CW reciever with Tubes
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RF-powered sidetone oscillator
A sidetone oscillator is a specific type of audio astable multivibrator. Keying is achieved by turning the oscillator on and off through the application of a positive DC potential, which is generated from the RF signal to the reset terminal...
handheld RF-Powermeter for multiple sensors up to 12 GHz
A few years ago, a diode-sensor based RF power meter was built using a 68HC11 microprocessor. Prior to that, an analog RF power meter with a thermal power sensor was developed. The datasheets for logarithmic amplifiers, which promised a measurement...
Taylor Source Follower
A setup was created using 22 used octal tubes, specifically 6.3-volt, 600mA controlled-warm-up tubes (predominantly 6SN7s), along with 22 octal tube sockets and an old extension cord. The sockets were wired in series and connected to a wall socket, resulting...
WIRELESS MICROPHONE
An operational amplifier integrated circuit (741) amplifies the audio signal from microphone 1 (MIC1), with resistor R12 determining its gain. The amplified audio signal is then directed to the oscillator circuit, which includes transistor Q1 and associated components. D2 functions...
Wireless Auto Tachometer
Anyone performing their own automobile tune-ups knows how important it is to know your engine's speed. With this tachometer, you can measure your engine's speed without any connections or annoying timing lights.
The described tachometer is a non-invasive device designed for...
RF circuits
A field strength meter utilizing a biased Schottky detector employs a temperature-compensated Schottky diode within an amplified, untuned field strength indicator powered by two AA cells. This device indicates the relative field strength of RF fields ranging from a few...
2 Channels RF remote control
Remote controls are often needed to manage various electric devices. There are several types of remote controls available, including infrared, RF (Radio Frequency), and SMS. Basic short-range remote controls primarily utilize infrared and RF technology. A limitation of infrared is...
SEISMIC RADIO 500mHz - 200Hz frequency range
The most popular network is MED-NET, which encompasses the entire Mediterranean Sea with its observation points. The accompanying map illustrates these observation points. For more information about this network, which is part of the Italian Geophysical National Institute, the official...
remote control for electrical
A circuit for a remote control unit utilizes radio frequency signals to operate various electrical appliances. This remote control unit features four channels, which can be expanded to twelve. Unlike typical remote control circuits that rely on infrared light for...