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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.

HF Beam Calculator for Amateur Radio and CB Communications

How to calculate range for a VHF antenna with a simple formula and how to increase VHF coverage.

Platinum coast amateur radio society (pcars) w4mlb - melbourne florida, pcars provides hf, vhf, and uhf communications for any police fire and rescue emergency

This article reports and collect some frequencies used during 2020 Ukraine war and reported as being used by army forces. HF communications are still a crucial part of military communications and can ben monitored on web sdr radios available on the internet.

Amateur radio operators seeking local community and emergency communications involvement often look for active clubs. The Rock River Radio Club (RRRC) provides a platform for hams in Wisconsin to participate in weekly nets and monthly meetings, fostering camaraderie and operational readiness. Their activities include regular ARES/RACES nets, which are crucial for maintaining proficiency in emergency communication protocols and equipment. The club hosts weekly nets on both VHF/UHF and HF bands, allowing members to practice various modes and frequencies. These include a Monday evening net on the Juneau Repeater at _146.64 MHz_ (PL 123.0) and a Thursday evening net on the Knowles Repeater at _442.975 MHz_ (PL 123.0). An HF net operates on Saturdays at **3.947 MHz**, with an additional ARES/RACES net on Sundays at **3.967 MHz**. Monthly club meetings are held on the first Tuesday of each month at 7 PM in Randolph, Wisconsin, providing a consistent gathering point for members and prospective hams. The club also engages in public demonstrations, such as those at the Experimental Aircraft Association (EAA) Dodge County Chapter Fly-In, showcasing amateur radio to a broader audience.

Australian manufacturer of HF Communications Antenna Systems for Military, Comercial, Mining & Amateur Radio

SPX Communication Technologies, operating under the TCI International brand, presents a range of radio frequency (RF) solutions primarily for government, defense, and commercial sectors. The offerings include advanced systems for spectrum monitoring, communications intelligence (COMINT), and high-frequency (HF) and medium-frequency (MF) broadcasting and communication antenna systems. Specific product lines encompass _Blackbird_ COMINT systems, _Scout_ spectrum monitoring receivers, and various antenna arrays designed for robust performance in challenging RF environments. The resource details the capabilities of these systems, such as wideband signal detection, direction finding (DF), and signal analysis, crucial for intelligence gathering and regulatory compliance. It also highlights the engineering behind their antenna designs, which are optimized for specific frequency ranges and operational requirements, including high-power broadcast applications and secure military communications. The information presented emphasizes the integration of hardware and software for comprehensive RF situational awareness. The company's focus on empowering partners to "Command the Spectrum" underscores its commitment to delivering critical tools for signal interception, analysis, and management across diverse operational landscapes.

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.

100-watt UHF repeater (444.500+ PL100) and a 6-meter repeater (53.68- PL114.8) are owned and maintained by South County ARES to support emergency communications for Belmont, East Palo Alto, Foster City, Menlo Park/Atherton, Redwood City, San Carlos, San Mateo, and Woodside/Portola Valley. The organization emphasizes training, including weekly nets and practice sessions, to improve message passing accuracy and brevity, crucial skills for **emergency communication**. Resources like the San Mateo County Sheriff's Office Ham Radio Frequency Plan Recommendation and **Chirp-compatible CSV files** for Baofeng radios are provided. Participation in community events is encouraged to build skills and connections among members. The group operates without collecting dues, relying on donations and member contributions of time and expertise. Training pages are available for new hams and those seeking license upgrades, along with a "Tips for New Hams" section. The site also features a monthly calendar of events, including board meetings, general meetings, and hospital nets, alongside a newsletter, the "South County Communicator," and various operational documents like the Net Control Manual and SCARES Handbook.

The Utility DXers Forum (UDXF) provides a centralized platform for exchanging news and information concerning utility radio stations and signals operating within the 0 to 30 MHz spectrum. It specifically excludes broadcasting, pirate, and amateur radio transmissions, concentrating instead on a diverse array of other signals. The resource details the types of stations covered, including maritime coastal and ship stations, aeronautical ground and aircraft communications (voice, HFDL, Selcalls, Volmet), military operations, various beacons (NDB, driftnet, propagation, pirate, high-frequency), fax transmissions, numbers stations, diplomatic communications, clandestines, and other unusual signals. Further content addresses radar systems such as Over-the-Horizon, Ocean Wave, and CODAR, alongside ionosondes, chirpsounders, ALE-systems, Selcall-systems, and tone calls. Experimental stations and standard frequency and time stations are also within its scope. The forum also acknowledges utility radio-related amateur events like the International Lighthouse Weekend and Night of Nights, providing a broader context for listeners. The site offers sections for modes, hardware, software, a utility radio archive, digital BC & HF conditions, and a utility radio club archive, along with QSLs and pennants.

A summary, overview or tutorial covering the basics of Meteor Scatter or Meteor Burst Communications, a form of radio signal propagation often used at VHF.

Near Vertical Incidence Skywave propagation is a form of radio wave propagation used on the MF and HF bands to provide radio communications and broadcasting coverage over short distances, especially where the terrain contains obstacles.

Details the Big Thunder Amateur Radio Club (BTARC), a long-standing amateur radio organization based in Boone County, Illinois, established in 1962. It covers the club's mission to enhance the skills of local hams, promote radio knowledge, and foster social interaction among operators. The resource outlines BTARC's commitment to community service, including emergency communications support through RACES, and its active participation in events like Field Day, fox hunts, and public service communications for local races. Explains the club's history, including the establishment of its first repeater in the 1970s by members WD9JGH, Mike George, K9ORU, and Claude Horsman, WB9PMM, using a VHF Engineering kit and a Sinclair duplexer. It provides specifications for two club-maintained FM repeaters: a 2-meter repeater on 147.375 MHz (+600 KHz shift, 100.0 Hz PL tone) and a 70-cm repeater on 442.825 MHz (+5 MHz shift, 114.8 Hz PL tone). The club hosts a weekly 2-meter net on Sundays at 7:00 PM local time and holds monthly meetings on the second Thursday at the Spring Township Building in Belvidere, IL.

The VU2BBB repeater, located in Matheran, Maharashtra, commenced operations in the late 1980s, a significant undertaking by the Bombay Repeater Society. This repeater facilitates VHF and UHF communications for local amateur radio operators, providing extended range and improved signal reliability across challenging terrain. Its establishment marked a key development in regional amateur radio infrastructure, offering a crucial node for local nets and general QSO traffic. The repeater's operational parameters include specific input and output frequencies within the 2-meter band, typically utilizing a standard offset. CTCSS tones are often employed to mitigate interference and ensure selective access for authorized users, a common practice for repeaters in densely populated areas. Regular maintenance and upgrades ensure _VU2BBB_ remains a reliable asset for the amateur community, supporting emergency communications and daily amateur radio activities. The _Bombay Repeater Society_ continues to oversee its operation, reflecting a sustained commitment to local ham radio services.

Licensed since February 1991, IK1QBT Tony Gallo shares insights into his extensive amateur radio journey, highlighting his involvement in **DXpeditioning** and contesting. His page lists several callsigns he has operated under, including 3A/IK1QBT, TK/IK1QBT, IA5/IK1QBT, and as an operator for 4U9ITU and 4U0ITU, showcasing a broad range of international activity. Tony's background as an ex-Radio Officer in the Merchant Navy and a Radio Operator for the Italian Maritime Coast Radio Station "ICB/GenoaRadio" provides a unique perspective on radio communications. He is an active member of ARI, INORC, and HSC, and serves as secretary for the Marconi Club ARI LOANO, underscoring his deep engagement within the amateur radio community. His participation in multi-multi operator contest teams like IH9P in the CQWW-CW 2006 and the HQ Italian ARI Contest Team in the IARU HF (2004-05-06) demonstrates a strong commitment to competitive operating, primarily on **CW** and HF bands.

The _DL4EBY_ resource page provides operational data for Earth-Moon-Earth (EME) communications on VHF, UHF, and microwave bands. It includes a 432 MHz and above EME Directory in ASCII and HTML formats. _K1RQG_ provides 432 MHz and up EME Net Notes. EME Operating Procedures were confirmed at the EME Conference 2002 in Prague. A lunar calendar from _DL7APV_ is linked via _G4CCH_'s pages. Resources for CW contest operation include the _PED411i.zip_ file. A "Cheat Sheet 432 & up" is available for EME operations. The _Dubus_ 70cm CW EME Activity Event is referenced for moonbounce activity. DXZone Focus: Operating Activity | Global | EME, CW | VHF, UHF, Microwave

This Website is your resource for learning and enhancing your Morse Code / CW Communications skill

Comprod Communications specializes in the design and manufacturing of RF communication solutions, including a comprehensive range of antennas, duplexers, multicouplers, and combiners. The resource details their product categories, which encompass base station antennas, mobile antennas, transit antennas, and disguised antennas, alongside mounting solutions and in-building systems. It highlights the company's 40-year history in adapting offerings to client needs and anticipating industry trends, emphasizing product durability and low maintenance for harsh environments. The company's offerings are presented as high-quality, designed to withstand extreme conditions from Arctic cold to equatorial heat and humidity. The site mentions solutions and technical sales support, training, and site analysis and system design as part of their service portfolio. It also references being a market leader trusted by over 1,000 customers worldwide, positioning itself as a partner for RF communication needs.

RF amplifier products from NP Technologies, Inc. encompass a wide array of specialized designs, including highly linear Class A broadband amplifiers, crucial for maintaining signal integrity across various frequencies. Their portfolio also features cell band amplifiers, specifically engineered for cellular communication infrastructure, and pulse amplifiers, which are vital in applications requiring high-power, short-duration signal bursts. The company's manufacturing capabilities extend to AM and FM broadcast amplifiers, supporting radio transmission systems, and military VHF amplifiers, designed to meet rigorous defense specifications for robust and reliable communications. NP Technologies, Inc. emphasizes comprehensive development, design, manufacturing, and testing processes for all its RF amplifier offerings. This integrated approach ensures that each product, from initial concept to final deployment, adheres to stringent performance and reliability standards. The company's expertise in these areas allows for the creation of custom solutions tailored to specific client requirements, addressing complex RF challenges in diverse operational environments. Their product range demonstrates a commitment to serving multiple sectors, including commercial broadcasting, telecommunications, and defense. The focus on specialized amplifier types underscores their technical depth in RF engineering.

The Badger Contesters is a club of like-minded hams who are interested in VHF/UHF/SHF weak signal communications. Our geographic focus is Wisconsin, however hams in Northern Illinois, Michigan's UP, and Eastern Minnesota are welcome to join us.

The Barrow Amateur Radio Emergency Service Club (BARES) serves as a local hub for amateur radio operators in Barrow County, Georgia, focusing on community engagement and emergency preparedness. Established in 2007, the club provides a platform for hams to connect, share knowledge, and participate in various radio activities. Members often engage in public service events, offering communications support, and conduct regular meetings to discuss technical topics and operational procedures. BARES emphasizes the importance of emergency communications, with members frequently training for and participating in simulated emergency tests (SETs) and real-world disaster response scenarios. The club maintains a focus on local area coverage, ensuring reliable communication infrastructure is available when traditional systems fail. Their activities often involve operating on _VHF_ and _UHF_ bands for local nets and _HF_ for longer-distance emergency coordination. Key activities include field day operations, technical workshops, and supporting local events with radio communications.

Presents the full owner's manual for the _Drake R-4C_ communications receiver, specifically a late version edition. This resource outlines the comprehensive operational instructions, covering everything from initial setup and tuning to advanced features and controls. Hams can reference detailed diagrams and explanations for proper signal reception across various amateur bands. The manual includes critical information for alignment procedures, ensuring the receiver performs to its optimal specifications. It details the steps required for calibrating the internal circuitry, which is essential for maintaining sensitivity and selectivity over time. My experience with vintage Drake gear confirms the value of these original documents for accurate adjustments. Furthermore, the document provides insights into troubleshooting common issues and performing routine maintenance. It serves as an authoritative guide for anyone operating or servicing this classic piece of amateur radio equipment, helping to preserve its functionality for years of DXing and ragchewing.

The Eastman Amateur Radio Club (VE4TG) operates a **VHF repeater** at 146.73 MHz and a **UHF repeater** at 444.15 MHz, both located at the Manitoba Hydro gas-fired generating station near Selkirk. These repeaters are situated on the power plant roof, leveraging its infrastructure for antenna placement. The club's primary objective is to offer a reliable local repeater site for members in the East Selkirk and Lockport areas, ensuring consistent amateur radio access. Beyond routine communication, the club maintains a standby communications link to assist local municipal authorities during emergencies requiring communications support. The unique repeater site location at a generating station provides a robust backup power supply, enhancing reliability. The club also organizes activities such as a weekly net and participates in WARC Field Day, fostering community engagement and operational readiness.

This DIY vertical multi-band Windom antenna offers a practical and effective solution for amateur radio enthusiasts seeking a versatile and compact antenna for HF communications. Its simplicity of construction, multi-band capability, and favorable performance make it a valuable addition to any radio shack. The article provides detailed instructions on constructing the antenna and balun, along with diagrams and component specifications. Field tests demonstrated successful contacts with stations across Europe and North America on 14, 18, and 28 MHz. The antenna exhibited comparable performance to a W3DZZ dipole and outperformed a Cobweb antenna on 18 MHz. Low noise levels were observed, effectively suppressing background noise.

The High Point Amateur Radio Club (HPARC), operating under the callsign W4UA, provides a central hub for amateur radio enthusiasts in High Point, North Carolina, and surrounding communities. The club's website outlines its long-standing traditions and civic service, which date back to the 1930s, highlighting its sustained leadership and strong membership support over decades. It serves as a resource for individuals interested in obtaining or upgrading an FCC amateur radio license, offering assistance through direct contact with club officers. The site also features a newsletter archive for meeting notices and information on club activities, including Field Day. HPARC's diverse membership shares a common interest in the amateur radio hobby, encompassing various aspects such as VHF, UHF, HF, and digital modes like D-STAR. The club's commitment to public service is evident through its involvement in ARES and Skywarn, alongside educational initiatives for new hams and those pursuing license upgrades. The site also lists repeaters and provides information on emergency communications, technical projects, and participation in events like DXCC and contests, reflecting the broad interests of its members.

High Speed Multimedia (HSMM) radio, as introduced by John Champa, K8OCL, represents a significant advancement in amateur radio's digital capabilities, moving beyond traditional keyboard modes like packet radio. This initiative, driven by ARRL's Technology Task Force, focuses on developing high-speed digital radio networks capable of up to 20 megabits per second. HSMM primarily facilitates digital voice (DV) and digital video (ADV), enabling real-time video transmission from emergency scenes to an EOC without expensive ATV gear, often requiring only a laptop, a PCMCIA card, a digital camera, and a small antenna. The working group's initial efforts concentrate on cultivating microwave skills within the amateur community to build and support portable and fixed high-speed radio-based local networking, or **RLANs**. These networks prove invaluable for RACES and ARES organizations, as well as homeland security and other emergency communications. Field Day exercises and simulated emergency tests (SETs) are encouraged to hone skills in rapid site surveys and deploying broadband HSMM microwave radio networks, with examples like linking Field Day logging stations or antenna test results at the Midwest VHF-UHF Society Picnic 2003. Getting started with HSMM often involves adapting off-the-shelf **IEEE 802.11** (WiFi) equipment to comply with amateur radio regulations, typically operating in the 2.4 GHz ISM bands. While consumer WiFi gear has range limitations under Part 15 rules, proper setup under amateur regulations can extend coverage significantly, with test networks like the Hinternet achieving 5-15 mile ranges at 54 M bit/s using small mast-mounted dish antennas. Careful selection of equipment with external antenna ports, high transmit power, and low receive sensitivity is crucial, along with using low-loss coaxial cable like LMR-400 for optimal performance at these frequencies.

A personal blog about amateur radio activities, including homebrew, bitx, ubitx, mcHF, JT65, FT8 and more digital communications.

Amateur radio repeaters, often designated by an "R" number like _R6_ or _R5_, serve as crucial infrastructure for extending VHF/UHF communications range. This resource from Essex Ham explains the fundamental concept of a repeater, detailing how it receives on one frequency and simultaneously retransmits on another, typically with a 600 kHz offset for 2-meter repeaters. Understanding the input and output frequencies, along with the required CTCSS tone, is essential for successful access, ensuring your signal is processed and relayed across a wider service area. The article clarifies the importance of using the correct _CTCSS_ (Continuous Tone-Coded Squelch System) tone, often referred to as a sub-audible tone, to activate a specific repeater. It also touches upon the concept of _simplex_ operation versus repeater use, highlighting the benefits of repeaters for mobile and handheld transceivers. Proper operating procedures, such as listening before transmitting and keeping transmissions concise, are emphasized to maintain good amateur practice on shared repeater assets.

Discovering a solution for limited space, the inverted L HF antenna emerges as a stellar performer. Half the size of a dipole, it ensures optimal installation in restricted areas, maintaining superb transmission (TX) and reception (RX) characteristics. Spectrum Communications' multi-band version, featuring traps, proves even more space-friendly without compromising performance. A fiberglass pole offers sturdy support, while proper grounding, an RF choke, and occasional tuning contribute to a high-performing and reliable antenna system.

QSK 2500 enhances HF amplifiers by enabling full break-in (_QSK_) operation, allowing for seamless communication during CW transmissions. This device supports **all** HF transceivers that are QSK-compatible, ensuring versatility across various setups. The QSK 2500 facilitates quick switching between transmit and receive modes, which is crucial for effective DXing and contesting. With its straightforward installation, operators can achieve **improved** responsiveness in their communications without the need for extensive modifications to their existing amplifiers. This project is particularly beneficial for those engaged in high-speed CW operations, where timing is critical.

The Davis County Amateur Radio Club (DCARC) serves as a focal point for licensed amateur radio operators in Davis County, Utah, fostering community and promoting radio communication interests. Members engage in various aspects of the hobby, including local nets, public service events, and technical discussions. The club's activities often involve supporting emergency communications preparedness and providing opportunities for skill development among its members. DCARC maintains a presence in the local ham radio scene, facilitating contacts and knowledge exchange. They frequently participate in events like _Field Day_ and offer resources for those interested in obtaining or upgrading their amateur radio licenses. The club also supports local repeaters, ensuring reliable VHF/UHF communication infrastructure for the region. Their website, dcarc.net, provides information on club meetings, upcoming events, and contact details for prospective members.

The Delta Amateur Radio Club (DARC) serves as a community organization for amateur radio operators in the Memphis, Tennessee area, providing resources and activities centered around two-way radio communication. The club maintains the W4BS repeater system, which operates on 147.060 MHz with a +600 kHz offset and a 100 Hz PL tone, facilitating local VHF communications. DARC actively supports the Amateur Radio Emergency Service (ARES), preparing members for public service and disaster response through training and coordinated drills. The club also hosts regular meetings and events, fostering camaraderie and technical skill development among its members. Membership in the Delta Amateur Radio Club offers opportunities for participation in various amateur radio activities, including field day operations and local nets. The W4BS repeater provides reliable coverage across the Memphis metropolitan area, serving as a critical asset for both daily ragchewing and emergency traffic handling. DARC's affiliation with the Amateur Radio Relay League (ARRL) ensures access to national resources and advocacy, reinforcing the club's commitment to promoting amateur radio and public service within the community. The club's focus on emergency communications strengthens local preparedness.

Amateur radio operators in northwestern Wisconsin often seek local community and technical support, which the Barron County Amateur Radio Association (BCARA) provides. This organization facilitates regular meetings, nets, and events, connecting hams across the region for shared learning and operational experiences. Members engage in various aspects of the hobby, from contesting and DXing to emergency communications and technical projects, reinforcing local Elmering traditions. The BCARA maintains a presence on social media, including a Facebook group with over **100** members, enabling real-time communication and event coordination. The club also supports local public service events, demonstrating the practical utility of amateur radio. Their activities encompass both VHF/UHF operations and _HF bands_, ensuring a broad appeal to operators with diverse interests and equipment setups.

TelExpress provides a wide array of RF and data connectivity products, including various coaxial cables like LMR-series equivalents, fiber optic cables, and Ethernet solutions. Their inventory supports diverse amateur radio and telecommunications requirements, from antenna feedlines to network infrastructure. The site emphasizes bulk cable availability and custom assembly services, catering to both individual hams and larger installations. Key offerings include _low-loss coax_ for HF and VHF/UHF applications, along with a comprehensive selection of RF connectors. They also supply patch panels, Ethernet cables (Cat5e/Cat6), and general wireless and telecom hardware. Customers can find components for building robust station infrastructure, ensuring signal integrity across various frequency bands. The platform facilitates procurement of essential parts for new builds or upgrades, supporting reliable RF system performance.

Online HF Communication prediction system provided by the Australian Governament Buerau of Metereology allow to predict usable frequency rage for radiocommunications between two stations allowing to specify frequency and date range. This tool allow calculation with different methods and algorithms

Explains the fundamental purpose of a repeater, detailing how these automated relay stations overcome distance and terrain limitations for VHF/UHF communications. It traces the historical development from early Bell Telephone Labs "relay" stations in 1922 to Art Gentry, W6MEP's, pioneering K6MYK amateur radio repeater in the mid-1950s, which remains active today. The resource clarifies the distinction between simplex and duplex operation, including the unique function of a "parrot repeater" for single-frequency recording and playback. Delving into the internal workings, the guide breaks down a repeater into its core components: the antenna system, feedline (often _Heliax_ or hardline for minimal loss), duplexer, receiver, transmitter, and controller. It emphasizes the critical role of the duplexer in preventing receiver desensitization by isolating transmit and receive signals, even with distinct frequencies. The discussion highlights the importance of high-performance, durable antennas and low-loss feedlines, citing examples of equipment installed in the 1960s and 1970s that are still in perfect working order. Operating a repeater is also covered, with an explanation of frequency offset (e.g., the 600 kHz standard for 2 meters) and the function of _CTCSS_ (PL tone) for access. It outlines standard input/output offsets for various bands, from 6 meters to 23 centimeters, while noting regional variations. The guide also touches on features like autopatch and Digital Voice Recorders (DVRs), providing a solid foundation for understanding repeater technology and usage.

HF digital mode transmissions, voice transmissions in HF and VHF Bands collected in several XLS files by Relic Radio communications

This page provides a list of UK scanner frequencies, specifically focusing on the Police UHF bands. It is a useful resource for hams interested in monitoring and listening to police communications in the UK. The page offers a detailed breakdown of frequencies used by the police, allowing hams to stay informed and connected to emergency services in their area.

This project introduces the SN 1/8 mobile antenna, a compact and mechanically stable alternative to traditional 1/41/4 or 5/85/8 wave antennas. Designed for VHF/UHF mobile communications, this 20 cm antenna offers superior performance in moving environments. Its spherical radiation pattern enhances reflections, providing a 2 dB gain. Ideal for vehicle use, it is discreet, easy to install, and resistant to vibrations, making it a practical choice for mobile users seeking reliable and efficient communication. In French.

Ribbit is a novel digital text messaging mode for VHF/UHF communications for recreational and emergency use which radically increases the density of information transmitted by spectrum used. It leverages the computing power of the modern smartphone to increase the capabilities of any Handy Talkie without requiring any additional hardware or cable. A Ribbit message is fixed in duration at 1250 milliseconds. It is sent over audio modulation with a 2kHz bandwidth centered on 1.5kHz. It is preceded by 400ms of white noise to open analog squelch circuits.

The HB9CV antenna calculator aids amateur radio enthusiasts in designing antennas for VHF and UHF bands. By inputting the working frequency, users can obtain crucial dimensions like dipole lengths and distances. The tool, based on the HFSS antenna model, provides data on impedance, VSWR, and gain, optimizing front/back radiation ratios. It includes tips for fine-tuning using a Г-matching balun and compensating capacitor, ensuring effective performance and minimal VSWR for enhanced radio communications and direction finding.

The resource details active HF radio networks maintained by foreign ministries for diplomatic communications, specifically listing operational schedules and frequencies. It currently covers networks for Bulgaria, Czechia, Egypt, North Korea, Russia, Tunisia, and the United States. The content provides specific operational parameters for these government-run shortwave stations. Information includes details on _legacy modes_ of operation and specific transmission times. The site also includes schedules for various _number stations_ which often utilize similar HF spectrum allocations. The data presented aids in identifying and monitoring these unique, non-amateur radio signals across the shortwave bands. Specific sections are dedicated to the networks of North Korea and the United States, offering granular data for each.

Robust PACKET, developed by Spezielle Communications Systeme GmbH & Co. KG (SCS), is an OFDM variant of the amateur PACKET mode specifically engineered for HF operation. This mode utilizes a 500 Hz bandwidth with 60 Hz carrier spacing, employing OFDM with 8 DBPSK or DQPSK carriers. It supports 200 bps using BPSK and 600 bps with DQPSK, with each subcarrier operating at a constant rate of 50 Bd. Robust PACKET leverages the AX-25 frame protocol for data transmission, similar to standard PACKET. Compared to traditional PACKET, Robust PACKET demonstrates enhanced resilience against multipath propagation and fading effects, critical for reliable HF communications. It also exhibits a more efficient spectral footprint, with sidebands extending only to 500 Hz, whereas 300 Bd FSK PACKET can produce sidebands up to 730 Hz. Operational frequencies for Robust PACKET include 3.61 MHz, 7.0473 MHz, 10.1473 MHz, and 14.1033 MHz, with specific regional frequencies also documented. Decoding software options for Robust PACKET include Wavecom W-Code and Wavecom W-Spectra. The mode is primarily supported by SCS's 'Tracker / DSP TNC' hardware.

Learn how to design a Hentenna antenna, a portable asymmetrical double-loop antenna ideal for amateur HF or VHF bands. This page provides details on constructing and optimizing the antenna for maximum performance in DX communications. Discover how altering the antenna's vertical feed section can adjust the VSWR resonant frequency and how changing the support pole's position can alter the beam direction. Originally developed by Japanese 6-meter operators, the 'Hentenna' offers a unique design that allows for horizontal polarization when vertically oriented. Explore radiation patterns, VSWR charts, and antenna currents diagrams to optimize your antenna's performance for long-distance contacts.

Listen to HF communications via the KiwiSDR online receiver located in Badgad IRAQ locator LM23fh. This web receiver is running a MLA 30+ antenna and can be tuned easily on all HF bands from 10 to 80 meters.

Icom IC-R75 tabletop HF communications receiver came onto the market back in 1999 and was taken out of production in late 2015. Frequency coverage is from 30 hz right to 60 MHz. This allows one to catch the 6 Meter amateur band as well.

Learn how an experienced ham radio operator designed and built a compact shack in their motor home. Discover the considerations, challenges, and solutions involved in setting up a radio station in a small space without damaging the vehicle. Find out which radios were chosen for VHF/UHF scanning, HF communications, and QRP operations. Get insights on cabinet design, speaker placement, and radio cabling for a functional and portable ham radio setup on the road.

Spectrum Communications specializes in a range of communication products, including antennas and cables for HF, VHF, and UHF (RX & TX), CB radio boards, electronic components, RX & TX boxed products, PCB products, and general accessories for testing and alignment.

The Olivia digital mode, a **Multi-Frequency Shift Keying (MFSK)** radioteletype protocol, is specifically engineered for robust communication under difficult propagation conditions on shortwave radio bands from 3 MHz to 30 MHz. Developed by Pawel Jalocha in 2003, Olivia signals can be decoded even when the noise amplitude exceeds the digital signal by over ten times, making it highly effective for transmitting ASCII characters across noisy channels with significant fading and propagation phasing. Early on-the-air tests by Fred OH/DK4ZC and Les VK2DSG on the Europe-Australia 20-meter path demonstrated intercontinental contacts with as little as one-watt RF power under favorable conditions. Common Olivia modes are designated as X/Y, where X represents the number of tones and Y is the bandwidth in Hertz, with examples including 8/250, 16/500, and 32/1000. The resource clarifies that Olivia, unlike some other digital modes, produces a constant envelope, allowing RF power amplifiers to achieve greater conversion efficiencies and making it less prone to non-linearity. Operators are advised that **Automatic Level Control (ALC)** can be set higher than no meter movement for MFSK modulation, as long as it's not driven past its high limit, contrary to common misinformation about other digital modes. The Olivia community encourages voluntary channelization on suggested calling frequencies, such as 14.0725 MHz for 8/250, to facilitate initial contacts, especially for signals below the noise floor. The Olivia Digital DXers Club provides links to Groups.io, Facebook, and Discord for community engagement and offers details on QSO parties.