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Operating in a Single Operator Two Radios (SO2R) setup, especially with beverage antennas, often exposes the receiving radio's front-end to significant RF energy from the transmitting radio. This resource details a practical, homebrew receiver protection circuit designed to mitigate this risk. The core of the design involves a non-inductive 2W 22 Ohm carbon composition resistor in series with the RX antenna line, followed by two stacks of four fast-switching diodes (e.g., _1N914_) configured in opposite polarizations. This arrangement effectively clamps the incoming voltage to approximately 2.8 V peak-to-peak, safeguarding sensitive receiver input components. The series resistor plays a crucial role by absorbing excess power, preventing the diodes from exceeding their current ratings and potentially failing open, which would leave the receiver unprotected. The author, _N4KG_, measured up to 50 watts of coupled power between 80M slopers on the same tower, highlighting the necessity of such protection. The design is presented as a cost-effective solution to prevent damage to receiver input transformers, with the author noting successful protection of a receiver even after a resistor showed signs of overheating. This simple circuit can be integrated via a transverter plug, offering a robust defense against high RF input.

The RemoteTx ham radio remote control system is an economical way to control your amateur radio station through the Internet with a phone, tablet, Mac or PC. There are 3 main parts to the solution. Conveniently operate your station with a smartphone, tablet or laptop anywhere you have Internet access.

UK frequency list provide reference table to lister to Police scanner channels UHF VHF, Amateur Repeaters, Ambulance CB Radio CoastGuard Rescue, marine VHF, Military and more.

A web page devoted to the handicapped hams of the world.

BARA is an ARRL affiliated club in Barry County, Michigan, which is located in the southwestern part of the Lower Peninsula.

A Dutch website dedicated to weather satellite reception with many documents related to antennas, software and techniques on receiving signals from weather satellites.

North Carolina's Largest 2M Repeater Network

Bird 4314 RF Power Meter Battery Replacement

Hawaii Emergency Amateur Radio Club

Garland, Texas RACES/ARES team web site. We are part of the Dallas County RACES council group. Amateur Radio Resource Typing is an important topic. All are welcome to our resources.

LA3ZA Unofficial Guide to Elecraft K2 Modifications

Entities First Worked from Hong Kong on 50MHz

An end-fed half wave antenna matching unit made of 3:24 turns ratio on a FT140-43 toroid with a 150pF capacitor across the input.

28.222mhz transmitting with 2 watts of power

Modifications for Retevis RT3 / Tytera MD-380 includes Hardware Modifications, Codeplugs, Software / Firmware Modifications.

A review of the 30 meter MonoGap Antenna. This review covers from the unboxing go the Gap product, the assembly of the elements, the test and tuning phase and a performance report during the years

DMR in Helena, Montana. Experiments in Digital Amateur Radio Communications

Online Wifi shop based in Greece

The RACES ARES Disaster Assistance Repeaters (RADAR) group was formed by a team of amateur radio operators dedicated to providing high quality repeater communications for amateurs involved in public service communications or response to emergency/disaster situations.

HF Ham Radio net

Station notes, personal informations and some links

The Vibroplex Collector’s Page details the history and identification of Vibroplex semi-automatic telegraph keys, commonly known as "bugs." It traces the evolution from Horace G. Martin's 1902 Autoplex, which required a battery, to the fully mechanical Vibroplex patented in 1904. The resource explains how these keys generate automatic dots and manual dashes, helping telegraphers mitigate Repetitive Motion Disorder (RMD) and increase sending speed, thus improving their earnings. The site also covers the initial design by Alfred Vail in 1844, Jesse Bunnell's 1881 "Triumph Key," and William O. Coffe's 1904 "Mecograph." This page assists owners in identifying their Vibroplex models and determining their manufacturing dates, providing insights into the company's long history and notable figures like J. E. Albright. It notes that approximately 300,000 Vibroplexes have been produced since 1904, with the Original model still in production after more than 90 years. The resource also touches upon various Vibroplex models, including unusual, scarce, and common types, alongside legal and illegal clones from other manufacturers.

These were some of the steps I took to setup my Allstar link node/server and some of the modifications that I did to it.

DF0WD/DL4YHF's Longwave Overview details amateur radio operations on the 135.7 to 137.8 kHz segment in Germany. The author outlines the "inofficial" European band plan, specifying segments for QRSS, TX tests, beacons, conventional CW, and data modes. Early LF activities at DF0WD began with a 20-watt CW transmitter, later upgraded to a homemade linear transverter capable of 100 watts, driven by an Icom IC706 on 10.137 MHz. The station's antenna system includes a 200-meter wire, approximately 10 meters above ground, supported by football field light-masts. Despite its length, the antenna's efficiency is noted as very low due to the immense wavelength of about 2.2 km. The author's experience highlights the significant challenge of achieving effective radiated power (EIRP) on LF, estimating DF0WD's EIRP at around 80 milliwatts based on field strength measurements from PA0SE. DF0WD/DL4YHF has successfully worked numerous countries on 136 kHz CW, including DL, F, G, GI, GM, GU, GW, HB9, HB0, LX, OE, OH, OK, OM, ON, OZ, PA, and SM. The author also mentions ongoing efforts to log contacts with CT, EI, LA/LG, and to complete a two-way QSO with Italy, demonstrating persistent activity on this challenging band.

General station info and Paddle Museum (online display of keys and paddles)

Polish radio station

The Stu Rockafellow Amateur Radio Society was founded in 1960 and has been affiliated with the ARRL for 45 years.

New Zealand Association of Radio Transmitters Auckland Branch 02

A HF power amplifier with a push-pull of AFT09MS015N. The (small-signal) gain of the amplifier is around 26 dB in the lower HF band and goes down to about 24 dB on the higher end and still around 21 dB at 50 MHz. Its input matching is relatively good at the lower HF and degrades above 10 MHz.

How to add the YF-122CN 300 Hz CW filter or YAESU XF-119SN 2,3 Khz SSB filter in the Yaesu FT-857

A project to turn a Raspberry Pi into a very versatile tracker, digipeater and an iGate

W3FPR fixed level AF output fot the Elecraft K2

NARL homepage, the namibian amateur radio league

Associacao de Radioamadores de Amadora-Sintra Portugal

This article include a circuit that allows a cheap 0-1mA meter to be used as a micro-ammeter or a milli-voltmeter

lighthouses and lightships of ireland and northern ireland with arlhs reference numbers for all irish lights

Wakulla Springs, Florida U.S.A.

The BikeLoop antenna project details the construction of a double magnetic loop antenna optimized for VLF frequencies, specifically around 136 kHz. This innovative design incorporates two orthogonal loops, which significantly enhance reception capabilities. Key construction hints include utilizing lightweight bicycle rims for the antenna structure, making it easy to transport and set up in various locations. The document provides valuable mathematical and electrical insights into the antenna's performance, alongside practical reception tests conducted in the Italian Alps, showcasing its effectiveness in capturing various VLF signals, including Sferics and FSK transmissions. Proper setup is crucial for optimal performance. The project emphasizes the importance of grounding and avoiding interference from nearby electrical sources. The reception tests revealed the antenna's ability to capture a range of signals, demonstrating its practical application for enthusiasts interested in VLF reception and antenna experimentation. Overall, the BikeLoop serves as an excellent starting point for those looking to explore the world of VLF frequencies and enhance their antenna-building skills.

issued by the members of YO2KJI

Amateur Radio Amateur Radio Manuals & Books Computer Books & Programs Computer Hardware Rare & Hard to Find Books amateur radio,electronics ,electronis parts,tubes, amplifiers,towners, beam antennas and more

San Rafael, CA ham radio club

The Primary N6OCS Repeater is located at 5700 feet on Santiago Peak in the Santa Ana mountains.

Product information, resources, enhancements and links of the popular ICOM IC-756PRO III

March/April 2010 will be QRV from March 16th till April 4th on IOTA NA-100, 6-80m - mainly in RTTY, PSK and SSB QSL via DL7AFS

This PDF document outlines the process for establishing an **OpenWebRX+** station utilizing Software Defined Radio (SDR) devices on a Linux platform, specifically Debian Bookworm. It details the capabilities of such a setup, including reception across various frequency bands supported by the SDR hardware and the decoding of multiple modes like FM, WideFM, SSB, AM, ADSB, FT8, and CW, with examples provided for FT8 reception and mapping, sensor data, and ADSB. The guide recommends specific hardware configurations, suggesting older x86-64 laptops with 4GB RAM or Raspberry Pi 4 models for the host system. For SDR devices, it endorses **RTL-SDRv3/v4** or HackRF, noting the necessary driver installations for RTL-SDR. The software installation sequence is meticulously laid out, from installing Debian Bookworm to adding OpenWebRX+ repositories, installing the application, and configuring device-specific drivers. Authored by Christian Horn (JL1AYH), the resource also includes a brief personal background of the author. It concludes with instructions for accessing the OpenWebRX+ interface via a web browser, either locally or remotely over a network, and provides contact information for further inquiries.

Radioamadorismo ,amador, ciência, comunicação, rádio, hooby, experiências from Brazil by PY3AB

Documents S21RC's construction of an impedance transformer harness for a VHF/UHF cross yagi, utilizing 20m of _RG179_ cable. Details the creation of a DIY RF sampler with a -50dB sampling output, primarily for measuring HF radio PA section output with a Spectrum Analyzer, also applicable for _Pure Signal_ transmission. Chronicles the deployment of a 200m long beverage antenna for the _S21DX IOTA_ operation in 2022, positioned 2m above ground. Discusses the construction of a 3-element short beam for 10m to replace a previous 2-element antenna, with assistance from S21DW. Provides guidance on operating cheap _PA-70_ and _PA-100_ type Chinese SSPAs using IRF530 MOSFETs, emphasizing the necessity of a final LPF. Outlines the design and construction of a fully isolated interface for radio-to-computer connections, supporting various digital modes with isolated ground, audio transformers for IN/OUT, optical isolation for CAT/CIV, and isolated PTT/COS lines. Includes a log of software updates, such as the _HMI/TFT for NX8048K070_ and _2.1.14 Lite_ release with bug fixes for PEP hold and gradual watt decay.

SDR as an RFI site survey tool. This article will show how a site survey tool was built to use in RFI mitigation.

Northern New Jersey, New York City/Long Island and Westchester County frequency coordination