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Demonstrates the construction of a **remote antenna tuner** utilizing a standard radio-controlled (RC) servo mechanism to adjust a variable capacitor. The design focuses on enabling remote tuning for narrow-bandwidth antennas, specifically mentioning frame and packing crate antennas, from within the shack. It covers the mechanical arrangement for integrating the servo with a capacitor and provides a circuit diagram for a control unit that generates the necessary 0.5mS to 1.5mS pulse-width modulation (PWM) signals to drive the servo's 180-degree rotation. This setup was successfully tested with up to 20 watts RF power without arcing or adverse effects on the servo, though tuning was performed at 1 watt for VSWR readings. The resource highlights the use of inexpensive, readily available components, such as Futaba servos, and details critical considerations like power supply decoupling with a 47uF capacitor to prevent unintended servo movement upon power-off. The system provides a practical solution for optimizing antenna performance for specific frequencies without manual adjustment at the antenna itself.

Need a variable power supply that is short circuit protected and over voltage protected; Here is a good one that can be built cheap by VE3IVJ

1.2-30V 1.5A variable regulated power supply

The m0xpd keyer project utilizes a PIC16F628A microcontroller, offering Iambic A and B modes, adjustable speed from 5 to 40 WPM, and variable weight control. It incorporates a sidetone generator with adjustable frequency and volume, along with a PTT output for transceiver control. The design includes a 16-pin DIL IC socket for the PIC, a 3.5mm stereo jack for the paddle, and a 3.5mm mono jack for the PTT output. Powering the keyer requires a 9V DC supply, which is regulated down to 5V for the PIC. The circuit board layout is designed for through-hole components, facilitating home construction. A detailed schematic and a parts list are provided, guiding builders through the assembly process. The project also discusses the firmware programming for the PIC16F628A, essential for the keyer's functionality. Construction details cover component placement and wiring, ensuring proper operation. The keyer's compact size makes it suitable for portable or shack use, providing a reliable CW interface.

1.2 to 30 Volts 1.5 Amps Power Supply

Variable Power Supply for the bench