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The free pdf book is a compilation of articles congenial to QRP published on 2003- 2005 years at free e- magazine AntenTop. 17 Mb pdf file.

Yo5ofh j-pole antenna plans for 2 and 6 meters

This free windows application is used for simply triggering PTT via DTR/RTS COM port pins. It supports remote PTT triggering with ptt2dtr as the server.

40mm diameter grey PVC pipe with a length of 9.5cm

This Arduino project decode ICOM CAT frequency information and switch antennas according to preset values. RX and TX antennas can even be different, a project by ON7EQ

The page describes the construction of a simple omnidirectional, vertically-polarised dipole antenna for two metres using coaxial cable. It can be used indoors or outdoors, with no extravagant gain claims. The project is low-cost and can be completed in about 20 minutes.

Build a 5 watt, 80 meter QRP CW Transceiver Designed by N1HFX

The 20m monoband 4-1000 amplifier, by Jelmer (pa5r), Herman (pa0ten) and Frans (pa5ca)

The I0JXX is an italian company that offers market their projects, also sells electronic products of high quality, both for Ham, both Broadcast and their accessories. VHF Antennas, mosfet power amplifiers, filters, insulators, power dividers, telescopic poles, antenna masts

This program simulates a HF link, using sound card and WIN95 by Michael Keller, DL6iAK

6x2 coaxial remote antenna switch, completed unit showing weatherproof relay box and station control unit.

QRP Kits and Projects for the low power Amateur Radio enthusiast

A homebrew fishing-rod vertical using a very nice design from EB5EKT. This antenna works 20, 30, and 40M bands by selecting the tap points using alligator clips

The Contesters Choice

This antenna allow transmission and reception on all bands between 7Mhz and 28 Mhz. Similar in concept to the Miracle Whip by VK3YE

The W6AMT Beacons is a Windows program which automates the collection of radio propagation data. HF data is collected by monitoring the worldwide network of NCDXF / IARU HF beacons.

A low-level voltage meter and could even be used for audio purposes.

The project outlines the process for constructing a low-power FM broadcast transmitter using a Raspberry Pi Zero, a simple wire antenna, and battery power. It details the software installation steps for PiFM and MPG123, essential for generating and transmitting audio. The resource provides instructions for configuring the Raspberry Pi to broadcast FM signals, including command-line operations for initiating transmission and playing audio files. It specifically focuses on the Raspberry Pi Zero's capabilities for this application, highlighting its cost-effectiveness and minimal hardware requirements. The content presents a practical, hands-on approach to creating a basic FM transmitter, suitable for short-range, experimental broadcasting. It includes guidance on testing the FM output and ensuring proper operation of the software components. The project emphasizes the use of readily available components and open-source software to achieve functional RF output.

1.2-30V 1.5A variable regulated power supply

UM58 a regenerative receiver project

Portuguese page, from VLF to some GHz, antennas, projects, EME, NDB DX and more.

Open source libraries and utilities to support using digital signatures for Amateur radio QSL system information like eqsl and lotw. Available for windows macos e linux.

A NorCal Project A Crappie, not crappy, portable antenna

The St. Louis Vertical Revisited by Dave Gauding, NF0R here are a few ideas and observations on the St. Louis Vertical

Signalprocessing for SSB - Direct Conversion Receiver using Phasemethod for Sideband Supression, does all necessary signalprocessing for Direct conversion Receivers using IQ-mixer for demodulation.

A quick vertical for 160 meters portable use

If your local repeater has got you singing the PL tone blues, then read on. For less than $10, an inexpensive PL tone generator can be constructed that will bring new life into that old non-PL rig.

Demonstrates the essential steps for winding **toroidal cores**, a fundamental skill for amateur radio operators engaged in homebrewing and kit building. It addresses the critical aspects of selecting the correct core material and wire gauge, emphasizing the importance of precise turn counting and consistent winding tension to ensure optimal circuit performance. The resource details methods for preparing the wire, including techniques for safely removing enamel insulation from leads using flame, sandpaper, or a solder pot, and provides guidance on tinning the exposed wire. Explains the process of mounting the wound toroid onto a printed circuit board, highlighting the need for careful lead placement and secure soldering to prevent shorts and ensure mechanical stability. It also offers a practical formula for calculating the required wire length based on the desired number of turns and the specific **toroid** size, referencing common core types like T-50 and FT-240. The guide stresses the importance of verifying the inductance of the wound component, often using an inductance meter, to confirm it matches design specifications. Provides practical tips for handling multi-filar windings and managing short lead lengths, which can be particularly challenging. It underscores the necessity of meticulous attention to detail throughout the winding and installation process to achieve reliable and efficient RF circuits.

Local and DX contacts from tight spaces, it works from 40 to 17 meters

Demonstrates the construction of two distinct wideband RF preamplifiers, detailing their component requirements and performance characteristics. The first design leverages monolithic microwave integrated circuits (MMICs) such as the MAR-6, MAR-8, or PGA103, offering a broad frequency response from DC to 2 GHz with a gain of 22.5 dB at 100 MHz and a noise figure typically below 3 dB. This MMIC-based amplifier incorporates protection against power supply transients and features a 50 Ohm input/output impedance, operating from an 8-20 volt supply with low current drain. The second preamplifier design utilizes a BSX-20 transistor, providing amplification across the 14 MHz to 550 MHz range. This simpler, more economical build achieves an average gain of 12 dB at 145 MHz and a noise figure of approximately 1.1 dB. It operates from a 7-15 volt battery supply with a current draw of 6 mA. Both projects emphasize critical construction techniques, such as maintaining short RF connections, ensuring 50 Ohm impedance paths, and mounting the circuit within a shielded enclosure to optimize performance and minimize noise. The resource also discusses phantom power options for antenna-mounted preamplifiers and precautions for use with transceivers, including output protection diodes and static bleeders.

Circuit diagrams to homebrew different baluns by vk2awx

Homebrewed SWR meters projects by G3TXQ

Lots of projects and introductions to RDF and T Hunting

80 metre ceramic resonator VXO CW Transmitter by VK1PK

Sales tubes for amplifiers like GS-23B,GS-31B,GS-35B,GU-34B,GU-43B,GU-74B,GU-84B. Include links to aplifier homebrew projects

Build an HF antenna tuner by VK5AJL

FAR Circuits is exclusively a manufacturer of Printed Circuit Boards for electronic projects that are used by the Amateur Radio and electronic hobby enthusiast.

Excellent poster representing the electromagnetic spectrum from 31.2 mHz to 6.52 EHz, PDF file poster designed by Anthony Tekatch

Remotely controlled antenna switch that can switch between 5 antennas

A pdf file with schematics of an ssb and cw filter AF amplifier

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.

Projects and design atv de ik1hgi Progetti, circuits, master, fotos in Italian

This vertical antenna consist of a 18 meters telescopic pole and allow operations from 160 to 30 meters band, project by Daniel Zimmerman N3OX

Contains digimodes, antenna projects, DX info and lots more

EB4EQA's Projects GSM1800 moxon square antenna

This strange looking antenna is a combination of Coupled-Resonator principle by K9AY and a quarter stubs to achieve low angle radiation pattern. Designed with 4nec2 NEC based antenna modeler and optimizer for 145/220/440MHz bands

Sometimes amateurs like to home-brew their power supplies instead of purchasing one off the shelf at any of the major ham radio retail dealers.

Enabling IC 706 for 4 meter band modification in italian.

Fox Delta Amateur Radio Projects & Kits