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Allow the reception of amateur signals on domestic AM-only short wave receivers article and project by VK3YE

This project was intended to accompany the stealth antenna project. Author want to see how effective a noise canceller could be in reducing the background noise floor when attic / stealth antennas are being used.

Simple 6 Metre DX Antenna based on an article by LB Cebick in QST May 2002 on a Quad Turnstile antenna. This antenna is basically two full wave loops mounted at right angles fed 90 degrees out of phase to produce an omni-directional horizontally polarized pattern

DragonOS is a linux distribution dedicate to Software Defined Radio. It leverages the portability, security, and power of Lubuntu Linux as a delivery package and operating environment for a pre-installed suite of the most powerful and accessible open source SDR software. DragonOS has verified support for a range of inexpensive and powerful SDR hardware, including RTL-SDR, HackRF One, LimeSDR, BladeRF, and many others.

N3OX three meters Flex Vertical, a Short, Frequency Agile Vertical for 40 meters

The idea makes use of a very simple direct conversion receiver on the band of interest.

A collection of modifications and improvements to the Ameritron ALS-600 ham radio RF power amplifier

Collection of Kenwood TL-922 linear amplifier modifications

A project with schematic to build a receiver for 80 meters band by VK1PK

This resource details the construction of a Moxon rectangle antenna, a two-element wire beam, drawing inspiration from a _QST_ article by Allen Baker, KG4JJH, and a project group led by KD6WD. It outlines the use of _AC6LA_ software for critical measurements (A-E) to design the antenna for specific bands like 17 meters, emphasizing the simplicity of adjusting frequency and wire size. The guide covers material selection for spreaders, such as telescoping fiberglass fishing poles, and various hub constructions, including aluminum tubing and PVC joints, with accompanying images. The author shares practical insights from building multiple Moxons for 10, 15, 17, and 20 meters, noting consistent 1:1 SWR at design frequencies and broadbanded performance. It describes the feedpoint assembly using a 1:1 Yagi current balun and wire nuts for robust, adjustable connections. The resource also discusses element insulators made from Lucite strips and attachment methods to spreaders using plastic wire ties and duct tape, ensuring precise element spacing. Performance observations include significant signal improvements (4-5 S units) over quad loops and a unique "DX-Vane" effect where the suspended antenna self-aligns with the strongest DX signal. The author also recounts an unsuccessful attempt at a dual-band 17/20 meter Moxon, concluding that the Moxon is inherently a monoband antenna, supported by _EZNEC_ plots for a 17-meter design.

Project Condor16 VHF transceiver

This transmitter was first constructed in 1987 and provided the author with his first real rig, capable of distances of more than about 100 metres.Use a 6GV8 tube.

FLMSG is a simple forms management editor for the amateur radio supported standard message formats. Form data can be transferred between computers either using standard internet email or via radio frequency broadcasts typically made by an amateur radio operator on your behalf.

This project is based around the recent HF1 QRP transceiver by Ashhar Farhan, VU2ESE. The transceiver is an interesting SSB design with wide tuning range from 0-30MHz and should cover several amateur bands. The schematic for the transceiver can be found on the Minima mail list in this post with a PDF attachment

Modify a KPC-9612 to give a total of four analog input for remote monitoring and telemetry.

Variable Power Supply for the bench

Make and automatic antenna tuner based on Arduino and using economic card. This ATU Project can be installed outdoors and controlled remotely by an rs485 link

AX.25 Packet Modem homebrew project on Arduino

A battery voltage booster project with pictures and schematic by KD7W

The Microsniffer is a fully autoranging VHF or UHF sniffer which has been designed for those who are foxhunting on a budget.

This converter uses the popular NE602 mixer/oscillator chip and allows reception of signals below 500 kHz on a 3.5 – 4 MHz HF receiver

An HF vertical antenna by N3OX with a flexible capacitance hat

Two find dipoles one for 75/40/20 and the other for 20/15. These 2 dipoles are at right angles to each other and the 20/15 dipole is located about 6 feet below the 75/40/20 fan dipole.

The CSV19 is an homemade antenna launcher project. In this article you can find pictures, drawing, and material list

Heathkit SB220 refurbishing by PA5CA

A 70 MHz QRP transverter project

Constructing a compact directional antenna for the 17-meter band, this resource details the build process for a Moxon rectangle, a two-element Yagi variant with folded-back elements. It covers the antenna's evolution from the _VK2ABQ beam_ and provides specific dimensions for a version built using fishing pole whips. The content includes a discussion of the antenna's radiation pattern, feedpoint impedance, and its inherent front-to-back ratio, which is often superior to a standard two-element Yagi. Practical considerations for element spacing and material choices are also addressed, alongside a visual representation of the antenna's physical layout. Performance data presented includes a comparison showing the Moxon rectangle's **2.5 dB gain** over a half-wave dipole and a front-to-back ratio of **20 dB**. The resource also touches upon the antenna's relatively wide bandwidth for a two-element beam and its suitability for portable operations due to its compact footprint. It offers insights into optimizing the design for specific operating conditions and discusses the advantages of its lower take-off angle compared to omnidirectional wire antennas, making it effective for DX contacts on the 17-meter band.

This code practice oscillator project uses a 555 timer IC. Includes a Schematic Diagram of the morse code oscillator

Some modifications for the Tigertronics Signalink USB sound card radio interface

Elecraft K3 vs. ICOM IC-781 vs. Kenwood TS-850: comparative Measurements and Experience

The document explains the technical aspects of how the Internet Radio Linking Project (IRLP) works, focusing on the use of VoIP streaming software under the Linux operating system. It details the audio sampling, compression, transmission, reception, and playback processes involved in IRLP communication.

L4B by Drake amplifier mod

The SETI League, Inc., founded in 1994, focused on participatory science, developing technology to seek definitive answers to the question of extraterrestrial intelligence. The organization operated in five dozen countries across all seven continents, maintaining the quest for cosmic companions through the efforts of its 1500 members. Although the organization shuttered its virtual doors after thirty years in 2024, the website remains for educational and historical purposes, documenting past research and activities. Key technical resources include the _SETI League Mini-Manual_ for constructing a 12 GHz radio telescope under $200, and software like _SETIFox for Windows_ and _Radio Eyes_ for radio astronomy sky viewing. The site also features _Project Argus_ detections, moonbounce signal detections, and space probe signal detections, providing concrete examples of amateur radio astronomy applications. Publications such as the quarterly newsletter _SearchLites_ and various articles by Dr. SETI (H. Paul Shuch, Ph.D.) are available, alongside information on the Third Penn State SETI Symposium in 2025. The site also offers insights into hydrogen line emission observations, presented in time domain, frequency domain, waterfall, and surface plot formats.

A project for a Moxon antenna for 7 MHz with pictures and EZNEC model

Christoph Petermann DF9CY DRM demonstration receiver project including Circuit Diagram and component list

A Linux Smith charting program. You can enter either discrete components or transmission lines, see the results on screen and/or generate Postscript output. Component values can be changed numerically or using scrollbar

This article was first published in CQ-TV issue 208. Author try to explain digital television in layman's terms and without getting too involved in mathematics.

Build this noise reducing system to enhance audio of your speaker. A project by kg4jjh

This is a description of how KO4BB built his tower. It is provided in the hope that it will be useful to anyone want to setup his own ham radio tower.

iota mapping project - a mapping resource for the IOTA (Islands On The Air) award program

This circuit is very simple and has a fantastic range of potential uses.

Collection of ATV projects

QJackRcd is a simple stereo recorder for Jack with few features as silence processing for automatic pause, file splitting, background file post-processing.

The VersaBeacon is a frequency agile, modulation agile RF source using a DDS chip and minimal support circuitry. It covers a frequency span of 1MHz to 150MHz in 1 Hz steps and provides a variety of modulations

A synthesized 2.3 GHz Amateur Television (ATV) transmitter design, conceived by Ian G6TVJ, is presented, targeting broadcast-quality video performance on the 13cm band and extending up to 2.6 GHz. The core of the design utilizes a commercial Z-comm Voltage Controlled Oscillator (VCO) that tunes from 2.2-2.7 GHz, providing a +10 dBm output and simplifying RF alignment. This VCO's stability, originally intended for narrowband applications, readily accepts high-frequency video modulation, contributing to the transmitter's robust performance. The exciter stage, incorporating a Mini Circuits VNA 25 MMIC amplifier, boosts the signal to +16dBm, while a Plessey SP4982 prescaler divides the output frequency for the synthesizer. The synthesizer employs a Motorola MC145151 CMOS parallel IC, favored over the common Plessey SP5060 for its superior video modulation characteristics and ease of programming without microprocessors. This choice addresses issues like LF tilt and distorted field syncs often seen with SP5060 designs, particularly when operating through repeaters or over long distances. The MC145151 divides the signal further, enabling precise frequency stepping, with programming handled by EPROMs for channel selection and LED display. The loop filter network, critical for video integrity, was developed through experimentation to prevent the PLL from reacting to video modulation, ensuring a clean transmitted picture. The transmitter incorporates a Down East Microwave commercial power amplifier module, delivering approximately 1.6W output, driven by the exciter through a 3dB attenuator. Construction involves surface-mount SHF components on micro-strip lines etched onto double-sided fiberglass board, housed within a tinplate box. The design boasts no AC coupling in the video path, preserving low-frequency response, a common failing in other ATV transmitters. Performance tests with a 50Hz square wave revealed no LF distortion, and a calibrated "Pulse & Bar" signal showed a near 100% HF response, demonstrating its capability for high-quality ATV transmissions.

The CAT and audio interface version 3 project by PA5CA presents a comprehensive solution for integrating amateur radio transceivers with computer sound cards, facilitating digital mode operation and CAT control. It includes detailed schematics for the interface circuitry, illustrating the isolation transformers for audio paths and optocouplers for CAT data lines, ensuring robust electrical separation between radio and PC. The resource also provides PCB layouts, enabling constructors to fabricate their own boards for this specific design. The project outlines the component selection and assembly process, emphasizing the use of readily available parts to build a reliable interface. It addresses common challenges in sound card interfacing, such as ground loops and RF interference, through its isolated design. This construction guide offers practical insights into building a functional interface, making it suitable for hams interested in DIY radio accessories for digital modes like FT8, RTTY, and PSK31.

NHRC-2 Based Repeater Controller A perfect controller for a simple repeater or link, or portable/solar powered system.

A Tape Measure Beam Antenna for Radio Direction Finding based on WB2HOL design.

Homebrewing a vhf bicone antenna with 8 clothes hangers and 4 feet of Sch40 non-metallic rigid conduit

A well documented Heathkit SB-200 restoration project by NT1K