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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.

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.

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

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

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

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

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

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

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

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

QRQ or Copying CW over 70 wpm

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

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

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

Homebrewing a Gamma Match to tune yagi antennas

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.

Yaesu FT817 all band, all mode handheld transceiver article.

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.

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

An home made low pass filter for 70 MHz by IK0VAQ

An homebrew audio mixer for the ham shack by GW6ITJ

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

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

An 80m transceiver using just 14 parts plus crystal and earpiece

A simplified Guide to the FT8. Dxpedition mode. By Stefano IK2HKT – Rel. 2.0.0 - January 2019. This document explains how to configure WSJT to work on F/H mode DXPedtions, how to operate and make a call to a dxpedition calling CQ in FT8 Fox Mode.

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.

Digital voice on Amateur Radio - devoted to the discussion of digitized voice and data over analog emission modes.

An home made FETer QRP transceiver for the 80 meters band

Article from 73 Amateur Radio Today about experimenting on ferrite loops transmitting loop antennas for 80 and 160 meters bands.

The _ISS Detector_ Android application, with over 5 million downloads, offers precise predictions for visible passes of the International Space Station. It notifies users minutes before an overhead pass, integrating local weather conditions to ensure optimal viewing opportunities. The core functionality focuses on the ISS, but in-app purchases extend its capabilities to track other celestial and artificial objects. Optional extensions, available via in-app purchase, allow users to monitor dozens of amateur radio and weather satellites, providing real-time transmitter information and Doppler frequencies. Additional extensions cover _Starlink_ satellites, the _Hubble Space Telescope_, rocket stages, bright satellites, comets, and planets, expanding the scope beyond the ISS to a broader range of observable space phenomena. The app's interface is designed for ease of use, displaying pass times, directions, and elevation. It adapts predictions based on the user's GPS location, ensuring accurate local forecasts. The latest update, dated April 3, 2026, includes corrections for magnitude values and various speed and stability optimizations.

There are many designs for building preamps each with their own advantages and disvantages. In this PDF Article author reviews several different types.

Design and build a 6 meter 2-element Moxon antenna mostly from available aluminum tubing and angle stock.

Hone your Morse code skills with this entry-level project. Article includes the full schematic of the CW Trainer, describes the sketch and how to operate the morse code trainer.

This document is a must read for anyone considering building a good low cost HF multi-band antenna system. The author combine in this document four important ingredients to produce simple but effective antenna system, like antennas of non resonant length, line attenuation, the transmatch and the balun

About Coax Traps, NC4FB examine the operation of coax traps through modeling.

The author who works successfully via EME on this band wants to describe his own yagi design and give some of hints for the construction. by Heinrich F. Reckemeyer, DJ9YW

A 160W linear amplifier for 4 meters band based on GI0GDP

Cushcraft XM240 transformation into a Moxon antenna by W6NL

Have you ever thought of setting up a portable HF station for an activity ?

Introduction to WSPR beacons. Article describe WSPR2 and WSPR15 beaconing mode and include a frequency reference table for both WSPR modes

Adding 17 meter band to Mosley TA-33M yagi antenna

Marshall G. Emm, N1FN, meticulously examines iambic keying, dissecting its historical introduction in the late 1950s with transistorized electronic keyers and its purported advantages. The resource defines keying systems, electronic keyers, and various paddle types, including single-lever and dual-lever paddles, clarifying the distinction between iambic keyers and the iambic sending technique itself. It details the two main types of squeeze keying: true squeeze for alternating dot-dash strings and character insertion for specific elements within a character. N1FN critically evaluates the actual efficiency gains of iambic keying, referencing Chuck Adams, K7QO's, keystroke analysis. While a straight key to bug transition yields a 34.1% reduction and a bug to non-iambic keyer offers 16.1%, iambic keying provides only an 11% theoretical improvement. However, considering typical QSO text and Morse code's inherent optimization for common letters, the practical efficiency gain is estimated at a modest 4-6%. The article also highlights how iambic keying's reliance on precise timing gates can impose a speed limit, making it less effective above 40 WPM, where many operators revert to non-iambic methods or single-lever paddles.

This is a schematic drawing of a project for the construction of a portable mast that can easily be made with PVC pipes.

Getting started on RTTY contesting. A PDF by ED Muns, presented at CTU conterst university, about amateur radio RTTY Contesting

This is a QST Article published in January 1982 by W1FB D. Demaw and HH Beverage and is a complete review of the original article published in 1922, which updates and reivew the beverage antenna theory and developlment, explaining the antenna design of transformers and gives accurate reports on antenna general performance.

Technical supplement manual of the Yaesu FT-8800R in english

How can the current "flowing" out of the top of a mobile loading coil be greater than the current "flowing" into the bottom of the coil?

PDF manual of the TW4040 The Adventurer MonobanderTM TransWorld Antennas

APRS-Webserver, that presents aprs-data and maps for free using Google Maps api. The position data is imported from aprs.org, winlink.org and echolink.org. The map data are partially commercial and free. This server is for amateur radio purposes only.

Manual of the BD-35 Dual Band VHF UHF RF power amplifier by Mirage Amp