A Broadcast Receiver for Use in Automobiles

The purpose of this paper is to present several important features affecting the design of a broadcast receiver for use in automobiles. The design of the receiver is carried along step by step with special reference to (1) type of collector, (2) ignition shielding, (3) electrical characteristics of receiver, (4) physical structure of receiver, (5) power supply. From measurements made on an experimental receiver installed in an automobile the ignition interference is found to be greatest at the higher frequencies in the tuning range. Observations made during a road test of the receiver indicate a normal service range of from 50 to 100 miles on such stations as WJZ, WOR, and WEAF. The severe fluctuation of the signal encountered in travel through hilly country indicates the desirability of some form of automatic volume control.