security alarm circuit

A Portable Antenna Matching Unit - A small HF antenna tuner project for qrp operations. Includes circuit diagrams pictures and test results by GW4ALG

Newcastle Scan, Live Scanner - A live stream of radio scanner, You will Emergency Services, Police, Fire, Ambulance, Rescue, Transit officers, plus non ES like transport, media, taxis, couriers, buses, security just about anything. From Newcastle Australia

Wire Harness Assemblies - Printed Circuit Board, Custom Overmold Cable Assembly, Box Build, System Integration, Sheet Metal

IC-746PRO TX Problem - The IC-746PRO is a great rig. But it has a few reliability issues, especially with the earlier-production units. This article addresses four problem areas:. IC151 on the RF Unit. Driver circuit on the PA Unit. HRX-muting circuit on the CTRL Unit. Predriver on the PA Unit.

M.C. Howard Electronics - Distributor of Common Electronic Components Such As Memory, Integrated Circuits, Discrete Components, Cables And Services. We Also Provide Prom Programming, Simm Manufacturing, Testing And Custom Kitting.

DERF electronics corporation - Distributor of electronic components like diodes Transistors Microcontrollers Microprocessors connectors, switches, relays, integrated circuits, eproms, leds

AP Circuits - Printed circuit board fabrication

5Spice - Analog circuit simulation program for the typical circuit designer. Commercial version for windows

NL5 Circuit Simulator - Analog circuit simulator for Windows (not a SPICE). A great tool for students, amateurs, as well as for experienced engineers. Free Demo.

WaveCon ProCap - Microwave/ RF Circuit Design and Analysis Software

HamTime - Announce your callsign at least once every ten minutes. HamTime runs in the corner of the screen and gives you an audible alarm when that announcement is due.

Enable Low Cost RF Power Amplifiers - A new paradigm for low cost, reliable RF amplifier ‘pallets’ has been enabled by new circuit design, manufacturing and thermal management techniques

Power Aamps RF voltages - This test circuit is easy to duplicate, and demonstrates the extreme voltages that appear in an amplifier when the load is improper for the amount of drive power applied.

Build a Remote Control Antenna Switch - Remote Control Antenna Switch made with two circuits board

Antenna Selector - This project was built to be able to experience with more of an antenna and also in turn to be able to have a system that offers security to the receivers, carrying out the discharge to ground of the antennas

A fool-proof VOX - A circuit which had been used in many other application before. The configuration described here is optimized for IPHONE/radio operation.

KI5YN QLF Filter - A microprocessor based interface designed to go between a standard Morse code key and a radio transmitter. The circuit receives a signal from the key, processes it, and re-transmits it to the radio.

QRP AM(cw) Transmitter for 10 meters - In this project, you will make a simple low-power broadcast-type circuit, using a crystal oscillator integrated circuit and an a collector modulated AM oscillator.

Lightning Protection : Protecting each I/O line - KB22UT Article on how protecting ham radio station and in particular I/O Lines such as AC power, coax cable, control circuits, telephone line.

HV power supplies - WV0NNI 2,800 VDC @ 2 Amps Continuous Variac adjusts filament voltage. A voltage doubler circuit, well suited for smaller, compact linear amplifiers.

Designing Op Amp Audio PreAmplifiers - Design guidelines for Op Amp audio preamplifier circuits by Mike Martell N1HFX

How to desolder components - Learn how to correctly desolder electronic components from printed circuit boards

How to solder - Key facts about how to solder, how to solder wire, how to solder pcb's, and including general soldering techniques and the best ways of making good solder joints for electronic circuits and construction. Includes video

Sound Card interface - Interface to insulate the radio circuits from the computer by VK2GWK

Using An Oscilloscope - It allows you to take a peek into a circuit to see what is happening has it happens, irrespective of the speed with which it is taking place