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Open source software designed to control and program the Japan Radio Co. NRD-545 receiver.

The KP3AV Systems website offers a detailed listing of amateur radio repeaters across Puerto Rico, including operational frequencies and tones for VHF and UHF bands. It features sections dedicated to digital modes like DMR and C4FM, as well as information on FRS, GMRS, and MURS. The resource also includes articles on emergency communications protocols and provides access to Spanish-language manuals for various radio equipment. Recent content covers the new open-source FT2 mode for WSJT-X Improved, upcoming 60-meter band frequency allocations and power restrictions effective February 13, 2026, and discussions on 2-meter contacts with Desecheo Island from Puerto Rico. The site also presents U.S. amateur radio band plans and highlights local contesters like Manuel WP4TZ, offering practical insights into portable operations and contest participation.

K4JRG GAP titan dx specifications

Cloudlog is a web-based amateur radio logging application built with PHP and MySQL, supporting station logging activities from HF to microwave. It integrates with companion tools for CAT control and automation, offering a flexible solution for managing QSO data. The application provides a self-hosted platform for amateur radio operators to maintain their logbooks, facilitating interaction with various ham radio operations. Its open-source nature allows for community contributions and customization, enhancing its utility for diverse operating preferences. Originally started by Peter, **2E0SQL**, Cloudlog was designed to enable simple interaction with the Ham Radio Deluxe logbook using MySQL.

The Double Bazooka Dipole is a very efficient single band antenna which is very quite,and does not require the use of a balun. This antenna consists of coax (RG58) with the shield split at the center and the feedline attached to the open ends.

Demonstrates various practical amateur radio projects and technical discussions through video episodes. One episode details cutting and retuning a _1/4 wave shorted stub_ from 101.7 MHz to 107.5 MHz to safeguard a transmitter's driver stage, alongside insights into advanced _160-meter antenna systems_ like eight-circle arrays and beverage antennas. Another segment covers upgrading firmware on an _ATS-20+_ receiver using AverDudes for improved display and functionality, and a detailed guide on using D-Star DR mode on an _ICOM ID-52A_ for international repeater programming. Additional content includes a deep dive into _OpenHamClock_ as a potential replacement for the HamClock project, updates on _Raspberry Pi 5_ running Trixie OS, and a review of the Choyong LC90 Internet radio with AI integration. The series also features "Ham College" episodes, which meticulously prepare viewers for the Technician Exam by covering topics such as antenna and transmission line measurements, SWR interpretation, and the functions of basic electronic components like rectifiers, relays, and transistors. Practical advice on coaxial cable characteristics, dummy loads, and proper soldering techniques is also provided.

An Arduino based CW contest keyer addon, ideated and designed for the use in conbination with the K3NG Arduino keyer open-source firmware.

Amateur Radio - Antenna Zoning Book by Fred Hopengarten Telecommunications Lawyer

Shelby amateur radio club's VHF emergency net is open to all within the repeater's coverage area. 146.880 and 147.345 are the repeater frequencies. Shelby Radio Club is the sponsor of the Shelby hamfest.

tk150 is open source, multi-platform cloning software for the Standard (Yaesu) VR-150 portable receiver.

Codec2 is an open source low bit rate speech codec designed for communications quality speech at 2400 bit/s and below. Applications include low bandwidth HF/VHF digital radio and VOIP trunking.

tk3 is open source software designed for the ICOM IC-R3 receiver. Though tk3 is intended chiefly for Linux, MacOS X, and BSD users, it will work on Microsoft Windows too.

Based on a simple project based on a 2 elements Yagi for 20m band, and then becomed a triband yagi with a open-sleeve feed system

This resource provides a unique historical audio archive of 50 MHz DX contacts, documenting significant F2 and Es propagation events experienced by PA2S (formerly PA2HJS) since 1978. The collection includes recordings of beacons and two-way QSOs with stations across North America, South America, Asia, Australia, Europe, and Africa. Specific entries detail contacts with rare DX entities such as ZS6PW, VE1AVX, C5AEH, J52US, TR8CA, LU8MBL, VK8ZLX, and various Japanese stations, often noting the mode (SSB or CW) and propagation type. The archive also highlights challenging pile-up situations and frustrating near-misses during major openings. The recordings, initially in RealAudio format for solar cycles 21 and 22 and later in MP3 for cycle 23, offer a practical illustration of 6-meter band conditions over several solar cycles. The content allows hams to listen to actual signals from different continents, observing signal characteristics like typical TEP fading from 5H3RA or strong F2 backscatter from OZ1BVW. It provides a comparative perspective on propagation effectiveness between solar cycles, noting that cycle 23, while not as robust as previous cycles, still yielded interesting openings. The archive serves as a valuable educational tool for understanding real-world 50 MHz DXing and propagation phenomena.

tk7 is open source software designed for the ICOM IC-Q7 walkie-talkie. Though tk7 is intended chiefly for Linux, MacOS X, and BSD users, it will work on Microsoft Windows too.

On this page are designs for Dual Band 2M / 70cm antennas. All antennas are 50 ohm designed driver. These Yagis have a unique element called a Open Sleeve. 4 Element 5 element and 9 element Dual Band - 2M / 70cm antenna projects

Discussion at towertalk about coax cable feed lines vs Open Wire Lines

An online interactive grid square map made with openstreet map. Just point and click and zoom in to determine an accurate grid square locator till 10 digit resolution

Presents the Holy Cluster, a contemporary DX cluster service offering real-time amateur radio spot data. This platform integrates a dynamic graphical map to visualize current contacts, enhancing situational awareness for DXers and contesters. Developed by an Israeli group of developers and supported by the Israeli Association of Radio Communication (IARC), the Holy Cluster aggregates DX spots from various sources, including traditional telnet clusters, the Reverse Beacon Network (RBN), and PSK Reporter, providing a comprehensive view of band activity. The cluster's design emphasizes a user-friendly interface for monitoring DX activity across multiple bands, including dedicated support for JOTA (Jamboree On The Air) operations. Its aggregation capabilities allow operators to quickly identify propagation openings and active stations, streamlining the process of making two-way radio contacts. The integration of RBN and PSK Reporter data offers insights into propagation conditions and station reception reports, which can be invaluable for optimizing antenna direction and operating strategies.

Around 200 electronic circuits in pdf format or images, There are also over 1000 links to useful electronics, freeware, open source websites. There are some 100 useful documents, software and pcbs too. Mainly industrial electronics, instrumentation. Covers Various aspects of electronics and basics of circuit design.

The Null-modem emulator is an open source kernel-mode virtual serial port driver for Windows, available freely under GPL license.Allows you to create an unlimited number of virtual COM port pairs and use any pair to connect one COM port based application to another.

Wrexham is in North Wale's and our club is open to all radio fans

Open source project offers a solution to remote control of your Amateur radio station. Base for connecting other components and their remote control. The main advantage is low cost and adaptability

The ANAN series SDRs are based on the OpenHPSDR open source designs, these are 4th generation radios and represent the state-of-the-art in current Amateur radio SDR design.

Presents the VHFDX.EU web cluster, a specialized resource for VHF, UHF, and microwave DX spotting. It details the cluster's functionality, including real-time spot aggregation and a DXCluster Map interface for visualizing activity. The resource highlights its integration with the MMMonVHF backbone, ensuring a robust data flow for monitoring band openings and propagation events across higher frequencies. It also references reviews of the ON4KST and N0UK chat systems, which are frequently used in conjunction with VHF DX operations. The platform offers a mobile-optimized view for on-the-go access to DX spots, catering to portable and mobile operators. It further provides daily ES (Sporadic E) spot summaries, a critical feature for VHF operators tracking this specific propagation mode. The cluster serves as a central point for operators to share and receive information on rare grid squares, contest activity, and general band conditions above 50 MHz.

A friendly and open group that likes to organize DX-expeditions like F/ON6JUN/P, OZ/OR0MO

C.A.R.L.A. is a growing network of repeaters providing coverage across Northern & Central California and Western Nevada. It is intended to be used as a reliable communications resource during significant local, regional and wide area incidents, and is open to all licensed amateur radio operators

Discussion about open wire line on tower talk

The Short Mountain Repeater Club (W4YXA) maintains an open repeater operating at 146.910 MHz using a negative offset (146.310 MHz). The repeater is located about 60 miles SSE of Nashville, Tennessee

KB9AMG's Top WSPR Spots presents a focused online tool for monitoring **2-way WSPR reports**, specifically detailing propagation data from February 2026 through March 2026. This resource aggregates _WSPRnet_ data, allowing radio amateurs to observe weak signal propagation conditions across various bands. The interface is straightforward, presenting callsigns, frequencies, signal-to-noise ratios, and distances for each reported contact, which is crucial for understanding current band openings and signal paths. The utility of this WSPR spotter lies in its ability to quickly visualize global propagation. Users can identify active stations and assess signal viability over long distances, with reports often showing contacts spanning thousands of kilometers. For instance, a typical WSPR report might indicate a signal from Europe reaching North America with a _SNR_ of -25 dB, demonstrating effective low-power communication. This data is invaluable for planning DX operations or evaluating antenna performance under actual propagation conditions.

Operating a ham station often involves encountering radio frequency interference (RFI), RF feedback, or RF burns, which are frequently misattributed to poor equipment grounding. This resource meticulously dissects these assumptions, asserting that RF grounds on the operating desk often merely mask more significant system flaws. It identifies five primary causes for RF problems, including antenna system design flaws, proximity of the antenna to the operating position, DC power supply ground loops, equipment design defects, and poorly installed connectors or defective cables. The content emphasizes that issues like "hot cabinets" or changes in SWR when connecting a ground indicate substantial RF flowing over wiring or cabinets, a phenomenon known as common-mode current. The article provides detailed explanations of common-mode current generation, particularly from single-wire fed antennas like longwires, random wires, and OCF dipoles, which inherently present high levels of RF in the shack. It also illustrates how vertical antennas, lacking a perfect ground system, can excite feed lines with significant common-mode current. Through simulations, the author demonstrates how a dipole without a proper _balun_ can cause RF problems at the operating desk, showing current patterns and voltage distributions on feed line shields. The discussion extends to the proper application of _RF isolators_ and _ferrite beads_, clarifying their role in modifying common-mode impedance on cable shields and cautioning against their use as a band-aid for fundamental system defects. The resource advocates for correcting the actual source of RF problems, such as antenna system issues or poor connector mounting, rather than relying on internal shack grounding or isolators. It highlights that properly functioning two-conductor feed lines, like coaxial or open-wire lines, should result in minimal RF levels at the operating position, even without a desk RF ground. The author shares personal experience, noting that his stations since the late 1970s have operated without RF grounds at the desks, relying instead on proper antenna system design and feed line integrity.

Monitoring real-time amateur radio activity is essential for DXers and contesters seeking rare contacts or tracking propagation. This online service aggregates DX spots from various **DX Cluster** networks, presenting them visually on a world map. Users can observe new spots as they appear, facilitating quick identification of active stations and potential openings. The platform offers filtering capabilities, allowing operators to narrow down displayed spots by specific bands such as 160m, 80m, 40m, 20m, 10m, and even VHF/UHF segments like 70cm and 23cm. Further refinement is possible by selecting the source continent of the spotter or the continent of the DX station, which assists in strategic operating. The service also includes a "Hot Now" list, highlighting currently active stations with recent spots. This dynamic display supports informed decision-making for pursuing **DX contacts** across different bands and geographical regions.

Awards issued and managed by OEVSV

Demonstrates a specialized DX cluster monitoring application, _DxWatcher_, designed for Windows environments. It processes DX spots received via Telnet/Internet, presenting them in a filtered table and a dynamic bandmap. The software integrates with transceivers, specifically the FT-2000, to read VFO frequency and enable one-click tuning to spotted stations. _DxWatcher_ version 1.0.3.0, released on 13 June 2020, includes minor bugfixes and improvements such as enhanced recovery from suspend mode. Key features include configurable bandmap position and size, automatic opening, and bolding of spots received within the last **10 minutes**. The application utilizes the standard _ctry.dat_ file for DXCC country analysis, allowing users to update it for current DXCC status. Source code, developed in C# with MS Visual Studio 2008, is freely available, encouraging modification and sharing while requesting retention of the original author's callsign.

An open design exercise in interface archaeology, that decodes the input from a classic Morse key to send twitter messages

DragonOS is a linux distribution dedicate to Software Defined Radio. It leverages the portability, security, and power of Lubuntu Linux as a delivery package and operating environment for a pre-installed suite of the most powerful and accessible open source SDR software. DragonOS has verified support for a range of inexpensive and powerful SDR hardware, including RTL-SDR, HackRF One, LimeSDR, BladeRF, and many others.

Electroswitch Electronic Products specializes in the design and manufacture of various switch types, including rotary, toggle, pushbutton, and rocker switches, as well as encoders and indicator lights. The company provides commercial and MIL-spec compliant components, detailing features such as spring return, push/pull to turn, adjustable stop, concentric shaft, and keylock configurations for their rotary switch lines. Specific product series like the M5-series enclosed frame rotary switches are highlighted, demonstrating their engineering capabilities. The resource offers a Rotary Switch Configurator to assist customers in selecting appropriate components based on application requirements. It categorizes switches by construction, such as enclosed frame, open frame, military grade, sealed, subminiature, blade, and power options for rotary switches. Toggle switches are presented in miniature, full-size, military grade, and sealed variants, while pushbutton switches include ultra-miniature, miniature, standard, and sealed types. Further product details cover rocker switches in subminiature, miniature, and sealed configurations, alongside thumb switches. Encoder offerings include magnetic and mechanical types with options like concentric shafts and push-to-turn functionality. Indicator lights are available for both commercial rectangular panel mount and MIL-spec applications, featuring configurations such as Press-to-Test, Watertight, EMI Shielded, and Dimmable options.

The construction principles for open-sleeve elements in antennas

A searchable database of online websdr receivers, lists OpenWebRX, KiWi SDR and WebSDR from all over the world, providing a web interface to search and filter links to websdr

dnx274.org - cb-mailbox dbo274 and the famous packet radio mailbox software openbcm

The Broadcast Employees Amateur Radio Society, Inc. (BEARS) operates an extensive network of **VHF and UHF repeaters** across New York, the Hudson Valley, Long Island, and New Jersey, accessible to all licensed amateur radio operators. This resource details the club's structure as a 501c3 tax-exempt non-profit, emphasizing its role in providing ham radio training, testing, and critical communications support to various public and private emergency response agencies. Key repeaters include W2ABC/RPT on 147.27 MHz with a 141.3 PL tone, serving as a central point for club activities and broader network access. BEARS is also a founding member of the **Disney Amateur Radio Interconnect (DARI)**, a consortium of open, linked VHF and UHF repeaters spanning major metropolitan areas such as Philadelphia, Baltimore/Washington DC, Orlando, Bristol, Los Angeles, and Boston. This interconnected system facilitates wide-area communication for members and supports emergency preparedness efforts across multiple regions. The club's focus extends beyond Disney employees, welcoming aspiring and current hams from outside the company to participate in its activities and utilize its robust repeater infrastructure.

A General-Interest ARRL Affiliate Operating Open Repeaters in Canon City, Colorado

The Hermes-Lite is a low-cost direct down/up conversion software defined amateur radio HF transceiver based on a broadband modem chip and the Hermes SDR project. It is entirely open source and open hardware, including the tools used for design and fabrication files. Over 300 Hermes-Lite 2.0 units have been successfully built.

The Tri-County CW Amateur Radio Club, operating under the callsign _W3TCW_, is situated in North Huntingdon, Pennsylvania, just southeast of Pittsburgh. This organization extends an open invitation to all licensed amateur radio operators, regardless of age or experience level, to participate in its activities and community. The club maintains a web presence detailing various aspects of its operations, including a calendar of events, a member roster, and contact information. It also provides resources related to _VE Testing_ and links to other local clubs and the _ARRL_ section website. Historical content, such as information from _Field Day 2008_, is also referenced.

Reports indicate the PA1RBZ DX Cluster, previously accessible via telnet at pa1rbz.dyndns.org on port 9000, is no longer operational. The QSL.net hosting platform displays a 404 error, indicating the specific page or file for the cluster's web interface or related information is missing. This service was designed to provide amateur radio operators with real-time DX spotting data, facilitating long-distance contacts across various bands. The cluster's primary function was to aggregate and disseminate DX spots, allowing users to monitor current propagation conditions and identify active stations. Such systems are crucial tools for DXers and contesters, enabling rapid response to new openings and rare DX entities. QSL.net, which hosts over 30,000 amateur radio websites, provides these services free of charge to hams, relying on user donations for operational continuity.

The Hamilton Amateur Radio Club operates the VE3NCF repeater, 146.760- and 444.075+MHz. It is open for use by all Hams

Arduino code for buidling Yaesu VX8r Handheld Transmitter-compatible GPS. A compatbile GPS unit, made with open-source and generally available components, that can be used to proivde the position and velocity information for the Yaesu HT

A simple dipole for 40m band feeded with 450-Ohm openwire feedline includes MMANA Gal files to download

The **Arlington Amateur Radio Club** (K5SLD) website details club activities, including a weekly Taco Tuesday net on their 147.140 MHz repeater with a 110.9 Hz PL tone. The club, organized in July 1955 by 22 hams, also hosts monthly dining events and promotes Community Emergency Response Team (CERT) training through the Arlington Fire Department. Membership renewal information for 2026 dues is prominently featured, with an online payment option and a donation button available on the "Pay Dues" page. Club communications extend to a dedicated Facebook page for members and the wider amateur radio community. The site lists upcoming contests and encourages participation in local events. The 2-meter repeater net is open to all, fostering local camaraderie and technical exchange among hams in the Arlington, Texas area, regardless of club affiliation.

OpenRepeater is a low cost, low power, but feature rich duplex repeater controller suitable for setting up a temporary / emergency repeater systems with radios that can be run on portable power. Download the latest OpenRepeater software for your Raspberry Pi 2/3/3B+/4. This image contains everything you need to get up and running quickly.