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Harris Platinum I Solid State Channel 2, and 3 TV Amplifier Modules for use, on 50 or 70 MHz

This caution applies to all Icom HF transceivers. Based on a discussion with Matt Erickson, KK5DR

Manufacturer of RF generators, attenuators, counters and LCR meters

The San Bernardino Microwave Society, operating under the callsign _W6IFE_, serves as a significant technical hub for amateur radio operators specializing in frequencies above 1 GHz. This organization's influence extends across Southern California, providing a centralized resource for advanced RF experimentation and **regional frequency management** within the microwave spectrum. Its permanent value lies in its extensive archive of technical papers and project documentation, which are critical for operators engaged in high-frequency design and deployment. The society's infrastructure is primarily intellectual, focusing on the dissemination of specialized knowledge rather than a conventional repeater network. It offers a robust collection of technical papers from prominent members like K6PIP, K6BLG, and WA6EXV, covering topics such as Rubidium oscillator data, logging software, and filter design. This resource facilitates advanced amateur radio operations, including participation in microwave contests and the development of custom transverters for bands like 24 GHz. The site also details various member projects, such as the Owens Valley Radio Observatory Project, showcasing practical applications of **RF propagation analysis** and system integration. DXZone Focus: Microwave | Technical Papers | RF Propagation | Contest Results

Vintage radio and scientific apparatus by john jenkins, include antique radios, Horn Loudspeakers, Vacuum Tubes, A.C. Receivers

A Web forum dedicated to HF underground and in particular to Shortwave Pirate Radio Forums and Spy Numbers listenings

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.

Amateur radio, commercial, two way handheld and mobile transceiver manufacturer produce VHF UHF analogn and digital DMR two-way radio

BU2AI and BU2AO Taipei City, Taiwan

Since 2011, crkits offer radio kits that you cannot find on eBay or AliExpress. Includes HT-1A 20/40m Dual Band CW Transceiver Kit, D4D DSB Transceiver Kit for Digital Mode, R3500D ARDF Receiver, CW Transceiver Kit

Designs and manufactures high quality, dependable power products.

Some recent videos of the new Mid Class RTX by ICOM, the IC-7610 HF+50MHz amateur radio transceiver.

Dec 5 – 13, 2010 J6BP by Caribbean Buddies Dxpeditions.

L32 LogSync application will allow you to sync your Logger32 logbook with various services and servers. Provide interface for Logger32 and LoTW EQSL ClubLog HRDLog QRZ.com

NYQsl.com - Full 2-sided color cards of excellent quality. Individual designs available. Fast turnaround based in NY USA

Ultra High Efficiency Alternative Energy System Controllers

Yahoo discussion list for Kenwood TS-850, TS-450 and TS-690 users

Middle Georgia USA contesting station. Consistent record holder in 160 meter and 40 meter contests.

Repeaters: 146.970 444.475 La Crosse, Wisconsin

Designed for portable operation, it runs on 12v, and has an OCXO-based local oscillator.

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

Shortwave radio listening club in Brazil

How to build a complete Single-Sideband amateur radio transceiver from scratch. Article published on hackaday dot com includes an introduction to radio architectures, ssb receivers and tramsitter

Posting notable DX contacts

Software Defined Radio, QIRX is 64-Bit software, based on TCP/IP raw data, running with any RTL-SDR dongle being driven by rtl-tcp.exe.

K3WWP QSLing page. QSLing information and resources.

Effects of ice an snow in a wire dipole antennas

Marquette, in the upper peninsula of Michigan (MI)

This article is about two excellent small helical antennas for the two meters band. With performance close to that of full sized antennas, these small helical antennas are low in profile but high in efficiency.

A document describing the reparing and restoration of an old Heathkit SB-101 power amplifier

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.

This is a blog about AJ4JD's radio activities.

Kingston, Ontario, Canada A RAC Affiliated Club

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.

ham radio forum

How to setup a band-tracking panoramic signal display to work along to your transceiver.

Documents the operational experiences and technical insights of amateur radio station VA3STL, offering a firsthand account of various on-air activities and equipment. The blog features a detailed narrative of a **QRP transatlantic QSO** on 12m SSB, achieving a 55 report with 10W to a mobile station in Italy using a homebrew 90ft doublet antenna. It also introduces the _Ten-Tec 539_ QRP HF transceiver, a 10W output rig covering 80m through 10m, designed for portable operations and featuring DSP and dual VFOs. The resource also delves into historical radio technology, specifically the "Gibson Girl" survival radio, an emergency transmitter operating on 500kHz (and later 8280/8364 kHz) with a hand-cranked generator and kite-deployed antenna. This section explores its origins from German designs and its use during World War II, including its distinctive curved shape for ergonomic hand-cranking. Further historical content includes a visit to Signal Hill in St. John's, Newfoundland, commemorating Marconi's reception of the first transatlantic radio signal in 1901. The post describes the Cabot Tower exhibit and the VO1AA station, highlighting the site's significance despite the thick fog during the visit. It also showcases a homebrewed _Marconi-style straight key_ by WB9LPU, crafted to celebrate the centenary of Marconi's achievement.

WT4Y Amateur Radio, stealth antennas, computerized logs, QSL card images

The current page presents a domain name for sale, rather than providing amateur radio content. It outlines the process for acquiring the _ae5x.com_ domain, including a direct purchase price of **$3,795** or a 24-month payment plan at $158.13 per month with 0% interest. The service emphasizes quick delivery, secure shopping via SSL encryption, and a 30-day money-back guarantee. Information regarding domain transfers to other registrars like GoDaddy is provided, noting that transfers can take up to 5 days and payment plan domains are ineligible until fully paid. The purchase includes only the domain name, with hosting and web design services needing to be sourced separately. Privacy protection options through NameBright.com are also mentioned.

How much bandwidth does it take to send Morse code? by Mark Amos, W8XR

This FM wireless mike can transmit voice signals to any FM Radio receiver 100 meters away.

K2KW notes on verticals antennas

ZW5B ARRL affiliated DX Group

The resource, "Conventional Use of Transmission Line," meticulously details the operational principles of transmission lines, emphasizing the Transverse Electromagnetic (TEM) mode of energy transfer. It clarifies that for a line to function purely as a transmission line, all currents must be confined internally, with external fields ideally zero. The discussion differentiates between balanced and unbalanced lines, asserting that while both require equal and opposite currents within the conductors, the key distinction lies in the voltage relationship of each conductor to the surrounding environment. It highlights that a good antenna pattern does not inherently confirm proper feeder balance, and that common-mode currents can lead to RF in the shack and increased noise levels, even without pattern distortion. The article further explains that a transmission line can become a radiating conductor if energy is applied in a non-TEM mode, leading to common-mode issues. It cites classic texts like Jordan and Balmain's "_Electromagnetic Waves and Radiating Systems_" and Kraus's "_Antennas_" to support its definitions of TEM mode operation. The content also explores non-transmission line applications of parallel or concentric conductors, such as _coaxial dipoles_ and _folded dipoles_, which intentionally operate in non-TEM modes for antenna functionality. The author, _W8JI_, stresses that simply measuring equal currents is insufficient to confirm a balanced feeder; phase and voltage balance to ground are equally critical.

An interesting guide about APRS (Automatic Position Reporting System) and to Digipeating through the International Space Station - ISS

Monst IR

JTAlert provides several audio and Visual alerts for WSJT-X & JTDX software. JTAlert generate audio and visual alerts for several alert conditions, logs automatically to several ham radio log books software like hrd dxkeeper,log4om, interoperates with web services and it supports dxlab suite.

A Phased Array Switchbox by ComTek founder K8UR, switch your 4-Square in 8 directions and control it remotely over the internet

If your antenna is fixed in one direction, you will notice that your antenna works perfectly only during fall and spring.

The World Radiosport Team Championship (WRTC) is a unique on-site ham radio competition, typically held every four years, bringing together top operators globally. Unlike traditional contests where participants operate from their home QTH, WRTC competitors travel to a designated location and operate from identical stations under field conditions, ensuring a level playing field. Past events have taken place in diverse locations such as Seattle (1990), Slovenia (2000), Russia (2010), and Italy (2023), showcasing the international scope of this **radiosport** challenge. Because each WRTC event is organized by a dedicated, volunteer-driven committee, historical information and results often become dispersed across various online platforms. This resource serves as a centralized repository, diligently collecting and preserving data from all previous WRTC competitions. It provides a consistent point of reference for participants, enthusiasts, and researchers interested in the history and evolution of this premier **DX contesting** event. The WRTC Sanctioning Committee officially endorses this site, ensuring its accuracy and completeness.