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Using Chokes and Traps: how to make them, how they work.

An interesting article on pedestrian portable HF DXing

Android Echolink client to connect to the echo link network

An operating guide for the com IC-2720H VHF/UHF Radio, includes Turning the power On or Off, Selecting the Output Power, Activating Memory Mode, Operating in Memory Mode

The "Shortish Guide to Using an Oscilloscope" elucidates the fundamental operation of oscilloscopes, detailing the purpose and function of vertical, horizontal, and triggering controls. It explains how vertical gain in Volts/cm and horizontal scale in sec/cm enable measurement of signal amplitude and timing, respectively. The resource differentiates between analog and digital scopes, noting that digital scopes often feature "soft" controls and are inherently storage scopes capable of capturing non-repetitive events. The guide dedicates a significant section to the critical role of oscilloscope probes, emphasizing their design to transmit waveforms without distortion or added noise. It explains the concept of a 10x passive scope probe, which reduces circuit loading by a factor of ten and eliminates waveform distortion through probe compensation, typically adjusted using a 1kHz square wave reference output. The document also provides practical advice on probe care and compensation procedures. Further sections address grounding considerations, explaining how a scope measures voltage relative to its chassis ground, which is tied to the protective earth. It offers troubleshooting steps for a blank screen and outlines essential good practices, such as checking input gain and probe attenuation, while explicitly warning against misusing probes or connecting the ground clip to mains voltage.

This EXCEL Program Worksheet calculates the common-mode impedance of a 1:1 Guanella (current) balun which is placed at the feed point of a balanced antenna system fed via coax.

If you like building good antennas, this one is for you. The J-pole is a slim, omnidirectional, half-wave antenna fed at the end through a quarter-wave shorted transmission line. Its predecessor is the famous Zepp antenna developed for the Zeppelin airship.

GW6ITJ articles on morse code, learning techniques, clubs and organizations and a custom learning software.

Dubus article about DL6WU long yagi antennas for 23 cm band Article is both in german and english. Yagi antennas are valid alternative to dishes for troposcatter operations. This article explains design and mechanical data for 1296 MHz Yagi Antennas

Amateur radio map of Italy with WW locators, provinces abbreviations and Call sign Prefixes, in a A3 size PDF file free to download, made available by IU3KJL Davide

A low cost, low power microwave transverter so that you can operate easily on 70cm band even with a HF or VHF transceiver

Roach pole vertical antenna for 40 and 30 meters band featuring good performance on short skips contacts compared to wire dipole

This article is about a home made project of a whip antenna for 2 meters band. Includes lenght of whip for all frequencies from 140 MHz to 151 MHz both in mm and inches

Adapted from a similar project by NA4IT. Made with one quarter wave 2 meter radiating element pointing upward and it is surrounded by four 70 cm elements.

This antenna is a vertical loop antenna mounted on a 8 meters high grounded mast with an input impedance of 50 Ohms without a matching device

In this article, author examine stresses placed on common-mode chokes (aka baluns) as hams use/abuse them, examine the efficiency of simple dipole multi- band antennas and their feed systems. Stressing a Balun.

Read more about the purpose, policies, and procedures of The National Traffic System in this 48 pages PDF File

Display your current Maidenhead locator with 10 digit precision. It also computes bearing and distance to a set of target locations using locator or latitude / longitude. Useful to align antennas in VHF / UHF / microwave DX activities. No network or fancy maps usage, so it can be used even in remote locations.

An inverted V Dipole antenna for HF bands, working on 10 20 40 and 80 meters band. PDF Presentation

A PDF Presetation from the W0DXCC Forum on how to improve the performances of the popular Yaesu FT-2000 transceiver

The ICOM IC-7610 SDR HF/50MHz Transceiver Basic Manual in English PDF File 13 MB

A Quick start guide to NPR New Packet Radio on 70 cm band by the NPR author Guillaume F4HDK. This presentation introducte basic concepts of this niew digital protocol, and guide the user to the first modem configuration both of client and master modems. Includes a final recap of commands.

The N1HFX thermal cooling fan controller project details a practical circuit designed to manage cooling fan operation based on temperature, a common requirement for high-power amateur radio equipment. This build utilizes a **LM34** temperature sensor, providing a linear voltage output directly proportional to Fahrenheit degrees, simplifying the control logic. The circuit's core functionality involves a comparator that activates the fan when a preset temperature threshold is exceeded, ensuring efficient cooling and reducing unnecessary fan noise. This controller is particularly useful for amplifiers, power supplies, or transceivers that generate significant heat during operation. The design incorporates a _TIP120 Darlington transistor_ to drive the fan, capable of handling up to 5 amps, making it suitable for a range of fan sizes and current requirements. Field results indicate stable temperature regulation, preventing thermal runaway in enclosed environments. Construction involves readily available components, making it an accessible project for hams looking to optimize their station's thermal management.

A classic document originally presented in Proceedings of the Institute of Radio Engineers in 1937 and is, still today, the standard referenced by the FCC, text books and many amateur radio publications.

Utility-Driven Tradeoff Analysis, if you want to geto on the microwave bands , you will have to choose the proper antenna for your operating conditions. How to decide is not always easy, and you may also decide to build your own antenna.

Supporting wire antennas with squid poles

An interesting guide to aerials comparing height, gain and angles

A light and sturdy Quad for 10 and 15 meters. Basic Quad antenna design considerations. Building and assembling a dual band HF QUAD antenna, designing and joining cross-arms and boom, assembling spreader and element wire installation notes. QST article.

Midwest Mountain Thunder CB Radio Group is a group of CB SSB operators that started in the Midwest as a branch off of the Washington State group. good clean radio

The Kenwood MC60A with preamp, suffers from RF feedback, a search on the web reveals the extent of the problem. This document explain how to fix this problem.

Switching Regulator Basics By Mike Martell N1HFX

Building an amateur station for competitive radiosport involves a number of critical steps, regardless of the band or bands you focus on. These include, but are certainly not limited to: Station layout, Equipment interconnection and switching, Inter-station interference, Antenna selection. Radio interface with the logging program, CW and voice keyer integration, Rotator control

Acom 1010 operating manual in english PDF File

A very well done presentation about End-Fed Half-Wave antennas. This PDF document contains a summary of experiences in how to build custom EFHW antennas. Includes an interesting comparison table of UnUn configurations with recommended toroids, Wire size, turns and capacitors. An useful recap on common errors in building homebrew EFHW Ununs completes the document.

A two element beam antenna for ten meters band. This home-brew two-element beam is the perfect introduction to rolling your own gain antenna

This tutorial provides background information on the decibel and instructions for performing calculations involving decibels. This tutorial combines information from several authors, including Bob DeVarney, W1ICW; Walter Bahnzaf, WB1ANE; and Ward Silver, NOAX

This article will explain a few of the ways author use an external SDR and Linrad to enhance his K3 experience. Linrad is one of many available SDR receiver programs. The same could be done with any radio that lets you access its IF frequency output. Article from NCJ Nov Dec 2019

The Homebase-10 is a wire halo antenna for 10m built with DIY store parts, effective despite its small size. Includes a dual-band version for 10m and 6m with gain around 0 to -2dBd, near omnidirectional pattern, and horizontal polarization. Overview based on a 2008 Practical Wireless article.

Article appeared on 73 amateur radio today in 1999 on how to unlock the secrets of sending precise Morse Code. Article contains hints on how use the stright key and the sideswiper key, but even the electronic keyers or the semiautomatic keys.

A QRSS beacon on 30 meter band project wind and solar powered based on a loop antenna.

Can Home Solar Power and Ham Radio Coexist? It is possible, with minimal interference from the solar power system, provided you make some modifications.

Operating pedestrian mobile by G3XBM

A complete guide to start operating EME. In this document, that is the result of several years of experimenting, the author summarize the steps to begin on Earth-Moon-Earth communications

Living in a no antenna deed restricted community sounds bad for a HAM, but it means you just need to be more creative. I have found this will not stop your DXCC activities and many of my local HAM club members will agree

The IC703 features a built-in DSP filter and auto ATU as well as speech processing an a CW keyer with 3 message memories. It is an ideal all-in-one ham station for QRPers.

The **LDG Z100 Autotuner** review by GW6ITJ details the unit's practical application and performance in a ham shack environment. Initially acquired to replace an MFJ-902, the Z100 is noted for its ease of use, though the author observes it doesn't quite match the impedance range of the older MFJ unit. This hands-on assessment provides a real-world perspective on its capabilities for 100-watt operation across the HF bands. GW6ITJ specifically mentions the Z100's suitability for 3.5 MHz and higher frequencies, indicating its utility for common HF operations. The review focuses on user experience rather than technical specifications, directing readers to the LDG website for detailed data and manuals. This approach highlights the tuner's operational characteristics from a user's perspective. The author's experience with the Z100 suggests it's a reliable choice for general amateur radio use, particularly for those seeking a straightforward autotuner. The comparison to the MFJ-902 offers a valuable benchmark for hams considering a similar upgrade or new acquisition, emphasizing practical differences in impedance matching.

No exotic claims are made for this antenna. Author just tried a few WSPR experiments on 40 meters and was surprised with the results. What appears below may inspire you to try something equally off-the-wall, to see what happens.

A club dedicated to Hellschreiber, or Hell, a unique, HF digital mode for sending and receiving text using facsimile technology

A folded dipole is an antenna, with two conductors connected on both sides, and folded to form a cylindrical closed shape, to which feed is given at the center.

Utah D-Star Users Discussion Group