Stancor Standard Transformer Corporation ST-202A Передатчик
Radio Transmitter Kit


Stancor Model ST-202-A fulfills the demand for a compact, desk type, high frequency, radio Transmitter having substantial power output- Internal circuits for radiotelephony were purposely omitted to satisfy the “strictly CW1' operator as well as to offer the "phone man11 a choice of either amplitude or frequency modulation. Hence, either type of modulation may be ultimately applied. Such important features as six band coverage (10, 11, 15, 20, 40, and 80 meters), inter- and intra-band flexibility, and extreme simplicity of adjustment and control w ere included without resorting to complexities. Base of construction was given paramount consideration in the design of this unit. The ST-202-A incorporates a novel and highly simplified band-switching exciter circuit involving only two receiving type tubes, a single deck coil turret, and one tuning capacitor. The radio frequency power Amplifier employs a triode transmitting tube in a balanced, neutralized circuit for stable, trouble-free operation. For this position, several tubes are recommended (see ACCESSORIES) and a choice may be made according to the dictates of the individual operator. To meet all of the requirements of the various triodes listed, the ST-202-A provides a range of Amplifier filament voltages of 5.0, 6.3, and 7.5, and a wide range, neutralizing capacitor. The Amplifier tank circuit uses 150 watt plug-in inductors of standard availability, one being required for cach major frequency range. A link coil, with variable coupling adjustment, facilitates proper loading of the Amplifier by the Antenna system. Quick channel shifting is accomplished by pancl-switch selection of six different frequencies. Separate power supplies develop 350 volts DC for the exciter stages and 1,000 volts DC for the Amplifier stage. The exciter Power Supply is electrically inverted so that it may also provide a grid bias potential for the Amplifier tube. Further, this system allows simultaneous screen keying of both exciter tubes, giving clean-cut, telegraphic signals along with the highly desirable “break-in” feature of operation. Both grid and plate current readings of the final Amplifier tube arc taken with a single milliammeter employed in a switching system. Suitable terminals at the rear of the cabinet provide connections to an Antenna system, a telegraph key, a remote standbyr switch, an Antenna changeover relay, and an amplitude modulator. An extractor type fuse receptacle and the 117 volt AC line cord are also located at the rear. The output of a frequency modulator or a variable frequency Oscillator may be introduced into one of the six crystal sockets.

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2016 09 18