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A quarter-wave vertical antenna design for HF operation offers a practical solution for radio amateurs seeking a compact and efficient multi-band radiator. This project details the construction of a 5-band HF vertical, drawing inspiration from established commercial products such as the _DX COMMANDER_ and the MV6. The design emphasizes ease of assembly and disassembly, making it suitable for portable operations or installations with limited space. The article provides insights into various construction methods and offers practical tips for building a robust yet lightweight antenna. It highlights the benefits of a vertical configuration for DX contacts, particularly on the lower HF bands, and discusses real-world performance observations. The antenna is designed to cover multiple HF bands, providing versatility for various operating scenarios. Operators can achieve significant DX results with this type of antenna, often comparable to more complex arrays, especially when deployed with an effective ground system. The project aims to empower hams to build a capable antenna without significant financial outlay.

PathSim is a Windows program that can be used to simulate radio propagation paths using a soundcard and/or wave files as the source and destination.

A short wave regenerative receiver project by Charles Kitchin, N1TEV

The concept of the "Hula Loop" came after many years of building medium wave loops of varying size, shape and performance. Usually these loops are constructed on a square wooden frame, with wire being wrapped around the periphery

Free VHF/UHF/Microwave contest logging software for rovers and non-rovers - Runs under Linux, Windows, etc.

This article is a follow-up of Dallas Lankford's article Icom IC-746 Pro: Impressions and Mods, published on www.kongsfjord.no and (partially) in the Swedish Short Wave Bulletin.

If the display lamps in your TS-2000 go out. They can be replaced with LEDs.

The National Radio Club is the world's oldest and largest Medium Wave DX club, founded in 1933.

N3FJP's ARRL Field Day Contest Log 6.6.10 is a dedicated software solution for Windows 7 through Windows 11, specifically tailored for the annual ARRL Field Day event in June. This program provides essential contesting features such as duplicate checking, including partials, and a dynamic list of sections that change color upon being worked. It seamlessly interfaces with popular digital mode software like WSJT-X, Fldigi, and JTAlert via API, and supports rig control for most Elecraft, Icom, Kenwood, and Yaesu transceivers. The software also generates computer-generated CW via serial port or Winkeyer, plays wave files, and offers DX spotting capabilities. Operators can leverage its fully networkable design to allow multiple PCs to update a single log file simultaneously, enhancing club operations during Field Day. The program outputs ASCII log, dupe, and summary files for contest submission and provides real-time statistics. A quick start video is available to guide new users through the basics of the software. Registration for permanent use costs $8.99, or it can be obtained as part of the N3FJP Software Package, which includes over one hundred amateur radio programs for a one-time fee of $59.99.

Designs and manufactures a comprehensive line of microwave communications equipment for television broadcast, video, telemetry, and electronic surveillance applications.

Why 6 meter hams design the best antennas

The diagram below shows the basic arrangement of the 2m Half-Wave version of the antenna. A 6m diagram is available too.

About numbers stations, and their criptic transmissions, where to listen to them and some audio recording samples by fascinating shortwaves

a comprehensive listing of both Military and Civil HF networks from Australia and it's surrounding neighbours as well as from countries around the world.

Generating Morse code audio files from text input is the primary function of _MorseGen v1.2_, a utility designed for amateur radio operators. The software allows users to specify the tone frequency and words-per-minute (WPM) speed for the generated CW. A key feature is its ability to create a WAVE audio file containing the Morse code, which can then be used in various applications. The program also supports repeating the generated CW sequence at user-defined intervals, making it particularly useful for creating station identification signals or beacons. The practical application of this tool extends to automated station identification, especially for repeaters or digital mode gateways that require a CW ident. By producing a standard _WAVE file_, the output is compatible with most audio playback systems and software. This functionality provides a straightforward method for integrating custom Morse code messages into existing amateur radio setups, eliminating the need for external hardware keyers for simple identification tasks. The adjustable parameters offer flexibility to match specific operational requirements or personal preferences for CW characteristics.

This article describes how to use a phone line as a shortwave receiving antenna, but be carefull telephone lines present a potential shock hazard, use at your own risk

This 1:49 transformer is used with wires any multiple of 1/2 wavelength. This is not a matching network, it's a wideband transformer and it has some advantages compared to LC matching

Homebrew a 1/4 wave 80 meter vertical using aluminium tubing

The Grid Yagi (or Grid Quad) is a high performance yagi antenna that can be built with readily obtainable inexpensive materials. Described here is a 6 element 2 meter version with a boom length of about 1 wavelength, shown

Shortwave dxing newsletter, Cumbre DX is dedicated to reporting what's hot in regional and international shortwave broadcast listening

A quarter wave ground plane for 70 cm

Using the T2FD antenna for shortwave listening by AB1KW

A comprehensive collection of DX information consisting of news, audio files, station profiles, equipment articles, discussion forum, DXpedition reports and logs for mediumwave, shortwave and FM DXers.

Long Waves, Short Antennas, designing antennas for MF and LF communications

Demonstrates the construction of two distinct wideband RF preamplifiers, detailing their component requirements and performance characteristics. The first design leverages monolithic microwave integrated circuits (MMICs) such as the MAR-6, MAR-8, or PGA103, offering a broad frequency response from DC to 2 GHz with a gain of 22.5 dB at 100 MHz and a noise figure typically below 3 dB. This MMIC-based amplifier incorporates protection against power supply transients and features a 50 Ohm input/output impedance, operating from an 8-20 volt supply with low current drain. The second preamplifier design utilizes a BSX-20 transistor, providing amplification across the 14 MHz to 550 MHz range. This simpler, more economical build achieves an average gain of 12 dB at 145 MHz and a noise figure of approximately 1.1 dB. It operates from a 7-15 volt battery supply with a current draw of 6 mA. Both projects emphasize critical construction techniques, such as maintaining short RF connections, ensuring 50 Ohm impedance paths, and mounting the circuit within a shielded enclosure to optimize performance and minimize noise. The resource also discusses phantom power options for antenna-mounted preamplifiers and precautions for use with transceivers, including output protection diodes and static bleeders.

A monoband end-fed half wave for 10m, 20m or any other HF band, includes a PDF with detailed information to build your own monoband or multiband antenna

Terrasat Communications specializes in advanced RF technology for satellite communication, focusing on _Intelligent Block Up Converters_ (IBUCs) and Solid State Power Amplifiers (SSPAs). These products are engineered to enhance satellite link performance, offering features like extended frequency ranges and high power efficiency. The IBUC series, for instance, integrates a BUC with an SSPA, enabling operators to install, configure, and monitor units for both commercial and military satellite applications, ensuring reliable, high-performance connectivity worldwide. The company's offerings support various satellite bands, including C, X, Ku, and Ka, providing solutions for diverse operational requirements. Their technology is designed for robust field performance, with products like the _IBUC2_ and _IBUCG_ models demonstrating the integration of advanced diagnostics and control capabilities, which are crucial for maintaining optimal signal integrity in demanding environments. Terrasat's focus on _SSPA_ technology underscores a commitment to power efficiency and compact design.

DOS Freeware, DSPBOX is an attempt to code the Texas Instruments DSK 'C50 in such a way to make it behave like a commercial DSP noise reduction unit, like the NIR-12, the TimeWave 599+ and others. Not only the noise reduction function has been implemented, but automatic notch, AGC and Band Pass have as well.

HFCC manages and co-ordinates global databases of international shortwave broadcasting in keeping with International Radio Regulations of the ITU. Operational Schedule, available for free download and iteractive schedule

Understanding high-frequency (HF) skywave propagation is crucial for amateur radio operators seeking to optimize long-distance communications. This resource details the fundamental principles of HF radio propagation, including the properties of electromagnetic waves, the characteristics of various HF bands, and distinct propagation modes such as skywave, ground wave, and line-of-sight. It places significant emphasis on the ionosphere's pivotal role in refracting HF waves, explaining how solar activity directly influences ionospheric conditions and, consequently, propagation paths. The resource integrates real-time monitoring capabilities, featuring dynamic charts and data from DX clusters, WSPRnet, and the Reverse Beacon Network, which allow users to track current band activity and propagation conditions globally. It also delves into advanced topics like Near Vertical Incidence Skywave (NVIS) and gray line propagation, providing insights into ionosonde data and various propagation prediction models. The site presents a detailed analysis of solar-terrestrial interactions, geomagnetic indices, and space weather phenomena, illustrating their direct impact on HF communication reliability. Practical tools and applications are highlighted, including real-time QSO planners, online Maximum Usable Frequency (MUF) maps, and alerts for solar flares or geomagnetic storms. The guide systematically breaks down complex concepts into accessible chapters, offering a structured approach to learning about ionospheric regions, diurnal and seasonal effects, and the interpretation of propagation indicators like foF2, MUF, and Lowest Usable Frequency (LUF). This makes it a robust reference for hams aiming to deepen their technical understanding and improve operational effectiveness.

HFUnderground.com is dedicated to documenting longwave, mediumwave, and shortwave stations, including broadcasters, utility/military stations, pirate radio and spy numbers stations.

The half wave dipole antenna is a simple and practical antenna model that consists of a half wavelength long centre fed conductor.

The SQUARE-Pole is a 1/2-wave dipole that has been bent into a square by WB2VUO

An Active antenna designed for VLF and shortwave radio reception. A small antenna capable of excellent performances on low bands, made on a copper plate and introductio to active antennas.

This is a 200 Watt PEP step up transformer for end fed full and half wave antennas without radials, designed as a 200 Watt PEP

The Crossed Field Antenna (CFA) is one of the applications of Correction of Maxwell's Equations which was used over 150 years ago which was proved these days that the Magnetic Field Source is only the Displacement Current not the Conduction Current . These Corrections was made by an Egyptian Doctor Engineer Fathi Kabbary , who reached the New Correct Theory which shows that the height and efficiency of the antenna doesn't depend on the wavelength

Helical antennas invented by John Kraus give a circular polarized wave. They are one of the easiest to design. Find a tube with a circumference equal to one wavelength, and wrap wire in a helix spaced a quarter wavelengt

Here you will find broadcast, pirate, and clandestine information including loggings, QSLs tips, and last-minute news

Loop antennae have been used from ELF to UHF since the beginning of radiocommunications. At low frequencies, the main problem for loop antennae is to have enough sensitivity; the antenna being very small respect to the wavelength the collected energy is also small. To increase the output level the loop may be made resonant, so loosing it%u2019s intrinsic aperiodic characteristics.

Offers Scanners, Shortwave, Wide-Band receivers, accessories from Icom, AOR, Sangean and Grundig.

This project will enable you to build a monoband long wire inverted vee with 3/4 wave length sides that will have a bit of gain

HD Communications Corp specializes in **RF and microwave amplifiers** engineered for demanding communication, defense, and industrial applications. Their product line includes precision-built, high-power solutions, along with RF connectors, filters, HF cables, and various accessories. The company also supplies tower hardware, valves, and tubes, catering to a broad spectrum of radio frequency infrastructure needs. Beyond amplifiers, HD Communications offers a range of **RF filters**, including low-pass filters, antenna filters, and solutions for RFI/TVI mitigation. Their inventory encompasses essential components like coaxial cable and various connector types, supporting both amateur radio and professional installations. The company operates as a manufacturer and vendor, providing direct sales of its specialized RF products.

It consists of a radiating wire with a length equal to the half-wave of the fundamental frequency for which the antenna is cut.

Recordings of shortwave numbers stations

This program displays solar-terrestrial data for radio waves propagation that is provided by the N0NBH web-service.

Antenna accessories and related products

Demonstrates the design and construction of a 9-element Yagi antenna for the **70 cm band** (432 MHz), based on the DK7ZB concept. The resource details EZNEC+ calculations for a single antenna, providing gain, sidelobe suppression, and front-to-back ratio figures. It also presents a comprehensive analysis of stacking two such antennas, including optimal stacking distance (1000 mm) and the resulting performance enhancements for the stacked array, such as an increased gain of 17.03 dBi. The article includes detailed drawings, wire file dimensions in millimeters, and azimuth/elevation plots for both single and stacked configurations. Practical construction steps are documented with original photographs, illustrating element mounting, the **28 Ohm matching system** using two quarter-wave 75 Ohm transmission lines, and the critical N-connector wiring. It also covers the iterative process of fine-tuning the driven element length to achieve a return loss of 20 dB, validating the EZNEC+ simulation results with actual measurements.

This application note is designed to help the reader understand how balun transformers can be used in today's RF/Microwave communication applications.

by Lou Blasco VK3ALB