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The FieldComm Association, based in Central Virginia, operates as a specialized amateur radio club with a primary interest in emergency communications. Members engage in various technical aspects of radio, including digital modes, QRP operations, and DXing. The association provides a platform for hams to develop skills in field deployment and reliable communication under challenging conditions, often leveraging modern digital protocols. This organization's activities support the practical application of amateur radio for public service, emphasizing readiness and operational proficiency. Members collaborate on projects and share knowledge, fostering expertise in areas like portable station setup and efficient data transmission. The focus on emergency communications distinguishes its operational priorities from general interest clubs, aligning its efforts with community preparedness.

Info about operarting permissions in other countries

This resource examines the appropriate use of /M (mobile) and /P (portable) suffixes in amateur radio callsigns, specifically within the context of the UK Amateur Radio Licence. It addresses common ambiguities and challenges in determining operational status, such as operating from a summit or while walking. The discussion references the licence version in force before February 21, 2024, noting that while current regulations recommend but do not specify suffix use, the prior definitions remain relevant for understanding common practice. The content dissects key sections of the licence, including "Notes to the licence" (d)(i-iii) which outlines /A, /P, and /M usage based on location, and "Temporary Location" (jj) which defines /P operations. It also clarifies "Mobile" (17(1)(x)) as operating in or on a vehicle, on a pedestrian, or on a vessel on inland waters. The author provides examples and recommendations for choosing between /M and /P when both might apply, such as when operating from a parked car with a deployed mast or using a handheld on a summit. Historical notes from M1MAJ, G8ADD, and G6MZX are included, tracing the evolution of suffix rules from pre-BR68 days to the 1977 licence version. These historical perspectives highlight how past regulations have influenced current interpretations and persistent myths regarding /M usage. The resource emphasizes making an informed choice based on the licence and communicating the station's operational circumstances clearly.

Find out about the latest launch and mission to the Mir Space Station or Shuttle now consolidated in a single web site

The **KC0KJF** personal amateur radio page provides a collection of resources for fellow hams, particularly those interested in operations within southwest Missouri. It offers detailed listings for **Missouri repeaters** on both 2 meters and 70 centimeters, serving as a practical reference for local VHF/UHF communication. The site also includes information about the operator's station setup and antenna projects, such as a dipole and a bazooka antenna, which can offer insights into basic antenna construction and deployment. Beyond local repeater data, the page features links to the FCC Part 97 rules, essential for understanding amateur radio regulations. The operator, licensed as a Technician Class since April 16, 2001, shares his journey from Citizen's Band Radio to amateur radio, driven by a lifelong fascination with shortwave listening. This narrative provides context for the resource's focus on practical operating information and foundational regulatory knowledge. Additional content covers specific equipment like the 2-meter/70-centimeter Arrow Antenna, useful for hams considering portable or fixed station VHF/UHF setups.

The ATV User's Group is a subgroup of the Auckland VHF Group, Club call ZL1BQ, compromising of persons interested in the transmission and reception of Amateur Television

In the VLF portion of the spectrum it is easy to listen to the emissions created by the Earth itself. These emissions are generated by many different mechanisms and are often beautiful to listen to. Coverage on LF and MF frequencies

Low power radio modules - supplying rf modules, rf transceivers, radiometrix transmitters receivers, low power radio modules, scada, frequency hopping, 900 mhz, wireless data transmission, data telemetry, gps modules & receivers and more

From the Publishers of EPE, this specialist niche publication is of interest to vintage radio enthusiasts, offering step-by-step rebuilds of selected receivers and helpful ideas and advice. Published every other month, each issue contains articles on radio restoration and repairs, histories, circuit diagrams, nostalgic memories and adverts by specialists.

A 200 kHz bandwidth digital transmission system for image transfer in the Amateur Service is under development, specifically targeting VHF allocations. John B. Stephensen, KD6OZH, leads this project under an FCC Special Temporary Authority (STA) valid until September 10, 2006, authorizing emissions up to 200 kHz bandwidth in the 50.3-50.8 MHz segment. Current regulations typically limit bandwidths to 20 kHz on VHF amateur bands, making this STA crucial for testing wideband digital modes. The modem, a modified **OFDM** (Orthogonal Frequency Division Multiplexed) unit, was initially tested on the 70-cm band. It splits a high-rate data stream into multiple low-rate subcarriers to mitigate multipath echoes. The system uses a DCP-1 card with a Xilinx XC3S400 FPGA and Oki Semiconductor ML67Q5003 microcontroller. The transmitter, located at 36d 46m 30s N, 119d 46m 22s W, generates 150 WPEP into an 8 dBi gain vertical antenna, while the mobile receiver uses a Ham-stick. Three data formats for 50, 100, and 200 kHz channels are being tested, with encoded data rates of 96, 192, and 384 kbps. Verilog code for the VHF OFDM modem is 95% simulated, with modifications from the UHF version including increased filter coefficient precision and a change from Ungerboeck **TCM** to BICM for improved performance over fading paths. Final tests will involve one-way over-the-air measurements of bit error rates and coverage area.

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.

HB9BZA's LoTW users list, originally compiled since 2005 from DX-Cluster and user submissions, now primarily leverages the official ARRL full users list released on July 29th, 2017. This resource details 228,012 calls across 340 current DXCC entities, with the latest update noted on March 2, 2026. It offers various formats, including a full list, text versions, and breakdowns by country, providing valuable insights into LoTW participation for DXers. While the ARRL's official list with "last upload" dates diminished the original list's unique utility, HB9BZA's site continues to offer statistics and user counts by country, which remain of interest. The author, HB9BZA, expresses gratitude to contributors who helped maintain the list's accuracy over many years, achieving an impressive 96.4% match with the ARRL's data before the official release. Knowing which stations are LoTW active encourages more hams to join the system, demonstrating that even rare DXCC entities like Ducie Island or Heard Island can be confirmed quickly. For instance, HB9BZA recounts a 36-minute QSL confirmation for a 3A2MW contact. The list also integrates with the RXCLUS packet radio/telnet client, enhancing DXCC award tracking by identifying LoTW participants and utilizing upload dates for alarms.

A handy piece of test equipment useful for HF bands, can absorb a 200W modulated carrier for almost 2 minutes. It is housed in a tin and part filled with dry sand that helps in power dissipation

The mission of the HDXA is to encourage DX activites in Eastern Nebraska and Western Iowa. The HDXA is a ARRL Affiliated Club with members promoting & sharing DX information and experiences.

In this article the author provides some guidelines on how to solve a common problem when stacking different types of yagi antennas on the same mast, limiting the effects on gain and radiation pattern of both antennas

Our Mission: To provide emergency communications to central Ohio public safety, emergency, health, government and relief agencies in times of disaster.

The mission of this Association is to foster and promote the hobby of Amateur Radio, to provide repeater systems for the Amateur Radio community, to provide public service and emergency communications when needed, to provide education for licensing, and to provide a forum for members to meet and exchange information, share experiences, and socialize with one another.

Transmission Line 75 ohm to 50 ohm Transformers

The **Solarcon A99** vertical antenna, a half-wave over a quarter-wave variable mutual inductance design, primarily serves the 11-meter CB band but also finds use on 10 and 12 meters for amateur radio operators. Its simple construction, consisting of three fiberglass sections and a 16 AWG radiating element, makes it an accessible option for new operators or those seeking an easy-to-install base station antenna without complex mounting requirements. Despite claims of 9.9 dBi gain being widely considered exaggerated, and a manufacturer rating of 2000 watts power handling often viewed with skepticism (with 300 watts suggested as a practical limit), the A99 maintains popularity due to its low cost and ease of deployment. It typically tunes to a 1.2-1.3 SWR out of the box, requiring minimal adjustment via its two tuning rings. Its high angle of radiation allows for effective local communication even when mounted at low heights, such as 8-10 feet off the ground. However, the A99 is known for significant RF bleed-over issues, particularly when operated with higher power or mounted close to residential electronics. While its internal design is often described as cheap, the antenna exhibits remarkable durability, frequently lasting a decade or more in various weather conditions. Its affordability and straightforward setup continue to make it a go-to choice for many radio enthusiasts.

Manually programming D-Star handheld transceivers like the _Icom ID-51A_ and _ID-31A_ can be a straightforward process, enabling operators to configure repeaters, simplex frequencies, and D-Star specific settings without relying on computer software. This method is particularly useful for field operations or when quick adjustments are needed, allowing hams to set up callsign routing, DR mode, and reflector links directly from the radio's interface. Understanding the menu structure and key sequences is crucial for efficient on-the-fly programming. Operators often find manual programming invaluable for activating new D-Star repeaters encountered during travel or for participating in local nets where specific G2 or G3 gateway configurations are required. While software like _CS-51_ offers convenience for bulk programming, the ability to manually input frequencies and D-Star parameters ensures operational flexibility. This approach also helps hams troubleshoot connectivity issues by verifying individual settings directly on the transceiver, ensuring proper D-Star registration and gateway access.

A portable swiss quad antenna project made with components and parts that can be dismounted, in German

Maker of filters, oscillators, cristals Coils, Toroidal Inductions, Solenoids, Bifilar wound Solenoids, Trifilar Solenoids and Transformers Located in Kansas City, Missouri

Personal site of Russian DXer Dmitri Mezin. Contains a fresh edition of his Signal bulletin, archive of all previous issues and QSL gallery.

An Energy Analysis at an Impedance Discontinuity in an RF Transmission Line

Le radio blog mondial, hosted on MSN Spaces, focused on shortwave listening (SWL) activities and DX news. The platform served as a blog for Guy, detailing his SWL experiences and observations of radio signals from various global broadcasters and utility stations. Content included reports on propagation conditions, reception quality, and identification of stations across the shortwave spectrum. The blog regularly featured updates on DX newsletters and bulletins, providing a resource for SWL enthusiasts seeking information on rare or distant signal catches. It covered topics relevant to the SWL community, such as antenna setups for improved reception and techniques for identifying obscure transmissions. The site aimed to share insights into the dynamic world of international broadcasting and clandestine operations. Specific entries often detailed frequency observations and time-of-day reception logs.

There are several reasons that can cause coax line radiation, most of them are related to wrong or missing use of a balun, but none can be imputed to load mismatch.

Observing extremely slow CW (QRSS) signals requires specialized reception and display techniques, often involving long-term signal integration to make faint traces visible. This resource compiles numerous screenshots from active QRSS grabbers globally, providing a visual record of signal propagation and operational activity on specific amateur bands. Each entry typically includes the callsign of the grabber station, its grid square, and often the band being monitored, such as 40 meters or 30 meters. The compendium presents a diverse array of grabber outputs, with examples from North America, Asia-Pacific, and Europe. Notable stations featured include _W5GB_ at New Mexico State University, _VE1VDM_ in Canada, and _I2NDT_ (the author's own grabber). The collection illustrates the unique visual signatures of QRSS transmissions, where signals appear as faint lines or patterns against a noise floor, often over extended periods. The utility of such a collection lies in its ability to demonstrate real-world QRSS signal characteristics and the geographical distribution of active grabber sites. It serves as a historical snapshot of QRSS activity, allowing operators to compare signal traces and observe propagation phenomena across different continents.

Homebrew Tubes/LDMOS amplifiers, Antenna, accessories, adventures in 9Q, DX, UN missions, Contests, and more.

Digital voice on Amateur Radio - devoted to the discussion of digitized voice and data over analog emission modes.

Constructing a high-power 70cm solid-state amplifier presents unique challenges, particularly when aiming for 500 watts output using modern LDMOS devices. This resource details the author's experience building a 70cm amplifier based on a _Freescale MRFE6VP5600H_ transistor, initially from an RFHAM kit. It meticulously outlines the necessary modifications to achieve advertised performance, including optimizing input and output matching, correcting bias circuitry, and ensuring proper output balun connections for stability. The author shares specific adjustments, such as trimming the prototyping board for better transistor fit, drilling additional mounting holes for improved heat sinking, and replacing original matching capacitors with a single _20pf MIN02 metal mica_ for superior output. A critical fix involved jumpering gate decoupling pads to balance the push-pull transistor halves, which increased output to 580W and improved IMD. The resource also highlights a crucial correction to the output balun connection, initially reversed in the _Dubus_ article schematic, which resolved intermittent stability issues. Test results are provided, showing input power, output power, and drain current at 50V, demonstrating the amplifier's performance after modifications. This practical account offers valuable insights for hams undertaking similar high-power UHF amplifier projects, especially those working with LDMOS devices and kit-based constructions.

Approximately 2.8% annual decline in Australian amateur radio licenses was observed over the five years leading up to 2002, a trend that prompted further analysis of the country's amateur population. This resource examines licensing statistics and demographic shifts within the Australian amateur radio community between 1998 and 2007, utilizing available data to identify patterns in license issuance and renewal. The study focuses on **population trends** and the underlying factors contributing to changes in the number of active **amateur radio operators**. It provides insights into the health and growth trajectory of the hobby in Australia during this specific period. Understanding these demographic shifts is crucial for clubs, regulatory bodies, and equipment manufacturers to adapt strategies and foster engagement.

The _ISS Detector_ Android application, with over 5 million downloads, offers precise predictions for visible passes of the International Space Station. It notifies users minutes before an overhead pass, integrating local weather conditions to ensure optimal viewing opportunities. The core functionality focuses on the ISS, but in-app purchases extend its capabilities to track other celestial and artificial objects. Optional extensions, available via in-app purchase, allow users to monitor dozens of amateur radio and weather satellites, providing real-time transmitter information and Doppler frequencies. Additional extensions cover _Starlink_ satellites, the _Hubble Space Telescope_, rocket stages, bright satellites, comets, and planets, expanding the scope beyond the ISS to a broader range of observable space phenomena. The app's interface is designed for ease of use, displaying pass times, directions, and elevation. It adapts predictions based on the user's GPS location, ensuring accurate local forecasts. The latest update, dated April 3, 2026, includes corrections for magnitude values and various speed and stability optimizations.

Personal Blog devoted to ham radio topics, amateur radio issues, social impact of ham radio and opinion.

About DRM, the DRM standard, emission types, upfrading your old HF RX to DRM

Q15X25 is a packet modem with a KISS/AX.25 interface designed for HF transmission of AX.25 packets and TCP/IP using Automatic Repeat reQuest (ARQ) and forward error correction (FEC).

A well done introduction to Packet Radio by WB9LOZ

Established around 1968, the Wichita Amateur Radio Society (W.A.R.S.) N5WF provides a central hub for amateur radio operators in the Wichita Falls, Texas area. The society actively supports local ham radio interests, fostering community engagement and technical development among its members. W.A.R.S. is known for its commitment to public service communications and promoting the amateur radio hobby through various activities and educational initiatives. The society's activities often include field operations, technical presentations, and participation in emergency communications drills, which align with its mission to support the amateur radio community. Members frequently engage in _DXing_ and _contesting_, sharing their experiences and knowledge to help others improve their operating skills. The club also maintains local repeaters, providing essential infrastructure for regional communications.

Provides broadcast times, frequencies and power of the network emissions. Airs mediumwave, FM, shortwave and RealAudio broadcasts

How to measure the characteristic impedance of a unknown transmission line using MiniVNA

Operating the _Icom IC-746_ HF/VHF transceiver often presents specific technical questions, and this resource compiles a comprehensive Frequently Asked Questions (FAQ) document in an ASCII text format. It details common inquiries and solutions related to the rig's functionality, accessories, and potential modifications. The content is structured into distinct sections addressing general information, power supplies, antennas, microphones, keyers, amplifiers, TNC integration, and optional IF filters. The FAQ provides practical guidance on topics such as configuring the internal automatic antenna tuning unit (ATU), selecting appropriate power supplies, and understanding microphone pin-outs. It also delves into advanced subjects like computer control via CI-V, wiring for PSK31 operation, and troubleshooting common issues like low S-meter readings on 2m FM or loose tuning shafts. Specific questions cover the installation of optional IF filters, comparing Inrad versus Icom filters, and optimizing filter combinations for various modes. Furthermore, the document outlines various hardware and firmware modifications, including those for increasing monitor volume, replacing LCD driver transistors, and implementing a "poor man's TCXO." It even touches upon untested modifications, such as replacing PIN diodes in the demodulator. The FAQ also lists manual errata and discrepancies, offering a robust knowledge base for IC-746 owners seeking to optimize their station or resolve operational challenges.

The NCVEC is a not-for-profit voluntary association, with membership comprised of the various Federal Communications Commission (FCC) certified Volunteer Examiner Coordinators (VECs).

A presentation of the NBEMS and the importance of data transmission in Digital EmComm.

Understanding the operational impact of Broadband over Power Line (BPL) on amateur radio communications is crucial for any radio amateur, especially given the potential for significant radio frequency interference (RFI). This ARRL tutorial delves into the technical aspects of BPL, explaining how the technology operates by transmitting data over existing electrical power lines, which can inadvertently radiate broadband noise across various amateur bands. My own field experience, particularly on the lower HF bands, has often involved tracking down noise sources that exhibit characteristics consistent with BPL emissions, making this a pertinent topic for maintaining clear receive conditions. The resource further details the specific FCC rules and regulations implemented to restrict BPL deployment. These regulations aim to protect licensed radio services, including amateur radio, from harmful interference. It outlines the technical standards and operational limitations imposed on BPL systems to minimize their impact on the electromagnetic spectrum, a critical aspect for contesters and DXers alike. For those engaged in RFI mitigation, the tutorial provides a foundational understanding of the regulatory framework that can be leveraged when addressing BPL-related interference issues. It serves as a valuable reference for hams seeking to comprehend the technical challenges and regulatory solutions surrounding this pervasive noise source.

Windows Logbook, contest and award system available in free and paid version. Product is dismissed and usnupported author is SK.

Design a parallel circular wire balanced transmission line with this online calculator. This calculator is a tool for designing balanced transmission lines with a specific desired characteristic impedance Zc and made of parallel circular conductors of a given diameter d.

PACTOR can be viewed as a combination of two earlier digital modes, packet radio and AMateur Teleprinting Over Radio (AMTOR). PACTOR provides improved throughput because its transmission speed adapts to the quality of the link and it uses Huffman compressed characters.

This resource, a blog from the Penang Amateur Radio Club (PARC), offers insights into various aspects of amateur radio in Malaysia. One post details monitoring Automatic Terminal Information Service (ATIS) on the 2m band, providing specific frequencies like 122.750 MHz AM for Butterworth and 126.400 MHz AM for Penang, along with sample aviation weather and operational data. Another entry critiques the lengthy and costly process of obtaining an amateur radio license in Malaysia, contrasting it with the more streamlined FCC licensing system in the United States, citing a 1-year wait and RM 414 (USD 125) for 10 years in Malaysia versus 3 weeks and USD 14 for 10 years in the US. The blog also covers internal club matters, such as the 2007 Annual General Meeting (AGM) attendance and council elections, highlighting member dissatisfaction with outdated newsletters and a call for "reformasi." Additionally, it presents local phonetic alphabets in Bahasa Malaysia and Chinese, and discusses monitoring AM broadcast bands for international stations like Voice of America on 1575 kHz and Zhong Yang Ren Min Guang Bo Dian Tai on 1134 kHz, offering alternatives to local 2m repeater chatter. The author, "firstclass," shares personal observations and criticisms regarding the Malaysian ham radio landscape.

Broadband over power lines (BPL) is a technique for transmission of high speed data (broadband Internet) over powerlines. Access BPL technology injects radio frequency energy into powerlines which were not designed for transmission of radio frequency energy, and leak substantial energy that causes interference to radiocommunications service

NOAA HRPT - High Rate Picture Transmission, the main source of high quality data from polar orbiting meteorological satellites

West St. Louis County Police and Fire Live Audio Feed