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An inexpensive rechargeable CMOS battery system that can be built from readily available parts.

Donwload the Kenwood TL-922A user Manual

Review of Cushcraft MA-5B multiband Antenna after some days of usage.

A home made 4:1 Ferrite QRO Bal-un with a FB 241-61 Type K

Find out how much to adjust the length of a quarter wave whip or a half wave dipole rather than the outright cut-and-try method.

Printable Quick Reference Card for Yaesu VX-7R

W5UXH version of OZ1JHM Morse Code decoder project

Accurate frequency measurement is crucial for amateur radio operators, particularly when building or troubleshooting transceivers and test equipment. This resource details the construction of a _PIC microcontroller_-based frequency counter, providing a practical solution for precise frequency display. The design incorporates an LCD readout, offering clear visual feedback of measured frequencies. The counter can operate as a standalone unit, useful for general bench testing, or be integrated directly into a receiver. Its built-in offset functionality allows for seamless integration, enabling the display of the received signal frequency rather than the intermediate frequency. The project focuses on accessible components and construction techniques, making it suitable for homebrew enthusiasts. Key features include a measurement range up to **50 MHz** and a compact form factor.

The resource details the construction of a multiband trap-style Inverted-V antenna designed for operation on 3.5 MHz, 7 MHz, 14 MHz, 21 MHz, and 28 MHz. It presents specific winding data for the traps, including the number of turns, wire gauge, and coil former dimensions, crucial for achieving resonance on the target bands. The document provides a parts list and a diagram illustrating the antenna's physical layout and trap placement. It outlines the process for building the traps using PVC pipe formers and specifies the required capacitor values for each trap. The design emphasizes a practical approach to achieving multiband operation with a single feedline, a common goal for HF operators with limited space. The document includes a table with antenna segment lengths for each band, allowing for precise replication of the design. It also offers insights into tuning and adjustment, ensuring the antenna performs optimally across the designated amateur radio bands.

Skin effect and proximity effect on making coils with stranded wire. An interesting comparison on making coils.

Construct a compact, 20 meter rotatable dipole antenna of durable weather worthy components supported at a single point obviating the need for multiple supports and multiple support ropes crossing the yard.

May 2015 Radcom Article on common-mode chokes that can be used for control cables, phone lines, but mostly on typical HF antenna systems. This article explain what common mode chokes does, why you meay need one, properties common mode chokes should have, how to build and measure performances.

An interesting article on guanella baluns that cover several aspects of homebrewing 1:1 and 4:1 current baluns by KN9B

A 17 3/4-inch radiating element and 18 3/4-inch ground plane radials form the basis of this quarter-wave ground plane antenna for 2 meters FM. The design, attributed to AA1PG, utilizes a panel-mount SO-239 UHF connector and three lengths of #12 copper wire, with a total material cost estimated at $3.00. Construction involves soldering the elements directly to the SO-239, emphasizing thorough solder flow for robust connections. Recommended feedline includes _RG-8X_ for longer runs, with _RG-58_ acceptable for shorter lengths, cautioning against _RG-174_ for VHF applications due to high loss. The antenna is designed for elevated deployment, such as in trees or on roof gables, to maximize line-of-sight propagation. It aims to improve repeater access compared to typical rubber duck antennas, even with low power output.

Ten essential tips and truisms for understanding HF antenna: Non-resonant wire dipole antennas fed with open-wire line and an antenna tuner can function effectively as multiband antennas, as detailed in "The Classic Multiband Dipole Antenna" by WB8IMY in March 2004 QST. Coaxial cable, unlike balanced parallel-wire feed lines, can cause RF to travel on the outer shield braid, leading to RF feedback to the station; a 1:1 balun at the dipole center can mitigate this by isolating the unbalanced coaxial feed line. Antenna gain is achieved by shaping and directing RF energy, with beam antennas concentrating power in a specific direction, and wire antennas also exhibiting shaped radiation patterns. An antenna tuner's primary role is to match the transceiver's 50-ohm output to the antenna system's impedance, allowing modern transceivers to deliver full power. Wire antennas do not always require center feeding; end-fed long wires or off-center-fed dipoles (like the Windom) can be used, though they often necessitate an antenna tuner and a counterpoise or radial network. Dipole antennas do not need to be perfectly horizontal; their legs can be bent or inclined, which affects feed point impedance and may require SWR experimentation with coaxial feed. Vertical antennas shorter than a half wavelength require an efficient ground system, typically comprising elevated or buried radial wires, with more radials generally leading to better efficiency. A 1:1 SWR indicates an impedance match but does not guarantee antenna efficiency; an inefficient vertical antenna with a poor ground system can show a low SWR while wasting most RF as heat. Investing in high-quality, low-loss feed line, especially coaxial cable, is crucial for maximizing RF signal transfer and overall antenna system performance.

The Ameritron ALS-600 600-Watt HF Power Amplifier review by AD5X

QST Magazine, 1991 July, review of the Kenwood TS-850S 160-10 Meter Transceiver

**LDG Z100** automatic tuner repair focuses on toroid replacement and troubleshooting. The guide provides detailed steps for diagnosing and fixing common issues with the toroid, which is crucial for the tuner's performance. It includes specific instructions on disassembling the unit, identifying faulty components, and sourcing replacements. The document is technical, requiring familiarity with electronic components and soldering techniques. It emphasizes the importance of using the correct toroid specifications to ensure optimal functionality. Successful repair of the **LDG Z100** ATU restores its ability to match a wide range of antennas, enhancing transmission efficiency. The guide compares the performance before and after the repair, highlighting improvements in SWR readings and overall reliability. Practical application of this repair extends the life of the tuner, making it a cost-effective solution for amateur radio operators. The document serves as a reference for similar repairs on other models, providing insights into common issues and solutions. It is a valuable resource for those looking to maintain their equipment without resorting to professional services.

An ham radio contest log sheet in a PDF US letter printable format, can be used for portable operations, free to print and download.

Diamond W8010 Multiband Dipole Modifications

VK Contest Log (VKCL) is a free contest log software specialising in Australasian contests but also covering some international ones too. Author is SK, you can donwnload the latest version 4.15.

Slot cubes are folded skeleton slot antennas with widened, folded dipoles bent into a cube to reduce size. QST Article 12 2019

50MHz Collapsible 2 Element Mini Beam antenna, an overview the development of the 6MBA.

A handy piece of test equipment useful for HF bands, can absorb a 200W modulated carrier for almost 2 minutes. It is housed in a tin and part filled with dry sand that helps in power dissipation

This article is about a simple vertical end-fed-half-wave wire antenna for 10 meters that can be used in case of restricted space.

Globe-S for RTL1090 is a light radar viewer for RTL1090. It communciates via a HTTP interface and can be interfaced over long distances.

Ameritron QSK 5 PC mod for AL80B

IARU Region 3 bandplan Revised 12 March 2019

This app will give you a 16 tone DTMF keypad and the ability to generate custom DTMF sequences, and set the duration and tone to silence ratio. Includes the characters 1234567890*# and the menu tones ABCD. You may enter a custom sequence via the keypad, soft keyboard, or speech if your device already has speech-to-text capability. This is basically a touch tone telephone keypad, which may be of interest to amateur ham radio repeater operators

Six elements yagi antenna for 6 meters band. This antenna design is based on the QuickYagi 4 software by WA7RAI, uses a 6.5 m boom, feature 12.0 dBi gain and 35dB front/back

In this article the author provides some guidelines on how to solve a common problem when stacking different types of yagi antennas on the same mast, limiting the effects on gain and radiation pattern of both antennas

Study of the Coaxial Dipole: Just how does this thing work.

Calculate the value of an unknown resistor with this free program for windows

Manually programming D-Star handheld transceivers like the _Icom ID-51A_ and _ID-31A_ can be a straightforward process, enabling operators to configure repeaters, simplex frequencies, and D-Star specific settings without relying on computer software. This method is particularly useful for field operations or when quick adjustments are needed, allowing hams to set up callsign routing, DR mode, and reflector links directly from the radio's interface. Understanding the menu structure and key sequences is crucial for efficient on-the-fly programming. Operators often find manual programming invaluable for activating new D-Star repeaters encountered during travel or for participating in local nets where specific G2 or G3 gateway configurations are required. While software like _CS-51_ offers convenience for bulk programming, the ability to manually input frequencies and D-Star parameters ensures operational flexibility. This approach also helps hams troubleshoot connectivity issues by verifying individual settings directly on the transceiver, ensuring proper D-Star registration and gateway access.

A transceiver front-end protector in high signal level environments. An homemade RF limiter to protect your receiver front-end from high radio frequency.

A complete guide to undestand and know how electret condensor microphone elements works by K3DAV

Layman level explanations of "seemingly" mysterious LF MF and HF propagation occurrences.

This manual is an edited version of the GAP supplied document, complete with diagrams, pictures and assembling notes by Mitch Baum AE2A. This is 29 pages document in PDF Format.

This sweeper built for a narrow bandwidth filter adjustment, use a simple 555 version sawtooth wave generator.

Receive and listen to FM and AM radio broadcasts on your browser or ChromeBook using an RTL2832U-based USB digital TV tuner.

QRQ or Copying CW over 70 wpm

Effectively teaching amateur radio licensing classes requires more than just technical knowledge; it demands strong pedagogical skills and organizational acumen. This guide addresses the practical aspects of conducting successful amateur radio courses, emphasizing the instructor's role as an educational manager rather than merely a knowledge dispenser. It explores various class organizational structures, including traditional weekly sessions and _hybrid_ full-day formats, noting that many small meetings are often preferable for student engagement. The resource also provides strategies for finding suitable class locations, from public libraries and community centers to navigating public and private school systems, highlighting the importance of stressing the public service aspect of amateur radio to potential hosts. Key sections delve into effective classroom management, stressing the importance of preparation, a structured routine, and creating a comfortable learning environment. It details the VARK learning styles (Visual, Aural, Read/write, Kinesthetic), advocating for teaching methods that engage multiple senses to enhance student comprehension. The guide also offers advice on breaking down complex technical material, defining unfamiliar vocabulary, and making theoretical concepts practical through real-world examples. It includes a sample entry-level license syllabus covering topics like the nature of amateur radio, technical basics, transmitter/receiver fundamentals, and antennas, providing a framework for instructors to build their curriculum.

Homebrewing a Gamma Match to tune yagi antennas

Experimenting vertical wire antennas for 40 and 20 meters supported by balloons resulting in excellent gain in RX and good overall performance against horizontal dipole

Yaesu FT817 all band, all mode handheld transceiver article.

This is a presentation used at OVARC on the LindenBlad antenna construction. The presentation cover several topics about this antenna, from the basic antenna design, to the guide on how to contruct a custom lindenblad antenna for the 2 meters band and and 70 centimenters band.

An home made low pass filter for 70 MHz by IK0VAQ

An Energy Analysis at an Impedance Discontinuity in an RF Transmission Line

An homebrew audio mixer for the ham shack by GW6ITJ

Want to operate on 40 meters but only have a space a little over 16X16 ? Try this antenna.