Show U edited by 0 douglas editor of radio B I 1 0 C L A high signal intensity equal to fourtunes Four Tubes Is obtained from this two tube reflex outfit principle of the reflex circuit depends on the ability of a three dec clec vacuum tube to permit currents of 0 different frequencies to pass through it at the some time the frequencies quen cies of the currents induced in a radio antenna system are very rapid varying lit in value front from about BOO to 1 kilo cycles per second depending on wave lengths tills this current in the antenna system Is generally termed the radio frequency current in it reflex system these radio frequency currents art usually amplified to increase their intensity before impressing them on the rectifier or detector which converts contorts these high frequency currents into currents of audible frequency after rectification these currents tire are then amplified ns as were tile the radio currents by a th three ree ol electrode act rode vacuum tube here lies the particular advantage of the reflex ref flex system over other systems la in other systems after rectification tho the rectified fled radio or audio currents are amplified by additional tubes for this purpose in a reflex system before these input radio frequency currents are rectified fled they are relm pressed back on the tubes which amplified them at radio frequency and when rectified tire at audio frequency before belig passed on to tile the receivers or loud speaker to be converted to sound waves there are a number of methods of utilizing the reflex principle among which are the type of reflex wherein the reflex action proceeds from tile input to tile tho output tube in direct progression gres sion and where the reflex action Is performed in moro than ono one tube then there la ii tho the so called inverse duplex system wherein the reflect action Is not progressive but Is inverted back toward the input tubes in the ella circuits tho reflex action Is progressive progress he from the input but Is only utilized in ono one tube duo due to tile tho complexity of controlling f radio frequency it Is not possible to successfully stabilize a system wherein tile the reflex action Is included in more than ono one stage it Is not a matter of balancing the loads in the various tubes as it can be readily shown that the loads caused by tiny any audio sig signals gials on the tubes in these circuits are never such that tho the few maro macro watts of radio signals addition tilly illy impressed upon them would over loin load them ns fig has been many thues stilted stated in general there tire practically two forms of using vacuum tubes as radio frequency 1 e the coupling may be either tunable or fixed the tunable type transformers aru aro sn designed chilt they may be tuned imlay y by a variable ar lable condenser lit in the other type the transformers transformer colw a certain range without tuning the latter are brond broad and make for unselective reception it Is imperative that it if selectivity Is a to be lind find acre where radio frequency amplification fi la Is employed the coupling trans formers must permit tuning adjustment by a vi variable triable tuning device such its ag a variable condenser because tile transformer Is actually tuned timed to the signal with this type tipe of radio frequency amplification not only great selectivity to Is obtained but greater amplification Is likewise secured elther cither a vacuum tube t we or three electrode or any of the many forms forma of crystal rectifiers flers of high frequency fie quency currents can be used ns as a rectifier we e are told Ilo however wever in a reflex circuit due to the particular location in tile the circuit and inherent characteristics of the detector a crystal rectifier will bo be more satisfactory dy by the use af the proper crystal rectifier an excellent controlling effect on the stability of tile tho entire circuit may be had tilts athla feature Is not generally known knoten but Is demonstrated in the stability of the circuits using title this form forin of n detector not every crystal rectifier which might posese high rectifying rectify ing properties will hill bo be found tile the best for this pair purpose due to tho the fact that the crystal can call be made to provide a stabilizing effect on tile lie reflex action of the circuit the axed fixed type of crystal naturally requiring no adjustment if correctly designed affords the best form of 0 rec tiller for the reflex circuit another point of interest Is the fact that not every audio transformer can bo be used in a reflex circuit in a reflex circuit tile the audio transformer la Is asso elated dated with the radio frequency our currents of the circuits and requires it design and construction differing from tho the regular audio transformer |