simple field strength indicator

A practically proven small circuit that is very popular with many model fliers, as it enables them to verify that their remote control transmitter is actually transmitting. Any doubt as to whether a fault lies in the receiver or transmit- ter is also quickly resolved. The only active element in the circuit is a transistor that is used as a con- trolled resistance in one of the arms of a metering bridge. The base of the transistor is connected to the wire or rod aerial. The increasing HF voltage at the base of the aerial drives the transistor so that the bridge is brought 0.5 . simple field strength indicator out of equilibrium. A current then flows through B2, the mA meter, and the collector-emitter junction of the 85435 transistor. The meter should be zeroed with P1before the transmitter is switched on. 1 V5 . . 4V5