Transmitter schematics | Next Electronics

The transmitter features a VXO circuit that drives a keyed amplifier. This keyed amplifier powers an MRF 476 final amplifier, producing approximately 2 watts of output. Additionally, a solid-state T-R switch is incorporated for the receiver. The component values provided...

Antenna Circuits / Schematics

This document presents plans for a simple ground plane antenna that is effective in the FM band (88-108 MHz). It is constructed from a small plastic disk. The 6 x 6 loop antenna, designed by Graham Maynard, is highlighted as...

Visual modulation indicator

The brightness of the indicator lamp changes in accordance with the modulated RF signal. Adjust resistor R2 while the transmitter is on (modulated) until the lamp flashes in sync with the modulation. Cl = 5 pF, C2 = 100 pF, Dl...

loop antennas

A loop antenna is a radio antenna made up of a loop (or loops) of wire, tubing, or other electrical conductor with its ends connected to a balanced transmission line. This design includes two distinct types of antennas: the small...

Oscillator circuits

For successful circuit-building exercises, follow these steps: Measure and record all component values before constructing the circuit, selecting resistor values that are sufficiently high to minimize the risk of damaging any active components. In case of significant errors (greater than...

Four channel RF remote control

This is a simple RF transmitter circuit utilizing the Holtek HT-12E encoder chip and an AM 418MHz transmitter module (WZ-X01). The use of hybrid RF transmit/receive modules simplifies the construction of the RF remote control. The transmitter can operate with...

Emergency Egg Locator Beacon (EELB)

This project was inspired by a circuit that a friend, Simon Field, showcased. He built a simple transmitter circuit using a 1 MHz "can" oscillator and a serial connector. In his circuit, he utilized a computer to turn the transmitter...

Rf-actuated-relay

Automatic antenna switching or RF power indication can be achieved with this circuit. Relay will key with less than 150 mW drive on 2 m. The circuit designed for automatic antenna switching or RF power indication utilizes a relay that is...

Four Foot Box Loop Antenna

Please find attached your copy of my four foot unamplified box loop. It will tune from 525 kHz to about 1710 kHz covering the entire Broadcast Band. The umbrella stand described in the article is the type you would use...