RF-Radio Fre

RF Dual DC Motor Controller

The transmitter circuit consists of WZ-X01 RF module, Holtek HT-640 encoder and 8-bit A/D converter. U1 ADC0804 converts the analog voltage to digital data; U2 encodes that data (D0~D6) along with D6, D7 and transmitting through the RF transmitter module. The potentiometer VR1 varies the voltage to the A/D U1 pin6, since only the lower […]

Easy Radio Wave Alarm

Radio Wave Alarm by Rev. Thomas Scarborough – scarboro@iafrica.com This simple circuit is sure to have the police beating a path to your door – however, it has the added advantage of alerting you to their presence even before their footsteps fall on the doormat. radio wave alarm The circuit transmits on Medium Wave (this […]

UHF Preamplifier by MPSH10 transistor

This circuit is designed to work at UHF frequencies in the range 450-800MHz. It has a gain of around 10dB and is suitable for boosting weak TV signals. The circuit is shown below The MPSH10 transistor used is available from Maplin Electronics order code CR01B. Alternatives that may be used instead are BF180 and BCY90. […]

300 MHz Prescaler by MCT10280

A preamp that drives the CMOS counter input and a divide by 10 prescaler to extend the range of A Little More Serious Frequency Meter. The MCT10280 prescaler can be set to divide by 80, 40, 20, or 10, as a function of which pins are tied to the power supply. I set this one […]

HF/VHF/UHF preamp using one BSX-20 by 2N2369

This preamp is protected to a certain degree for accidental TX (+/- 5watt) at the output, but no guarentee is given that your BSX20 will survive. So make the needed precautions to prevent this from occuring when used in a TX type situation (like between your antenna and transceiver). Use a RF-sensing circuit instead. Read […]

VHF Preamplifier 15-20 dB

The actual preamplifier in this circuit is a practical wideband amplfier that gives about 15 – 20dB of gain from 1.8 MHz through to well over 200 MHz. You will no-doubt replace this circuit for your own favorite amplifier for the band you are interested in. The 2.2mH chokes should have an absolute minimum reactance […]

Coil-less FM Transmitter by IC 40106

The RF oscillator using the inverter N2 and 10.7Mhz ceramic filter is driving the parallel combination of N4 to N6 through N3.Since these inverters are in parallel the output impedance will be low so that it can directly drive an aerial of 1/4th wavelength. Since the output of N4-N6 is square wave there will be […]

BA1404 HI-FI Stereo FM Transmitter

Whether you want to create your own radio station, transmit the music around the house, or simply create a wireless link between your iPod and a receiver in your car, this transmitter will let you do these things easily. With BA1404 HI-FI Stereo transmitter you will be able to transmit MP3 music from your iPod, […]

Simple FM transmitter with a single transistor by 2N2222

Mini FM transmitters take place as one of the standard circuit types in an amateur electronics fan’s beginning steps. When done right, they provide very clear wireless sound transmission through an ordinary FM radio over a remarkable distance. I’ve seen lots of designs through the years, some of them were so simple, some of them […]

500mW FM Transmitter by BC549

The TX500 is a simple to build 500mW FM Transmitter. It consists of three blocks; modulator / oscillator, two stage 500mW VHF amplifier and LED based power meter. The TX500 allows to transmit audio signals to FM band at frequencies from 88 MHz to 108 MHz. Due to the very low power consumption of less […]