Building Coaxial Traps
- This page describes the design and construction materials W8WWV used to build a coaxial cable trap. A coaxial cable trap is a parallel resonant circuit that is usually inserted in an antenna element to enable multiband operation.
Multi Band Antenna Traps
- These devices are called Traps, but they are actually more like frequency sensitive switches. They are parallel resonant, high Q, tuned circuits which provide a very high impedance at their frequency of resonance.
A remote antenna tuner
- Interesting project to remotely control, using a servo control circuit, a common commercial antenna tuner by N30X
Emtech ZM-2 Antenna Tuner Kit
- The Emtech ZM-2 Antenna Tuner is a nifty little portable transmatch for QRP (low power). It utilizes the well-known Z-match circuit, which is especially useful for balanced antennas (like dipoles and loops).
Canadian Antique Radios Schematics Diagrams Service
- We specialize in canadian antique radio schematics for vintage tube radios made in canada. we carry lots of factory electronic circuit schematic diagrams as well as all rcc / radio college of canada service data 1920's - 70's.
E. H. Armstrong
- Radio's premier inventor, Edwin H. Armstrong was responsible for the Regenerative Circuit (1912), the Superheterodyne Circuit (1918), the Superregenerative Circuit (1922) and the complete FM System (1933).
- Free PCB software is a snap to learn and use. For the first time, designing circuit boards is simple for the beginner and efficient for the professional.
- Commercia, productive and easy-to-use electronic circuit schematic drawing tool Featuring full hierarchical design, standard and custom netlist formats, extensive symbol libraries, scripting and customization features and much more.
External Keypad for FT-817
- An external keypad for FT-817(ND), for the serious portable/field-day contester/operator. Homebrew it with the free firmware and public circuit diagram.
The circuit is very simple and takes power supply from the ACC port of the radio
Universal QRP Transmitter
- Here's the homebrew Universal QRP transmitter adapted from work by Wes Hayward - W7ZOI. The circuit originally appeared in QRP Classics published in 1980 by the ARRL