Abstract: A radiosonde comprising a transmitter, a modulating oscillator, a control circuit for the oscillator and sensing elements to be switched into and out of said control circuit, characterized in that a solid state switching circuit is utilized for switching the sensing elements into and out of said control circuit to produce atmospheric information signals and with the sensing elements out of the control circuit there is produced a reference signal which reflects essentially the same impedance from the solid state switching circuit as is reflected in the atmospheric information signals thereby providing for evaluation of the information signals.

Abstract: A multiple contact rotary switch comprises a rotatable staff to which an armature is electrically and physically mounted. A plurality of pins is spaced equi-radially away from the staff and around the staff, and the armature is arranged to move past each of the pins in turn as the staff rotates. The armature is flexible and spring-like, so that it maintains contact with any one pin for as long as it can, then springs forwardly to contact the next pin. A low power SPDT switch is thereby provided. The switch may operate extremely slowly, with no switch contact dead-break or teasing.