The A.C. Browning-Drake

Radio Record, Volume III, Issue 11, 27 September 1929, Page 30

The A.C. Browning--Drake

An Omission ON page 86 of our special issue last week: we referred to a: diagram depicting the method of mounting the primaries for Browning-Drake coils. This diagram was inadvertently omitted. It is appended here with a redescription of the coils. ‘Having completed the aerial coil, leave a.gsmall space and proceed with the wiring of the regenaformer. ‘This will comprise 65 turns of 24 gauge D.C.C. wire, or 57 turns of D.S.C. If eapacity reaction is to be employed tap the coil at the 15th turn from the secondary proper. Wind: a further 26 turns on the end of this coil, tapping it as before at the end of the secondary. winding proper. Separate both coils with a sharp knife. The primary for this regenaformer is jumble wound and placed under the

first turn of the secondary coil. "It comprises 14:-turns of 30 guage D.S.C. wire, There are three typical ways of making this coil, the diameter in every case being such that the coil can be slipped inside the end of the. secondary without leaving an appreciable space between the two coils, though there must be proper insulation between them, otherwise a "short" of the B

potential .may ‘result, The three ; methods are shown in a diagram. One is a bunch of tirns of the requisite diameter, bound together in places with twine. The second method is to build up a slotted.former of cardboard, the slot round the periphery measuring barely 3-16in. each way. The third method is to turn a. similar former ont of wood. Rotatizig ticklers are closewound upon a short former of small dimensions; the turns should not be spaced on ticklers. There is no need to endeavour to make the tickler as large as can bé rotated in the end of the secondary. A small tickler with a few more turns to compensate will give _eyen better results,