Making a Valve radio
#valve radio
#RF
#radio
#vacuum tube
#amplifier
#tuner
#receiver
#vintage electronics
#analog circuits
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Amazing All-Band Receiver
The Amazing All-Band Receiver is essentially a diode detector followed by a high-gain audio amplifier. This device is not a multi-band receiver; it captures all signals simultaneously. The detector utilizes a biased Schottky diode for superior sensitivity and bandwidth, enabling...
RF wireless allarm magnetic switch PIC16F84
This circuit was formed to create a wireless alarm from a normal magnetic contact. By fixing the magnet to the leaf of a door, or swing of a drawer, it is easy to reveal the opening. To transmit the signal...
Grounded Grid Amplifiers
Floating the grid above ground is detrimental for RF performance and arc protection. The connection of the control grid to ground is critical for stability. It is essential to keep the grid connection to ground as wide and short as...
RF OSCILLATOR CIRCUITS
A widely recognized circuit is the Hartley oscillator, which is characterized by a tapped coil within the LC tank circuit. The tap point of the coil is grounded. The oscillator's amplifier section functions as a common-emitter amplifier, resulting in the...
4 Band Double Tuned Preselector
The circuit requires an RF input, which can be sourced from either a long wire or a loop antenna. The preamplifier operates within a frequency range from 550 kHz (Medium Wave) up to 30 MHz in the shortwave band. The...
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...
Hands-off-intercom
Amplifier A increases the microphone's output to a usable level. The output signal is fed to op amp B, which inverts the signal by 180 degrees. A balance-control potentiometer connects across the outputs of amplifiers A and B. If an...
RF Field Strength Meter Circuit
A sensitive and reliable RF field strength meter is an invaluable instrument in amateur radio and radio-controlled model applications. This field strength meter is utilized to align antennas for optimal gain and to determine the transmission range of radio controllers....
Amplifier Output Delay with Relay Schematic Diagram
This is a minimal circuit designed for individual audio amplifier projects to control the presenter output relay. The purpose of this circuit is to manage the relay that activates the speaker output within the audio amplifier. The circuit introduces a...