Abstract: The SHF output power and channel frequency switching apparatus having an SHF power amplifier for amplifying an SHF signal and supplying the amplified SHF output power signal to a transmitting antenna, an amplification degree control circuit for controlling the amplification degree of the amplifier, an output power change-over switch for switching a plurality of levels of the SHF output power, a channel frequency change-over switch for switching channel frequencies of the output power signal, a memory having stored therein a table of control signals which are selected to have proper values for the respective positions of each of the output power change-over switch and the channel frequency change-over switch in order that a necessary output power level can be produced each time the channel frequency change-over switch is operated to switch, a control signal supply unit for reading from the table the control signals corresponding to the output power and channel frequency specified by the SHF output power change

Abstract: A helical scan type video tape recorder, in which the wrap-around angle of the magnetic tape around the revolving drum is relatively large, provides fluctuations to the drum motor start-up torque and the reel motor torque for performing start-up of the revolving head drum with magnetic tape wrapped therearound when the recorder is operated in the stand-by mode. Fluctuations in the drum motor start-up torque and those in the reel motor torque are mutually synchronized in opposite directions, whereby when one is stepped up for increase in the revolving head drum start-up torque, tension in the magnetic tape wrapped around the drum is weakened, and conversely when the revolving head drum torque is decreased, tension in the magnetic tape is strengthened, thereby assuring start-up operations of the revolving head drum even when adherence has occurred between the magnetic tape and the revolving head drum.