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Fixing the IC-7000 noisy audio that can occur when IC-7000 audio output is connected to Hi-Fi earphones or external speaker.

Loop Antenna Basics and Regulatory Compliance for Short-Range Radio

Design for a dual-band CW transceiver using the AD9834 Direct Digital Synthesizer

HSMM Experiments on the 6M Amateur radio Band

A portable USB SO2R box made with Arduino

Here are 10 tips and truisms that every ham should know about antennas, by W20QI

As used on the new GB3VHF 144.43MHz Beacon

Quarter wave groundplane antenna for 2 meters FM by AA1PG

A new, simple way to build the Eggbeater Antenna. This document introduces a new, simpler way to build the Eggbeater antenna. It also introduces a technically proper way to construct the Eggbeater antenna in order to achieve the best result.

PDF document for IC-7300 beginners. The ICOM IC-7300 is an HF + 6 meter, multi-mode, self-contained Software Defined Radio (SDR) transceiver with knobs, buttons and a touch screen. It also has a real-time spectrum display with pan adapter and water fall displays.

Notes on using the QST propagation charts to determine propagation conditions

A amateur radio guide to RFI, ferrites, baluns, and audio interfacing by K9YC

Building a Resonant Feed line Dipole for 2 Meters

PDF File of the Kenwood TM-710A user manual

A 200 kHz bandwidth digital transmission system for image transfer in the Amateur Service is under development, specifically targeting VHF allocations. John B. Stephensen, KD6OZH, leads this project under an FCC Special Temporary Authority (STA) valid until September 10, 2006, authorizing emissions up to 200 kHz bandwidth in the 50.3-50.8 MHz segment. Current regulations typically limit bandwidths to 20 kHz on VHF amateur bands, making this STA crucial for testing wideband digital modes. The modem, a modified **OFDM** (Orthogonal Frequency Division Multiplexed) unit, was initially tested on the 70-cm band. It splits a high-rate data stream into multiple low-rate subcarriers to mitigate multipath echoes. The system uses a DCP-1 card with a Xilinx XC3S400 FPGA and Oki Semiconductor ML67Q5003 microcontroller. The transmitter, located at 36d 46m 30s N, 119d 46m 22s W, generates 150 WPEP into an 8 dBi gain vertical antenna, while the mobile receiver uses a Ham-stick. Three data formats for 50, 100, and 200 kHz channels are being tested, with encoded data rates of 96, 192, and 384 kbps. Verilog code for the VHF OFDM modem is 95% simulated, with modifications from the UHF version including increased filter coefficient precision and a change from Ungerboeck **TCM** to BICM for improved performance over fading paths. Final tests will involve one-way over-the-air measurements of bit error rates and coverage area.

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

This is a concept paper, not a constuction article. There are too many variables to propose a one size fits all design. However, this paper should give you the basic idea how to do it

New Zealand Amateur Radio 70, 32 & 23 cm (UHF) Repeaters

YAESU FT-1000MP Mark V ESSB Modifications pdf file

G3SEK answers to some practical questions on builing the N2PK VNA Vector Network Analyser

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

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

Joe Carr's Radio Tech-Notes Installing Coaxial Connectors

Kenwood TS 480 english manual in pdf format

Interface APRS to a weather station

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

All about stacking and matching yagi antennas.

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

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 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

IC-7600 User Evaluation and Test Report by VA7OJ

Clean Up Your Signals with Band-Pass Filters

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

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.

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.

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

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

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

Introduction to Raspberry Pi and possible usages in amateur radio, PDF presentation.

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.

Cheap and light portable 2m Yagi

An information paper by the International Amateur Radio Union, History of 40m allocation, propagation properties of 7 Mhz band

Developing a protection plan against lightning

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

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.

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

An article on RFD antennas, resonant feed-line antennas