The 3-Dimensional Radio Mapping Experiment (SBH) on ISEE-C

The SBH experiment on ISEE-C will provide maps of the large scale structure of the interplanetary magnetic field from ten solar radii altitude to the Earth orbit, in and out of the ecliptic. These data are necessary to improve our understanding of the solar wind flow and of the propagation of solar disturbances to the Earth magnetosphere whose reactions will be simultaneously studied by ISEE-A and -B. The SBH instrument will track type III solar radio bursts at 24 frequencies in the range 30 kHz-2 MHz thus providing the positions of 24 points along the line of force which guides the electrons producing the radio radiation. The antennas are two dipoles: one (90 m long) in the spin plane, the other (15 m long) along the spin axis. The receiver was designed for high sensitivity (0.3 μV in 3 kHz BW), high intermodulation rejection (80 dB/1 μV input for order 2 products), large dynamic range (70 dB), high selectivity (-30-dB response 6.5 kHz away from the center frequency of 10.7 MHz for the 3 kHz BW channels), and high reliability (expected orbital life: 3 years).