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The J-pole antenna calculator helps users design custom J-pole antennas for specific frequency bands. It provides dimensions for key antenna sections based on the chosen frequency and material’s velocity factor. The calculator also offers insights into J-pole antenna mechanics, velocity factors, and mounting tips, making it ideal for enthusiasts creating antennas for amateur or mobile radio communications.

Being frequently away from home, the author owner of an Elecraft KX3 missed the opportunity to work /M. They devised a portable antenna solution, incorporating a coil and car body, enabling multi-band tuning. Despite its unconventional design, the antenna exhibits promising performance, resembling a vertical dipole.

Experimenting and testing vertical antenna for HF bands on mobile operations.

The article describes a high-gain, compact beam antenna design for the 2-meter band (144-146 MHz). The NSH 4x4 Boomer is a 4-element antenna that is mounted on a 4-foot boom with an 8.2 dB gain, 1.2:1 SWR, and a front-to-back ratio of 18 db. It is designed for mobile operations and little area, making it perfect for field usage such as disaster management. The design employs regularly spaced parts with a straightforward gamma match for tuning, and the construction materials include a square boom and polished aluminum tubes. In local and portable tests, the antenna worked regularly, achieving contact distances of up to 15 kilometers.

A simple, portable logger tailored for activities like Parks on the Air, Field Day, and more. HAMRS is a fast, user-friendly logging program designed for portable ham radio activities such as POTA, SOTA, and ARRL Field Day. Developed by Jarrett Green, it features an intuitive interface optimized for small screens and multiple platforms, including macOS, Windows, Ubuntu, Raspbian, iOS, and Android. HAMRS provides dedicated logging fields for portable operations, ensuring efficiency in the field. The desktop versions are free, while mobile apps require a small purchase. Its simplicity, cross-platform compatibility, and ease of use make it a valuable tool for amateur radio operators in portable settings.

The most basic form of repeater receives communication on one frequency and re-transmits it on a different frequency, a process known as duplex communication. This capability significantly extends the range of handheld and mobile radios, as repeaters are typically situated at elevated locations with high-gain antennas and greater transmit power. Repeaters commonly operate with FM modulation on the VHF (30 MHz – 300 MHz) and UHF (300 MHz – 3 GHz) amateur bands, which are ideal for portable and mobile devices. Access to repeaters is often controlled by a CTCSS or PL tone, an inaudible signal that prevents the repeater from retransmitting background noise. This mechanism ensures efficient use of the frequency and prevents illegal continuous transmission. Canadian regulations, for instance, require an Advanced amateur radio license and an available frequency within the band to set up a repeater, each assigned a unique call sign and transmit frequency. Configuring a radio for repeater use involves knowing the repeater's transmit frequency, its receive frequency offset (e.g., -600 KHz for VHF or +5 MHz for UHF), and the necessary CTCSS tone. The article references resources like Repeater Book for locating repeaters and provides practical examples for initiating and concluding a basic repeater session, emphasizing clear identification and concise communication.

PH0NO conducted field tests comparing a mobile antenna (DX-UHV) to an end-fed half-wave wire. Results on 20m showed the end-fed wire outperforming the mobile antenna, with a significant difference in signal strength. On 40m, the end-fed wire surpassed the mobile antenna in spots and reach. While the mobile antenna is more practical, the end-fed wire offers superior performance. Further testing is planned.

Online browser-based resource for your computer, tablet or other mobile device. Use this review and practice exam resource with the current editions of ARRL License Manuals.

The resource details the construction of a J-pole vertical antenna specifically engineered for motorcycle mounting, addressing the common issue of interference with top cases. It outlines the fabrication process, beginning with an aluminum angle bracket for secure attachment to the lateral support, followed by the creation of the antenna's base from an 8mm threaded rod bent into a U-shape, approximately **40mm** wide. The article specifies the precise method for coaxial cable connections using eyelets and 3mm screws, ensuring robust contact. Further construction steps involve fitting a 10mm aluminum tube onto the threaded rod, with a screw securing the radiating element and establishing core contact. The design prioritizes mechanical stability against vehicle vibrations over fine-tuning SWR with sliding collars. Initial testing yielded a _SWR_ of **1.2** across a significant portion of the band, with improvements noted by optimizing the coaxial braid contact point near the support bracket. The document provides practical insights into material selection and assembly, emphasizing durability for mobile operation. It concludes with aesthetic options, allowing the builder to paint the antenna or retain its natural aluminum finish, making it a functional and adaptable solution for UHF motorcycle communications.

his historical account traces the development of car radios from Marconi's mobile wireless telegraph station on a steam engine vehicle in 1901 to Motorola's iconic car radio models in the 1930s. It highlights key milestones such as Alfred Grebe's radio-telephone experiments on Long Island and the introduction of Marconi-Phone 8 radios by the Daimler Company in England. The narrative explores technological advancements, including the transition from TRF to Super-Heterodyne circuitry and the integration of push-button controls. The evolution from vacuum tubes to transistors and compact discs is also documented, showcasing the continuous innovation in automotive entertainment systems.

AllScan is a free and open-source web app for AllStar nodes that provides Favorites Management features, AllStarLink Stats integration, and connection monitoring and control functions. Shows your favorites in a Dashboard summary table with Keyed status, Connected Node count and other statistics. Continually scans the status of each favorite using ASL's Stats API data showing which favorites are active and have recently been active. Allows favorites to be connected with a single click (optionally automatically disconnecting any currently connected nodes first). Allows the Favorites Table to be sorted by Node#, Name, Description, Location, etc. Favorites can be added/deleted simply by entering the node# and clicking a button. These features finally give AllStar nodes similar memory management and scan capabilities that analog radios have had for decades. AllScan is mobile-friendly and optimized for ease of use on both small and large screens. AllScan follows the latest web development standards, with PHP, JavaScript, HTML, and CSS cleanly partitioned, runs on both ASL and HamVOIP, and is very easy to install, configure, and update.

This software enables remote monitoring of the Kenwood TS-590SG HF transceiver. Based on a lightweight, text-based monitor was developed using Python and ncurses. It connects via rigctld, displaying key metrics like frequency, power, SWR, and TX/RX state with minimal data usage. Ideal for low-bandwidth remote operation, it works over SSH or mobile data. The software is open-source under GPL v3.

This **PDF report** documents a _maritime mobile_ DXpedition operating from the _Southern Ocean_ near Antarctica, detailing antenna deployment strategies on a sailing vessel. It addresses power management systems for remote operations and propagation characteristics specific to polar regions on **20m and 40m** bands. Operational strategies include managing high-density pileups using split frequency operation and maintaining signal integrity during periods of high aurora activity. Equipment considerations cover specific transceiver models like the Icom IC-7300, antenna types optimized for marine vessel installation, and battery power systems for extended periods without shore power. The resource also examines the use of satellite communication for real-time log uploads and QSL confirmation from remote locations, and discusses mitigating signal degradation from ice accumulation on antennas. DXZone Focus: PDF report | Maritime Mobile DXpedition | Polar Propagation | Split Frequency Operation

Off Grid Ham discusses the benefits of mobile ham radio operation in addition to fixed or semi-fixed base stations. The article highlights the challenges of antenna placement on vehicles, emphasizing the importance of a good ground plane for optimal performance. Tradeoffs between performance and appearance are inevitable, especially with modern vehicles that have plastic body panels. Bonding the coax shield to the car frame is often necessary to establish a good ground plane. Mobile ham radio operation is a valuable option that fills in the gaps left by fixed stations, offering flexibility and convenience for hams on the go.

When installing a mobile antenna, optimal placement significantly impacts performance. Factors such as gain, antenna type, ground plane availability, mounting style, and environment must be considered. Antenna designs, such as 1/4 wave and 5/8 wave, have distinct radiation patterns ideal for specific settings—urban areas or flat terrains, respectively. Ground plane size requirements differ by frequency, impacting effectiveness. Among vehicle mounting options, the car roof center provides the best ground plane and minimal obstruction, ensuring peak performance, especially at higher frequencies like 800 MHz.

Use of the band as Amateur Radio is secondary in this band to federal radiolocation systems, industrial, scientific and medical devices, federal fixed and mobile systems and the M-LMS. Bandplans for hams. Allocation in 902 - 928 MHz

Detailing a Yaesu FT-857 and ATAS-120 installation in a 1997 Toyota Tacoma, the author used Polar Plot to map signal strength. Using a hand truck with a laptop, FT-817, and an Iron Horse antenna, they circled a chalk-outlined 100-foot diameter, revealing potential nulls towards the truck's rear and through the cab, offering insights into antenna performance.

The four-page _APRS Symbol Table_ (Revision H) systematically lists 96 primary and 96 alternate Automatic Packet Reporting System symbols, each with its corresponding GPSxyz Index, a concise description, and a visual icon. For instance, the primary symbol '!' (GPSxyz BB) represents a "Police Stn," while its alternate counterpart '!' (GPSxyz OB) signifies "Emergency." The resource clearly delineates how specific ASCII characters map to distinct graphical representations on APRS displays, crucial for accurate situational awareness. It presents a direct, tabular format, making it an efficient reference for operators needing to quickly identify or interpret the myriad of icons used in APRS mapping applications. The table covers a broad spectrum of common APRS entities, from fixed stations like "Digi" (#) and "Home" (-) to mobile units such as "Car" (>) and "Plane sm" ('), alongside various weather phenomena and emergency services. Compiled by VK4KTP and featuring images by WA8LMF, the document serves as a definitive guide for understanding the visual language of APRS. It is particularly useful for those involved in tactical communications, public service events, or general APRS tracking, ensuring consistent symbol interpretation across different platforms and user interfaces.

The Kenwood TS-50 is a reliable 25-year-old mobile HF radio, widely used in DX operations but lacking CAT and DATA ports for modern logging or contest software. To overcome this, a custom CW interface was built using an USB to TTL module (FT232/FT232RL) and an optocoupler (e.g., 4N25, H11A1) for galvanic isolation. This setup enables the TS-50 to connect with a computer via USB, facilitating integration with software like LOGGER32 and Win-Test. The interface is cost-effective and driver-free for Windows XP and 7, making it an accessible solution for enhancing the TS-50's functionality.

This page serves as a comprehensive guide for hams, providing open-sourced information that is community-driven and multilingual. It is designed to be accessible to anyone, regardless of language, and can be used offline without internet access. Users can contribute to its development and even install it as an app on their mobile browser. Ideal for ham radio operators looking for a versatile and collaborative resource.

Illustrates the potential for radio frequency (RF) energy from amateur transceivers to interfere with vehicle electronics, drawing parallels to military _Radio Frequency Vehicle Stopper_ (RFVS) technology. The resource details personal experiences with VHF/UHF signals activating household devices and then pivots to the complexities of RF interaction with automotive systems, noting the development of multi-frequency RFVS (MFRFVS) to overcome vehicle-specific vulnerabilities. It highlights that while car manufacturers conduct RF immunity tests, the rigor varies, with luxury brands likely performing more extensive evaluations than others who merely meet minimal certification. The article explores practical considerations for mobile amateur radio installations, suggesting antenna placement over the car, using lower power output, and proper grounding to mitigate adverse effects. It acknowledges the lack of comprehensive data on RF/vehicle combinations but emphasizes that adherence to these basic principles can reduce risks. The author shares observations of unexplained car computer codes in a 2002 SUV, speculating on potential RF induction. Concerns are raised about the increasing complexity and interconnectedness of modern car electronics, including Bluetooth, remote access, and electronic control systems for critical functions like steering and braking. The article points out the diminishing space for third-party installations in contemporary vehicles and references the ARRL's stance on auto manufacturer policies regarding amateur radio installations, which generally advise against them.

This online project documentation details the construction of a hands-free microphone interface unit designed for _mobile_ amateur radio operation. The curriculum covers the integration of electret microphone elements with amateur radio transceivers, specifically addressing **VHF** band communication. It outlines the circuitry for a switch box that provides an interface between various radio models and microphone types. The guide specifies the inclusion of a **1750 Hz** tone-burst generator for accessing amateur radio repeaters, an operational protocol for many VHF systems. Design considerations include the reduction of ambient vehicle noise through an adjustable audio input level control. The project provides schematics and wiring diagrams for connecting the interface unit to specific amateur radio transceivers, including the Yaesu FT-817. It addresses the selection and adaptation of readily available electret microphone and earpiece assemblies, initially sourced from mobile phone accessories, and later from dedicated headset units. The design incorporates a control mechanism for radio functions, enabling hands-free operation during _mobile_ excursions. Circuit details cover power supply considerations for the electret microphone and signal routing for both transmit audio and received audio monitoring. The documentation specifies component selection for the switch box, ensuring compatibility with common amateur radio microphone input impedances and output levels. This includes considerations for PTT line switching and audio path isolation. DXZone Focus: Online Project Documentation | Hands-Free Mobile Microphone Interface | Electret Microphone Integration | 1750 Hz Tone-Burst Generation

Presents an online retail platform for amateur radio operators, showcasing a diverse inventory of equipment and accessories. The site lists popular transceivers such as the _Icom IC-7300_ and _Icom IC-7610_, alongside various antenna solutions including base, HT, mobile, and end-fed designs. Operators can find coaxial cable, including bulk options and products from "The Wire Man," essential for shack setup. The platform also stocks crimping and stripping tools, adapters, and power supplies, crucial for station maintenance and construction. Test equipment like _RigExpert Analyzers_ and accessories such as Daiwa meters and _West Mountain Radio_ Power Poles are available. Additionally, the site offers software from _Ham Radio Deluxe_ and _RT Systems_, catering to logging and radio programming needs. Shipping policies include free shipping on C.Crane Radios and most orders over $100.00 within the lower 48 states, providing clear purchasing incentives.

The Anytone AT-D878UVII Plus, a dual-band transceiver, supports both Analog and DMR modes, providing versatile communication options for amateur radio operators. This model is complemented by the Anytone AT-6666 Pro, which delivers a substantial 80W output, catering to users requiring higher power for their radio operations. For mobile and off-road applications, RadioSmart Solutions features a 4x4 Mobile Radio Package Deal, which includes the RTS DV-2135s Mobile Two-Way Radio. This package is specifically designed for reliable communication in challenging environments, often encountered during off-road adventures. An _RSS Rugged Off-Road Antenna_ is also available, engineered to withstand harsh conditions and ensure robust performance. The product range addresses the needs of individuals seeking durable and functional communication solutions for both general amateur radio use and specialized mobile deployments.

The resource details the use of LoRa for AX.25 packet radio and APRS, focusing on practical implementation. It specifies UK LoRa APRS frequency and modulation settings: **439.9125 MHz**, 125kHz bandwidth, SF12, and CR 4/5. The content provides a mini how-to for setting up an iGate using VS Code and _Platformio IDE_, with specific instructions for a Lilygo LoRa32 V2.1_1.6 board, including configuration for Wi-Fi, beaconing, and APRS-IS passcode. It also covers tracker setup using a Lilygo T-Beam Supreme, detailing firmware flashing and configuration for mobile operation. The guide differentiates LoRa APRS from traditional connected-mode packet radio, explaining why common LoRa APRS firmware is unsuitable for full AX.25 packet due to its TNC2-style payload structure. It explores alternative solutions for true LoRa packet radio, such as using an _RNode_ TNC or Raspberry Pi LoRa TNCs, and provides commands for RNode firmware installation and configuration for serial KISS operation. The resource also touches upon licensing requirements for unattended Digipeaters in the UK, noting the need for ETCC coordination and MB7Uxx callsigns.

Demonstrates the operational status and reach of the LoRa APRS infrastructure, providing a live mapping and logging service for network participants. Users can verify network coverage, monitor _iGates_, and track mobile stations, observing messages and real-time network activity. The platform offers insights into station locations and data flow within the LoRa APRS system, which is crucial for understanding the performance of LoRa technology in Automatic Packet Reporting System applications. This utility helps amateur radio operators understand where transmissions are being received and processed by iGates, and how mobile units are moving within the network. The site's analysis tools provide RF performance monitoring and metrics, enabling users to assess network efficiency and identify areas for improvement. For example, operators can see how many packets are received by specific iGates, or track the path of a mobile station over a **100 km** range, offering practical insights into signal propagation and network reliability for _packet radio_ enthusiasts.

The State QSO Party Challenge is an annual program recognizing amateur radio operators' participation in U.S. State and Canadian Province QSO parties. To qualify for the SQP Challenge, participants must make at least two QSOs in a minimum of two SQP Approved QP contests and submit their scores to 3830Scores.com. The site details the SQP Mobile/Portable Challenge, an overlay competition encouraging mobile/portable operations, with scoring identical to the main SQP Challenge: (Number of QPs entered) x (Number of QSOs) = Score. Eligibility for the Mobile/Portable Challenge requires prior qualification for the SQP Challenge. The website also mentions a State QSO Party Club Challenge and provides contact information for questions. The 2026 SQP Challenge will be dedicated to Stan Zawrotny, K4SBZ, a key team member instrumental in the program's development. Participants are recognized for reaching five levels of achievement: Bronze, Silver, Gold, Platinum, and Diamond. Scores are calculated by totaling reported contacts and multiplying by the number of SQPs entered year-to-date, encouraging more entries and longer operating times. The Worked All QSO Parties (WAQP) program, sponsored by Icom America, offers certificates for participating in at least 50% of approved contests, with a goal of participating in all. WAQP requires submitting a log with at least two valid contacts to the contest manager, in addition to the 3830scores.com submission.