Show cam compensator for uni control facilitates manufacture of sets to tune with similar dial readings the use of a single dial for controlling the wave wae changing devices contained in a radio receiving set seems to be the goil goat in modern construction st the problem lias has been to design a device of stich a simple nature that its cost would allow it to be used in reasonably low priced sets the invention of a washington man inan appears fo 0 o he be a stop step in tills direction this provides a means of varying the wave length of the several circuits simultaneously with the exact relationship tion ship required by a means that does aviah 11 N with ith ponde ponderous find and expensive methods heretofore proposed in sets normally using two or more control dials for tuning the slight 6 C 7 ar 4 7 1461 sketch of cam compensator condenser variations in manufacture will prevent two apparently similar tuning circuits from resonating to the same frequency at corresponding correspond lug dial settings over the u hole range of the tuner I 1 it these discrepancies in capacity or inductance can be overcome the condensers or colls coils can be varied from the shaft of a single dial auxiliary tuning device one manner of doing tills this Is by menns means of what Is known as a compensator PL pen ns sator ator the compensator Is IR on an auxiliary tuning device which supplements the wain main tuning device denice the common example of tills this Is the hie miniature condenser called a vernier condenser which Is I 1 abed for the one fine tuning variations in many sets the vernier Is not usually called a compensating pen sating device though the action Is exactly the same except that the latter Is usually controlled from 6 the same control as the device it supplements the invention described here Is a means of compensating for the varl actions of manufacture tai alie main fea ture of which la Is a earn cam the cam Is a i very precise precis e means of producing intricate movements in machinery and consists of a disk on which rests one arm of a leer by varying the outline of the disk the lever arm may be made to rise fall or remain stationary tio nary as the cam revolves the diagram figure 2 illustrates how the capacity of a condenser may insy be caused to vary from borroni by a bent stator plate this Is greatly exaggerated ag ng for the rake fake of clearness the dent in ili the hie plate at point A will cause a slight decrease in the capacity apa cIty from that normally had when the plate fu fol bullos llos lovis the dotted clotted line tills this decrease Is to be made up by compensation the condenser barked C drift and controller controlled by the rani cam Is the compensating condenser awl and M the main condenser the two are connected as chomi oil and then to the ln inductance duc tance as in figure 1 any number of these units may be mounted on the same shaft the outline et cf the cam D Is maikel out from points found by trial of the circuit on different wave lengths after the cams are cut the he system will always elways be in in resonance no DO matter what the wave lengths in form of Varlo meters inductances may also be used in the form of 0 vario meters with tills this scheme in tact fact mot any combination of capacity and inductance may ile be made to function in tills this manner the compensation required Is usually very small and in the case of capacity compensation the lie condenser would be about the same size as the more commonly known vernier condenser for the experimenter who would like to try out such a compensator lead disks could be cast and these would be easy to cut to the proper form with the more sed sens itle itlie and selective sets such as the super and neutro dynes it will require considerable care to make the cams cains but once done the results should make it worthwhile worth while to build the sot set with h tills this feature fe iture boston globe |