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An online calculator for designing and evaluating capacitors based on the capacitor's area, separation, number, and dielectric constant

Amateur radio antennas manufacturer based in Italy. Produces HF end-fed, dipoles, and other wire antenna types, mono band and multi band antennas.

Electronic Products Design Inc based in North Carolina, offers you custom design of transformers, coils, and telemetry control systems.

Master Callsign Database Editor allows to create and modify Super Check Partial database files used by many contesting programs in DTA and SCP formats. The files produced by Master Editor in DTA format can be used with CT, WriteLog, TRlog, SD, and others. The SCP versions of the produced files are for use with Win-Test, N1MM+, and others. Master Editor allows to create a callsign database from a separate log or from a set of logs in the Batch Import mode.

DK7IH QRP transceiver for 14 MHz. This small and compact home made transceiver with a max power output of 5W, the VFO module is based on the clock oscillator chip Si5351A by Silicon Labs ATmega168 and OLED 1306

A quarter wave vertical omni-directional antenna for 7 MHz. Formulas for dimensions in feet and meters are provided. Ideal radial angle is between 35° and 45°. Velocity factor (Vf) varies based on coax type.

A windows program to learn Morse code and doing QSO in CW. The training course contains 39 Lessons based on Koch method. It can sends only letters, only numbers, only punctuation

The Narrow Band Emergency Messaging System (NBEMS - pronounced N-beams) is a suite of software programs based around Fldigi and designed for point-to-point, fast, error-free, emergency messaging which takes up very little space on the ham bands.

A CW Contest Simulator, a simulator for the weekly CWT contests sponsored by CWops, based on Arduino Nano

UK based manufacturer of digital mode PC fully isolated interfaces. Includes several types of interfaces including USB interfaces for CW and Digital modes

All available frequencies & offsets configurations for repeaters can be downloaded as database for Kenwood MCP-2A memory channel programming software for TM-D710 & TM-V71. Zip file is no more available from the author, but the full table of frequencies is still online

The K3NG Keyer is an open source Arduino based CW (Morse Code) keyer with a lot of features and flexibility, rivaling commercial keyers which often cost significantly more.

Pro-Link products, coax cable manufacturer specialize in a comprehensive range of Fibre Optic Cables, 50ohm and 75ohm Coaxial Cables, RF Cables, 10Base-T Cables, Connectors and Networking Products

These band filters are based on 3 or 5 sections Butterworth band pass filters, maintaining 50 Ohm impedance, and when built around toroidal inductors, can be made very compact.

A dedicaed vertical antenna for 80 meters band based on a 40 meter vertical experiment

The Monongalia Wireless Association is the oldest active amateur radio club in Monongalia County. Based in Morgantown,WV

A multiple page article about assembling the antenna system, this section includes informations on constructing of the concrete tower base, starting from setting up correctly the foundations in relation to the antenna height.

A vertical antenna for 160 meters band based on the K6MM vertical with some enhancements and modifications on the main capacitance hat

QSO Relay is a Windows desktop application that listens for contacts being forwarded from WSJT-X/JT65-HF and JTAlertX and write to Ham Radio Deluxe Logbook v6.x database

Surrey radio contact club (srcc) - an amateur radio club based in Croydon, Surrey, UK

Amateur radio dealer and on-line shop of major ham radio market brands, established in 1990, based in Poland.

Malcom Technical Support Radio Electronics Repair, ICOM Authorized Service Center, also service 1988 and newer Kenwood HF/VHF/UHF transceivers based in Toledo, WA USA

The Sutton & Cheam Radio Society has a 60 year history. We are an Affiliated Society of the Radio Society of Great Britain (RSGB) and are based in the London Borough of Sutton.

This page details my building of a 100 Watt Power Amplifier for the 432 MHz Band based on two Motorola MRF646 transistors taking inspiration by Carlo Gnaccarini VK3PY, formerly VK3BRZ

Dealer in HF, RF and microwave components based in Italy, offering a wide product catalog for amateur radio projects and more.

DxDozer is a Windows-based amateur radio logbook designed for both new and experienced DXers, featuring a robust logging system with extensive search capabilities. It offers seamless integration with FT8, displaying received stations from WSJT-X in a DX Cluster-like view, indicating LoTW status and prior contacts, and initiating QSOs directly. The software supports an unlimited number of callsign logbooks and allows multiple operators to log simultaneously to a single database, enhancing its utility for multi-operator stations or contest operations. The application includes a sophisticated DX Cluster with highly configurable filters based on band, mode, continent, worked/confirmed status, and LoTW participation, enabling users to monitor specific calls or countries. DxDozer simplifies QSL management by facilitating one-button uploads to LoTW and ClubLog, and downloads of new confirmed QSOs, with a dedicated field for QSL medium. The software provides both 'Easy' and 'Expert' modes to cater to different user proficiency levels, and is available via a yearly subscription after an initial free trial period.

The calculator designs the Yagi-Uda antenna based on the DL6WU model with boom correction, following the G3SEK-DL6WU method. It optimizes the antenna for maximum gain and allows adjustment of passive elements without affecting SWR. DL6WU antennas are known for their high gain, minimal sensitivity to nearby objects, and stable performance in various weather conditions.

10 Elements Cross-Yagi Antenna for 433 MHz. The base of the 10el antenna is the recalculated RA6FOO antenna.Circular polarization is realized - by a phasing quarter-wave line, matching of horizontal and vertical polarization antennas

Based in Filwood, Bristol England

Small company based in Santa Maria, California, designing and manufacturing electronic products for amateur radio, education, and commercial users. Product line includes APRS devices for real-time vehicle tracking, weather monitoring, and remote telemetry, as well as the ADS-SR1 Simplex Repeater, the ADS-WS1 Weather Station, the SSTVCAM slow-scan TV camera, and GTRANS protocol translator for Garmin FMI.

Manufacturer of two way radios based in Shenzhen China. Retevis produce commercial, personal and amateur radio handheld and mobile transceivers, either for analog and digital modes. Retevis produce also two-way radio accessories and repeaters.

Provides a robust logging solution for amateur radio operators across multiple operating systems, QLog simplifies the process of recording contacts and managing station data. It leverages the _Qt framework_ for its graphical user interface and stores all QSO information efficiently in a local SQLite database, ensuring data integrity and accessibility. This design choice supports a streamlined user experience for daily logging activities. QLog supports essential logbook functionalities, enabling hams to accurately document their two-way radio contacts. While not specifically designed for high-speed contest operation, it serves as a reliable tool for general amateur radio logging, allowing operators to maintain detailed records of their on-air achievements and station activities. Its cross-platform compatibility, including Linux, Windows, and macOS, makes it a versatile option for a wide range of amateur radio enthusiasts seeking a free and functional logging application. The project is a fork from _7h0ma5/QLog_, indicating a continued development path.

A hexagonal beam is a form of the Yagi antenna which is based on parasitic principles developed early in the last century in Japan for achieving gain in one direction.How HexBeam antennas works. A hexagonal beam operates exactly like Yagi antenna, but instead of a driven element that is straight like a dipole, it is a wire bent into the shape of the letter M.

Illustrates the fundamental principles of radio repeaters, detailing their role in extending communication range beyond line-of-sight limitations. It begins by defining _simplex communication_ as a direct radio-to-radio link, effective only when no obstructions impede the signal path. The resource then introduces the concept of a repeater (or base station) strategically positioned on elevated terrain, such as a mountain, to overcome geographical barriers. The article clarifies the repeater's operational mechanism: it receives a signal on one frequency and simultaneously re-transmits it on a different frequency, enabling users on opposite sides of an obstruction to communicate. This _duplex operation_ is likened to satellite communication for VHF propagation, but with a fixed terrestrial station. Specific examples of signal paths are provided, showing how a handheld radio transmits up to the repeater, which then relays the message down to another user, effectively bypassing obstacles like hills or large buildings.

This is the website of the Meirion Amateur Radio Society, based in gwynedd north wales

NanoVNA based on edy555, use the odd harmonic extension of si5351 to support the measurement frequency up to 900MHz. GitHub repository.

A mircovert antenna assembled for the 40m version of the DL7PE antenna. A one meter long aluminum tube with 24mm diameter is used for the base (element 1) and a 50cm aluminum tube with 20mm diameter for element 2 (the extention). A pvc pipe, 34cm long and with a diameter of 38mm, is used to wind the coil on (1mm enamelled copper wire).

The map display allows you to select by locator, or clicking on the map, where you want to calculate the probability of Sporadic-E by building a combination EPI, Es Probability Index, based on factors using many of the known parameters which can effect Es. T

UHSDR stands for UniversalHamSoftwareDefinedRadio. The project provides the firmware to run standalone HAM transceivers. It currently supports STM32F4 and STM32F7 MCU based QSD designs.

In pursuit of enhanced station efficiency, the author describes crafting an Arduino-based smart antenna switcher for an SO2R setup. Faced with manual antenna switching challenges during contests, the project utilizes a Logos Electromechanical 4x4 Driver Shield and a Power Screw shield for seamless functionality. Despite its raw appearance, the automatic switcher proves indispensable in contest scenarios, prompting considerations for future improvements and standardization of station control protocols.

Strictly Ham has a large retail presence in Australia and welcomes inquiries from New Zealand, the Pacific and Asia. Strictly Ham offers a comprehensive range of high quality Amateur, CB and Marine products, based in Victoria Australia

Pass Recorder is a small application that records audio from satellite passes based on tracking data it receives from the commonly used SatPC32 application

S.C.A.R.T is a club based in the Southampton area of the UK open to everybody who is interested in amateur television and video related subjects.

Echelford amateur radio society is based in ashford, middlesex, uk. has about 80 members.

Ham radio club based in Fort lee NJ USA

South manceshter radio and computer club, based in sale cheshire, an active radio and computing club with weekly talks

The ICOM IC-7610 SDR HF/50MHz Transceiver official product page with product specifications, option accessories and video at ICOM UK

Cable manufacturer based in Italy, produces coax cables fo RF applications including 50 Ohm low loss cables for amateur radio applications.

Conventional scanner frequencies for the San Francisco Bay Area, now in a fully searchable database

This 160 meter Delta Loop antenna is made of Hard drawn copper wire AWG 10, the two upper side are 148.5 foot each base wire is 240.9 foot, the feed point at 30.69 foot to one corner, feed with 450 Homs balanced line to an antenna tuner on the ground, then with 50 homs coax to the shack.