Show crystal control may be required of stations there Is nothing quite as annoying to the broadcast listener as a station which allows allow a its wave waie length to won wan der about in a haphazard manner ninner ii A station con can lie be anade to maintain a constant frequent frequency v by the simple ex of applying a elezo electric eleeta le crystal in the proper way us as ex planned hy by at thornton dow in the radio broadcast magazine quartz Is the most commonly used crystal which has piezoelectric electric qualities this particular quality of crystals Is manifest by bv ill the fact that upon the Pris passage sage of an electric current throng then them in a certain direction the it 11 lons will be chinked changed and con ver aversely sely it if the crystal la Is in the tbt right way a voltage Is 19 produced procup d ily eoin combining hInIng the crystal with a vacuum who nhe it Is possible to cruh the crystal act as a monitor for ans desired frequency at which the tub will oscillate osel lInte the frequency freo unc of osell lotion of the he crystal Is 19 dependent upon its physical dimensions it Is re fore possible licis sible to accurately grind and calibrate cali britte a crystal so chrit it will birc any desired frequency or woe wave length when coupled in the proper aln alt it to la comparatively capy ea for 0 broadcasting station to procure 8 crystal which will oscillate tit at the th wove wave length which the station Is sup posed to operate on then by bv read ing it a verv erv simple indicator the sta tion rna MRY lie be delit kei t on the wave wae ten lenorth ath d to it many of the higher class stations suit lons are using ohp elezo trie cristal estal now non and their fre quency or 01 wave lenorth lit Is kept con cant within ln it ft very ven small traction fraction of one per pent ent stations tat loni which are con trolled strolled in this way do not phe give the li tile least in tuning I 1 to their wave ant and in many caw jisc arp used as stanyard standard of frequency measure fame dav da wh whan n the tangle of wave vate length Is oil nil ironed out find and at least some me semblance of nf control Is I 1 obtained again it will he bo required that enri eney and every een station he be pro bided vided alth fill ft a control I 1 |