The Birmingham age-herald., 1922-08-20
Cause of Cracking Sounds

O. Will you kindly tell me the correct method of tuning RIA 10. used with a two-step amplifier? Why Is 1t that at times my set sounds like fire-crackers going off, making clicking sounds? I have listened to different sets, and they sound nico and sweet. believe my receiver Is a very well made one, and am sure this is not due to static, for when 1t starts l take off the lead-in and it stills keeps up. There are days when 1 have no interrupting sounds at all. J. P.
 A. Place the dial which controls the rotor coil of the vario- coupler in it's maximum position; then tune the primary switches for the station you desire to listen to. leaving the plate variometer at minimum adjustment. You will have to listen-in very care fully for the signals, as they will be comparatively weak. As soon as you receive them, adjust the secondary condenser and the rotor of the vario- coupler very, very carefully and very, very slowly, as a slight adjustment of either of these two will throw out a station completely. As soon as you have obtained the signals that you desire, then adjust the plate vario- meter until you get maximum strength of signals. This should be at point just below where the set commences to howl. The reason that you get this bowling and roaring at the present time is because you have too much regeneration as we'll as too much filament current in the<de- tector tube. I would advise you to adjust both of these very carefully. 
 Using Rotor for TfckIer
 O. l am going to build a set using a 4S-plate condenser-.001, a 3-plate Vernier condenser and 14 tap, with the taps in the coupler primary. Would this give the same results as the variometer reactor used in tho R. c. set. or would I have to get a Would the ticlSler coil be hooked on the primary or the secondary cir cult? F. B. McB.
 A. l would suggest that you rse the primary winding of the vario- coupler In series with the 43-plate condenser for your aerial tuning cir cult, and use the rotor coil of the vario-coupler as the regeneration or tickler coil.
 Leading Coil for 5000 Meters
 & NOuid IL Dt pIdCtiCdl tO Tidhc loading coils large enough to re- ceive 5000 meters? understand quite bit of code, so would get some enjoyment out of having so large a loading coll If you think a loading coil SO large would be stretching 1t too far, then I should like to make them large enough to get wvP--1,450 meters. Or would it be better If I made bank wound vario- coupler of 5000 meters! How much wire would I need on primary and secondary and how many taps should be taken and how spaced? Also, what would be the best sized wire to use? w. D. B.
 A. It would be perfectly all right to load up your inductance so that you can receive stations using wave lengths up to 5000 meters. The best way to do this is to make bank wound coil on a tube 3M inches in diameter and AZ inches long, using No. 24 S. S. c. wire in three banks You will need approximately 4oC turns of wire. Eight taps should pc taken off this. the first at ths twentieth turn, the second at tne twenty eighth turn. the third at tne quick change available from ono wave length t the other. The ao- justments also must be taken care of by an operator and not by a corps of radio engineers and must De as inexpensive as possible.
 New system Promising