ANSWERS TO CORRESPONDENTS

Radio Record, Volume I, Issue 23, 23 December 1927, Page 15

ANSWERS TO CORRESPONDENTS

A.N.J. {Dunedin).-(1) No need to take condenser plates out if you pnt fewer turns on ewil. WNuniber of plates now it would be required to find how many to take out for given value. (2) Vor 2jdiam. sevondary coil use 70 turns. Average tickler turns, 16. (3) Certainly there is a big difference between close and space-wound coils. (4) For turns on 2} primary you will have to experiment to suit the R.F. value, If you want voltage let me know what valves vou will use. Why not keep to specifications, and build a set that will give good service, unless you are using parts already on hand? G.A\. (Wanganui).-If you find the set unsatisfactory, the originators _ of the circuit will be able to help you. A.B.C. (Christchurch) asks the following :-In what character does the human body (e.¢., hand to fland) act in a_ radio circuit, and at what approximate yalne fi.e., in. electrical units)?" The earth-capacity value of the human body appears to be what is required, The electrostatic capacity of the earth, considered as a sphere of conducting material, works out at 72/190,000 of a fsarad; that is, 720 microfarads, so that the capacity of a human bedy would be a proportionate fraction of this amount. W.ILP. (near Cambridge) has completed the Browning Drake, and says: "Commenting on the whole set, now Working perfectly satisfactorily, I must say that it is the best thing I have struck in receivers during my five yeers’ radio experimenting." "Rrowning-Drake’’? {Stratford).-The crackle, ‘something like static,’? can he caused by a dry B battery. The Short-wave converter now being described will suit vou well. It works splendidly with the Browning-Drake amplifier.

O0ed(rt Next Week "Crystal Receiver Construction"