circuit design

2.4GHz Colliner Antenna Design - Antenna for 802.11 applications

Log Periodic of Another Sort - A log periodic dipole array (LPDA) antenna design that offer continuous low SWR in 13-30MHz range

MFJ-940 modification - The MFJ-940 VERSA TUNER II is a useful little antenna tuner for the HF-bands. However it suffers from a minor design error, which can be easily rectified.

HamRadioTube - A site like Youtube but designed for for the Amateur Radio community

Sandpiper Aerial Technology LTD - Sandpiper has been designing and manufacturing aerials for over 25 years. Offer HF Dipoles and verticals, VHF UHF Yagi, collinears and other beam antennas, elical antennas,quagi,moxon, and portable antennas, tripods mounts and fiberglass poles

FMI - FMI provides superior solutions in the design and manufacture of frequency control devices including Voltage Controlled Temperature Compensated Crystal Oscillators (VCTCXO), voltage controlled crystal oscillator (VCXO), Temperature Compensated Crystal Oscillators (TCXO), crystal clock oscillators, high temperature oscillators, surface mount and crystal oscillator products, phase locked sources and more.

Astrodyne - Dedicated to the design, manufacturing, technical support, and delivery of innovative and cost effective power solutions for worldwide applications. AC/DC switching power supplies and DC/DC converters.

KD1JV Designs - QRP Kits and Projects for the low power Amateur Radio enthusiast

OSCAR 11 - Designed and built by the University of Surrey's Spacecraft Engineering Research Group - UoSAT in the United Kingdom,

OSCAR-22 - UoSAT-OSCAR-22 is the most recent spacecraft in a series of Amateur Radio communications satellites designed and built by the Department of Electrical Engineering at the University of Surrey in Guildford, Surrey, England.

Solar Panel Store - Focus on solar power products that function in the harshest environments, designed for years of reliable service.

Resistor Finder - Resistor Finder is a program that allows the electronics designer or hobbyist to find a combination of 2 resistors that, when connected in parallel, will provide the best match to a desired resistance.

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

BeamFinder - BeamFinder is a software tool designed to conduct analyses for radio amateurs interested in radio propagation studies. It provides a large 2500 x 1800 pixel screen map of the world which displays calculated results from sophisticated models, dx data and other sources of information

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

Microwave RF Amplifier Design Tutorial - This tutorial will set out the design stages required to design a theoretical microwave amplifier

Highly linear rf power amplifier design - The need of high linearity is one of the principal drivers in the design of power amplifiers for new generation applications

Desgin Power amplifiers with Genesys - Article on how use Genesys sowftware to design RF power amplifiers

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.

Power Gride Tubes - Article on tubes and their usage in power amplifiers design. Explain failures of tube in RF power amplifiers, a common problem in the SB-220 SB-221, TL-922 and other amplifiers.

50 Mhz Amplifier - This is a homebrew 100 watt six meter linear amplifier. The project was designed by Pat Bunn - N4LTA, and was featured in the October 1990 issue QST magazine.

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

Tools and Links for RF Power Amplifier Builders - This document lists a few tools, documents and websites which are valuable in the design and construction of amateur RF power amplifiers. The list is small but it represents a good starting point for the amateur amplifier builder.

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

VK5JST Aerial Analyser - This antenna anlyzer project was published in the May 2005 issue of the Australian magazine "Amateur Radio", and has been designed using parts which are very readily available