QST, Dec 1958, p. 188.
QST, Apr 1959, p. 170, 175.
QST, Mar 1961, p. 110.
QST, Oct 1962, p. 139.
The P&H compressor-amplifier worked on both transmit and receive. It installed in the microphone line of a phone transmitter and prevented over-modulation by using broadcast-type compression. The AFC-2 also applied compression and band-pass filtering to received signals. It had a built-in power supply.
Model AFC-1 (3 x 3 x 5) requires an external power source (often available from transmitter or receiver) and contains a 90-3500 cycle bandpass audio filter.
Model AFC-2 (5 x 5 x 7) has a built-in power supply and a switch controlled BROAD-MEDIUM-SHARP audio filter.
Model AFC-2CW is identical to the AFC-2 except for much sharper audio filters. It is intended for use with filter type exciters and for CW reception when used in the speaker line of receivers.
These are AVC type compressors. Operation is instantaneous, with no pumping effect. Built-in audio filters and separate high and low impedance circuits.
High Impedance threshold is set at –52 DB and will provide up to 50 DB of compression with negligable distortion.
Low Impedance threshold is set at –25 DB, and will provide up to 40 DB of compression when used between the speaker and the audio output of a receiver; resulting in excellent AVC action from receivers with poor RF AVC characteristics.
Model AFC-1 with tubes (less power supply), $32.95
Model AFC-2 or AFC-2CW complete, $54.95
