555 circuit diagram

G3SEK's Amateur Radio Technical Notebook - A lot of good informations concerning antennas, filters, moonbounce, and circuitry data.

HF Aerial Design - A novel approach to aerial evaluation with diagrams and graphs by G3CWI

SuperCircuits - ATV accessories manufacturer

XMATCH Antenna Tuner - Ham Radio Antenna Tuners--Full Legal Power--Patented Circuit--Outstanding Efficiency and Power Capability

Almost all digital electronics - This site is dedicated to electronics hobbyists, engineers, and Radio Amateurs interested in circuit design, homebrew and kit projects.

Yaesu 920 & SoundCard - This circuit provides an interface between the Yaesu 920 transceiver and IBM computer sound card which allows data transfer and control of PSK31, RTTY, KEYBOARD CW, and SSTV modes for Amateur Radio

The Sunspot Cycle - Sunspot Numbers, The Butterfly Diagram, the Greenwich sunspot data and sunspot realted infos.

PolarPlot - Freeware antenna software that lets you see what the polar diagram of your rotatable beam actually looks like where it is operating. With PolarPlot you can measure the polar diagram of the antenna and check for abnormalities - compare plots taken before and after changes to the design or location - check the -3dB beamwidth - look at the front to back ratio - see the size and position of the sidelobes.

Elise Software Corporation - Elise Software, OUTPUTMASTER, windows professional software for Printed circuit board, post processor, Gerbers, Drill files, ODB++, files generated fast and simply.

TrueTTY Priority listing - Program for amateur radio digital communications via a sound card. Supported modes are RTTY (Baudot code), ASCII (7 or 8 bits), PSK31 (BPSK and QPSK) and AMTOR-FEC (SITOR-B, NAVTEX). SELFEC SITOR decoding is possible also. No additional hardware required, need only a sound card. Optionally you can use simple circuit fo PTT-control. Can cooperate with RZ4AG AAlog logger.

Zelscope  ^pop - Zelscope is a Windows software that converts your PC into a dual-trace storage oscilloscope and spectrum analyzer. It uses your computer's sound card as analog-to-digital converter, presenting a real-time waveform or spectrum of the signal - which can be music, speech, or output from an electronic circuit.

PLL2 - 2nd Order phase locked loop design for passive and active circuits. Bode plot, step response, design parameters

AAVoice digital voice processor Priority listing - "Digital voice processor for amateur radio operators. It use prepared ""wav""-files for transmition. Can work in the beacon mode. Optionally you can use simple circuit for PTT-control. It has a lot macros for tramsmitting. Can cooperate with RZ4AG AALog logger."

432 MHz EME PreAmplifier - 432 MHz EME low noise amplifier. Circuit, components and image by Christoph Petermann DF9CY

Galaxy radio mods  ^pop - Galaxy web site updates and additions with modifications, diagrams, and schematics for galaxy radios

Radio-TNC wiring - Radio-TNC wiring diagrams index

The Islander HF RTX - A practical solution by Cuban radio amateurs, hybrid circuit with mostly defunct TV set parts.

TS-440S Improvements - Various circuit improvements for the TS-440S by Richard L. Measures, AG6K

TS-430S Improvements - Circuit improvements for the TS-430S by Richard L. Measures, AG6K

TL-922 Improvements - Circuit improvements for the TL-922 by Richard L. Measures, AG6K

RS232 Interface - This simple circuit is intended for older Kenwood radios and was presented in chapter 22 of the ARRL Handbook.

Radio Beacon Controller - Diagram shows a block diagram of a Radio Beacon

Kenwood Connector Diagrams and Pinouts - Kenwood Ham Equipment Connector Diagrams and Pinouts (1999)

Defpom CB and HAM radio mods  ^pop - Circuit diagrams, CB and HAM mods, alignments, data sheets and pinouts, a massive site with over 600 pages of free info

50 MHz Transverter idea - Complete 144/50 MHz transverter with GaAs Fet LNA and 400 mW out. No printed circuit board. Schematics and images by Christoph Petermann DF9CY