~ Early Web Links ~

CircuitsArchive is a free, web-based archive of electronic circuit schematics covering everything from audio gear and battery monitors to filters, telephone interfaces, and microprocessor circuits. Maintained by Nicola Asuni since 1998, it offers a well-organized collection of PCB designs and projects useful to hobbyists and engineers alike.

Tonne Software offers a catalog of free and low-cost electrical engineering programs for Windows, covering filter design, meter scale drawing, great-circle mapping, Smith charts, and more. The site also hosts technical articles and tutorials on topics like speech processing, AM demodulators, and CW bandpass filters, many published or submitted to QEX magazine.

Alan Yates (VK2ZAY) runs a sprawling electronics and amateur radio laboratory notebook covering homebrew circuits, microcontrollers, high voltage experiments, pyrotechnics, antennas, and much more. With over 260 articles, engineering calculators, and an annual Advent Calendar of Circuits series, this is a genuine treasure trove for hands-on electronics hobbyists.

WhiskeyTangoHotel.Com is a hobbyist electronics and amateur radio blog featuring hands-on projects like ESP32 microcontroller builds, temperature logging with Node-RED, and Morse code analysis tools. The site blends practical hardware tutorials with radio operator interests, making it a great find for tinkerers who enjoy cheap microcontrollers and DIY data visualization.

RF Cafe is a comprehensive resource for RF and electronics engineers, offering formulas, reference data, vintage magazine archives, software tools, forums, and a massive parts and services directory. Running since 1996, the site blends technical depth with nostalgia, featuring scanned articles from classic publications like QST, Popular Electronics, and Radio-Craft alongside modern engineering utilities.

Mostly DIY RF is a specialized resource for amateur radio builders, offering PCB kits and detailed documentation for RF circuits including IF amplifiers, low-pass filters, VFOs, crystal filters, and MMIC amplifiers. The site covers designs by well-known ham radio engineers like Hayward and Kopski, making high-performance transceiver building accessible to hobbyists.

Bill Meara's Gadgeteer site is a celebration of electronic homebrewing, centered on ham radio projects including DSB and SSB rigs, tube receivers, and QRP builds alongside a popular podcast called SolderSmoke. The site also ventures into amateur astronomy, model rocketry, and kite aerial photography, making it a rich destination for technically adventurous hobbyists.

Bitstream Technologies curates an extensive directory of electronics resources spanning circuit archives, DSP tools, embedded systems, robotics, PCB design, and IC information. A well-organized link library for engineers and hobbyists, covering everything from FPGA design tools to repair and test equipment references.

Cryothene is a technically-minded personal blog covering electronics projects, embedded systems, reverse engineering, and 3D printing, with standout documentation of a custom display driver project called Sharpie spanning many installments. The site also mixes in anime opinions, game reviews, and occasional recipes, but the dominant draw is its detailed hardware and microcontroller writeups.

A comprehensive free electronics and electrical engineering reference hub covering everything from basic electricity and Ohm's Law to advanced RF design, DSP, amateur radio, and circuit simulation. With hundreds of curated links, formulas, tutorials, data sheets, and calculators organized across multiple phases of learning, it serves as a structured self-study guide for electronics enthusiasts and engineers alike.