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Schematic diagram of a two tone audio oscillator by VK3YE

Custom EMI Filters, AC DC Three phase filters by Filter Concepts Inc.

This page introduces the world IARU Grid Locator system, and discusses how to find out what your own Grid Locator is.

Product specialist for semiconductors and electron tubes based in Belgium

Sponsored by the Scandinavian Amateur Radio Teleprinter Group

Project Ham: Cushcraft MA5B installation by Gary VE7AS

Sell quality electronic components, equipment, and accessories. Test equipment, RF Modules, Power supplies, PCB, Stepper motors.

Operates as a universal client for Software Defined Radios, SDRoxide provides a robust platform for amateur radio operators to engage in diverse modes and activities. It integrates a **GPU panadapter** for real-time spectrum visualization, dual VFOs for flexible tuning, and advanced neural noise reduction to enhance weak-signal reception. The software supports a comprehensive suite of digital modes, including FT8, JS8, RTTY, and PSK, alongside built-in skimmers for automated signal detection. Its capabilities extend to Winlink radio email, 868 MHz ISM sensor decoding, and hands-free satellite operation with continuous Doppler correction and Hamlib rotator tracking. The client offers native drivers for popular SDR hardware like RTL-SDR, RX-888, and HackRF One, covering a wide frequency range from 1 MHz to 6 GHz. It also interfaces with CAT-controlled transceivers via Hamlib and Flrig, allowing a second SDR to function as a panadapter. Network dongles, SpyServer, KiwiSDR, and OpenHPSDR Ethernet SDRs are also supported, providing flexibility for remote and local operations. Beyond core radio functions, SDRoxide incorporates a live 3D space-weather globe with aurora and lightning displays, real-time satellite tracking with TLE updates, and a measured propagation heat map. It includes a full-featured logbook with DX cluster spots, award tracking for **DXCC** and WAS, and direct QSL upload integration with services like eQSL and Club Log, streamlining post-QSO management.

Amateur Radio - US Navy - New York City Home of the Virtual Collins Radio Museum

Icom 706MkIIG Filters, Make a narrow CW filter work in SSB for the digital modes

Manufacturer of low cost RF signal generators and portable measuring instruments.

A blog from poland about VHF and Satellite operations, including D-Star. Many pictures and movies from this active vhf dxer

A multi-band off centre fed dipole, designed to operate on all bands from 40m (7MHz) to 6m (50MHz). Author claims it will operate on 40, 30, 20, 17, 15, 12 and 10m without an ATU (SWR <3:1) plus 6m with an ATU.

Using an oscilloscope to tune a Tesla coil for resonance includes video and instructions

_AT Auto_ is an automatic antenna tuner designed for amateur radio enthusiasts seeking efficient and reliable tuning solutions. This device automates the tuning process, allowing operators to focus on communication rather than manual adjustments. The tuner is compatible with a range of transceivers, enhancing its versatility in different shack setups. Its design incorporates advanced circuitry to ensure optimal performance across various bands. The _AT Auto_ tuner is particularly useful for those operating in HF bands, providing seamless transitions between frequencies. Its integration capabilities with other shack automation products make it a valuable component for modern amateur radio stations. The tuner supports multiple modes, including _SSB_ and _CW_, catering to diverse operating preferences. Its robust construction and user-friendly interface contribute to its appeal among both seasoned operators and those new to the hobby. Kessler Engineering's focus on innovation and quality is evident in the _AT Auto_'s design. The tuner is part of a broader product line that includes shack automation solutions, reflecting the company's commitment to enhancing amateur radio operations. Despite the website redesign, the tuner remains a key offering in their product portfolio.

Coaxial cable stripping for PL-259 connectors requires precise measurements to ensure optimal RF performance and mechanical integrity. For RG-8X, the outer jacket is stripped 1/2 inch, the braid 5/16 inch, and the dielectric 1/8 inch, leaving the center conductor exposed. RG-58 preparation involves a 1/2 inch jacket strip, 1/4 inch braid strip, and 1/8 inch dielectric strip. These specific dimensions facilitate proper soldering and crimping, minimizing impedance discontinuities at the connector interface. Different coaxial cable types, such as RG-8 and RG-213, necessitate varied stripping lengths due to their construction. The _PL-259_ connector, a common UHF type, relies on these exact preparations for a secure fit and low-loss connection. Incorrect stripping can lead to high SWR, RF leakage, and mechanical failure, impacting overall station efficiency. The guide details these critical dimensions for several popular coax cables. Using a dedicated _coax stripper_ tool or precise measurements with a utility knife improves consistency.

N-channel scalable coherent receiver that employs the RTL-SDR technology in order to create inexpensive multi-channel receiving systems.

For a discriminator output in an Icom IC-R7100, some mechanical work is required.

Sanyo Eneloop rechargeable AA batteries. For QRP purposes, these batteries are great as a 10-cell pack

SVARA - Saginaw Valley Amateur Radio Association

This is the blog for the M0BGR Amateur Radio Station. I am based in London, England but frequently go out mobile or portable.

Fanpage of SN7H Contest Team

VK3RGU 438.375 MHz Gippsland Repeater in Australia

Learn to recognize Morse code at 25 WPM and not memorize DITs and DAHs at 5 WPM. This app will train you to hear and send Morse code at 25 WPM using an approach very similar to the Koch method.

3905 Century Club offer nets on 20, 40, 75, 80, and 160 meters operating with a mixture of SSB, CW, RTTY and PSK-31 modes

Bucktown Visas and Passports, Inc. processes all of your international documents in as little as 24-48 hours from Chicago, Illinois.

Grid Calculator allows you to calculate either a grid square locator or the latitude and longitude of a location. Grid Calculator can be used to calculate a Great Circle bearing and distance between two stations in statute miles, nautical miles, and kilometers.

MikroTik is a Latvian company which founded in 1995 to develop routers and wireless ISP systems. Wifi Routers, router boards, switches, interfaces and enclosures.

The Pro 95 is a dual trunking handheld scanner designed by GRE and sold by Radio Shack

Encode/decode On-Off audio pulses for remote control of projects

A 0-30 MHz step attenuator, constructed from switchable Pi attenuation pads, provides a practical tool for evaluating receiver sensitivity and calibrating S-meters. The design utilizes readily available 5% tolerance resistors, with values derived from paralleled components to achieve specific attenuation steps. A schematic (Fig 1) illustrates the circuit, including PCB pad shielding, while a table details required and actual resistor values, along with percentage differences. Measurements of voltage input versus output at various frequencies are used to calculate dB attenuation, presented in a graph (Fig 4). The resource includes formulas for determining output voltage from a known input and a comprehensive 0-40 dB voltage multiplier table, which is crucial for precise signal level management. The project also references external attenuator calculators and equations for further study. Photos (1-3) provide visual guidance for the assembled unit, showing bottom, top, and front views. The project emphasizes the use of **Pi attenuation pads** and **receiver sensitivity** evaluation, offering a hands-on approach to RF signal management.

Use these Variac auto transformers for specific application requirements that include, but are not limited to, home coffee roasting, tube amps, and more.

The Fresno Amateur Radio Club was originally founded in the early days of Amateur Radio as the San Joaquin Valley Radio Club and affiliated with the ARRL on April 5, 1934.

Ham radio equipment pages including Collins, National, Hallicrafters, and Hammerlund radios.

Dedicated to the Indiana D-Star Amateur Radio Users

Presented is a historical collection of short-wave listening (SWL) QSL cards, primarily from the late 1930s and early 1940s, offering a glimpse into early international broadcasting and the technical pursuits of SWL operators like Les Miles during that era. The resource showcases specific QSLs from stations such as _Broadcasting Corporation of Japan_, _XGOY - The Central Broadcasting Administration_ in Chungking, China, and _Australian broadcasting ship, Kanimbla VK9MI_, each with reception dates and frequencies like 11.90MHz or 9.525MHz. It highlights the self-sufficiency of SWL enthusiasts who constructed and maintained their own radio and test equipment, evoking the sensory experience of vintage valve receivers. The collection provides concrete examples of international broadcast stations active before and during World War II, including _2RO3 - Rome_ and _WRUL - World Wide Broadcasting Foundation_ from Boston. Each QSL entry details the station, location, reception date, and often the frequency, such as 9.63MHz or 11.26MHz, allowing for historical verification of broadcast schedules. The resource also briefly mentions the operational details of the _VK9MI_ offshore radio station, directing readers to further information on its history. This compilation serves as a tangible record of global radio communication during a pivotal historical period.

Primary, Ion, and Polymer, a lithium battery primer, learn the differences between and varied uses for these diverse types of lithium batteries.

Cable dealer of custom and standard cables, tools and testers,

Sending the Audio from the Receiver to the Recorder, from the Recorder to the EQ, and sending the Audio from the EQ or Recorder to the Transmitter

Arduino-based Automatic Amateur Radio Antenna Tuner

Ham shack located in a caravan and run by solar power. This page describes VK5SW experience of converting an old, disused and rundown caravan, to a fully functional solar powered Ham Radio shack.

Amateur Radio related activities of HB9EGA

The premier flea market for radio, electronics, Computer & communications equipment in Indianapolis

Isle of Man Repeaters maintained by David Osborn GD4HOZ this site covers the VHF repeater GB3GD and UHF internet linked 70cm repeater GB3IM. Using Allstar software for linking GB3IM is the only site in the uk to have three transmitters. Supported by the Isle of Man Amateur Radio Society

A nice blog about DXing, Shortwave Radio Listening (SWL) and Amateur (Ham) Radio by VK3BVW

The HARAOA Group have orginized to go to Broughton Island(OC-212) from the 5th until the 7th February 2010.

Active Receiving Antennas, designed for reception of shortwave, mediumwave and longwave signals and VHF/UHF signals

Shortwave radio listening club in Brazil

Technical details of the Drake R-4C receiver

Hot Springs Village AR