Multi-Elmac

  • Multi-Elmac AF-67 Trans-Citer ham radio XMTR

    Description

    1.1 GENERAL. THE MULTI-ELMAC 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.


    1.2 DIMENSIONS. The maximum external dimensions of the AF-67 Trans-citer, excluding projections of control knobs, is 11 1/4 inches wide, 7 inches high, and 8 1/2 inches deep behind panel. Approximate weight is 18 pounds.


    1.3 CIRCUIT DESCRIPTION. The AF-67 Trans-citer employs a variable frequency oscillator with output on wither 1.75 to 2.0 Mc. or 3.5 to 4.0 Mc. 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 of 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 on the AF-67 Trans-citer 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 scale is directly calibrated in megacycles for each of the amateur bands.


    1.4 TUBE COMPLIMENT. The AF-67 Trans-citer is supplied complete with all tubes, tested in the individual unit, as follows: 

    6AK6 Oscillator
    6BJ6 Reactance Modulator
    6AG5 Buffer-multiplier
    6AQ5 RF Driver
    6146 Final RF Amplifier
    6AU6 Speech amplifier
    12AU7 AF Driver
    5881 (2) PP Modulators
    OB2 Voltage regulator
    #44 (2) Pilot Bulbs

     

    1.5 OUTPUT. The AF-67 Trans-citer is designed for use with a resonant antenna 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 MULTI-ELMAC AF-67 is designed for a maximum plate power input of 60 (sixty) 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.

    1.6 AUDIO. The modulation transformer is provided with a 500 ohm output tap brought to the power plug for driving the grids of high powered modulators. The 5881's will deliver approximately 40 watts of audio with a plate supply of 500 volts.

    1.7 POWER SUPPLY. The AF-67 Trans-citer was intentionally 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 of the AF-67 Trans-citer 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. A suitable MULTI-ELMAC power supply MODEL PS-2V for portable or fixed station operation from 115 volt AC lines is available.

    1.8 POWER CONNECTOR. A 15 prong female connector is provided with each unit. The 15 prong connector allows all circuits to be arranged for maximum flexibility. Making it possible to use the AF-67 Trans-citer in various types of installations.
    1.9 ACCESSORIES. The following accessories are available for use with the AF-67 Trans-citer:

    PS-2V --- A universal 115 volt AC power supply. (Supplies 6 or 12 volts AC for filaments and two separate high voltages.)
    CFS-1 --- Cable with a 15 prong female connector and fanning strip to connect the AF-67 to the PS-2V power supply.

     

    Multi-Elmac AF-67 White Paper

    AF-67 Mods & Maintenance by John Conley, W7ZFB

     

  • Multi-Elmac PMR-7 Amateur Radio Receiver

     

    Description

    1.1 GENERAL. The MULTI-ELMAC PMR-7 RADIO RECEIVER is a ten tube double conversion superheterodyne covering the 160, 80, 40, 20, 15, and 10 meter amateur bands, plus the standard broadcast band. Designed primarily as an efficient communications receiver for mobile use, it is also especially suitable, because of its small size, for (1) marine and aircraft installations; (2) portable operation; and (3) as a fixed station or monitoring receiver. It is not intended as a converter to accessory to another unit, but a complete receiver, employing a separate power supply and speaker as described in this manual. Every effort has been made to furnish the user with an extremely stable receiver of rugged construction, compact layout, and high sensitivity.

    1.2 DIMENSIONS. The maximum external dimensions of the PMR-7 receiver, including the control knobs are: height 4 5/8", width, 7", and depth, 11 1/2". The depth behind the panel is 9 7/8". The net weight of the receiver is 8 1/2 pounds.

    Accessories

    The ESS-3 "S" Meter is an accessory external 0 - 1 milliampere meter calibrated in "S" units for use with the Multi-Elmac PMR-7 receivers.

     

  •  Multi-Elmac PS-2V power supply

    Specifications

    • 6V. @ 6A. OR 12V. @ 3A. AC for filaments.
    • 230 volts @ 80 ma. DC output.
    • 475 volts @ 170 ma. DC output.
    • Separate filament and plate transformers.
    • Jones barrier strip for convenient connections.
    • Includes a mounted switch which can be used for AC "on-off" or "transmit-receive" switch.
    • Cabinet matches AF-67 Trans-citer.
    • Primary circuit fused.
    • Separate rectifier and filter circuits for each DC output.
    • Both DC supplies use choke input filters
    • Uses 1 - 5U4G and 1 - 6X5GT tube.
    • 24 volt tap on filament transformer for control or bias supply.
    • Size, 11 1/4" wide, 7" high, 8 1/2" deep.
    • Weight, 26 lbs.
    • Designed for use with the Multi-Elmac AF-67 Trans-Citer or a variety of other applications.

  • IssuePageTitleAuthor
    Oct 1958 QST75Modifications to the Elmac AF67Stewart, Harry - W8PSV
    (now AA4IB)
    Jul 1960 QST60Multi-Elmac M1070 Power-Supply Notes (Hints and Kinks)Stewart, Harry, W8PSV
    (now AA4IB)
    Feb 1991ER 27 Elmac AF-67 Audio Mod

    Seaman

    April 1991ER 28 Elmac AF-67 Modulator Fix

    Winfield

    Jul 1992 ER14The Multi-Elmac CompanySalter
    May 1994ER 20 Multi-Elmac Co., Follow up to in ER #39

    Goldstone

    April 1999ER 12 The Elmac AF-67 Trans-Citer

    This email address is being protected from spambots. You need JavaScript enabled to view it.

    May 1999ER 12 The Elmac AF-68 Trans-Citer

    This email address is being protected from spambots. You need JavaScript enabled to view it.

     

     

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    External Resources 

    Multi-Elmac AM Net

    Wednesday Nights at 7:00 PM CST, 3.880 MHz (except for first Wednesday of month).