Simple radio circit diagram
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valved transmitter for 3.5 MHz
This transmitter project is a highly efficient, rugged, and simple low-power continuous wave (C.W.) unit delivering more than 10W. It is crystal-controlled with stabilized high tension (H.T.) and features a buffer stage between the crystal oscillator and power amplifier stages,...
ANTENNA DESIGN FOR FM TRANSMITTER
Two aluminum rods, each of length "L" in meters, are connected through an insulator as illustrated in the figure. A 75-ohm cable is fed from the center, similar to a conventional TV antenna.
This configuration describes a basic antenna system utilizing...
Transmitter Servicing Course
With the equipment ready for operation, the main line switch (S-831), the emergency switch (S-12), and the main line contactor contacts (K-831B) are all closed. The keying relay main contacts (K-1C) ground the center tap of the MO filament secondary...
Radio remote control circuit
The receiver circuit depicted in the figure requires the insertion of a plug into the radio headphone jack. When the radio receiver detects a signal from the transmitter, an audio signal is output from the jack. This signal is then...
Telegraph Transmitter in the Pilot Radios Radio Design magazine 1930s
The TPTG transmitter has been transformed into a modern TNT model. This transmitter can utilize the existing K-111 power pack for both the transmitter and receiver, eliminating the need for a separate power supply unit. Building this compact transmitter allows...
Interfacing MaxTrac Mobile Radios to Repeater Controllers
This article outlines a reliable, straightforward, and universal method for interfacing Motorola mobile radios from the MaxTrac, Radius, and GM300 series with common repeater controllers. The information provided is also relevant for radio interfaces used in IRLP or EchoLink applications....
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...
RF Signal Attenuator up to 30dB for 1MHz - 500MHz Input
This is a PIN diode-based RF signal attenuator circuit that operates with input frequencies ranging from 1 MHz to 500 MHz. PIN diodes are among the most commonly used components in RF applications.
The RF signal attenuator circuit utilizing PIN diodes...
A 30 Mtr Direct Conversion Receiver for QRSS
The schematic for the crystal bandpass filter/amplifier board is illustrated, along with images of the assembled and boxed unit. The signal frequency bandpass filter is constructed over a ground plane and enclosed in a separate housing measuring 75 x 75...