Yaesu FT-847 Modification Manual page 8

2. Modifying RX
Amplifier and bandpass filter 70MHz diagram:
Amplifier circuit is a classic and needs no further explanation. The application
includes possibility of adjustable gain by changing the bias voltage of the first gate G1
by small potentiometer, which may be replaced by a fixed resistor in some cases.
Coupling coil consist of 3 turns of 0.5 mm insulated wire (one more than in the
TX filter) to get proper filter response.
Filters set ready to install in the TRX:
And here's a prototype amplifier before installing: