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The NCDXF/IARU International Beacon Project operates a worldwide network of 18 high-frequency radio beacons, continuously transmitting on 14.100, 18.110, 21.150, 24.930, and 28.200 MHz. These beacons, initially launched in 1979 with a single station and expanded to the current 18-beacon system in 1995, provide reliable signals for both amateur and commercial users to assess current **ionospheric propagation** conditions. The system's design, construction, and operation are managed by volunteers, covering hardware and shipping costs. The resource details the evolution of the beacon network, including the transition from Kenwood TS-50s transmitters to Icom IC-7200 radios with a new controller design implemented in 2015. It explains how listening for these 100-watt signals, transmitted to vertical antennas, allows operators to determine band openings and optimal propagation paths globally. The content also references three QST articles providing historical context and technical specifics of the beacon project. Practical information includes methods for identifying transmitting beacons via a schedule or specialized software like FAROS and Skimmer, which integrates with the **Reverse Beacon Network** for automated monitoring.

Open source software designed for the ICOM IC-R5 receiver. Linux, MacOS X and Windows

Official ADIF Site. ADIF is an open standard for exchange of data between ham radio software packages available from different vendors.

Optimizing the ZS6BKW antenna for full HF band coverage often requires specific modifications beyond its standard configuration. This resource details several enhancements, beginning with a simple series capacitor to improve 80m SWR, a technique W5DXP found effective for permanent installation due to its minimal impact on higher bands. Further improvements include a 10-inch parallel open stub for 10m resonance, shifting the frequency to 28.4 MHz with an SWR of approximately 1.8:1, a practical solution for Technician class operators. The document then explores a switchable matching section, adding or subtracting one foot of ladder line at the 1:1 choke-balun, which significantly impacts higher frequency bands and eliminates the need for a tuner on 17m. W5DXP's _AIM-4170D_ antenna analyzer measurements confirm these effects. More advanced modifications involve a parallel capacitor for further 80m SWR reduction, requiring remote switching for multi-band operation, and relay-switched parallel capacitors at specific points on the 450-ohm matching section to achieve low SWR on 60m, 30m, and 15m. These detailed steps, including _Smith chart_ analyses for the challenging bands, aim to transform the ZS6BKW into a truly all-HF-band antenna, reflecting W5DXP's practical experience in antenna tuning.

Rock Hill SC Hamfest on Oct 6 at Knights Stadium Exit 88 off I-77 Giant paved fleamarket, VE testing 10 AM, Talk-in 147.03 -600 Open 6 AM

There are 2 possible TX extensions on the E version, either full TX (1.705 - 30 MHz) or just open up 5 MHz (cut the R968 jumper and make it into a K version). This mod has been tested on TS 590S and not on TS 590SG

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

The _Italian VHF Beacons_ resource provides a detailed listing of active and QRT amateur radio beacons operating across VHF, UHF, and SHF bands within Italy. Each entry specifies the beacon's callsign (e.g., IQ1SP/B), operating frequency (e.g., 144.411 MHz), QTH locator (e.g., JN44VC), effective radiated power (ERP) in watts, and antenna configuration (e.g., Big Wheel, 4x Dipole, Yagi). This data is crucial for radio amateurs involved in propagation studies, equipment testing, and long-distance (DX) communication on these higher frequency bands, offering fixed signal sources for monitoring. This compilation, last updated in October 2005, serves as a historical snapshot of Italian beacon activity. For instance, it lists several 144 MHz beacons with ERPs ranging from **0.1W** to **10W**, and higher frequency beacons such as I8EMG/B on 1296.880 MHz and I3EME/B on 24192.132 MHz. The inclusion of QRT (Quiet Radio Teletype) status for many entries indicates the dynamic nature of beacon operations over time. Users can utilize this information to identify potential signal sources for band openings or to calibrate their receiving equipment against known transmissions.

Building the WB2HOL foxhunting beam antenna

open source software designed for the Yaesu VR-120 receiver.

Homebrew Light-weight Open-wire feedline for Portable Ops by N5ESE

The Elecraft K2 transceiver requires specific modifications for optimal soundcard digital mode operation, particularly for PSK31. The original article, circa 2001, details initial challenges with manual PTT and speech compression settings. A key modification involves adding headphone audio and a compression disable signal to the K2's microphone jack, utilizing pins 4 and 5. The **COMP0** signal, active low, is shorted to ground via a non-inverting open collector switch circuit, comprising two resistors and two transistors, mounted on the SSB board near U3. This circuit provides effective control of an analog signal line with good noise immunity. The switchbox itself repurposes a computer COM port switch, using only two of its original connectors and four of the nine poles. It integrates a microphone preamplifier, a PTT circuit built with 'flying leads' construction, and RCA jacks for soundcard connections. A trimpot adjusts the audio drive to the K2. The central DB9 connector links to the K2's mic connector via a shielded RS232 serial cable, ensuring proper grounding and signal routing. An external footswitch PTT jack is also included. Further enhancements include a **noise-canceling microphone** preamp based on a QST December 2000 article, adapted for Heil mic elements. This preamp, built with pseudo-Manhattan style construction, provides a gain of approximately 2 by changing emitter resistors (R9 and R16) from 680 ohms to 330 ohms. A 10-ohm series resistor and 47 µF capacitor on the +5V supply mitigate noise spikes.

Open-Source Software Implementation of a DRM (Digital Radio Mondiale) Receiver. Dream runs on virtually any pc and requires a receiver front-end to work as a real radio.

As the sunspots return and DX propagation conditions to improve, the age old problem with QRM begins to show up on the amateur bands. Thif filter help you on improving reception

The 80m TX described here is the well known ON7YD ATX-80 and timer, combined and re-engineered to fit a readily available enclosure by G3ZOI

An open collaborated project for creating base libraries and applications to allow the passing of information from the host computer to the D-STAR radio and vice versa.

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

An inexpensive rechargeable CMOS battery system that can be built from readily available parts.

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.

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

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.

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

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.

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.

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.

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

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

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.

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.

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.

Openaprs is a site dedicated to bringing you aprs tracking data and weather information.

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

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

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.

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.

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.

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

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

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.

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

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.