New Britain herald., 1922-12-26
General History of Manu- facture of Wireless Out fits and Their Component Parts by an Expert.
(By John Liston. General Electric
 Company).

y
 Important progress was made dur
 ing 1922 in the design and manufac
 turc Of radio telephone and tele
 graph apparatus. both for commcr
 cial and amateur purposes. Tho sal
 of amateur equipment made spec
 tacular Increase. due to the student
 aroused interest of tho public in tn
 new application or radio to broad casting.
 The line of standardized compo nent parts which had been original, designed for commercial purpose was later produced for the amateur Broadcast receivers were built, mak ing use of these parts and liAo O sectional units such as the tuning unit, the three stage radio frcquenc, amplifler unit and the detector- am plifier unit was developed. The mair idea in these sets was the production of receivers, each of which would serve definite function separately and could also be easily combined.
 The general tendency in receiving tubes was toward reducing the power consumption in the tube filaments The first attempt resulted in de- tector and amplifier tube using 4 empere in tho filamen; superseding one previously using one ampere. Later a tube using only 60 milliam- peres for the filament was equally successful.
 These new tubes made it possible to use dry cells for the filament ex- citation, and two new receivers were produced One, a portable set, con- tains sensitive tuning system, de- ector and single stage audio fre- quency amplifier. The set is very compact and light, particularly when considered from the point of view of performance. The other set is sim liar in is electrical characteristics to the first one, except that it has two stages of audio frequency amplifica- tion instead of one. A club speaker is part of the set; and this, the radio apparatus, the tubes and batteries are all arranged inside cabinet.
 Broadcast Receiving.
 One of the interesting applications of broadcast receiving was the install lation aboard several Pullman trains of equipment for entertaining the passengers with concerts throughout their journey and to keep them in formed on such topics as weather, market and stock reports
 In the line of commercial equip ments. new requirements were met, due in many cases to broadcasting 1 In one case, power company sought IiA <aIn otv with which it could provide during times of storm against possible inter- ruption of communication between several of it's stations 75 miles apart. | At the same time, signals from near by broadcasting stations operating onl Se0 meters were not to interfere with ! operation of this station on the only Available wave length of 400 meters. | The set was to be operated through | remote control from a desk stand by he regular power house switchboard operators and to require no attention except that usually given to such moving parts as motors and general DTS. This set was designed and in- stalled and is operating successfully. For the use of amateurs and for on small boats and yachts here was produced small radio telephone transmitter having an out put of 20 watt in the antenna. It is built so that it can be operated , ither from motor generator set or rom a kenotron rectifier which was , designed for. this equipment. It can Ilso be used on telegraph transmit CT either continuous wave or inter-