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About basics of the horn antenna used for many rf microwave antenna applications.

PDF File of the IC R7100 communication receiver service manual

The M0KGK keyer with variable speed and weight controls utilising a low cost PIC microcontroller.

Running D-Rats on a Raspberry Pi documentation and instruction by n0so

W5ALT Antenna notes for a dummy dedicated to restricted space antennas

The function of the XPhase is based on the fact that the interfering signal, received by an auxiliary antenna, is added phase-shifted to the signal received from the main antenna. When the phase-shift is more or less 180°, the interfering signal is canceled out.

Experiments on vertical antennas among the trees by ik2egl

There are several reasons that can cause coax line radiation, most of them are related to wrong or missing use of a balun, but none can be imputed to load mismatch.

Key facts about how to solder, how to solder wire, how to solder pcb's, and including general soldering techniques and the best ways of making good solder joints for electronic circuits and construction. Includes video

Demonstrates a specialized **DX cluster** designed to support the annual Jamboree On The Air (JOTA) event, facilitating real-time spotting for participating Scout stations. While its web interface has been discontinued due to security concerns, the cluster remains fully operational and accessible through standard cluster software. Operators can connect to the JOTA cluster by pointing their client to www.pi4raz.nl on port 7300. This setup allows for the exchange of **DX spots** and other operational information relevant to JOTA participants, ensuring that Scouts and their amateur radio mentors can continue to make contacts and log stations during the event.

An home made transmitter for 40m CW

G4URH - Coax cable types, specifications and data

Amateur Radio Station M3PHP, Peter Goodhall.

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.

A test and comparison of real attenuation of N-type connectors and PL-259 connectors on UHF bands, domonstrating that connectors are almost equivalent.

Online Log 9U4U

A simple free running oscillator oscillating at the receiver\'s IF (intermediate frequency) beats with the incoming signals in either CW or SSB and the resultant audio frequency goes to the AF amplifier.

Forum thread about the Yaesu VX-170 at trainorders.com

This article describe the principles of baluns when referred to devices used to balance unbalanced systems, like a coax cable and a dipole antenna

Online calculator, to convert dbWatts to Watts and vice-versa, or ERP and EIRP by G4URH

How to measure the characteristic impedance of a unknown transmission line using MiniVNA

Adapting a Wouxun/Kenwood USB cable as a Yaesu FT-817 FT-857 FT-897 CAT connection

Desgining crystal filters and find out crystal data by measuring it.

The Four Metres website offer a global overview graph of the four meter band plans world wide

A RF Probe circuit for the RADIO frequency experimenter to check the presence of a RF signal and also to measure its strength

Essentials or basics of RF signal generators or microwave signal generators, their facilities, capabilities and how they work.

Refurbishing my 10 years old Cushcraft A3S triband HF Antenna

A nice tutorial and the basics of the software defined radio, SDR, and links of software defined radios to JTRS, and general SDR receiver technology.

An overview of coax cable often called coaxial feeder or RF cable, used to feed antennas and deliver radio frequency power from one point to another

A project of a linear regulated for low noise power supply 16v, 10A

CASPERARC amateur radio club in Casper Wyoming

The complete Bozo's guide to JT65A by K3UK, learn how to install and operate WSJT software and start making QSO in weak signals operating modes

Convert any text in morse code mp3 file, you can choose speed from 5 to 50 wpm and tone frequency

Analyzing digital mode contacts, particularly those made with _WSJT-X_, often requires tools beyond the native logging capabilities to identify duplicates or perform deeper statistical analysis. This utility addresses that need by providing an external application that processes the _WSJT-X_ log file, typically _wsjtx_log.adi_, to extract and present contact data in a more flexible format. It demonstrates how to parse ADIF data from a popular digital mode program, offering insights into contact patterns and potential logging errors. The software facilitates the identification of duplicate QSOs, a critical function for contesters and DXers aiming for unique contacts. It also enables further analysis of the log data, which can be useful for tracking band slots, modes, and specific callsigns over time. The application provides a practical example of how external tools can augment the functionality of primary logging software, allowing for custom data manipulation and reporting that might not be available within the original program.

Mods.dk collection of Ameritron ALS-600 power amplifier

Complete instructions on tuning the Butternut HF2V on four bands, 80, 40 , 30 and 15 meters

This unit uses four capacitors, only two of which are variables, and a single tapped coil. It is built in a die-cast box, and has been tested up to 80W input power on 70MHz by G4CJZ

A forum post at WZ5Q with modifications of Kenwood TS-2000 audio fratures

Rotors and rotor controllers for amateur radio polish manufacturer.

The dbm online calculator and reference table for 50 Ohm

This is a description of how KO4BB built his tower. It is provided in the hope that it will be useful to anyone want to setup his own ham radio tower.

Horn Antennas theory and principles

Wouxun KG-UV8D Standard Programming Software. Used to adjust or expand the frequency range to the full authorized range of the radio and not beyond. 134-174MHz 400-519MHz This software will Not add the 2.5kHz step.

This tutorial will get you on the road to running your own live scanner feed on the Internet, be it railroad, fire/ems or law enforcement related.

The MMMonVHF database, curated by DL8EBW, currently lists 63,455 entries for VHF operators, providing a searchable resource for locating stations active on 144 MHz and higher bands. Operators can register their callsigns to be included, with specific criteria such as participation in _MS_ (Meteor Scatter), _WSJT_ modes, or _EME_ (Earth-Moon-Earth) operations required for inclusion in the `call3.txt` file. This resource facilitates VHF DX expeditions and contest planning by allowing users to identify potential contacts within a geographical area. The database supports various VHF/UHF operating modes, including those focused on weak signal propagation. Statistical data regarding the database entries is also presented, offering insights into the distribution of registered VHF activity.

Windows program to divide one big ADIF file to many shorter ADIF files, based on qso numers, in example to send it to LoTW.

1.5 dB of matched line loss can be calculated for a given transmission line using this online tool, which employs a model calibrated from empirical data. The calculator allows radio amateurs to input specific transmission line types, such as _RG-8_ or _RG-58_, and then determine the expected signal attenuation. This is crucial for optimizing antenna system efficiency and understanding power delivery to the radiating element, especially for HF and VHF operations where feedline losses can significantly impact performance. Beyond matched loss, the calculator also provides an estimate for mismatched loss if the Standing Wave Ratio (SWR) is specified. This feature helps operators quantify the additional power loss due to impedance discontinuities between the transceiver, feedline, and antenna, which is a common concern in amateur radio installations. Accurate loss calculations are vital for effective station design and for predicting actual radiated power. The tool's utility extends to various operating scenarios, from fixed station setups to portable deployments, aiding in the selection of appropriate feedline lengths and types to minimize signal degradation. Understanding these losses is a fundamental aspect of maximizing the effectiveness of any amateur radio antenna system.

Article by SWR by A. Nony Mous

Modification and verification of the FT847 to optimize 70 MHz performance by G4FUF

Indexes over 100 digitized amateur radio callbooks, primarily from the early to mid-20th century, providing a historical record of callsign assignments and licensee data. The collection facilitates research into past amateur radio operations, tracing callsign lineage, and identifying operators from specific eras. Each entry typically includes the callsign, licensee name, and geographic location as published in the original printed volumes. Users can browse the collection by publication date or utilize the search function to locate specific callsigns or names within the archived documents. The resource serves as a valuable repository for historical amateur radio data, supporting genealogical and operational research. Access to these scanned documents is provided directly through the Internet Archive platform, ensuring long-term preservation and availability of these historical amateur radio records.