40m transmitter circuit

40 meter double bazooka antenna - A double bazooka antenna plan for the cw portion of the 40 meter band by k0ru

Short 40m dipole - The GM4JMU Shortened 7Mhz Dipole

Feeding an End-Fed Antenna  ^pop - End-Fed antennas are NOT balanced systems; but neither are verticals, ground planes, discones, windoms, zepps, Marconis, half-slopers, et al. Additionally, the low-impedance antenna port of your transmitter/receiver is not balanced.

Vertical antenna for Vacation - Vertical Vacation Antenna for 80, 40 and 20 Meter-Band, by Herbert OE3BMB This antenna is a full size λ/4 for 20m and 40m band, and a shortened λ/4 for the 80m band. Generally on the 40m band the SWR is under 1,6. In 80m and 20m band at the resonant frequency the SWR is about 1,1.

Short Whip Antenna Tuner - Here is a circuit that will resonate a short whip antenna for the HF Bands.

ZL1BPU Rotator Controller - A very simple controller circuit, with fairly smart performance! The ZL1BPU Rotator Controller has been designed as an add-on unit for the popular Kenpro KR-400 and Yaesu G-400 rotators. The controller consists of a small circuit board which fits inside the rotator control box (see picture).

Rebuilding the Collins 516F-2 Power Supply - The Collins 516F-2 is a heavy-duty power supply for the KWM-2/2A transceivers and the 32S-1,2,3 series of Collins transmitters.

IZ3DVW/B - 40meter band beacon on 7,039.6 MHz

W3YY FSK CW PC interface - A FSK/CW PC interface that will allow a PC to key your transmitter producing either a pure FSK or CW signal

K6XX CW Indicator Kit - The purpose of this circuit is to light a LED in your radio when you tune to within +- 20hz of a cw signal. This makes for easy tuning of a cw signal by eye rather than by ear

Sights and Sounds of Digital Signals - Preview the waterfall signature of various digital signals and listen to the sound of the digital modes. Learn about the bandwidth requirements and why a linear transmitter path is critical to successful and correct use of many modes on the amateur bands by W1HKJ

Is HF propagation reciprocal - Some test circuits using the ACE-HF System Simulation & Visualization software, about reciprocal propagation on HF bands by NW7US

RF Circuit design basics - Ebook by Akira Matsuzawa Tokyo Institute of Technology, Building blocks in RF system and basic performances, Device characteristics in RF application , Low noise amplifier design, Mixer design and Oscillator design

Shortwave Converter - This is a simple circuit that when placed near an ordinary AM broadcast radio will allow you to receive international shortwave broadcasts in the 5-6 MHz band

ViPEC Network Analyzer - This program intended for electronic circuit analysis (mainly for Linux). ViPEC is a powerful tool for the analysis of high frequency, linear electrical networks.

Target 3001 PCB Design - Represents a new generation of CAD/CAE software for circuit design. Has been created to meet the requirements of professional design engineers.

Qucs - Quite Universal Circuit Simulator Priority listing - Qucs, briefly for Quite Universal Circuit Simulator, is an integrated circuit simulator which means you are able to setup a circuit with a graphical user interface (GUI) and simulate the large-signal, small-signal and noise behaviour of the circuit. After that simulation has finished you can view the simulation results on a presentation page or window. Run on Linux.

AA Battery Solar Charger - This almost trivial circuit may be used to charge a pair of AA or AAA sized rechargeable battery cells from sunlight.

TANKIT Priority listing - A free design aid for vacuum tube linear RF power amplifiers. Determine plate circuit operating parameters and design pi or pi-L tanks quickly and easily.

Chatterbox Transmitter and Receiver - 160 meters transmitter and receiver by G3NGD

FM Morse Code Keyer - A simple circuit which will generate a 700 Hz tone into any FM transceiver allowing an amateur to practice CW with another amateur on a 2 meter simplex frequency.

500mw CW Transmitter - A very quick and easy way to get on the air is to build a "Michigan Mighty Mite" CW transmitter for 160, 80, 40 or 30 meters. It can't get simpler than this. It has very few parts, costs almost nothing, and it works! Cost estimate $10 by VE6WTF

Signal generator to adjust a ssb-transmitter

Signal Generation Solution - Build an inexpensive RF signal generator

A reliable VOX PTT circuit - This VOX PTT has been designed with Echolink in mind, but it will work equaly as well with repeaters