The Night Owl Three

Radio Record, Volume V, Issue 23, 18 December 1931, Page 37

The Night Owl Three

Particulars of Broadcast Coil a me HE broadcast coil for the "Night Owl Three." is wound on a 4in. length of valve base extension former,

which is attached to a valve base in the manner described in the article on this receiver. Only two windings, a secondary and a reaction, are used, the aerial being taken straight to the former coil, thus obviating the use of « primary. When this receiver is used on the broadcast band, the variable series werial condenser should not be shorted out, or otherwise the P. and T..regulations will be contravened, A quarterb of No. 30 d.s.c., whieh is used for both windings, will be ample. After the former has been mounted on. the valve base the reaction winding, which in this particular coil is’ the lower, is commenced about 1-8in, from the bottom of the former. The wire is first taken through a hole, down to the "cathode pin" and soldered there, and the winding commenced, 45 turns are put on, another hole drilled, and the end taken to the filament pin nearest the cathode. The secondary winding is commenced 1-8in. above the reaction. A hole is drilled and the wire taken down to the "grid" pin and 180 turns then wound on. The top of the winding is taken to the "plate" pin. Because, unlike the short-wave ‘coils, no primary was used in this one; the filament pin —

and the plate pin must be connected inside the valve base with a "U" shay ed piece of wire. Despite the small capacity of the tuning condenser employed, this coil will cover the broadcast band between -approximately 240 metres and 520 metres. All the main N.Z. and Australian stations may thus be tuned in. The range of the coil is extended by varying the capacity of the series aerial condenser, but it will of course be realised that the readings at ‘which stations come in will not be constant unless the aeria] condenser settings are noted and used.