency Splitting of Solar Radio Bursts

As part of a new experimental and theoretical programme of solar radio research in Tasmania, a number of dynamic spectrographs are being built to obtain information of the amplitude, polarization and direction of arrival of radio bursts with high time and frequency resolution. The first two instruments, which have been in operation since early 1965, have the following specifications: (a) frequency range 8–230 Mc/s, bandwidth 200 kc/s sec−1, scan rate 200 sec−1; (b) frequency range 24–28 Mc/s, bandwidth 50 kc/s sec−1, scan rate 200 sec−1. Each uses a fixed log periodic antenna directed obliquely into a horizontal reflecting screen. In receiver (a), the first oscillator frequency is swept with a varactor over the range 440–662 Mc/s and there are three intermediate frequency amplifiers at 670 Mc/s, 50 Mc/s and 10 Mc/s respectively. Records of dynamic spectra are made on 35 mm film moving at 18 in./h for 8 h each day and intermittently with a film speed of 6 in./min during solar bursts. The operation of the faster cameras is initiated by the bursts.