Abstract :
The Radio Receivers Committee presents a brief review of the status and progress of engineering work on radio receivers during the past year of 1936. This review deals mainly with broadcast receivers. The broadcast receiver industry has shown healthy growth during the year. The unit sales have increased from 6,000,000 to 9,000,000 and the dollar sales from $300,000,000 to $500,000,000. The introduction of automatic frequency control in this country by several companies is an outstanding development of 1936 in the practical application of radio engineering. This improvement makes practical the "telephone-dial" selection of a few stations, which has recently been featured. Progress is noted also in the following features: manual control of selectivity for greater fidelity or selectivity, at the option of the listener; octal-base glass tubes; ballast tubes; beam amplifier tubes for greater power output; stabilizing feedback to reduce distortion; beam indicator tubes and color indicators for visual tuning; frequency bands above and below the "all-wave" range; fixed and adjustable iron-dust cozes in sharply tuned circuits; elevated antennas for motorcars; doublet antenna systems for noise reduction; noise impulse limiters; volume range expansion or compression; loud-speakers radiating more efficiently at low frequencies. Automatic control of selectivity by the use of stabilizing feedback has been the subject of major improvements not yet found in commercial receivers. Developments are noted in the field of television receivers, amateur receivers, other special communication receivers, and signal generators.
