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

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.

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

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.

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.

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

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

L4B by Drake amplifier mod

A 70 MHz QRP transverter project

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.

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

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.

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

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

A collection of audio amplifier projects by N1HFX

Collection of ATV projects

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 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

N1HFX project to improve PL tone encoder providing a more stable frequency

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

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

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

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.

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

A well documented Heathkit SB-200 restoration project by NT1K

Some techniques on homebrewing yagi antennas by VK5AJL

W6CQZ JT65-HF project on sourceforge, the Amateur Radio software for reception/transmission of JT65A protocol with an emphasis upon its usage in the High Frequency Amateur Bands. Project is currently paused.

A simple VHF quarter wave antenna from PL25

A project for a vertical antenna for 60 to 20 meters by KV5R

Battery-powered monitor designed to provide an audible indication of keying for those whose rigs lack a CW sidetone

Amateur projects to investigate radiowave propagation - G3PLX's chirp project, ionosonde database, and more

A Picaxe Morse Code keyer project with source code and links to useful resources by K6ACJ

A stepper switch controller made with arduino by N3OX

A really simple project to make a power meter measuring RF output powers from a few mW up to half a watt. A DIY amateur radio project for QRP enthusiasts

A home made project for an ATV RF power amplifier

Adding a 20m band pass filter for the Icom IC-706MkII(G) by ON7EQ

Constructing a dip oscillator provides radio amateurs with a fundamental piece of test equipment for resonant circuit analysis. This particular design, adapted by VK3YE from a concept by _Drew Diamond VK3XU_, details a practical build using readily available components. The unit incorporates four plug-in coils, covering a frequency range from **2.6 MHz to 55 MHz**, mounted on 5-pin DIN plugs for versatility. A salvaged two-gang air dielectric variable capacitor, fitted with a vernier reduction drive, serves as the tuning mechanism, with the smaller gang optimizing bandspread at higher frequencies. In practical application, the dip oscillator is used by setting the meter needle to approximately two-thirds scale. When the instrument's coil is brought near a tuned circuit under test, a noticeable dip in the meter reading indicates resonance. This allows for precise measurement of resonant frequencies in antennas, filters, and other RF circuitry, proving invaluable for homebrewing and troubleshooting. The design emphasizes short wire runs for stable operation, particularly at the higher end of its operational range.

Interfacing the Jabra 9450 flex wireless headset to the Icom IC 7300 ham radio trasceiver.

A shortwave radio listeners log book runs on Windows and MacOS Catalina and above. The KB6IBB SWL Logger is a program designed for the shortwave radio listener. It offers shortwave specific logging of stations, with most tasks handled automatically. The program also incorporates the use of EiBi shortwave database for logging and looking up various known shortwave stations world wide.

Add bands to your Hustler xBTV Series Vertical

A PTT switch from Home Depot parts

Schematic of a fast charger for Gel Cell batteries

Band filters for PA6Z made by PA9M, designed by W3NQN.

13cms and 23cms ATV my projects and builds. Also using wifi amps on 13cms, 13cms dish feeds using a Sky dish. GB3CZ

A great amateur radio shack desk done with a second hand solid core door, measuring 32 inches wide by 80 inches long.

Details on projects by WA3TFS published in QST magazine over the past few years. Includes an online shop with several ham radio kits, circuit boards, simple SDR transceivers

Modifications to an Ameritron ALS 600 power amplifier by AF6SA