Abstract: A transmitter/receiver system is provided wherein a transmitter of such system produces a transmitted signal frequency modulated in accordance with the level of a modulating signal and a receiving antenna has an output thereof coupled to a receiver through a switch means, for coupling or inhibiting signals received by the receiving antenna from passing to the receiver selectively in accordance with the level of the modulating signal.

Abstract: A foldable support rack for carrying bicycles on a vehicle, comprising a pair of vertical support members joined at their upper ends by a cross member, provided with horizontally projecting carrying members and supported on the vehicle bumper as an upright rectangular array. Interconnections between support members, cross member, and carrying members allow rack to be easily folded to minimum volume for storage, and extended and locked into open configuration for use. Means are provided for attachment to a variety of vehicle configurations without use of tools.