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VX-1 Electronic Voice Control


  • Voice-operated receiver and transmitter switching
  • Variable time control relay
  • Adaptable for remote control operation
  • Requires no transmitter or receiver alterations to operate
  • Voice controlled antenna relay voltage available
  • Completely self-contained—including power supply and cables

Attention all ham operators! Here is a new and exciting kit that will add greatly to your enjoyment in the ham shack. The model VX-1 Electronic Voice Control allows you to switch from receiver to transmitter merely by talking into your microphone. Instead of making long transmissions and risking possibility of losing the other fellow—this unique device lets you operate "break-in" even with an ordinary AM transmitter. You get the advantage of "telephone-type conversation" as in SSB but with regular AM transmission. The VX-1 represents a new concept in AM radio transmission.

The VX-1 combines an electronic voice operated relay with a receiver "muting" stage. This circuitry performs several operations. During listening periods, the receiver audio must be isolated from the microphone. This is accomplished by the anti-trip amplifier which causes an out-of-phase condition between the receiver audio and the operator's voice, allowing operation only when the operator speaks. When the operator talks into the microphone, the receiver is automatically muted by opening the voice coil of the speaker. At the same time, it will actuate your antenna relay switch on the transmitter. The unit is adjustable to all conditions by sensitivity and gain controls provided. In addition, a variable time delay control is incorporated to modify the "hold" time to suit the requirements of the individual operator.

The power supply, which furnishes the heater and high voltages, is built in for simplicity of operation. No external power is required. The controls consist of: time delay, VOX-standby-manual switch, off-on switch, receiver and transmitter sensitivity controls. The microphone input connector is also located on the front panel. A terminal strip is provided on the rear chassis apron for receiver and speaker connections and also for a 117 volt antenna relay. This unit is very easy to build with complete instructions provided for assembly and operation. Connection between the various units is also covered in detail with all necessary cable supplied.

The small size and attractive appearance of this fine unit will blend with your other equipment and will greatly simplify operation.

Although designed primarily for operation with the DX-100 Transmitter, the VX-1 can also be used in many other applications. Due to the preamplifier, which is built-in, and the associated circuitry, it may very easily be combined with a single sideband exciter, intercom system, recorder or dictaphone, etc. A current-carrying capacity of 15 amperes is available across pins 3 and 4 of the octal plug, and a current capacity of 5 amperes is also available.

The VX-1 may also be used as an auxiliary speech amplifier for feeding audio to an existing modulator or modulator driver stage. A length of microphone cable is furnished with the VX-1, to couple its output to the transmitter "mike" input connector. By making the connections as described in the manual a two-stage audio amplifier results.

Modernize your ham shack now and enjoy the convenience of automatic operation.

Specifications: Switched Circuits No Voltage Output... 1-13 amperes; 1-5 amperes. Switched Circuit with Voltage Output... 1-117 volts AC at 5 amperes. Tube Complement... 1—12AX7 speech amplifier, 1—12AT7 audio driver and anti-trip amplifier, 1—6AL5 bias voltage rectifier, 1—12BY7 relay switch tube. Power Requirements... 117 volts AC, 50-60 cycles. Cabinet Size... 7 3/8" W. x 4 5/8" H. x 4" D.

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