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Joe Carr's Radio Tech-Notes Installing Coaxial Connectors

All about stacking and matching yagi antennas.

KB22UT Article on how protecting ham radio station and in particular I/O Lines such as AC power, coax cable, control circuits, telephone line.

Restoration of Viking Valiant, Hammarlund SP-600 and Heathkit HX-10 Marauder by KG9OM and KJ4W

Interface APRS to a weather station

Mark Connelly, WA1ION article on Medium Frequency Amplifier Circuits in PDF format, include some RF amplifier schematics

PDF File of the IC R7100 communication receiver service manual

Technical Correspondence, QST, July 1990 - Why even "perfect" phased array element currents don't produce perfect patterns.

Balanced feed with coaxial line by John F. Clemens W9ERN

IC-7600 User Evaluation and Test Report by VA7OJ

This is about Small Antenna types and their properties which can help choosing proper antenna for high-frequency wireless communications as: two-way radio, microwave short links, repeaters, radio beacons or wireless telemetry

Who needs a GaAsFET? Tuning, constructions and Packaging by Paul Wade

A few thoughts on Multi Band VHF Aerials by Peter Ward VK3ZAV

Clean Up Your Signals with Band-Pass Filters

The 60-page PDF document, "Antenna Systems and Theory For The Non-Technical Ham" by Jim Abercrombie, N4JA, provides a foundational understanding of antenna systems. It explains basic antenna theory, including how antennas work, electromagnetic wave polarization, and the role of frequency. The resource details various antenna types such as flat top dipoles, inverted-V dipoles, shortened loaded dipoles, G5RV dipoles, Carolina Windoms, and end-fed configurations. Vertical antennas, including ground-mounted trapped verticals and inverted-L verticals, are also covered. Directional beam antennas like monoband Yagis, cubical quads, and log-periodic arrays are discussed. Propagation modes, including ground-wave, direct wave, and skywave propagation, are explained in detail, with specific attention to the D, E, and F layers of the ionosphere and their effects on HF communication. Technical concepts such as standing wave ratio, decibels, resistance, and reactance are defined, along with calculations for half-wave resonant dipole lengths. The document addresses feed-line radiation, balun applications, and critical antenna and tower safety considerations. It aims to dispel common antenna myths and educate hams on making informed antenna choices.

Download the official IC-705 RF direct sampling VHF, UHF, HF, D-Star all mode 10W QRP portable transceiver. Pre-release information in a PDF file all in English.

Around 200 electronic circuits in pdf format or images, There are also over 1000 links to useful electronics, freeware, open source websites. There are some 100 useful documents, software and pcbs too. Mainly industrial electronics, instrumentation. Covers Various aspects of electronics and basics of circuit design.

Wouxun KG-UVD1P Tips And Hints For Eyes-Free Operation

KN-Q10 Assembly Manual four band (3.5, 7, 14 & 21MHz) 5W SSB/CW transceiver kit Translated by BD6CR/4,

Cheap and light portable 2m Yagi

Developing a protection plan against lightning

A DIY Automatic Band Decoder (ABD) project, designed for dual-radio operation, addresses the common challenge of integrating band data with older transceivers lacking dedicated outputs. This particular build utilizes an AVR AT90S8515 microcontroller and a 16x2 Liquid Crystal Display (LCD) to provide band information, specifically targeting Kenwood rigs via a computer's LPT port. The design aims for cost-effectiveness while maintaining functionality, offering a solution for hams seeking to add automatic band switching capabilities to their station without significant expense. The project outlines the core components required, including the microcontroller, LCD, and an enclosure, noting that the Printed Circuit Board (PCB) fabrication and AVR programming might present challenges for some builders. It details the input requirements, such as a four-pin input and PTT for each radio, along with a 13.8V DC power supply. The decoder provides 2x6 outputs capable of sinking 500mA, suitable for controlling external devices like antenna switches or filters. Despite the original unit being damaged by a lightning strike in 2004, the author confirms its successful operation prior to the incident and mentions plans for a revised version. The resource includes a schematic in PDF format and images of the finished PCB and assembled unit, demonstrating the practical implementation of the design.

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

A well documented PDF document containing picture sequence taked during the repair of an Icom IC-7700 HF transceiver power amplifier module

An article on RFD antennas, resonant feed-line antennas

A 109 pages presentation in PDF File by Jim Brown K9YC on techniques in operatint the top band from a small lot.

A simple charger designed for charging 12 V sealed lead acid batteries, used by radio amateurs for portable operation Amp-Hr Class used by radio amateurs for portable/emergency operation.

Solar Power for Your Ham Station, It is Easier Than You Think QST article April 96 by KE0OG via Repeater-Builider.com

Cushcraft MA5B 20 / 17 / 15 / 12 / 10 Meter Beam Antenna assembly and installation manual

Wondering whether to spend a fine day with the YL or with the antenna? This article may help you decide by W1GV

PDF file of the Yaesu FT-991 manual

A free PDF from NASA about cubesat. Basic Concepts and Processes for First-Time CubeSat Developers. A great introduction document dedicated to Cubseat developers.

How it's misused and misunderstood, and why it's not useful.

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

High Speed Multimedia Radio Introduction by ARRL Working Group Chairman. Report of the High Speed Multimedia (HSMM) Working Group ARRL Board of Directors 2006 Annual Meeting January 22, 2004

These charts show the New Zealand bandplan

October 2003 QST article on working digital mondes with sound card interfaces

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

A look behind the scenes, learn how the ARRL laboratory evaluates new products, and what all those numbers mean to you by WA1SVF

Presentation about finding, restoring, updating and operating vintage Ham Radio by K4QKY and Bill Call, KJ4W

A dual band portable inverted V antenna for 80 and 40 meters band with dimensions for other bands and several assembling instruction

Solar Flux, Geomagnetic Activity indexes and interpreting their relation

JT44: New Digital Mode for Weak Signals

KK5DR review of the IC-7700 HF ICOM Transceiver

A presentatio about the European HamNet, a large scale high speed amateur radio multimedia network based on commercial wireless devices using mainly the 6cm band

Presents a concise guide for Amateur Radio operators participating in Jamboree-on-the-Air (JOTA), an annual event connecting approximately 500,000 Scouts and Guides worldwide via ham radio. The resource details how to initiate a voice contact, including the use of "CQ Jamboree JOTA" and proper signal reporting with the RST system. It also outlines the typical exchange information, such as name, QTH, Scout rank, and age, encouraging participants to practice their responses. Authored by Bill Wetherill, N2WG, the brochure provides a practical phonetics chart and a comprehensive Morse code dictionary, including punctuation and prosigns like AR and SK. It clarifies rules for third-party operation under the direct supervision of a licensed operator, noting restrictions on international contacts without specific government agreements. Additionally, the guide lists recommended World Scout Frequencies for SSB and CW across 80, 40, 20, 17, 15, 12, and 10 meters, emphasizing courteous operating procedures. It includes a section on common Q-signals like QRM, QRN, and QSL, alongside the Amateur's Code, which stresses considerate, loyal, progressive, friendly, balanced, and patriotic conduct.

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

Exploring these mysterious transmissions and how their strong following has created a niche in the community. Free article in PDF Format from QST November 2019

This webpage allows you to create custom QSL cards (confirmation of radio contact) as PDFs for printing. You can personalize them with images and information. The cards are standard size (5.5" x 3.5") but can be adjusted slightly for easier printing on regular paper. You'll need Adobe Acrobat Reader to view the PDFs. There's also an option to create a free account to save your information for future cards.

137 kHz propagation analysis details ground wave and sky wave mechanisms, drawing heavily from **CCIR Rec. 368-6** for ground wave field strength predictions and **CCIR Rep. 265-7** for sky wave modeling. The resource presents field strength values for 1 W ERP at varying distances, considering ground conductivity and permittivity for ground wave, and ionospheric height (70km daytime, 90km nighttime) for sky wave. Key factors like ionospheric focusing (factor "D"), reflection coefficient ("RC"), and antenna ground pattern factors ("Ft", "Fr") are quantified for 137 kHz, enabling calculation of sky wave field strength. Practical coverage ranges are derived for 137 kHz, showing useful ground wave coverage up to 1600 km over seawater and 1100 km over average ground, assuming a -9 dBuV/m noise floor. Sky wave coverage extends beyond 2200 km during night-time and winter daytime, but is negligible during summer daytime at solar minimum. The document also compares ground wave and sky wave strengths, identifying crossover distances at 550 km (night-time), 750 km (winter daytime), and 1250 km (summer daytime), where interference fading can occur. Adjustments for solar maximum conditions are provided, indicating 2-11 dB higher sky wave values depending on distance and season.