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When a broadcast antenna is to be placed on top of a building, there are special problems of feeding and grounding. The radiator is usually electrically short, that is, much less than one-quarter wavelength high.

You can shorten a vertical antenna by using a loading coil. This online calculator tells you how the amout of inductance your loading coil will need to have.

An interesting article on basics about Baluns, intoducing the skin effects on radio frequency currents and its effects on receiving and trasmitting article by VE7FO

Shortwave listening web site from Brazil

Blog post announcing that Ham Radio, shortwave listeners and broadcast band listeners will be protected by Law in Europe

A nice blog about DXing, Shortwave Radio Listening (SWL) and Amateur (Ham) Radio by VK3BVW

DL1OFC, operating from Hankensbüttel, Germany, shares insights into the fascinating hobby of amateur radio. While the station has been on hiatus since 2016, the site provides a valuable archive of activities and technical information. DL1OFC was active across various bands and modes, including 145.225 MHz FM, 430.225 MHz FM, 29.600 MHz FM, and DMR via DB0AGM on TS-1 TG-262 DL. Shortwave operations included SSB on the 40m through 10m bands, as well as 6m. The site details regional amateur radio activities in and around Hankensbüttel, offering a glimpse into local field days and community involvement. A notable feature is Die Isetalrunde, a regional amateur radio net covering the area from the Harz mountains to the sea. The site also includes general information on radio technology, tips for obtaining an amateur radio license, and discussions on VHF/HF propagation, including specifics on the 70 MHz band.

North american QRP CW Club, open to any licensed radio amateur or shortwave listener (SWL) worldwide with at least some interest in CW/QRP operation. Encouraging the use of CW and helping all hams increase CW speed and proficiency

Active Receiving Antennas, designed for reception of shortwave, mediumwave and longwave signals and VHF/UHF signals

A Web forum dedicated to HF underground and in particular to Shortwave Pirate Radio Forums and Spy Numbers listenings

Shortwave radio listening club in Brazil

An inexpensive portable radio that you can travel with. ATS-505 would be a good choice for a first-time purchaser of a shortwave radio.

Presented is a historical collection of short-wave listening (SWL) QSL cards, primarily from the late 1930s and early 1940s, offering a glimpse into early international broadcasting and the technical pursuits of SWL operators like Les Miles during that era. The resource showcases specific QSLs from stations such as _Broadcasting Corporation of Japan_, _XGOY - The Central Broadcasting Administration_ in Chungking, China, and _Australian broadcasting ship, Kanimbla VK9MI_, each with reception dates and frequencies like 11.90MHz or 9.525MHz. It highlights the self-sufficiency of SWL enthusiasts who constructed and maintained their own radio and test equipment, evoking the sensory experience of vintage valve receivers. The collection provides concrete examples of international broadcast stations active before and during World War II, including _2RO3 - Rome_ and _WRUL - World Wide Broadcasting Foundation_ from Boston. Each QSL entry details the station, location, reception date, and often the frequency, such as 9.63MHz or 11.26MHz, allowing for historical verification of broadcast schedules. The resource also briefly mentions the operational details of the _VK9MI_ offshore radio station, directing readers to further information on its history. This compilation serves as a tangible record of global radio communication during a pivotal historical period.

A quick and easy logging application designed for BCL and shortwave listeners, requires a recent Windows OS and .Net Framework

A top band shortened vertical antenna project. This project includes drawing and MMANA-GAL output screens.

Station QRP presents various **circuit diagrams** for constructing low-power AM vacuum tube shortwave transmitters, catering to enthusiasts interested in vintage radio technology. The resource details schematics ranging from simple to more complex designs, enabling hams to build their own QRP AM transmitters for operation on frequencies like 6.925 kHz AM. It emphasizes the use of vacuum tubes, providing a technical foundation for understanding and replicating classic shortwave broadcasting methods. The content is geared towards those who enjoy the hands-on aspect of electronics and the unique characteristics of tube-based RF circuits. Building these transmitters allows operators to experience the nostalgia of early shortwave radio, with the site specifically mentioning a pioneer station on 6.925 kHz AM. The designs facilitate experimentation with low-power AM transmission, offering practical application for homebrew projects. The focus on QRP (low power) operation aligns with a segment of the amateur radio community that values efficiency and minimalist setups, providing a distinct alternative to modern solid-state transceivers.

GARS official web site. Our club is for those with an interest in Amateur Radio and Shortwave Listening in the Grimsby and Cleethorpes areas of North East Lincolnshire.

Welcome to our line of Low Frequency, Natural Radio Research, Broadcast, Marine and Shortwave products. Our evolving product line is the result of our dedicated research efforts primarily in the areas of LF, VLF, MF, and HF.

Free ham radio utilities written in LabVIEW includes Open Wire Calculator, Dipole Peak/Null Angle Calculator, a Coil-Shortened Antenna Calculator ad interesting Round Coil Inductance Calculator and a Skyloop Antenna Calculator

On December 12, 1901, Guglielmo Marconi successfully received the first transatlantic wireless communication, a Morse code "S" (three dots), at 04:30 GMT. This article details the setup for this groundbreaking experiment, noting Marconi's receiver in St. John’s, Newfoundland, Canada, utilized a _coherer_ and an antenna elevated by balloons and kites. The transmitting station at Poldhu, Cornwall, England, featured twenty-four 200-foot ships' masts and a 25-kilowatt alternator. The resource explains how this contact disproved contemporary beliefs about radio wave limitations due to Earth's curvature, later understood through _ionospheric propagation_. It frames Marconi's achievement as the "very first DX" in amateur radio terms, defining DX as telegraphic shorthand for distance and _DXing_ as the hobby of receiving distant signals. The article also provides external links for further reading on Marconi's experiments and the science behind transatlantic radio signal reception.

Baofeng UV-B5 LCD background light is turned on only when some keys are pressed and stays on far a very short time. This article explains how to use flash switch which is used in UV-B6 version but in UV-B5 has no function.

A blog dedicated to military communications shortwave intercepts, sponsored by the Teak Publishing

Established in 1954, RAIBC is a national society and Charity, dedicated to supporting Radio Amateurs and Short-wave Listeners with disabilities. The RAIBC logo is recognised throughout the amateur radio world.

Documents the _XT1T_ DXpedition to Burkina Faso, active from February to March 2013. This operation provided DXers worldwide with an opportunity to work a relatively rare entity, with the team focusing on maximizing contacts across various bands and modes. The expedition utilized an online log provided by _IDT_ (Italian DXpedition Team), enabling immediate verification of contacts and facilitating QSL requests. The _IDT_ system allowed participants to check their QSOs shortly after they were made, a crucial feature for contesters and award hunters aiming for DXCC credit. The expedition's success was measured by the total number of unique contacts and countries worked, contributing significantly to the global DX community's pursuit of new entities.

Efficient Low Band Counterpoise for Restricted Circumstances Loss Avoidance Opportunities and Techniques for the Low Bands The short and linear FCP was designed to reduce ground losses from inadequate radial systems beneath inverted L and other vertical antennas.

The Tri-pole antenna, a clever modification of a standard dipole, allows for dual-band operation by integrating a third element. This design effectively shortens the overall dipole length by 10 to 20 percent, simplifying antenna rotation and offering a compact footprint. KK4OBI's article delves into the operational principles, using a 6 and 10-meter Tri-pole as a primary example, and provides comprehensive instructions for constructing any Tri-pole antenna within the 6 to 15-meter range. Key to the Tri-pole's performance is its off-center feed, necessitating a common mode choke at the feed point for optimal tuning and reduced noise. The author outlines a methodical approach to determining element dimensions, starting with a vertical element frequency calculated as 0.47 times the sum of the desired upper and lower band frequencies. This calculation, along with K-values derived from trend lines, guides the initial lengths for the horizontal arms, demonstrating how a 10m-6m Tri-pole can achieve a total horizontal length 78% shorter than a conventional 10-meter dipole. Tuning and balancing are critical, with the article detailing adjustments to arm lengths and the vertical element to achieve balanced SWR values, as validated through 4NEC2 simulations. Radiation patterns are analyzed at various elevations, showing gains around 5.7 dBi and favorable take-off angles for DX contacts. Construction details specify aluminum tubing dimensions, U-bolts, and an SO-239 connector, emphasizing the importance of a ferrite-based choke for wideband operation.

Number stations are shortwave transmissions from foreign intelligence agencies to spies in the field of foreign countries.

A rotary dipole antenna for 30 meters band. Each arm is about 12.5 ft and is constructed from telescoping fibreglass flag/fishing poles and short lengths of aluminium tubing. Two short lengths of glass-fibre rod were used to insulate the arms from the supporting hardware.

This channel is all about radio listening and dxing. I will be covering frequency bands like longwave, AM/MW and shortwave. I'm embarking on my renew interest in this hobby since my childhood.

A numbers station, also known as a one-way voice link (OWVL), is a special type of unusual radio broadcast, generally on the Short Wave (SW) radio bands

Antennas for Amateur Radio and short wave listening

Homemade receiver for 80 meters band. The receiver works very well (in fact better than some of its successors), especially the AGC makes listening to 80m QSOs a real pleasure. Sensitivity is not cutting-edge, but on a full-size short-wave antenna it is by fare sensitive enough.

Encrypted messages, fancy technology, spies use them all to communicate, but sometimes the best way to hide is in plain sight. Right now, broadcasting across the airwaves around the world, are automated, anonymous shortwave AM radio stations that most governments won't acknowledge even exist, much less explain

This page describes an entirely simple, One-Knob matchbox that will match this antenna efficiently on 40, 30 and 20m, using a simple circuit that can be switched between series-resonant and parallel-resonant with just one banana jumper

Documents S21RC's construction of an impedance transformer harness for a VHF/UHF cross yagi, utilizing 20m of _RG179_ cable. Details the creation of a DIY RF sampler with a -50dB sampling output, primarily for measuring HF radio PA section output with a Spectrum Analyzer, also applicable for _Pure Signal_ transmission. Chronicles the deployment of a 200m long beverage antenna for the _S21DX IOTA_ operation in 2022, positioned 2m above ground. Discusses the construction of a 3-element short beam for 10m to replace a previous 2-element antenna, with assistance from S21DW. Provides guidance on operating cheap _PA-70_ and _PA-100_ type Chinese SSPAs using IRF530 MOSFETs, emphasizing the necessity of a final LPF. Outlines the design and construction of a fully isolated interface for radio-to-computer connections, supporting various digital modes with isolated ground, audio transformers for IN/OUT, optical isolation for CAT/CIV, and isolated PTT/COS lines. Includes a log of software updates, such as the _HMI/TFT for NX8048K070_ and _2.1.14 Lite_ release with bug fixes for PEP hold and gradual watt decay.

A short 3 element LFA Yagi for 50MHz with a 1.94M boom. This antenna has been designed in order to minimise the upward and downward lobes typically seen the the EL plane on Yagi antennas.

Constructing a dual-band antenna for 40 and 20 meters often involves compromises in size or complexity. This resource presents a compact _open sleeve dipole_ design that addresses these challenges by using 450-ohm ladder line and folded elements to achieve a total length of approximately **17.17 meters**, significantly shorter than a full-size 40-meter dipole. The design leverages electromagnetic coupling, where a primary radiator handles the 40-meter band, and a second conductor resonates on 20 meters without direct electrical connection. This configuration eliminates the need for traditional traps, loading coils, or switching components, simplifying construction and reducing potential loss points. The antenna is fed with RG-58C/U coaxial cable, and a common-mode choke is recommended at the feed point to suppress sheath currents, ensuring a cleaner radiation pattern and minimizing RF in the shack. The design is well-suited for portable operations, field deployments, temporary installations, and restricted urban environments where space is a premium, offering solid performance on both HF bands.

Mitigating impulse-type noise, a common challenge in the **HF radio spectrum**, often requires specialized processing before the signal reaches the transceiver's receiver stages. The NR-1 addresses this by functioning as an RF interference removal device, specifically a noise blanker, targeting transient noise sources. Its operational range extends from 1.6 MHz to beyond 70 MHz, making it suitable for various amateur radio bands and general shortwave listening applications. Unlike QRM eliminators or X-phasers, the NR-1 does not require a separate noise antenna for its operation, simplifying its integration into existing station setups. The device's design focuses on wideband performance, allowing its use both within and outside the allocated amateur radio frequencies. Documentation detailing its operation is available, providing insights into its technical specifications and deployment. This unit is a hardware product, conceptualized and implemented by SV3ORA.

The build was an experiment to see if a tube receiver could be stable enough to receive digital shortwave radio broadcasts. The tube acts as both an oscillator and mixer, so the receiver is a type of direct conversion receiver.

A 60-foot available space, for example, might necessitate a shortened multiband dipole array to cover 80, 40, and 15 meters effectively. This resource details the construction of such an antenna, combining full-size and coil-loaded dipoles on a single feedline. It addresses the common challenge of fitting multiple HF bands into restricted physical footprints, providing practical guidance for hams with smaller backyards or portable operations. The core of the offering is an interactive calculator that determines required loading coil inductance and dipole lengths for various amateur bands from 160m to 10m. Users input their available space, and the tool provides dimensions, coil turns, and an efficiency rating (Good or Fair) based on the antenna's electrical length relative to a quarter-wavelength. It also suggests suitable _PVC_ pipe diameters for coil forms. The article further illustrates a center feed-point assembly using an 18-inch section of 2-inch _PVC_ pipe, detailing eye-bolt spacing and coaxial connector installation. It emphasizes the importance of adequate spacing between parallel dipoles and offers customization options for the feed-point, including the addition of a _Balun_ for improved feedline isolation.

A 3 band dipole antenna for 40-80-160 meter bands, It's made with easily available materials and is designed for inverted V mounting. The antenna is shortened for these bands, but still manages to make contacts in 80m and 160m with stations in Canada and the USA. The construction details are provided, including the dimensions of the antenna elements and the traps. The antenna is easy to build and provides good performance in all three bands. In Italian.

This is a very small vertical 160m antenna that fits in the loft of even my small house. It was built as a way of getting a signal out on 160m for local AM contacts, but the local noise level was far too high to allow it to be used at night for this purpose. However, on WSPR it did a pretty good job with WSPR spots from a very long way across Europe being received when running 2.5W out.

Many antennas and antenna designers neglect the true cause of loss. The major problem using short antennas is the reactance, not the length

This active antenna for the shortwave band provides surprising performance, even indoors. As the name implies, the main loop is made from a Hula-Hoop with the metallic paint stripped off and a single turn of 14AWG copper wire inserted inside the hoop.

FSQ is a Fast Simple QSO mode designed specifically for HF. It works well under NVIS and sunrise/sunset conditions on the lower bands, and also works well for short skip and grey-line on higher bands and can be used also on VHF FM.

This antenna just requires about 24m of free space instead of 41m that a normal half wave 80m antenna needs to hang up. The so called loaded dipole uses a coil in every dipole arm to electrically lengthen the mechanical too short dipole arms. Every coil has an inductivity of 120 microHenry.

A 30 cm antenna for the six meters band in japanese

Maybe not state-of-the-art technology but the author offers a quick and easy project for a Morse code practice oscillator using a 555 timer chip

This article shares the author's experience with building antennas. After putting a large magnetic loop project on hold, they decided to try a base-loaded vertical antenna. The author explains how they chose to design a new antenna from scratch, aiming for a frequency of 7 MHz. They describe the calculations needed to find the right coil inductance and how they used 3D-printed parts for the construction. The article wraps up with results from their initial tests, showing good communication on different bands and highlighting the success of their design.

Here is a formula and calculator for creating a loaded (shortened) quarter wave vertical or balanced dipole. The calculation refers to either a loaded 1/4 wave or a loaded dipole