Gang Condenser Tuning

Radio Record, Volume III, Issue 22, 13 December 1929, Page 29

Gang Condenser Tuning

HEN a number of circuits are being simultaneously tuned by means of ganged condensers, a difficulty sometimes arises owing tu the natural capacity in the aerial circuit due to the aerial and earth. In these circumstances the transformer in the radio frequency stages or the aerial tuning coil is apt to become tuned to a lower frequency than the other circuits, and it is. necessary to find some method for overcoming this effect. There are various ways in which this can be achieved, and perhaps the simplest of all is to leave the aerial circuit untuned and to. introduce instead a choke coil (or resist‘ance), connecting this between the grid and filament of the first valve. The radio frequency inter-valve coils are tuned by the condenser, and consequently it is a very much simpler matter to arrange the settings. This scheme will not be applicable in all cases, but in a large number of cases it provides a very easy way out of the difficulty and gives perfectly good * reception. — i oeteatearaaytnsionenannaypeasnessnasnaonansanail