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The TECLA Thirty, an early wireless age crystal set, is featured among a gallery of over 100 collectible headphones, with detailed close-up photos of vintage models. Several pages offer vintage headphones for sale, including Brandes, Baldwin, and Western Electric, suitable for crystal set use or collecting. Construction details are provided for a reproduction KILBOURNE AND CLARKE crystal set, built with vintage 1920s parts and featuring a miniature variable condenser for fine tuning. The resource also presents a project for a simple crystal radio and a 1-tube amplifier, complete with a schematic and component diagram, suitable for driving a horn speaker or amplifying weak signals for headphones. Instructions for mounting argentiferous galena detector crystals are included, along with information on MRL Handbooks covering crystal detectors and modern diodes. Additional projects include a 2A3 single-ended triode tube amplifier and two stereo tube amps using 12AX7, 6V6, 5Y3G, 6SN7, VT-25, and 5U4G tubes.

An interesting article on end fed half-wave wire antennas with a couple of original experiments. Author illustrate the role of the QRP matchbox, and a 40/20 meter antenna with a center stub making it a large bandwidth antenna for 40 and 20. Includes also an 80/40 end fed with the typical coil to make it available on 80 merts band.

N4L design and manufacture versatile, high-accuracy, easy to use instruments for power electronic test & measurement

CS5TRGM Tertulia Radioamadoristica Guglielmo Marconi

This resource provides a historical analysis of amateur radio call sign assignment policies in the United States, detailing regulatory shifts from the Department of Commerce to the Federal Radio Commission (FRC) and subsequently the Federal Communications Commission (FCC). It documents the evolution of call sign issuance, from early reissuance practices in the 1920s to the implementation of the Group Call Sign Assignment System on March 24, 1978. This system categorized call signs (e.g., 1x2, 2x1, 1x3, 2x3 formats) into groups A, B, C, and D, correlating with license classes such as Extra, Advanced, General, and Novice, and specifying prefixes for contiguous U.S. and territorial areas (e.g., _AH_, _KP_, _KL_). The document further details the legislative process leading to the modern Vanity Call Sign program, initiated by a petition in June 1990 and formalized by the Omnibus Budget Reconciliation Act of August 10, 1993. It outlines the FCC's adoption of final rules on December 23, 1994, and the subsequent fee structure, with the first vanity call sign issued on May 31, 1996, at a cost of **$30.00** for a ten-year term. The ARRL's proposed "starting gates" implementation strategy is also described, which phased in eligibility for vanity call signs based on license class and prior holder status. DXZone Focus: Historical Document | Regulatory Analysis | Call Sign Formats | Fee Structure

The QCX 5W CW Transceiver From QRP Labs, a detailed article describing from the unboxing of the component to the final assembly of the CW QRP Transceiver

Bird Technologies, The RF Experts - manufacturer of Analyzers, Attenuators, Terminations & Loads, Duplexer and Triplexers and RF Wattmeters

The radio beacon DI2AM on museum-ship in Rostock Schmarl

Drake Radio Service & Repair, Refurbishing Services

Launch of a hybrid rocket from high altitude by untsville Alabama L5 Society

High quality surge protector, lightning protection, surge protection, and power protection products

rpitx is a general radio frequency transmitter for Raspberry Pi which doesn't require any other hardware unless filter to avoid intererence. It can handle frequencies from 5 KHz up to 1500 MHz.

Sending and receiving text with Morse code light pulses across the room is a fun and cheap project you can do on a Raspberry Pi or Arduino or any other microcontroller. This post explains how I did it, and how you can do it too.

A blog by W1REI dedicated to ham radio hobby

Lawton Fort Sill Amateur Radio Club serving the Lawton and Fort Sill community.

233BG001 Stephane Homepage - News about 11M Band.

International Ham Radio DX Pedition San Adnres Isl - 12 Nov. - 25 Nov. 2017

Free Windows program intended to be used as a training aid for sending CW using an iambic Winkeyer from K1EL Systems. Iambic Master operates as a game. The objective of the game is to send the text in the Target box as accurately as possible.

New generation Hex Beam Antennas. VHQ HEX Products, located in Peterborough, NH, is owned and operated by David M. Lavoie. Our products are designed to solve issues encountered in Ham radio applications and move with todays configurations in an ever changing climate

VK9MT Mellish Reef 2014 DXpedition official web site. VK9MT 28 march - 9 April 2014

Spanish ham radio operator with links to spanish awards

On-line shop for coax cables, RF connectors, Lightning protectors, Create antenna rotators, antenna masts and mounts, amateur antennas by FlexaYagi, Tonna F9FT, ANjo-Antennen and M2 Antennas based in Eggolsheim Germany

Documents the _XT1T_ DXpedition to Burkina Faso, active from February to March 2013. This operation provided DXers worldwide with an opportunity to work a relatively rare entity, with the team focusing on maximizing contacts across various bands and modes. The expedition utilized an online log provided by _IDT_ (Italian DXpedition Team), enabling immediate verification of contacts and facilitating QSL requests. The _IDT_ system allowed participants to check their QSOs shortly after they were made, a crucial feature for contesters and award hunters aiming for DXCC credit. The expedition's success was measured by the total number of unique contacts and countries worked, contributing significantly to the global DX community's pursuit of new entities.

A small antenna for 50 MHz made with copper cable loading coils

A review of the Chinese version of uSDX USDR HF QRP Transceiver. Author made an extensive review of receiver and transmitter features.

Make them simple then Make them work. The LAZY H antenna is a general type of antenna that is in the curtain array family. By placing two 1 wavelength dipoles in a plane that is at right angles to the direction of maximum radiation and keeping the proper in-phase current condition to each element, you can achieve a high gain bi-directional antenna.

Sommer Antennas has been a manufacturer and producer of quality amateur radio antennas and antennas for professional use for more than 20 years.Developed by DJ2UT in Germany, our beams were first introduced to the U.S. market at the 1984 Dayton Hamvention

Efficient Low Band Counterpoise for Restricted Circumstances Loss Avoidance Opportunities and Techniques for the Low Bands The short and linear FCP was designed to reduce ground losses from inadequate radial systems beneath inverted L and other vertical antennas.

A multi tool Windows program that has been designed to offer the EMC RF and Radio Engineer a large variety of tools for Attenuation calculation, VSWR analysis, FIR Filter calculations, EMC system configuration, Radar testing , RF Filter calculation and much more without the need of a live internet connection.

A WSPR beacon project based on Arduino nano (atmega328P) based microcontroller

Yea Cabrillo2Adif is a free software for converting the radio logs from Cabrillo to Adif log format for MacOSX

Personal radio site, dedicated to ham radio DXing

A YL's experience in everything Ham Radio.

A home made end-fed half-wave antenna coupler with antenna lenght calculator and counterpoise calculator based on center frequency. Includes pictures and drawings along to antenna homebrewing instructions with a home made on air wound transformer

A multimeter with standard resistance sorting function

Calculate inductance online, with the cylindrical Coil Inductor Design Equations Formulas Calculator

Large picture and specifications of popular VHF UHF kenwood amateur radio transceiver

VHF-UHF receiver covers from 25 to 800 and 900 to 2000 MHz in the following modes: AM, AM-W, FM, FM-W, FM-N, USB and LSB

Provide communication service primarily to the public safety organizations

Northern Michigian Amateur Radio Club Inc. was founded on the principles of providing services to the local area Amateur Radio Service Groups and to public.This group of license amateur radio operator provide Emergency Communication during the time of weather related,disasters and man made emergencies.

All about RTTY, including audio samples, rtty software, video exaples and rtty related links

This page describes a comparison study on seven different beam antennas for 40 meters band. Yagi antennas, moxon antennas, mini horse all antennas are described with schema diagram , azimuth plot and SWR F/B Gain diagram

Balanced and Unbalanced Systems

Solomon Islands H44G/ Temotu Islands H40T - March 2013 by DL7DF

An article on how to measure electrical current with a digital multimeter or analogue multimeter.

This tutorial covers an introduction to RF, wireless, and high-frequency signals and systems, includes explaination of what is RF, why operate at Higher Frequencies, Frequency Shifting through Frequency Mixing.

W9TY, the Metro DX Club of South Suburban Chicago, Illinois, USA.

Download the latest firmware for the tyt md-380 VHF transceiver

Valon Technology designs and manufacturers low cost, reliable radio frequency products such as RF Synthesizer modules, RF Frequency Dividers and Phase Gain Detectors. Main markets are military/defense, test engineering, radio astronomy, research centers and universities