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Detecting stray RF voltages on station grounds, chassis, and interconnecting cables is crucial for preventing program and hardware failures in the shack. This article details the construction and application of an LED RF V-probe, which offers significantly higher sensitivity compared to conventional neon lamp indicators. The probe leverages two specific properties of modern red LEDs: their ability to glow at microampere currents and their rectification capability at frequencies up to tens of megahertz. The design features a simple circuit with two LEDs, allowing for indication of both positive and negative RF voltage half-waves. The minimum detectable RF voltage is approximately 2 V, a substantial improvement over the 40-60 V threshold of neon bulbs. The resource illustrates the probe's physical construction on a PCB and provides a direct comparison demonstrating its superior sensitivity in detecting RF fields near a coil. Two operational modes are described: a non-contact mode for high RF voltages (above 15-20 V) and a direct-contact mode for measuring lower RF voltages, with a safety caution for the latter. Practical examples show the probe's use in analyzing RF voltage distribution across a radio station setup at 1.84 MHz and 24.9 MHz, revealing insights into common-mode current issues and the effectiveness of mitigation strategies like adding radials.

Manually programming a Yaesu FTM-100 with hundreds of channels can be very fustrating. In this article the author highlights the difficulty of entering data with small buttons and the need to look up information for each channel. To avoid this tedious process author used RT Systems software as a solution. This program simplifies programming by allowing selection based on the radio model, download of frequencies from resources like RFinder, and quick loading onto the radio. While paid unlike the free CHIRP software used previously, the author emphasizes the time saved compared to manual entry, making the cost worthwhile.

The Zeppelin antenna, a J-type design, is presented as a two-band HF dipole, offering independent operation on harmonically related frequencies. This resource details its electrical configuration, comprising a half-wave radiator end-fed by a quarter-wave matching section, and explores its historical evolution from early Zeppelin airship applications to modern amateur radio use. The article specifically examines how a Zepp antenna tuned to 28.4 MHz (10 meters) exhibits a harmonic relationship with 15.4 MHz (20 meters), noting a frequency ratio of approximately 1.84:1, which deviates from a perfect 2:1 due to factors like elevation, wire separation, velocity factor, and end-effect. Antenna modeling results, including SWR sweeps at 28.4 MHz (1.1 SWR) and 15.4 MHz (1.6 SWR), are provided through Graph 1 and Graph 2, illustrating the antenna's performance across these bands. Current distribution patterns for both the 28.4 MHz (second harmonic) and 15.4 MHz (first harmonic) operations are visually represented in Figure 2 and Figure 3, respectively. The author also includes a 4NEC2 model's "Symbol Conversion file" definitions and calculated #14 wire dimensions for achieving resonance at 28.4 MHz, with the antenna positioned at a height of 33 feet. The discussion further highlights the antenna's versatility, suggesting its potential as a single-band, center-fed, 15.4 MHz half-wave folded end dipole when fed at a specific low current point. This analysis provides practical insights into constructing and optimizing a multi-band Zepp antenna for HF operations, emphasizing its unique harmonic characteristics and physical compactness.

Demonstrates the Automatic Packet Reporting System (APRS) as a radio-based system for real-time tactical data exchange, leveraging the internet for messages, alerts, and bulletins to enhance situational awareness. It explains how APRS displays data on a map, integrating objects with GPS coordinates, weather stations, and alerts, clarifying its primary function as vehicle tracking despite broader capabilities. The document traces APRS development from the late 1980s by Bob Bruninga, WB6APR, through its evolution from Connectionless Emergency Traffic System (CETS) to Automatic Position Reporting System, and finally to Automatic Packet Reporting System with widespread GPS availability. Specific functionalities covered include real-time position and status reporting, message and bulletin exchange, weather data, DF bearings, RF connectivity plots, and local object display. Newer features like Global Email, CQSRVR, APRStt (APRS touchtone) for DTMF-based position reporting on frequencies like 146.58 MHz, and AVRS (Automatic Voice Relay System) for callsign-to-callsign linking via Echolink or IRLP, particularly with transceivers like the D710, are detailed. The resource also mentions AI-FI (APRS WIFI) for laptop integration and the use of the AX.25 protocol on 144.390 MHz in North America. It further describes the role of digipeaters and Internet Gateway stations (IGates) in transporting packets and connecting the on-air APRS network to the APRS Internet System (APRS-IS). The document explains APRS as a random ALOHA network, emphasizing channel loading considerations.

EiBi-Tuner-v2 is an open-source macOS application designed to control amateur radio transceivers via the FLRIG interface, leveraging the EiBi-list for frequency management. This software provides a graphical user interface that emulates an older radio, allowing operators to tune their rigs based on the extensive EiBi database of broadcast stations and utility frequencies. The application is specifically compiled for macOS, offering a native experience for users of Apple's desktop operating system. The software's primary function is to simplify frequency selection and rig control by integrating the EiBi-list, which contains thousands of known frequencies, with FLRIG's robust transceiver control capabilities. This integration allows for rapid QSY to documented frequencies, potentially enhancing DXing and SWL activities by providing quick access to a vast array of signals. The open-source nature permits community contributions and modifications, ensuring adaptability and ongoing development for specific amateur radio operational needs.

HAMgpt offers a personalized amateur radio experience, leveraging AI to provide real-time operational guidance. It integrates live propagation data, current band conditions, and operator-specific context, including callsign, QTH, license class, and station equipment, to deliver relevant answers. The system can identify open HF, VHF, and UHF bands, suggest workable DXpeditions and POTA/SOTA activations, and provide accurate repeater offsets and CTCSS/DCS tones for local repeaters. Unlike general-purpose chatbots, HAMgpt avoids fabricating frequencies or license privileges, instead relying on actual data for its responses. It supports antenna design calculations for various types like Yagi, dipole, vertical, and magnetic loop antennas, offering to-scale dimensions. The platform also assists with license exam preparation and provides satellite pass predictions tailored to the user's location. It supports multiple countries, including the United States (FCC Technician, General, Extra), Canada, the United Kingdom, Australia, Japan, and Argentina, incorporating their specific band plans and power limits.

Operating an **Echolink** gateway on the 4-meter band presents unique opportunities for extending VHF communications, as demonstrated by the EI4FMG node. Situated at Fieldstown, Monasterboice, this gateway provides coverage across a significant portion of Ireland's east coast, leveraging a Tait TM8100 radio and an EI4JR Echolink interface logic. My own experience with similar setups confirms the importance of strategic site selection for maximizing reach, particularly with a 122-meter elevation above sea level. Access to the EI4FMG gateway, identified by node 57006, requires a **CTCSS** tone of 88.5 Hz, a standard practice for managing access and minimizing interference on shared frequencies. The system transmits with 15 watts of power and utilizes a Sigma CAT70 @5MAGL antenna, a configuration well-suited for regional VHF coverage. The gateway also features an auto-ID every 8 minutes, ensuring compliance and clear station identification. Users can interact with the gateway using various DTMF commands, allowing for connections to specific nodes, random repeater/link or conference nodes, and managing disconnections. These functionalities streamline the process of linking into the broader Echolink network, enabling local VHF operators to communicate globally through the internet backbone.

The Meshtastic project leverages _LoRa_ radio protocol to establish a long-range, off-grid communication platform, functioning as a decentralized mesh network. It facilitates sending and receiving text messages using inexpensive LoRa radios, eliminating reliance on traditional infrastructure or a smartphone for core mesh communication. Key features include encrypted communication, extended battery life, and optional GPS-based location services, with radios designed to rebroadcast messages to ensure delivery across the mesh. This system has demonstrated a record range of **331km** and is entirely community-driven and open source, with its codebase hosted on GitHub. Unlike conventional amateur radio, Meshtastic operates on LoRa frequencies generally accessible without specific licenses. Each Meshtastic radio can pair with one phone for message exchange, and support is provided by volunteers.

For amateur radio operators seeking resilient, off-grid communication, the _MeshCom_ firmware provides a robust solution for text-based messaging over a mesh network. Utilizing LoRa modulation and the APRS protocol, this firmware is designed for low-energy consumption and cost-effective hardware, primarily operating in the 70cm band. Nodes, identified by amateur radio callsigns, can send short text messages to all participants or directly to specific callsigns, functioning as repeaters to extend network reach. The system supports automatic status and position messages, with optional sensor data for WX-Data and Telemetry. MeshCom nodes can be configured as gateways to HAMNET or the internet, enhancing connectivity options. The project emphasizes a self-building and self-healing mesh network architecture, crucial for emergency communication scenarios. Operating frequencies include **433.175 MHz** (EU, USA, Africa), 439.9125 MHz (UK), and 433.925 MHz (Norway). The firmware is compatible with hardware platforms such as ESP32/LoRa modules, RAK-WISBLOCK, and ESP32-DEV4/E22-LoRa, offering a flexible deployment for various amateur radio applications.