Show V edited by 0 couglas carrop War rop editor of 0 radio merchandising AL wal f ia n w W basw m na 1 c it P 1 V l VM u T tt IM 40 1 FIGI roo rec this diagram illustrates ll lustrate how the double pole double throw switch Is 18 em aloyed wave lengths length depend upon position of switching device by F RANCIS FRANCIS H ARNI ARMSTRONG STRONG one of the lie problems lenig troubling many radio fans vt at the present time Is the adjustment of their sets to cover coer the higher wave wae lengths especially of and rac meters Onenie one method thod that alia may be applied to most rec ec cheis elvers in present day use all kiil particularly elioso lose ot of tile two Varl ometer and varlo coupler type Is ti by the addition of instruments I 1 called condensers where such load ing of capacity Is resorted to great care must be ex relied in securing regeneration over the wave ae length bands desired alost lost receiving sots sets embodying radio frequency will vl rema lemalu itt just as they ore art these are goyer governed ned by the range ge of transformers included in the of if the set pet and the general practice of most mok manufacturers hits has been to design their radio frequency transformers to cover a wave flave length ranse range of from 30 to ni meters eteri thorp there ts ri no question pi eadon regarding most of the transformers made todal its iia the lie majority run as high as the new wave ae length of meters in some cases where here a loop aerial Is employed in conjunction with a radio frequency set more turns of wire on the loop mily may have to be added in order to secure sufficient clent added inductance in this part of the circuit to cach the uwe desired the reason for this Is that tl lie 1 loop acts in this bis coso case as a tuning 1 inductance should the loop aerial be deficient in its in ill value balue the then if there Is no resident point to work on for the higher fava falve lengths length s better service may pe fie had bad if tile original loop I 1 Is 8 suppell supplied ad with a sufficient fent number of turns 0 on it its is f frame rame which tire an thin then varied by fileana means of a suitable tapping or gr a sv lulling arrangement loading three circuit tuner under this type of regenerator come conica I 1 I 1 the well known two varl ometer and circuit this type of apparatus ii has as the prize pirlie receiver of many a radio fan since it contains tile lie elements which give a pot et selectivity hut but since some gome new stations were ere injected into tho the ether it seems seeing that most or of the i se seta ts fall short of bringing in concerts on tile he longer waves with till tills set an c can ati be made to secure shorter wines with their maximum signal strength just as efficiently as when then using the longer wave length hands bands tills this arrangement arrone arranz ement consists ot ol employing a double pole double throw chiow IM lie ill or by bv the lisp of an sul switch tell the arst arrangement would be the better of nf the two for the beginner or novice since it 1 appears to be much simpler in the nc fie compagnin companying com compa nyIng fil dla iHm figure 1 one may get tin an iden idea linw how tile the double pole double throw switching arrange arrangement tent employed Is the wave ae lengths d di e aad entirely upon the position of the like twitching switching device dece in figurea 1 anti and 2 the condensers bra are 1712 represented present pd by bv C these condensers dens rs may be trade made at home or 01 they hey can be purchased tit nt any radio shop jit at the option of the builder if purchased the fixed type tipe condenser Is to be pr preferred ef erred in shopping around I 1 the fun fan will r run n into various types 0 of f fixed condensers tenny of them coli consisting of paper find tinfoil this type of conden tier should not be considered its is its iti c partly capacity a Is not uniform irk in recent tests some of these paper condensers gave gae no DO fixed reading whatsoever bat beier eu phonies ailed any oviliere liere fron from to mad merely by P pressing the lie efin condenser together with tile the lin gingotti gotti due to their loose construction creeps in and varies the capacity to the some same degree of what the fan should buy Is a condenser constructed constructed d of mien mica and copper toll foil machine machan e pressed or firmly clamped load circuit carefully where loading Is resorted to 19 great care must be exercised to bro procure cure regeneration on the higher wave bands A double pole double throw switch Is shown in figure 1 when the position of tile the switch Is such that it neither cuts in pr or out condensers the set Is st standard andara and will operate normally over its limit of wave wae length range should the conde condenser fiser switch bel be thrown to a position indicated for ilia ho meter stations then two condensers in series are cut into th the e circuit ilind and placed across the grid and secondary of coupler the switch thrown tin own to ao the position of 1000 meters hag a different effect it disconnects lill all previous pr con sections and adds cap capacity nelty from th the e plate cir circuit cult to the grid circuit I 1 tile the two condensers anre nr a connected in setles series the connect connection ibn being ma made de from the plate back to the Il nl ament lament another coonc connection Is then taken from the center of both condensers and placed to a point just prior to the grid gild condenser but in the grid circuit this then provides for regeneration aver over the entire wave length range up to 1000 meters the condenser values should average about capacity and as explained pla ined should be of the mica and copper foil type chy most of the sets tailed failed tj function properly Is due to the lie fact that regeneration was not available on the higher wave waya bands in figure 2 a cam switch or anti capacity switch arrangement la Is illustrated but this Is merely it a method of accomplishing the same result as the previously mentioned switch the appearance and arrangement of tile tha cam switch appeals to most radio tans fans and therefore Is 19 more often employed the amateur wl who to Is willing to make ills his own must bear in mind that toi foi proper results regeneration Is 4 essen flat on the alie higher wave bands ne new york sun nasom ra V P V P tal FIG 2 re rec rj ain fam switch orai OP antl capa ity switch Arana arrangement ement Is I 1 Me merely a method of ae comp lishIng same result redouble throw switch |