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Advanced QRP Low Cost Mosfets HF Linear Amplifier with schematics, IMD, gain data and more. Six articles about amateur radio.

The purpose of this page is to capture and document the Yaesu FT-101 series radios during the 1970's

The 6 Band Inverted L Antenna MK3 is a versatile multiband antenna designed for amateur radio operators. This antenna covers 160m, 80m, 40m, 20m, 15m, and 10m bands, making it suitable for a wide range of HF communications. The design is based on a W3DZZ configuration, incorporating traps for optimal performance. The MK3 version features a sturdy 5/8th CB mast, replacing the original timber mast, which enhances durability against harsh weather conditions. The antenna's construction allows for effective operation, particularly on the 40m band, where it has been successfully used to contact distant locations including ZL, VK, and Antarctica. Constructing this antenna requires careful attention to detail, especially regarding the radials and grounding. The traps resonate at specific frequencies, and additional resources are available for building coaxial traps. The antenna is designed to work efficiently without an ATU on the lower bands, while higher bands may require tuning. This project is ideal for both beginner and intermediate operators looking to enhance their station with a reliable multiband antenna.

A listing of 2m SSB nets around the US.

Described is a simple inverted-V antenna which, when used with a balanced ATU, can be used on all the main Radio Amateur HF bands (80, 40, 20, 15 and 10m). The cental support is made in such a way that the wire can be coiled up for storage when the antenna is taken down.

HF Communications Analysis and Prediction Tools for Amateur Radio and communications professionals. Featuring: WinCAP Wizard, Beacon-Time Wizard, GeoAlert-Extreme Wizard, ID Wizard, KTS Clock Screen Saver, NERDAlert 2000

Comparison chart between Cushcraft R8, Hy-Gain AV640 , Butternut HF6V, Gap Titan and Eco 7+

Amateur Radio software for transmission/reception of JT65 protocol. Brought to you by hb9hqx

Notes on homebrewing antennas by Chris G4CYA, from gamma matching, to phasing antennas, splitters and combiners, baluns and measuring techniques.

The MCP-F6/F7 software facilitates memory channel and menu data creation for the Kenwood TH-F6A, TH-F7A, and TH-F7E transceivers. It operates on _Windows_ XP (SP3+), Vista (SP2+), Windows 7 (RTM+), Windows 8 (RTM+), Windows 8.1 (RTM+), Windows 10, and Windows 11. System requirements include a CPU faster than the OS recommendation, RAM exceeding the OS recommendation, and **2 MB** of free hard drive space. Display resolution must be XGA (1024 x 768) or higher. Connectivity to the transceiver requires an optional PG-4Y (RS-232) or KPG-22U (USB 2.0) programming cable. The KPG-22U cable necessitates a virtual COM port driver installation. The software supports COM1 through COM20 for RS-232 communication. Installation requires administrator privileges and involves executing "setup.exe" from the extracted MFX101.zip archive. Uninstallation is performed via the Control Panel's "Uninstall a program" function or by re-executing "setup.exe." Created data files are not removed during uninstallation and require manual deletion. The software version is **1.01**. DXZone Focus: Kenwood TH-F6 F7 | Memory Management | Windows | RS-232

Constructing a Lindenblad antenna for 137MHz NOAA satellite reception involves specific design considerations for optimal performance. The resource details the use of 4mm galvanised steel fencing wire, 300-ohm television ribbon cable, and wood/plastic components for the antenna structure. Key dimensions for a 137.58MHz-resonant antenna are provided, derived from the ARRL Satellite Handbook, specifying s, l, w, and d as 42, 926, 893, and 654mm respectively. The antenna is designed for Right Hand Circularly Polarised (RHCP) signals, requiring the four folded dipole elements to be tilted clockwise by 30 degrees. A significant aspect covered is impedance matching between the antenna's 75-ohm impedance and a typical 50-ohm receiver input. A twelfth-wave matching transformer, constructed from 117mm sections of 50-ohm RG-58 and 75-ohm RG-59 coax with a 0.66 velocity factor, is described. The article also addresses coaxial cable and connector selection, recommending 75-ohm Type-N connectors for RG-6 cable in professional setups and F56/F59 connectors for general use, while strongly advising against PL-259/SO-259 connectors for VHF. Strategies for mitigating Radio Frequency Interference (RFI) are discussed, including antenna placement to shield from local TV transmitters and the use of commercial or DIY band-pass filters, such as cavity resonators or helical notch filters, along with ferrite chokes on coaxial cables. Antenna orientation is explored, noting the Lindenblad's 'cone of silence' directly overhead and its maximized sensitivity towards the horizon. An experimental vertical tilt of 90 degrees is presented as a method to improve overhead reception and reduce interference from strong horizontal signals, particularly relevant in high RFI environments like the Siding Spring Observatory site.

Interconnecting the YAesu FT-897 or 897D

SDR Receiver a compact high performance HF software defined radio receiver designed to be used in fixed or portable stations. Version 2 of the receiver is now available. It now has an RF pre-amplifier using a power MOSFET and other revisions to improve it's performance both as a stand alone receiver and as an IF panadaptor with HF and VHF transceivers.

This page includes fatures, specifications options and photos of the ICOM IC-746

The RigPix database entry provides a comprehensive technical overview of the Icom IC-746 amateur HF/VHF transceiver, detailing its operational parameters and physical characteristics. It specifies the transmit frequency ranges across 10-160 meters plus WARC bands, 50-54 MHz, and 144-146/148 MHz, alongside receive coverage from 0.03-60 MHz and 108-174 MHz. The resource outlines supported modes including AM, FM, SSB, CW, and RTTY, noting a tuning step resolution down to 1 Hz and a frequency stability of ±5 ppm. Key electrical specifications are presented, such as a 13.8 VDC power supply requirement, current drain figures for RX (1.8-2 A) and TX (Max 20 A), and RF output power ranging from 5-40 W for AM and 5-100 W for FM, SSB (PEP), and CW. The entry details the triple conversion superheterodyne receiver system, listing IF frequencies at 69.01 MHz, 9.01 MHz, and 455 KHz, along with sensitivity ratings for various modes and bands. Transmitter section specifics include modulation systems and spurious emission levels. Additional features like a built-in auto ATU, electronic keyer, simple spectrum scope, DSP, and CI-V computer control are noted. The page also lists related documents, modifications, and an extensive array of optional accessories, including various filters, microphones, and external tuners, providing a complete profile of the IC-746.

Excel sheet containing technical comparisons of commercial HF portable antennas compiled by ON4SKY. Includes pictures, manufacturer, db gain, band coverage, F/B ratio, price, weight and dimensions.

Ham Radio Tower Project at N0HR. Includes site plan, escavation, tower construction, HF antennas, grounding and lightning protection, coax and more.

AirMail is a HF radio mail program for sending and receiving messages via Pactor, either via the ham radio system or participating marine or commercial services

Presents the design and construction of the OK2FJ Bigatas, a portable, automatically tuned vertical antenna covering 80 through 10 meters. It details two distinct control systems: one utilizing BCD band data from Yaesu FT-857/897 transceivers, and another employing voltage level sensing for the Yaesu FT-817. The resource provides specific instructions for building the antenna's radiating element, loading coil with switchable taps, and the control circuitry, emphasizing the use of readily available components. The article outlines the physical construction of the antenna, including the use of duralumin tubes for the radiator and a PVC tube for the coil form. It specifies coil winding details, tap points, and the integration of radial wires for ground plane operation. The control electronics section provides schematics and component lists for both the BCD decoder (using a 74LS42 IC) and the voltage comparator (using an _LM3914_ bargraph driver), enabling rapid, automatic band switching without the minute-long tuning delays common in other systems. Crucially, the antenna achieves rapid band changes, with typical SWR values centered on common operating segments, such as **3.7 MHz** for 80m SSB. It also discusses modifications for CW operation on 80m and the trade-offs between antenna efficiency and full-range automatic tuning on higher HF bands, where manual adjustment of radiator length is suggested for optimal performance on 15m, 12m, and 10m. The resource includes construction photos and a discussion of cable requirements for reliable operation.

JJ0DRC's HF multi-band delta loop antenna project, initially conceived during the waning peak of Cycle 23, addresses the common challenge of achieving effective DX operation from a small residential lot in Japan. Dissatisfied with a ground plane antenna's performance in SSB pile-ups, the author sought a beam-like solution without a tower, drawing inspiration from a JJ1VKL article in CQ Ham Radio Sep. 2000. The antenna, constructed in October 2000, employs two 7.2-meter fishing rods (37% carbon fiber, reinforced with cyano-acrylate glue and aluminum tape) and 1mm enameled wire, fed by an Icom AH-4 external antenna tuner. While the exact beam pattern remains unmeasured, JJ0DRC observed a significantly higher callback rate compared to dipole antennas, particularly on higher bands. The system's circumference length of 15-20m is crucial for maintaining a good beam pattern across HF bands, though performance on lower bands like 80m, 40m, and 30m becomes less directional as the length deviates from a full wavelength. Ongoing maintenance addressed degradation issues, including aluminum tape cracking and wire breakage at connection points due to strong winds (often exceeding 10-15m/s in winter). The author reinforced rod connections with IRECTOR PIPE SYSTEM components and INSU-ROCK ties, and improved wire attachment methods using Cremona rope and epoxy bond to enhance durability.

The ICOM IC-7300 is a cutting-edge HF transceiver that has garnered significant attention since its release. This review, published by ARRL in QST, provides an in-depth analysis of its features, performance, and usability. The IC-7300 is known for its direct sampling technology, which enhances its sensitivity and selectivity, making it a favorite among amateur radio operators. The review covers various aspects, including the user interface, audio quality, and overall operational capabilities, providing valuable insights for both new and experienced hams. In addition to its technical specifications, the review discusses the IC-7300's performance in real-world scenarios, such as DXing and contesting. It highlights the transceiver's ability to handle weak signals and its versatility across different modes. The review serves as a helpful guide for those considering the IC-7300 for their station, offering a balanced perspective on its strengths and potential drawbacks. Overall, this review is an essential resource for anyone interested in the ICOM IC-7300 and its place in the amateur radio landscape.

Vortex Antenna Systems, radio communication antenna aanufacturer and supplier of antenna related hardware. Ham radio HF and VHF Antennas, antenna parts, mast and mounts.

The DXrobot, operational since 1999, offers a free, non-commercial service primarily for the VHF ham radio community. It specializes in automatic real-time E-skip warnings for **144 MHz** in both Europe and North America, delivered via email or SMS. Additionally, the system provides automatic aurora alerts for _50, 70, and 144 MHz_ openings through the same notification methods. Beyond real-time alerts, the DXrobot facilitates the reception of the latest DX-cluster spots via email, a feature useful for operators without immediate WWW or cluster access. The service also displays recent E-skip and aurora spots detected by the DXrobot on 50, 70, and 144 MHz, with updates every five minutes. Historical data includes lists of all DX spots from the previous day on 50, 70, and 144 MHz, updated daily. Key propagation data, such as MUF timeline, Solar X-rays, Geomagnetic Field, and Estimated Kp index, are also presented.

Summarizes a portion of the FCC rules 47 CFR 80.371(c) and 80.373(f)

WSJT-X and MAP65, open-source amateur radio programs, facilitate weak-signal digital communication. WSJT-X covers VHF/UHF to HF, decoding subthreshold signals. MAP65 optimizes for VHF/UHF EME with JT65. Free and GNU GPL licensed, WSJT-X is on Windows, Linux, and OS X, while MAP65 is Windows-only, supporting SDR hardware.

The Kenwood TH-F6A handheld transceiver can achieve an extended transmit frequency range of 137-174 MHz, 216-235 MHz, and 410-470 MHz by removing a specific diode and chip resistor from the main PCB. This modification also expands the receive range on the A-band to 142-152 MHz, 216-235 MHz, and 420-450 MHz. For the TH-F7E, the transmit range extends to 137-174 MHz and 410-470 MHz, with a corresponding receive range on the A-band. Performing these hardware changes will reset and initialize the radio's memory contents, necessitating prior backup of important channel frequencies. Instructions are provided for constructing a homemade PC programming cable compatible with the Kenwood TH-G71A, TH-F6A, and TH-F7E. The interface utilizes an RS-232-to-logic (0-3.3V) level-shifter and a full-duplex serial connection, adapting the Kenwood PG-4S cable schematic for the TH-G71's 2.5mm and 3.5mm phono plugs. Specific schematic tweaks include changing R1 from 150 ohms to 1K ohm to optimize power from the serial port and adding a 150K ohm resistor between the Radio TXD and ground to manage the 3.3V I/O pin. Detailed plug pinouts for the 2.5mm and 3.5mm connectors are presented, with the interface's TXD connecting to the ring of the 2.5mm plug and RxD to the shield of the 3.5mm plug. Ground connects to the shield of the 2.5mm plug, while the tips of both plugs are no-connects. Debugging procedures cover verifying positive and negative power rails from the serial port, checking component polarities, and testing level-shifting and inversion functions of the interface. Software setup involves enabling "TC ON" (Menu 15 for TH-G71, Menu 9 for TH-F6) and using Kenwood's MCP programming software.

The FTBVR5K software facilitates comprehensive memory management for the Yaesu VR-5000 scanning receiver, supporting operations such as modifying, moving, adding, deleting, masking, and unmasking individual memories. It allows for importing and exporting memory definitions via CSV files, sorting memories by frequency or name, and identifying duplicate frequencies within the receiver's configuration. The program also supports the creation and modification of bank definitions, management of PMS (Programmable Memory Scan) definitions, and adjustment of PMS scanning ranges. Additionally, users can print detailed reports of memories, banks, PMS definitions, rig settings, and S.CALL details, with visual cues like red highlighting for masked memories and yellow for the priority channel. FTBVR5K provides functionality to alter values within the VR-5000's Set and Config menus, and to change S.CALL station names and frequencies. The application operates on standard Windows PCs, including Windows XP, Vista, 7, 8, and 10, requiring an available COM port for transceiver connection, which can be a conventional serial port or a USB adapter. A minimum screen resolution of 800 x 600 is supported, with 1024 x 768 recommended for optimal usability.

The W6AMT Beacons is a Windows program which automates the collection of radio propagation data. HF data is collected by monitoring the worldwide network of NCDXF / IARU HF beacons.

CyberDX-CW is a software simulation of an amateur radio station monitoring the world. Generates a simulated radio environment, where the operator can tune all of the HF bands and actually hear computer generated station activity

The MFJ-940 VERSA TUNER II is a useful little antenna tuner for the HF-bands. However it suffers from a minor design error, which can be easily rectified.

A well documented article on a small magnetic loop antenna for the 40 meters band

Long path hf radio propagation is sometimes the best path to work dx, since the shortest path is not always the best path.

Compiling an extensive collection of technical information, the Repeater Builder's website serves as a critical resource for those involved in amateur and commercial repeater systems. It covers a broad spectrum of topics essential for the design, construction, and ongoing maintenance of these vital communication hubs, drawing from years of practical experience in the field. The site provides detailed insights into various aspects of repeater technology, including specific information on VHF and UHF bands, such as 2-meter systems. Users can find data related to repeater logic, control systems, and interfacing with other radio infrastructure, all presented with a focus on practical application. Authored by Kevin Custer, W3KKC, the content reflects a deep understanding of repeater operations and engineering, offering guidance that extends beyond basic setup to advanced troubleshooting and optimization.

Live space weather and propagation data, in RSS (XML) format.

Remote HF - VHF - UHF radio station using TS-2000 and remoterig devices

Presents the detailed construction of the _FLA25HV_ antenna, a specialized array optimized for Earth-Moon-Earth (EME) communications on the 2-meter band. This resource provides schematics and practical insights into building a high-gain antenna system capable of reflecting signals off the lunar surface, a challenging but rewarding aspect of amateur radio. It covers the mechanical and electrical considerations essential for achieving the precise pointing and signal strength required for successful moonbounce contacts, often yielding **20 dB** or more gain. Amateur radio operators pursuing EME operations require robust antenna systems and precise tracking capabilities. The FLA25HV design addresses these needs by focusing on element spacing, impedance matching, and structural integrity to withstand environmental factors while maintaining critical alignment for lunar reflections. Such systems are crucial for making contacts over distances exceeding **768,000 km**. This personal page serves as a practical guide for hams interested in constructing their own EME arrays, offering a glimpse into the technical dedication involved in pushing the boundaries of VHF/UHF propagation.

VHF/UHF DX site showing latest propagation, software, radio dealers, awards, maps etc.

Memory management program for the FT-60R/E FM handheld.

Largest general-purpose ham radio club in Twin Cities. Three repeaters, fully equipped two position HF club station, contesting, field day, and more.

A project for a multiband HF windom antenna by VE2CV and VE3KLO

An interesting article on building a 4 elements yagi antenna with gamma match for the 2 meter band. This article include two videos demonstrating assembling procedure by KG0ZZ

Features and specifications for Yaesu FT 857D

A new SDR-receiver from the italian SDR developers community. Low-cost, DDS-less Software Defined Radio full coverage receiver for all HF bands, used with powerful software on the PC for multi-mode operation

GitHub reposotory of QradioPredict, a radio propagation prediction tool for VHF-UHF, based on the Irregular Terrain Model, also known as Longley-Rice. Can be used as a repeater site planing tool. Has an internal APRS client which can be used to display stations as a landmark.

Video, how to build a 130 Watt Dummy Load for HF amateur radio

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

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

VQLog 3.1 - 782 is a shareware logbook program designed for Windows operating systems (95, 98, NT, 2000, ME, XP, Vista, 7, 10, or later), supporting resolutions of 800x600 or higher. It can also operate on macOS and Linux via virtualization software like Virtual PC for MAC, Oracle VirtualBox, or VMware. The software facilitates QSO access by date, callsign, prefix, square, DXCC, and other parameters, offering robust import capabilities for ADIF, Cabrillo, and ASCII files from various contest and logbook programs. Key features include comprehensive award tracking for DXCC, WAZ, WAC, WPX, WAS, IOTA, TPEA, DIE, VUCC, 100EACW, and up to 30 user-defined awards. It generates customizable summaries and graphical statistics for QSO activity, DX contests, Most Wanted Squares (MWS), propagation openings, and prefixes. VQLog supports DX-Spot reception and processing from DX-Cluster and PSK-Reporter with programmable warnings, integrates with callbook services like QRZ.COM and Buckmaster's CD, and offers online lookup. Electronic QSL and log upload support extends to LoTW, eQSL.cc, Clublog, and DXMAPS, with real-time updates for online logs. The program provides extended QSO information for VHF-DXers, including separate TX/RX frequencies, start/end times, propagation modes, and specific entry fields for MS, EME, and Tropo. CAT support for rig control and interfaces with ARSWIN and PstRotator for azimuth/elevation control are also included.

Cruise Ship and Maritime Monitoring Frequencies - cruise ship frequencies maritime scanning radios vhf uhf

IC706 Specifications by universal radio inc