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Able to cover all frequencies between 3.5 and about 10 MHz, the loop described here is directional, does not require a radial system, and stands just 1.8 metres tall. The antenna can be put together in a short time and is cheap by Peter Parker VK3YE ex VK1PK

The page provides detailed information on the G5RV antenna, its feeder arrangement, and efficient operation on HF bands from 3.5 to 28 MHz. It includes dimensions for installation in limited spaces, variations for different bands, and impedance matching details.

Schematics plans by K9GDT and all infos to build a 600 Watt HF Amplifier. The amplifier uses four Motorola MRF150 50 volt TMOS power FETs configured in push-pull/parallel and biased for class AB linear operation.

The 160/80m coaxial receiving loop antennas are designed to enhance reception on the top bands while minimizing noise. These antennas are particularly beneficial for operators with limited space, as they can be constructed using lightweight materials, making them portable and easy to deploy. The standalone 80m loop has a diameter of approximately four feet, allowing for easy rotation and installation above existing VHF antennas. Over the years, many amateur radio operators have turned to loop antennas as a viable alternative to traditional beverage antennas. The design allows for significant noise reduction, especially when paired with a quality pre-amplifier. Experimentation with various configurations has led to the discovery that diamond-shaped loops provide optimal performance. Users have reported a noticeable improvement in signal quality, making these loops a valuable addition to any low-band DXing setup.

2-Element parasitic Yagis for the Shortwave-Bands 10-12-15-17-20-30m. The antennas are feeded with the DK7ZB-match. A quarter-wave choke of coax is grounded at the socket.

Audio Spectrum Analyser Spectrum Lab or Speclab started as a simple FFT program running under DOS a long time ago, but it is now a specialized audio analyzer, filter, frequency converter, hum filter, data logger and more. Can be used for MTHELL QRSS, DFCW, PSK, MSK, Castle. Spectrum Lab is a free audio analysis tool, lets you see the hidden world of sound. It analyzes live audio or recordings, showing you the exact frequencies present. Watch sounds change over time with a waterfall display. Need to clean up your audio? It can filter out noise in real-time. Even play with radio signals by decoding and creating special modes! While ideal for amateur radio enthusiasts, anyone can explore the science of sound for free.

Online Yaesu FT-817 transceiver (receive only over the Net) using R.A.T.S. control software and MS Netmeeting for program access and audio. Asia's first online receiver, first online FT-817, and worlds first full-featured online receiver (operates just like a desktop radio including audio encoding time of less than 1 second). Operating from a flat in Kowloon, Hong Kong. Open to all.

This is a custom home made antenna, based on concept of commercial HF antennas, that may work on 160 meters too.

Contructing precedure and tune up of a dual band mobile antenna. This antenna is just a 1/4 wavelength resonator for both UHF and VHF band. It provides no GAIN as compared to other multi-section design.

how to modify a Cb linear amplifier to use in HAm HF band

4nec2 is a completely free Nec2, Nec4 and windows based tool for creating, viewing, optimizing and checking 2D and 3D style antenna geometry structures and generate, display and/or compare near/far-field radiation patterns for both the starting and experienced antenna modeler. Can be interfaced to HFwin32 propagation prediction software.

All these plans use the DK7ZB match

J-Poles with Wireman-cables for the quarterwave matching section, working on VHF and HF bands

A dual loop antenna, ZZ Wave Net HF Wire Antenna Project by VE6VIS. The antenna is basically a full wave 80 meter loop on top and a 40 meter loop on the bottom all supported from a 64 foot center support

Vertical transportable HF antenna by CT1BYR

The RXO Unitenna, a vertical wideband antenna, offers operation across the 7-21 MHz spectrum, covering the 40, 30, 20, 17, and 15-meter amateur bands. This design focuses on achieving a low SWR across a broad frequency range, making it suitable for general HF operation without requiring an external antenna tuner for minor SWR variations. The antenna utilizes a unique loading coil and matching network to maintain efficient radiation characteristics across its operational bandwidth. Construction details within the PDF document include specific dimensions for the radiating element and the counterpoise system, which is critical for vertical antenna performance. The design incorporates readily available materials, simplifying the build process for radio amateurs. Performance graphs illustrate the SWR characteristics across the 7 MHz to 21 MHz range, demonstrating the antenna's wideband capabilities. The document also provides guidance on feedline connection and grounding considerations for optimal field deployment. This vertical antenna configuration is particularly useful for hams with limited space, offering a compact footprint compared to horizontal wire antennas.

The project details a DIY SWR/Wattmeter designed around an _Arduino Uno_ shield, providing capabilities to measure RF power from 2 to **200 watts** and Standing Wave Ratio (SWR) for HF amateur radio bands. This construction features a compact design, integrating the measurement circuitry directly onto a custom PCB that interfaces with the Arduino Uno microcontroller. Key components include a directional coupler for sensing forward and reflected power, precision rectifiers, and analog-to-digital conversion for processing RF signals. The Arduino firmware handles calibration, calculations, and displays the results on an integrated LCD, offering real-time feedback on antenna system performance. The design prioritizes simplicity for homebrewers. Performance specifications indicate accurate readings within the **2-200W** power range, suitable for typical QRP to medium-power HF operations. The project provides schematics and a basic overview of the software logic.

Presents a web-based DX cluster interface, F5LEN Webcluster, which functions as a member node within the broader European DX Cluster network. It displays current DX spots across a wide range of amateur radio bands, from VLF through SHF, including specific bands like 1.8 MHz, 144 MHz, and 10 GHz, as well as satellite operations on QO-100. The service offers filtering options for various modes and activities, such as CW, QRP, IOTA, and specific VHF/UHF bands. Operators can access real-time propagation data, including Solar Flux Index (SFI), Sunspot Number (SSN), Kp index, and Auroral activity (Au), alongside tools for solar forecasts and tropospheric ducting predictions. The platform facilitates DX spotting by providing a centralized point for sharing and viewing contact information, aiding in DX hunting and contest operations. It also includes links to an Atlas, Sun tools, and a mobile version for portable access.

VHF magnetic loop atenna by ON1DHT

Operating on the HF bands, Kenwood's TS-990S and TS-890S transceivers represent their flagship offerings, providing advanced features for DXing and contesting. My personal experience with Kenwood gear, particularly the TS-590SG, confirms their reputation for solid receive performance and clean transmit audio, often noted in pileups. The TS-590SG, a popular choice for many hams, delivers reliable performance across the HF and 6-meter bands, making it a versatile station centerpiece. For VHF/UHF enthusiasts, the TH-D75A tribander offers 144, 220, and 430 MHz capabilities in a portable form factor. This handheld unit integrates D-STAR and APRS functionalities, appealing to operators who value digital modes and location-based services on the go. The inclusion of 220 MHz, a less common but valuable band, expands its utility for regional communications and specialized nets. Kenwood's enduring presence in the amateur radio market, dating back to 1955, underscores a commitment to quality and innovation. Their product range, from high-end base stations to feature-rich portables, continues to support a wide array of operating styles and technical requirements within the ham community.

WiNRADiO Communications, a division of Radixon Group, was established in 1996 to commercialize extensive research in radio communications. The company specializes in integrating radio and computing technologies, offering a diverse product range for government, military, security, and amateur radio enthusiasts. Their product line includes the WR-G65DDCe 'EXCALIBUR Sigma' HF/VHF SDR receiver, noted for its capabilities, and the G31DDC EXCALIBUR, recognized for its price/performance ratio in shortwave listening with improved AMS and Noise Blanker features. The company also produces the G39DDC series EXCELSIOR for serious monitoring, WR-G526e/G527e/G528e modular SDR solutions for high-performance applications like phase-coherent direction finding, and the low-cost WR-G305e/G305i VHF/UHF receivers. Professional counterparts, the WR-G315e/G315i, support APCO P25 decoders and trunking options. WiNRADiO's offerings extend to the PFSL-G3 field strength logging system for mobile signal coverage, advanced multichannel telemetry systems like the MS-8323, and specialized antennas such as the AX-31C Log-Periodic and AX-81S active HF antenna. DRM decoder software is available for G3 Series receivers, enabling clear reception of DRM broadcasts. The WSS-420 Weather Satellite Receiving System and various antenna rotators are also part of their product ecosystem. WiNRADiO supports multiple operating systems, with MacRadio for Apple Macintosh users and LiNRADiO for Linux developers, providing drivers and network receiver solutions like the RLX-810.

Magnetic loops are a compromise antenna and performance will be down on a full size-wire antenna particurlarly on lower HF Bands. This article compare this magnetic loop with a full-sized wire antenna on 80 meters by VK3YE

3 elements VHF Yagi homebrew antenna designed with YAGIMAX 3. Maximum forward GAIN is about 8,17 DBi. This antenna offering an effective radiation power 4 times greater of the transceiver output by SV1BSX

ON6MU project for a vhf uhf preamplifier

Schematics for a VHF UHF duplexer

Maco Manufacturing, HF Antennas, gamma matches, cable assemblies, power supply, swr meters, watt meters

Amateur radio HF nets

PropView is a free application that uses the included VOACAP, ICEPAC, and IONCAP engines to graphically display band openings between two locations over a specified 24 hour period. It can also build schedules for the IARU/HF beacon network and automatically QSY your transceiver to monitor each scheduled beacon.

This is a combination center and top loaded multiband antenna by Mark D. Lowell, N1LO PDF File

The Yaesu VL-1000 Quadra HF Linear amplifier

This sketch will read RF power and SWR from any SWR bridge, designed to work on VHF UHF bands

2 m. Band VHF Collinear with 2 Dipoles by sv1bsx

Download JT65-HF Amateur Radio software for reception/transmission of JT65A protocol with an emphasis upon its usage in the High Frequency Amateur Bands. This is the W6CQZ version not developed anymore.

WSJT-X, a creation of K1JT, offers specialized digital protocols meticulously optimized for challenging propagation paths such as EME (moonbounce), meteor scatter, and ionospheric scatter. This software excels at VHF/UHF frequencies, and also provides robust performance for LF, MF, and HF DXing, enabling contacts far below the audible threshold. The program decodes signals from ionized meteor trails and steady signals more than 10 dB below the audible threshold, a testament to its advanced digital signal processing. It integrates nearly all popular features from its predecessors, WSJT and WSPR, while adding comprehensive rig control and numerous other enhancements for the serious weak signal operator. Available for Windows, Linux, and Mac OS X, WSJT-X is an open-source project, allowing hams worldwide to download the latest versions and engage in cutting-edge weak signal communication.

EasyPal is a sophisticated digital Slow-Scan Television (SSTV) application that utilizes soundcard technology to encode and decode SSTV signals. Developed by the late Erik Sundstrup (VK4AES SK), this software has evolved into a versatile communication tool for amateur radio operators, extending beyond basic image transmission capabilities. EasyPal implements Digital Radio Mondiale (DRM) encoding technology, enabling efficient data transmission over narrow 2.5 KHz channels on both HF and VHF frequencies with remarkable speed. The application supports multiple file formats, including jpg, pdf, txt, doc, and xls, as well as specialized forms such as ICS-213 and ICS-213 (ARES). Additionally, EasyPal offers email functionality through designated repeater stations with internet access. Its responsive development history and robust feature set have established it as a premier digital SSTV solution in the amateur radio community, though users of Windows 11 should note specific configuration requirements to ensure optimal performance.

The resource provides detailed information about a five-band indoor magnetic loop antenna designed for amateur radio operators. This antenna is capable of operating on the 20, 17, 15, 12, and 10 meter bands, making it a versatile choice for various HF communications. Constructed from a single 3-meter length of 22 mm copper tube, the design emphasizes compactness and efficiency, which is particularly beneficial for operators with limited space. The page includes insights into the construction process, tuning, and operational tips, catering to both novice and experienced users. In addition to the technical specifications, the resource also discusses the advantages of using a magnetic loop antenna indoors, such as reduced interference and improved performance in urban environments. It serves as a practical guide for those interested in building their own antenna, offering a straightforward approach to antenna design and construction. Overall, this resource is a valuable addition to the toolkit of amateur radio enthusiasts looking to enhance their station with an effective indoor antenna solution.

Based on Motorola MRF454, schematics and component list

DJ9BV yagi antenna for 2 meters band

Presents a catalog of **QRP** transceivers, antenna tuners, and related accessories for amateur radio operators. The product line includes the ZM-2 antenna tuner, designed for efficient impedance matching across HF bands, and the NW-series QRP transceivers, offering low-power CW operation. Additionally, the site details various ladder line insulators and specialized connectors, emphasizing robust construction for field deployment and home station use. Each product listing provides specifications, operational parameters, and pricing information. Compares the features of different **QRP transceiver** models, such as the NW-40 and NW-20, highlighting their respective band coverage and power output capabilities. The ZM-2 tuner's performance is detailed with typical SWR reduction figures for various antenna types, demonstrating its utility for portable and fixed stations. Customer testimonials and product images illustrate the practical application and build quality of EMTECH's offerings, providing insights into their durability and ease of integration into existing amateur radio setups.

Continuos coverage HF Transceiver by I6WJB & I6YPK

We worry a lot about Standing Wave Ratio (SWR) in amateur radio since SWR is one indication of how well our antenna system is working. Most HF transceivers and antenna tuners have built in SWR meters. SWR is a measure of a transceiver' s output power verses the portion of that power reflected by the antenna system

A 144 MHz kilowatt amplifier project details the construction and performance of a high-power VHF linear using the GU74b tetrode. This Russian tube, equivalent to the Svetlana 4CX800, is noted for its conservative datasheet ratings, performing closer to 800-1000W anode dissipation in practical applications. The design prioritizes compactness and achieves 1.2 kW output with only 20W of drive power, demonstrating a 70% efficiency at 2.5 kV plate voltage. The amplifier has been successfully deployed in demanding _EME_ (Earth-Moon-Earth) operations since June 1994. Challenges encountered during development included achieving stability with a grid-1 input configuration. The author, _CT1DMK_, opted not to publish the full design due to its complexity, suggesting it might be difficult for less experienced builders to replicate successfully. However, he invites direct contact for those with specific interest in the design. Future plans include a "144MHz GS35b compact amplifier" project, promising another kilowatt-plus design. This resource offers insights into high-power VHF amplifier construction and the practical application of specific power tubes.

Duplexers for dual band radio are usually high pass filter and low pass filter combined in the same box. This circuit is a design within a cost of US$10.

2m SSB/CW-12.5 Ohm Yagis with extrem high gain and small bandwidth. These Yagis were constructed as ultra-light, portable Yagis with extrem high gain. They have small bandwidth and are working from 144,0-144,8MHz with good SWR.

Effective HF Mobile Antennas Keith WB2VUO, explains difficulties on gaining antennas efficiency on lower bands with mobile antennas.

Suitable antenna for owners of an IC706 or FT817, 857 and other HF portable transceivers. You can an be QRV in a few minutes on all ham-bands from 80m to 6m and even on 2m by PA0FBK

A full wave 2-meter VHF omnidirectional antenna by ON6MU

The Inverted L antenna is a versatile and efficient design suitable for small gardens, allowing amateur radio operators to operate on multiple bands. This project outlines the construction of a 5-band inverted L antenna, which can cover HF bands effectively. The design is particularly advantageous for those with limited space, as it requires minimal ground space while providing good performance. The antenna can be easily constructed using common materials, making it accessible for both beginners and experienced hams. In this guide, GM0ONX shares detailed instructions on how to build the inverted L antenna, including dimensions and tuning tips. The project emphasizes the importance of proper installation and grounding to ensure optimal performance. Additionally, it discusses the antenna's compatibility with various transceivers and the potential for portable operation. This resource is ideal for hams looking to enhance their station with a multiband antenna that performs well in limited space.

The Coax trap program computes design parameters for the construction of coaxial traps for HF usage. Typically these are constructed from PVC tube and RG58/59 coax

Merging Internet technology with Amateur Radio holds great promise. This article discusses the authors experiences in putting several Internet Remote Base stations on the air. By Stan Schretter, W4MQ, Brad Wyatt, K6WR, and Keith Lamonica, W7DXX