New Britain herald., 1925-12-07
DEADEN SQUEALS
 IN REGENERAT|VES
Plan for Elimination Of Annoy.
 ing Interference Outlined

The following article should be of special interest 10 those New Britain radio fans who possess the type of set known as regeneratve. It tells how to do away with tho sQuealing and interference cause by these ma chimes, thereby making them so un- popular generally.
 It Is copy of a circular recently sent out to Canadian fans by the radio branch of the Department of Marine and Fisheries of Canada and because of the valuable information which 1t contains, 1t is reprinted 1 here:
 "Thc principle of regeneration, as used in radio receiving sets, is that part of the output of the detector vacuum tube feeds back into its own input and thus greatly increases the volume of the signal.
 Unless controlled, this action will continue until the saturation point or climax is reached, the tube being then said to be in a state of osCilla- ton. When q receiving set is in 1 oscillation, 1t causes bowling and sQuealing in your own and your neighbours receiving sets. Rcgonera- ton should therefore never be al- lowed to proceed 10 this point.
 Effect of Oscillation.
 When q radio receiving set In a state of oscillation is being tuned to t broadcast station:
 CD It causes whistles In sets of all types which are tuned 10 the same station.
 (2) It distorts the quality of your own music.
 (3) It uses moro "B" battery pow | CT.
 (D It tends to reduce the life of the deteCtor tube.
 The interfering whistle which you hear in your receiving set may originate in your own set or it may be interference caused by your neighbor. To determine this point make the following test:
 "Leavc tho regeneration control in q fixed position, slowly rotate the tuning dial. and note particularly the change in the sound of the whistle. If the whistle rises and low CTS in pitch sympathctiCaly with the movement of your tuning dial 1t ln- dicatcs that your receiving set is in state of oscillation 10 other sets. On the other hand, if the whistle does not change in pitch corrcspond- ing to each movement Of your tun- ing dial, but simply varies in volume the whistle is interference produced by some other oscillating receiving set in the ncighborhood.
 Testing for Interference
 Many so-calIcd non -radiating re- ceivcrs will, under certain conditions radiate and thus cause interference
 If you are in doubt as to whether your set can cause interference Yol can check this by making the follow ing test, but be careful to do so at time when only few people arc
 
 listening in, so as not to cause an noyanCC:
 Gall a ncighbor on the telephone and ask him to listen in on par ticular station at pre-arrangcu time and then tune your set to the same station. Turn up your detcc- for tube filNment to normal and pu' the regeneration control 10 it's maxi mum; move your tuning dial 1lNt times slowly across the point core spending to the tuning ot that sia' ton, then telephone your ncighbol and ask him if he heard the interf'r' cncc corresponding to these ilN' movements Of the dial.
 If he heard your interference the probability is that hundreds of oth CTS have also been annoyed at times by radiation from your receiving set
 How to Tune
 CD Practice on tuning powerful .stations first and do not try to picF up weak distant stations until yo' become expert. (e) Use both hands, one hand fo the regeneration control and tn other hand for the tuning control. (S) Keep the regeneration con'ro always just below the point Of osclI 5 Iation, your set is then in the mos } sensitive condition.
 5 (4 If your set then nccldcnmI' II, s hrcalIs into oscillation, turn back tn regeneration control at once (5) Do not try to find station b : inc "whistlc." If your set is tun 7 ed just below the whistling poln' s the signals will come in clear an vour regeneration control can the be tuned little further 10 increas the volume. \ (6) Do not force regeneration l | an attempt to obtain loud speake | volume from a set not designed 10 l the purpose. ;, ' yNp