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One of the most useful antennas in the repertoire is the Marconi or quarter wave grounded vertical antenna. Its invention made it possible to halve the length of antennas, simplifying communications, especially at HF and below.

A quick and simple reference to various communications signals, such 10/11 Codes, Morse Code, Phonetic Alphabet, Police Color/Penal Codes, Q-Signals.

Leading supplier of low and high frequency electronic filter design products for the design of wireless telecommunications equipment, semiconductors and more

This is a packet radio software developed for amateur radio operators to provide IP communications. You can chat, send/receive e-mail, surf the web and so on via radio depending on your bandwidth. You don't need a TNC. You might have all of TNC features via SoundCard using SoundModem.

The Middle Tennessee Amateur Radio Society is composed of Hams in Middle Tennessee who are dedicated to promoting Amateur Radio, providing public service communications, and having FUN doing so.

Communications products, communication systems products, fiber optic cables, global messaging service, gyroscope and navigation systems

Meimaris Communication Equipment based in Greece

TX RX Systems Inc. offers a robust catalog of RF conditioning products, including **transmitter combiners**, receiver multicouplers, and various RF filters. Their extensive experience, spanning over 45 years in the RF and Land Mobile Radio (LMR) industries, underpins their specialized offerings. They provide solutions for in-building RF coverage, repeater systems, and general RF management, catering to the demanding requirements of professional radio communications. Their product line features **bidirectional amplifiers (BDAs)**, signal boosters, and cavity filters, essential components for optimizing radio system performance. The company emphasizes reliable solutions, leveraging decades of field-proven expertise in designing and manufacturing critical RF infrastructure. From duplexers to cell enhancers, TX RX Systems focuses on delivering high-quality RF components and integrated systems designed to ensure clear and consistent radio signal integrity across diverse operational environments.

Details Guglielmo Marconi's foundational contributions to radio communication, highlighting his 1898 Patent **7777** which introduced tuning circuits for independent simultaneous communications. Chronicles the historic transatlantic reception of the Morse code letter 'S' on December 12, 1901, from Poldhu, Cornwall, to St. John's, Newfoundland, a distance of over _3,500 kilometers_. The exhibit showcases early Marconi 10-inch spark transmitters, identical to those used on the _Titanic_, alongside Canadian Marconi crystal detector models. It also features high-end commercial receivers like the IP501, weighing **87 pounds** and originally priced at $595.00, demonstrating the robust construction and technological advancements of the era.

The Sarasota Emergency Radio Club, is an Amateur (Ham) Radio club in Sarasota, Florida, dedicated to provide emergency and public service communications.

AP Communications CB and Amatuer Electronics Sales

This online guide details the microphone pinout for the Kenwood TR-7950 transceiver, specifically addressing the wiring configuration for a dynamic mobile microphone with a **500 Ohm** impedance. It provides a pin-by-pin breakdown for the 6-pin microphone connector, identifying the function of each active pin. The resource specifies that Pin #1 is for the microphone audio (white wire), Pin #2 controls the _PTT_ (black wire), Pin #3 activates the memory down function (blue wire), and Pin #4 controls the memory up function (red wire). Pin #6 is designated as the ground connection, while Pin #5 remains unused in this configuration. The document focuses on the physical wiring necessary to restore microphone functionality to the Kenwood TR-7950, a transceiver capable of **45 watts** output on the _2m band_. It directly addresses the technical challenge of re-establishing correct electrical connections after microphone wires have been disconnected from the connector. The information facilitates proper microphone operation for simplex QSOs and other voice communications. DXZone Focus: Online Guide | Microphone Pinout | Kenwood TR-7950 | PTT Wiring

The main purpose of the county hunter's net is to facilitate the operations of those hams seeking to work all counties in the United State. It is also a useful place for CW emergency communications as there is almost always someone monitoring the frequencies.

"QEX is the ARRL "Forum for communications experimenters." QEX is published bimonthly, it features technical articles, columns, and other items of interest to radio amateurs and communications professionals

The multiuser/multitasking BayCom Packet Terminal Driver program is a general purpose communications package for communicating with a BayCom modem attached to your IBM-PC/clone in conjunction with the TFPCX Baycom driver software. The software will also work with a normal TNC if it supports KISS mode, such as the Kantronics range.

Garmin Kenwood Icom Vertex Alinco and more

A live police broadcast for the Detroit area police department. Michigan Public Safety Communications System (mpscs)

Canadiam ham radio dealer for Alinco, Alpha Delta,Bencher, Ameritron,Anli,Butternut,Comet,Daiwa,Cusfcraft,Icom,Kantronics,Laha,Vectronics,MFJ,Yaesu products

Luksa industries design and manufacture mechanically operated aluminum telescoping masts and telescoping tripods to support communications and military antennas

PSK31 is a digital communications mode which is intended for live keyboard-to-keyboard conversations, similar to radioteletype. Its data rate is 31.25 bauds (about 50 word-per-minute), and its narrow bandwidth (approximately 60 Hz at -26 dB) reduces its susceptibility to noise.

UR5FCM Log provides a centralized logging solution for amateur radio operators, designed to manage daily radio communications and integrate various digital modes. This software functions as a primary working center for a radio station, facilitating the recording and management of QSOs across different operating aspects. Since version 1.1.61, UR5FCM Log has incorporated enhanced features for digital mode operations, specifically supporting RTTY, BPSK, and SSTV. The application aims to streamline the logging process, offering tools for QSL management and general station record-keeping. It is developed for the Windows operating system, providing a graphical user interface for ease of use. The software includes capabilities for tracking various contact details and supports common amateur radio data formats for log exchange. Its development history spans from 2002 to 2005, with Igor I. Krinetsky credited as the author.

The YB7ZGP Pamaton Repeater operates on a frequency of 146.76 MHz, serving the Martapura District in Banjar, South Kalimantan, Indonesia. This VHF repeater provides local communication infrastructure for amateur radio operators in the region. The repeater's operation is managed by Syah Riyan, indicating a local amateur radio enthusiast or group maintains the station. Repeaters like YB7ZGP are critical for extending the range of VHF/UHF communications, allowing handheld and mobile transceivers to communicate over greater distances than line-of-sight. The 146.76 MHz frequency falls within the 2-meter band, a popular segment for local and regional amateur radio traffic, often utilized for emergency communications and general ragchewing. Information regarding the _Pamaton Repeater_ is presented on a blog platform, suggesting a community-driven effort to disseminate details about this local amateur radio asset.

RF shop is an Australia online retailer of Radio Communications, Electronics, RF and Microwave component products.

Establishing a robust, interconnected communication infrastructure across challenging terrain, the Island Trunk System (ITS) provides a network of open amateur radio repeaters for general and emergency communications throughout Vancouver Island, surrounding waters, and parts of the lower mainland on the West Coast of British Columbia, Canada. This system, largely off-grid, relies on solar power and batteries, necessitating careful operation, especially during night hours and low solar charging seasons, to preserve its energy resources. Maintaining the ITS involves significant effort from many hams, who appreciate adherence to regulations, including proper station identification. The system hosts a weekly social net every Monday evening at 8 PM, welcoming all participants, and also supports a Vancouver Island Region Emergency Radio Net each Wednesday at 19:15. Experimental projects like the Newcastle Ridge webcams, linked via 5.8 GHz broadband backhaul over 206 km to Nanaimo and Comox, demonstrate the innovative spirit within the ITS community. A new VHF repeater, operating on 146.880 MHz with a 141.3 Hz PL tone, was installed in Tofino, expanding system coverage.

Operating an amateur radio station often involves community engagement, and the Anne Arundel Amateur Radio Club (AARC) exemplifies this with a focus on public service and emergency communications. The club maintains repeaters, provides an Elmer program for new hams, and conducts training and testing sessions, fostering skill development across various age groups and experience levels. Members participate in activities ranging from contesting to kit building, promoting technical proficiency and camaraderie within the local ham radio community. The AARC hosts regular meetings on the first and third Thursday evenings, creating opportunities for fellowship and knowledge exchange. Their commitment extends to programs designed for kids, YLs, OMs, and both new and experienced operators, ensuring a broad appeal. This club's structure supports continuous learning and practical application of amateur radio principles, aligning with the core values of the hobby. Their emphasis on emergency preparedness highlights a critical aspect of amateur radio's public service mission.

Icom Kenwood Yaesu MyDel dealer, offer a wide range of ham radio products, transceivers, antennas, rotators, microphonrs, aerials, dummy loads, rf amplifiers and scanners based in UK

Special communications systems, the creators of pactor, TNC using DSP protocols

Radio frequency systems require robust protection against transient voltage events, which can severely damage sensitive equipment. This resource details a range of **RF surge protection** devices, including models with DC Pass, DC Block, Bias T, and Ultra Low PIM characteristics, designed to safeguard critical infrastructure. It also presents various RF filtering solutions and interconnect components, emphasizing their role in maintaining signal integrity and operational continuity across diverse applications. The site provides information on products engineered for both RF and data line protection, highlighting their utility in preventing downtime and equipment loss. Specific product categories encompass coaxial protectors, grounding items, and fiber optic solutions, indicating a broad scope of application from amateur radio installations to industrial and telecommunications networks. Furthermore, the resource mentions the availability of NOM-certified products and offers same-day shipping for many items, underscoring a commitment to rapid deployment and compliance with industry standards.

RailScan: A Place To Discuss All Aspects Of North American Railroad Radio Communications, Past Present and Future.

The South Brevard Amateur Radio Club is based in the Melbourne, Florida area and provides volunteer communications services to the public and provides a common organization for amateur radio operators in the south Brevard County area to operate under.

RTTY.COM has been established to focus on the many aspects of Amateur Radio Teletype (RTTY) and to present to the dedicated RTTYer, and to the curious, a location wherein one can find information relating to RTTY and BAUDOT communications.

Deploying robust antenna infrastructure for both fixed and portable operations often requires specialized support structures capable of withstanding environmental stresses while providing optimal radiating element placement. SMC offers a range of solutions, including pneumatic masts and push-up masts, designed to facilitate rapid deployment and reliable long-term support for various antenna types. Their product line encompasses antenna mounts, poles, and complete antenna systems, addressing the critical need for stable and efficient RF communication. The company's offerings extend to HF antennas, including dipoles and _NVIS_ (Near Vertical Incidence Skywave) antennas, which are crucial for short-range regional communications on bands like 80m and 40m. These systems are engineered for durability and performance, ensuring signal integrity across diverse operating conditions. With over **65 years** of experience, SMC has established itself as a global manufacturer in this niche. Their product portfolio also includes antenna support towers, catering to more permanent installations requiring significant height and load capacity for multiple arrays.

The multiuser/multitasking BPQ Packet Terminal Driver program is a general purpose communications package for communicating with a packet TNC or Baycom modem attached to your IBM-PC/clone in conjunction with the BPQ Node software.

The resource presents a detailed schematic for constructing a dual-band vertical antenna, specifically designed for operation on the 2-meter and 70-centimeter amateur radio bands. It illustrates the physical layout, critical dimensions, and component placement necessary for successful replication. Key elements such as the radiating elements, phasing sections, and feed point are clearly depicted, providing a visual guide for radio amateurs undertaking a homebrew antenna project. The diagram specifies the lengths for the VHF and UHF sections, indicating how these elements are integrated to achieve dual-band functionality from a single coaxial feedline. It also implies the use of common materials readily available to most experimenters, focusing on simplicity and effectiveness in its design. The visual format of a GIF image ensures direct access to the construction details without requiring extensive textual interpretation. This schematic serves as a practical reference for hams interested in building a compact, efficient vertical antenna for local and regional FM communications, offering a proven design for immediate implementation.

Presents a curated collection of newsletters dedicated to _Earth-Moon-Earth_ (EME) communications, primarily focusing on the 432 MHz band and higher microwave frequencies. The resource details various EME DX experiences and news contributions from operators like K2UYH (W6/PA0ZN), offering insights into successful moonbounce contacts and operational strategies. It serves as an archive of specialized content for those engaged in or interested in extreme weak-signal propagation via the moon. The newsletters provide practical information on achieving EME contacts, often including details on station setups, antenna arrays, and signal reports from challenging DX. For instance, operators might report achieving contacts over **750,000 km** round trip, demonstrating the feasibility of long-distance communication on UHF and microwave bands. The content differentiates itself by concentrating on the unique technical and operational aspects of EME, which contrasts significantly with terrestrial DXing, providing a specialized knowledge base for advanced amateur radio operators.

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

Founded in 2000 by Jim Weidner, K2JXW, a licensed ham operator for over 50 years, the ARLHS is the only society of its kind devoted to Maritime Communications, Ham Radio, Lighthouses, and Lightships.

Otto engineering is comprised of two divisions otto controls and otto communications. otto controls designs and manufactures a full line of switches and grips used in heavy equipment, aerospace, marine, medical and other demanding applications. otto communications designs and manufactures audio accessories for two-way radios used in public safety, police, fire, retail, hospitality manufacturing and other markets.

Scanning railroad communications in the toronto area

Los Angeles County Disaster Communications Service a public service organization using Amateur Radio

SCARA is active in various events throughout the year. Helping as a public service with communications at various events has been a strong point for our club

Showcasing a specialized product line, Advanced Receiver Research presents a comprehensive catalog of **low noise preamplifiers** and microwave **Gunnplexers**. The offerings span a broad spectrum of radio frequencies, from VLF, LF, MF, and HF bands up through VHF, UHF, and microwave, catering to diverse applications including amateur radio, commercial installations, and military systems. Their product range includes mast-mount preamplifiers, inline attenuators, power dividers, and various coaxial components. My own experience with similar low-noise front ends for weak-signal work on 2 meters and 70 centimeters underscores the critical role such components play in maximizing receiver sensitivity, especially when chasing distant DX or engaging in EME. The detailed product descriptions and technical specifications provided on the site allow operators to select the optimal preamplifier for their specific band and noise figure requirements, essential for improving signal-to-noise ratio. The site also lists specialized products for unique applications like Nuclear Magnetic Resonance (NMR) and Studio Transmitter Links (STL), demonstrating a depth of engineering capability beyond typical amateur radio fare. This breadth of offerings, coupled with clear ordering and warranty information, positions Advanced Receiver Research as a key supplier for high-performance RF components.

Operating on the 11-meter band, the Alfa Tango Argentina website serves as a digital hub for CB radio DX enthusiasts, particularly those affiliated with the _Alfa Tango_ international group. The resource primarily functions as a community portal, facilitating connections among members and promoting activities related to long-distance CB communications. It presents basic information about the group's presence in Argentina and emphasizes the social aspect of radio communication, framing participants as "friends who have never met." The site's content reflects the operational focus on **DXing** within the CB radio sphere, a practice that mirrors amateur radio's pursuit of distant contacts. While specific operational data or technical guides are not detailed, the site's existence supports the organizational structure of the Alfa Tango group, which coordinates activities across various countries.

Presents a Brazilian online portal dedicated to **amateur radio**, **CB radio**, and shortwave listening (SWL) communities. The platform facilitates free classified advertisements for radio equipment, including HF, VHF, and UHF transceivers, antennas, and accessories. It also aggregates a substantial collection of technical articles from Brazilian amateur radio operators (e.g., PY2DJW, PY1LJ, PY1LL/4LC), covering topics such as CW training with RufzXP, balun importance, and radio wave characteristics. Furthermore, the resource provides extensive links to Brazilian ham radio sites, clubs, international organizations, and official ANATEL (Brazilian National Telecommunications Agency) documents regarding licensing, equipment homologation, and regulations. The portal features sections for user evaluations of transactions, a "Top Ten" list of most visited pages, and a calendar of past and upcoming ham radio events across Brazil, including "Feirinhas" (local swap meets) and "Encontros de Radioamadores" (hamfests). It also includes a directory of ham radio related businesses and services in Brazil, such as antenna manufacturers (Diex), QSL card printers (Arte Final), and repair technicians (PY2MOK). The site also offers propagation maps, DX cluster links (e.g., DX-SUMMIT), and satellite tracking tools, making it a central hub for Brazilian radio amateurs seeking to buy, sell, learn, or connect with the community.

The European PSK Club, or EPC for short, is an informal club of amateur radio operators dedicated to maintaining high levels of amateur radio communications on PSK modes. Its purpose is to promote activity and good operating practice on the PSK modes on all amateur bands

Explore this high-resolution ITU Zones Map, a critical reference resource for amateur radio operators, international broadcasters, and telecommunications engineers. Originally established by the International Telecommunication Union – Radiocommunication Sector (ITU-R) Broadcasting Services Division (1999), this chart accurately divides the globe into 90 specific CIRAF zones. This authoritative visual guide is indispensable for planning High Frequency (HF) radio propagation, scheduling international broadcasts, and verifying locations for radio contests and awards. Distinct from the 40 CQ Zones, the ITU zoning system provides the official administrative framework used for global frequency management. This digitally enhanced version ensures maximum clarity of zone boundaries and numbering (e.g., Zone 28 for Central Europe), making it an essential tool for technical accuracy in logbooks and station management. It serves as a trustworthy standard for educators, hobbyists, and industry professionals alike.

Live Fire/EMS feed from Eastern King County, WA as dispatched by Eastside Communications

Speakers for Amateur Radio, 2-Way Radio, Shortwave and Scanner listening

Dish antenna and its theory and design for high performance applications such as satellite transmission and reception as well as microwave links. Parabolic Reflector Antenna: Dish Antenna The parabolic reflector antenna which is often called the dish antenna provides an antenna solution applicable for VHF and above where high gain and directivity are needed for all type of radio communications and radio reception.

Specialist in the design and supply of Radio Communications Equipment and Systems. West Sussex England. Antennas, traps and baluns inline isolators, Outbacker Antennas, Mobile Mounts and Accessories