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Fig. 1 illustrates the simple full break-in system used at WA8NQC. The ground end of the manual gain control, R1, is disconnected and an additional potentiometer, R2, wired as shown. R2 is adjusted to provide additional bias to the gain controlled stages of the receiver to prevent their overloading during key-down conditions. Gain is returned to normal when the key is up. Since K1 doesn't handle any r.f. power, it can be any light-duty relay with fast enough action to follow the keying.

Fig 1
Fig. 1. Full break-in station control used at WABNQC.

K1D.p.d.t. keying relay.
R1Receiver gain control.
R215,000 or 25,000-ohm potentiometer.

Jim Denby, WA8NQC.