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Information and digital audio samples of various modem modulation types

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

Address and links of many broadcasting stations

An old post by John Doty about effects of noise in longwire antenna.

How could we share the Beverage antennas on more than one station using this homemade remote antenna switch, a project by TK5EP

Meimaris Communication Equipment based in Greece

cocoaNEC 2.0 is an opensource Mac OS X application intended primarily for the design and modeling of antennas by Kok Chen, W7AY

An affiliate of the Philippine Amateur Radio Association, Inc.

A free to download and print, paper log sheet useful for portable amateur radio operations, in a PDF file.

Presents the DBO274 Citizen Band mailbox, a digital communication hub accessible via HTTP and Telnet, specifically catering to **CB radio** enthusiasts in Germany. This resource outlines its functionality for Packet and other digital emissions on the 11-meter band, a segment often overlooked by traditional amateur radio operators but vital for CB users seeking advanced communication methods. The author, DH8YMB, provides insights into its operation, reflecting practical experience with digital modes in the CB spectrum. The DBO274 serves as a bridge, enabling users to exchange messages and data packets, extending the reach and utility of standard CB transceivers. It represents a localized digital infrastructure, demonstrating how the 27 MHz band can support more than just voice contacts, incorporating elements of early internet-like communication within the CB community. This setup highlights the enduring innovation within the CB realm, adapting technologies like Packet Radio for a different user base. It underscores the versatility of radio communication, even on less conventional bands, for those interested in digital data exchange beyond the typical amateur allocations.

Every ham needs an RF power meter. Here is a high performance unit to build at home.

This simple modification is applicable to pretty much any 12 volt operated, positive earth equipment. by Chris Cox, N0UK, G4JEC

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.

ARRL affiliated organization

The Construction Principles for Duoband-Yagis 2m/70cm by DK7ZB

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.

Statistics based on FCC Database. Data is compared to previous perions.

An emergency service provided to the city of Mountain View, California and the surrounding communities in time of need.

QRP Station in a Bag is a complete QRP station in an old laptop PC carrying case (photo). It is a true "Work in Progress" in that wd8rif is constantly changing the contents of the bag as learn what works and what doesn't.

Audio and waterfall images of some sounds found on the RF spectrum

miLog provides an integrated software solution for amateur radio station management, encompassing logging, DXing, and contesting functionalities. The software is designed to operate on Windows 2000 and later versions, indicating a focus on stability and compatibility within the Microsoft ecosystem. Its feature set includes comprehensive logging capabilities, tools for DX operations, and specific modules tailored for competitive contesting, streamlining the workflow for operators engaged in these activities. The resource details the software's commercial availability and its primary functions, which extend to station control. This integration allows users to manage multiple aspects of their amateur radio operations from a single application, potentially reducing the need for disparate tools. The description also highlights support for various operating modes, suggesting flexibility for different communication protocols and techniques. While the page itself is minimal, it serves as a direct point of reference for miLog, outlining its core purpose and system requirements. The emphasis on a highly integrated approach distinguishes it as a tool aiming to consolidate essential ham radio software functions.

This is an 80 metre dipole that fits in a small spac

Kenwood Sales, Service, repairs, parts, FAQ, information

Amateur radio operators frequently seek efficient methods for logging contacts, particularly during contests or DXing sessions where speed and accuracy are paramount. MiniLogBook addresses this need by providing a streamlined logging utility designed for Windows environments. The software facilitates rapid entry of QSO data, offering an automated lookup feature for previous contacts based on recent callsigns, which significantly reduces redundant data entry. The application's distinctive utility lies in its integration capabilities with other ham radio software, specifically _MRP40_. Users can select text within the MRP40 receive window and, with a double-click, automatically insert that text into MiniLogBook. This feature is particularly advantageous for operators engaged in digital modes like RTTY or PSK, where copying callsigns and exchange information accurately and quickly is critical. The tool aims to simplify the logging workflow, allowing operators to focus more on the contact itself rather than manual data transcription. While primarily a logging tool, its focus on quick entry and interoperability with specific third-party software distinguishes it from more feature-rich logging suites. The software is distributed as freeware by _Polar Electric_, making it accessible without cost. Its small footprint and direct functionality cater to operators who prefer a minimalist approach to logging, prioritizing efficiency over extensive database management or advanced reporting features.

Dentron GLA-1000 Conversion, modification with 4 x PL/EL-519 or 2 x GI-7B

Examines various facets of online casino gaming, focusing on security, game selection, and payment solutions. It details the extensive gaming libraries offered by online casinos, which often feature over **4,500 games** from more than _75 top software providers_, including slots, live dealer games, and table games. The resource also covers stringent security standards, such as 256-bit SSL encryption and dual licensing from authorities like the _Malta Gaming Authority_, ensuring player fund segregation and data protection. Furthermore, the content explores diverse financial solutions, including traditional methods like Visa/Mastercard and modern options like Skrill, Neteller, and cryptocurrencies such as Bitcoin, with withdrawal times ranging from **0-6 hours** for e-wallets. It highlights mobile gaming experiences optimized for various devices using HTML5 technology, offering over 4,000 mobile-optimized games. The resource also delves into VIP rewards programs, loyalty benefits, and customer support channels, emphasizing quick response times.

Unix or linux programme atlc calculates the impedance of electrical transmission lines of totally arbitrary cross section.

Replicating vintage radio components addresses the challenge of restoring classic receivers and transmitters to their original aesthetic and functional condition. Many historical radios, particularly those from the _Golden Age of Radio_ (1920s-1940s), suffer from brittle or missing control knobs and trim pieces, making authentic restoration difficult. This resource focuses on manufacturing new parts that precisely match the originals, ensuring period-correct repairs. The service offers a vast catalog of reproduced items, with thousands of molds created since 1987. This extensive inventory includes a wide spectrum of knobs and pushbuttons, along with some plastic escutcheons, grills, and handles. The meticulous reproduction process ensures that restorers can find accurate replacements for brands like Philco, Collins, and Atwater Kent, preserving the historical integrity of these valuable pieces of radio history. The owner, Larry Bordonaro, has been in business since 1987, demonstrating deep experience in this niche.

Not-for-profit organization serving the radio monitoring community founded in 1962

AP Communications CB and Amatuer Electronics Sales

The 9A3MR contest QTH rental provides a fully equipped amateur radio station for DXpeditions or radio holidays on Murter Island, Croatia. The station features a Drake TR7 transceiver and a 16-meter tower with a rotator, suitable for various HF operations. Accommodations include a four-room apartment and a studio apartment, both within 200 meters of the beach, offering amenities like parking and a barbeque area. This QTH is located in Jezera, a fishing village with local stores and restaurants within a five-minute walk. While Murter Island itself does not qualify for IOTA due to a bridge connection, the Kornati Islands National Park (IOTA EU-170) is only 10 nautical miles away, with daily tourist tours available. The Krka National Park is also accessible by car, approximately 25 km distant, providing additional recreational opportunities.

Optimising a typical G5RV antenna by VK1OD

Adventures in amplified GPS antenna construction; an experiment

136kHz portable station project by PA4VHF Dick

The G5RV multiband HF antenna, designed by Louis Varney (G5RV) in 1946, is a popular compromise antenna offering good overall performance on most HF bands when paired with an external antenna tuner. The basic full-size G5RV measures 102 feet across the top for 80 through 10 meter operation and is fed at the center via a 34-foot low-loss feed-stub. This interaction between the radiating section and the feed-stub facilitates matching across 80-10 meters with a standard tuner, often eliminating the need for ladder line directly to the shack. The antenna's design center frequency is 14.150 MHz, configured as a 3/2-wave dipole on 20 meters, with its 102-foot length derived from long-wire antenna formulas. Construction details emphasize the matching section, which can be open wire, ladder line (window-type), or TV twin lead. Each type has a specific velocity factor (VF) affecting its physical length for an electrical half-wave on 14 MHz; for instance, open wire requires 33.7 feet (VF 0.97), ladder line 31.3 feet (VF 0.90), and TV twin lead 28.5 feet (VF 0.82). The article provides formulas for calculating these lengths and discusses the antenna's behavior on individual bands, from 3.5 MHz where it acts as a shortened dipole, to 28 MHz where it functions as two three-half-wave long-wire antennas fed in-phase. Practical construction notes include recommendations for vertical descent of the matching section, sealing the coax junction, providing strain relief, and winding a coaxial choke coil to mitigate common mode current. The resource also presents dimensions for double-size (204 ft) and half-size (51 ft) G5RV versions, along with their corresponding matching section lengths for various line types, making it a versatile reference for hams considering this classic wire antenna.

Practical and usable direct conversion receiver for the 40 m CW band

AM-6154 222MHz grid Conversion Information by N0UK

The website provides information on the Romanian Amateur Radio Federation's participation in the World Youth Radio Orienteering Championships in 2025. It includes details on the event, the participants, and their results.

The Smith Chart was originally created many years ago as an RF engineering aid by Phillip Smith of RCA.These pages includes extesnive documentation on smith carts.

Garmin Kenwood Icom Vertex Alinco and more

This is the table of contents to a list showing how the radio frequency spectrum is allocated to different users in the United States.

North Carolina ARRL Section Information

This modification will allow the MkIIG to transmit on most of the frequencies that it receives on.

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

The digital wattmeter project was created for the purpose of measuring power in the range of 300nw to 30w.

Amateur radio propagation studies (science, research, engineering, operating) and the BeamFinder propagation analysis software

The purpose of this page is to examine the performance of a typical Beverage when all variables except length are held constant

Useful pages of longwave operations, includes a lot of reference files, beacons list, sounds and pictures

The club was founded in 1981 by 17 Charlotte-area hams interested in DXing & contests

The Olivia transmission system is constructed of two layers: the lower, modulation layer is an (almost) classical Multi-Frequency Shift Keying (MFSK) and the higher layer is a Forward Error-Correcting (FEC) code based on Walsh functions.