circuit design

80 meters spiral loop antenna - N4SPP 80 meters band spiral loop antenna based on SM0VPO design

G4DCH Mobile Antennas - Designing and Building HF Antennas for mobile use

Microvert antennas by DL7PE - Progress in Design of Extremely Short Transmitting Antennas Short and still efficient, how is that possible? By Juergen Schaefer, DL7PE

Impedance Matching - Article by By David Knight and Nigel Williams on Impedance Matching, basic principles, popular matching networks, L-Network solutions, materials and components in impedance matching designs

432 MHz Antenna comparison chart - An extensive comparison chart for 70 cm antenna designs elaborated by DF9CY

ZS6BKW in Inverted-V format - ZS6BKW antenna design in inverted-v format antenna design at QRZ forums

Military Portable Auxiliary Power Units - Design, build and supply Military Diesel Operated Tactical generator sets, diesel generator sets, custom generators, auxiliary power units, portable power generators and tactical quiet generators used by the U.S. Navy and Air Force.

MegaPhase - MegaPhase designs, manufactures and sells coaxial cable assemblies to OEMs building advanced microwave and optical electronic systems, products include test cables, test adapters, flexible and semi-rigid cables used to connect system components inside a system, and coaxial connectors.

Cmpter Electronics - Cmpter Electronics is specialized in designs and manufactures RF Coaxial Connectors, RF Adapters, Cable Assembly and GPS Antennas for applications in the datacom/telecom, automotive, instrumentation aerospace and defense markets.

Martek Power - Martek Power designs and manufactures a wide of high performance power supplies for various industries. Power supplies AC-DC, DC-AC inverters, DC-DC, EMI Filters

ATV 432 MHz transmitter - ATV 432 MHz AM transmitter schematic

FT-817 DC Circuit Protection - A schematic for a DX circuit protection for the Yaesu FT-817, provides protection from the external power supply overvoltage by DL2LTO in german

Mini Circuits - RF / IF Microwave components DC to 20 GHz

Radio Active Style - T-Shirts - Radio Active Style, LLC designs and produces high quality and innovative t-shirts for hams, amateur radio operators, and shortwave listeners.

Sunstone PCB Design Software - Sunstone.com PCB123 PCB download software. Review Sunstone quality pcb design software. Free PCB software download for all of your business needs.

TK3 for IC-R3 - tk3 is open source software designed for the ICOM IC-R3 receiver. Though tk3 is intended chiefly for Linux, MacOS X, and BSD users, it will work on Microsoft Windows too.

HERALD P2P radio link design - Sw tool to design point-to-point multi-hop microwave links and networks, 400MHz to 58 GHz. Site/Hop Configuration; Customized Antenna & Radio Equipment Libraries; Link Budget; Path Profile Analysis ,clearance, reflections; import path profiles from SRTM maps, free download.

Plate choke design - The plate choke, as used in an HF tube type amplifier in this article.

HF power amplifier using GI7B - Gi7b is tube designed for microwaves but working good as HF amplifier. Idea is to build cheap, reliable HF amplifier covering 160 meters band.

PCB with kitchen appliances - Cheap and relatively easy way of making professional quality printed circuit boards at home

Low cost frequency counter - Low cost multifunctional seven digit LCD frequency counter, for your HAM radio shack

A simple iambic keyer - Iambic keyer with simple paddles and simple electronic circuit.

Digital Wattmeter - 300nW to 30W - The digital wattmeter project was created for the purpose of measuring power in the range of 300nw to 30w.

TenTec Omni VI AGC modification - Modification leaves nearly all of the existing Omni agc circuitry intact, simply add an audio detector which modifies the delay characteristics of the original system by G3IXQ

KK7UQ Interface - Complete design and construction manual of the mode II, printable labels, templates and info to interface digipan