Note
QST, Nov 1953, p. 103.
Allied Radio catalog 1955 (copyright 1954), p. 191.
Allied Radio catalog 1956 (copyright 1955), p. 199.
Walter Ashe catalog 1957 (probably issued in 1956), p. 9.
Allied Radio catalog 1958 (copyright 1957), p. 272.
Allied Radio catalog 1959 (issued 1958), p. 381.
Allied Radio catalog 1960 (copyright 1959), p. 394.
The AF-67 "Trans-citer" is a ten tube variable frequency or crystal controlled seven band transmitter or exciter. All circuits are simultaneously switched to the desired band by a single bandswitch lever. Designed as a complete transmitter for mobile or fixed installations, or an exciter to drive a higher power transmitter. When used as an exciter the 500 ohm tap on modulation transformer can be used to drive the higher power modulators.
The transmitter employs a variable frequency oscillator with output on either 1.75 to 2.0 MHz or 3.5 to 4.0 MHz. In addition to the V.F.O. feature, two crystal positions are included for operation on two spot frequencies. Any crystal that will work straight through, double, or quadruple to the desired frequency may be used. The oscillator circuit employs a voltage regulator tube to maintain the plate voltage at a constant level.
The multiplier stages are broad tuned with a front panel control for peaking the final grid, insuring best performance on all bands. The audio circuit is designed to use either a carbon microphone or a low output microphone such as a crystal or dynamic. A slide switch on the rear apron sets up the circuit for use with either type of microphone. A reactance tube modulator is incorporated in the variable frequency oscillator circuit for narrow-band-frequency-modulation.
The variable frequency oscillator dial and the meter scale are indirectly illuminated. The variable frequency oscillator dial scale is directly calibrated in megacycles for each of the amateur bands.
The AF-67 is designed for use with resonant antennas coupled to its output with a transmission line of 50 to 300 ohms impedance. Other impedance or balanced lines can be coupled through the use of an antenna tuning device. When used as an exciter the coupling link of the high powered final can be directly connected to the AF-67 with a suitable length of coaxial cable.
The transmitter has a maximum plate power input of 60 watts. Maximum ratings for this Trans-citer are 600 volts at 100 milliamperes; or 500 volts at 120 milliamperes. Full 100% modulation occurs when the modulator plate current swings to about 60% of the final plate current with normal voice frequencies.
The AF-67 was designed to use an external power supply in order to permit (a) use of PMR-6A receiver power supply to supply the low level stages, (b) use with an AC operated power supply at a fixed or portable location, (c) use of a dynamotor or vibrator supply in mobile installations, or (d) use of the Trans-citer as a driver-exciter for high powered transmitters. The Multi-Elmac power supply model PS-2V for portable or fixed station operation from 115 volt AC lines is recommended.
Tube Lineup
– 6AK6: Oscillator
– 6BJ6: Reactance modulator
– 6AG5: Buffer-multiplier
– 6AQ5: R.F. Driver
– 6146: Final R.F. Amplifier
– 6AU6: Speech amplifier
– 12AU7: A.F. Driver
– (2) 5881: Push-Pull Modulators
– OB2: Voltage regulator
PS-2V: A universal 115 volt AC power supply. (Supplies 6 or 12 volts AC for filaments and two separate high voltages.)
Uses the M-1070 mobile power supply.
References
Use on 6 meters. CQ, Oct 1958, p. 38.
