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A 4 elements Yagi-Uda antenna for 144.3 MHz plan with dimensions and yagimax dimension calculation

Presents a detailed resource for DXers interested in Non-Directional Radiobeacons (NDBs), MF, HF, and VHF propagation beacons, and various other radiobeacon types. The site offers access to downloadable information files, including an Abbreviations List, NDB List Country List, and NDB Publications List, which serve as foundational materials for newcomers to the hobby of beacon monitoring and DXing. It covers specialized topics such as DGPS beacons, GMDSS DSC mode, and NAVTEX mode, with dedicated sections providing in-depth explanations. A Beacon Photo Gallery showcases diverse radiobeacon types from around the globe, offering visual context for different systems encountered in the field. The platform also facilitates participation in unique monthly Coordinated Listening Events (CLEs), providing guidelines and schedules for these activities. The resource outlines various associated Groups.io lists, including the primary NDB List for radiobeacons (NDBs, Propagation Beacons, VOR systems), the DGPS List for DGPS DXing, Time Signals, LORAN, and WeFAX modes, and specialist groups like NavtexDX and DSC List for GMDSS-DSC. It details how to join these communities for further engagement and information exchange.

St. Louis Repeater runs four repeaters in the St. Louis Metro Area, including two with autopatch capability.

The goal of detuning is not to avoid resonance, but rather to minimize re-radiation and/or current in the interfering structure.

G3SEK answers to some practical questions on builing the N2PK VNA Vector Network Analyser

This article describes a generalised unit for interfacing a transceiver's TTL/CMOS interface to RS-232.

A website dedicated to 70 MHz Band

Slot cubes are folded skeleton slot antennas with widened, folded dipoles bent into a cube to reduce size. QST Article 12 2019

Antenna Systems & Solutions, Inc. carries antenna mounts, antenna guyed towers, antenna self-supporting towers, four legged towers, BX towers, poles, tower hardware, and wall mounts.

Presents the Holy Cluster, a contemporary DX cluster service offering real-time amateur radio spot data. This platform integrates a dynamic graphical map to visualize current contacts, enhancing situational awareness for DXers and contesters. Developed by an Israeli group of developers and supported by the Israeli Association of Radio Communication (IARC), the Holy Cluster aggregates DX spots from various sources, including traditional telnet clusters, the Reverse Beacon Network (RBN), and PSK Reporter, providing a comprehensive view of band activity. The cluster's design emphasizes a user-friendly interface for monitoring DX activity across multiple bands, including dedicated support for JOTA (Jamboree On The Air) operations. Its aggregation capabilities allow operators to quickly identify propagation openings and active stations, streamlining the process of making two-way radio contacts. The integration of RBN and PSK Reporter data offers insights into propagation conditions and station reception reports, which can be invaluable for optimizing antenna direction and operating strategies.

Notes on how to build an inverted V wire antenna with lenghts for all HF bands from 160 mtrs to 10 mtrs

WeatherExperts.Com, the premier online store for weather stations, instruments, anemometers, barometers, accesories, and satellite pictures. Excellent prices!

The InterCity Amateur Radio Club welcomes you to Mansfield, Ohio.

Interface APRS to a weather station

Online websdr receiver based in Rome Italy provides a nice user web interface and receiver most of the amateur radio HF bands

Antenna modeling discussions about What happens if... a dipole is bent horizontally, laterally, vertically. Zig-zag, meander, catenary curve. Effect of sag, elevation, radials. OCF off-center feed, harmonics. Includes 4NEC2 antenna models for each study.

This sweeper built for a narrow bandwidth filter adjustment, use a simple 555 version sawtooth wave generator.

Vintage radio equipment and memorabilia 1910 - 1950

Demonstrates a range of specialized radio frequency equipment and consulting services for amateur and professional applications. The offerings include _Vector-Finder_ direction finding antennas, various test equipment such as _gate dip meters_ and RF sniffers, and communications receiving adjuncts. Additionally, the company produces satellite antennas for weather satellite reception, voice amplification devices like the _Flex-Mike_, and custom prototype circuit boards. The company's product line addresses needs for precise RF measurement, signal detection, and specialized antenna systems, particularly for direction finding and satellite communications. Their historical association with National Radio (HRO) suggests a legacy in radio technology. The site also highlights a subsidiary, Sierra Mountain Products, which offers outdoor recreational gear, indicating a diversification beyond core RF manufacturing.

Ham radio shop in Hanstholm Denmark

SWR is Finland's first private shortwave station.

This test circuit is easy to duplicate, and demonstrates the extreme voltages that appear in an amplifier when the load is improper for the amount of drive power applied.

Photos and description of an EAC R-390A

Receive and listen to FM and AM radio broadcasts on your browser or ChromeBook using an RTL2832U-based USB digital TV tuner.

ScopeIIR: an Infinite Impulse Response (IIR) digital filter design tool for Windows. It designs high-order IIR filters based on analog filter prototypes, and can design lowpass, highpass, bandpass, and bandstop filters.

A Flemish association of shortwave listeners

an homemade ultra lightweight Morse code keyer paddle that can be used as a manual straight key

Monthly Amateur radio DX Peditions and Contest calendar at HamRadioWeb

6BTV (or 5BTV or 4BTV) mod for 12 and 17 meter bands, how to make a 7BTV or 8BTV or 9BTV, easy and cheap

Club page of the police amateur radio team-wb1gof of westford, massachusetts

PEP RF output power measurement, and examples RF output power measurements

A simple RF sweep generator circuit diagram by JF1OZL

Web Site of Ukrainian Club Amateur Radio station from Vernadsky Research Station on Galindez island EM1U

21 February to 6 March 2013 XT2TT Italian Dxpedition Team will be in Burkina Faso Online Log XT2TT and Live Stream

This antenna was designed for the CQ WW CW 2009 at EA8URL. All elements are made out of fishing rods with an insulated copper cable fixed on the rods by cable ties. Both fishing rods and cable are UV resistant.

An Energy Analysis at an Impedance Discontinuity in an RF Transmission Line

Magnetic Loop antenna for 20 to 80 meters band using home made butterfly condensator kit

cq-contest reflector comments about the performance of the EWE receive antennna collected by KA9FOX

Wolverine Power Systems provides generators, rental, service and repair located in Holland, Michigan.

Handheld Radio Pouches, Power Supplies, Solar Recharging Systems, GPS Navigation Devices and 12V Accessories

Attenuating output power to Yaesu FT-817 and interesting article for really QRP operations by PA1B

Independent non-profit-making federation that try to act as the link between the listeners and the free radio stations

Batterytech supplies NiMH, NiCd, and Li-ion battery packs, chargers, and analyzers, catering to a range of portable electronic devices including Ham Radio handheld transceivers. The product line supports popular amateur radio brands such as _Kenwood_, _Icom_, and _Yaesu_, providing power solutions for their portable models. Offerings extend to batteries for CB radios, scanners, and other two-way communication equipment, ensuring operators can maintain field operations. The inventory includes specific battery eliminators and replacement packs designed to meet the power requirements of various handheld radios. Customers can find suitable power accessories for digital cameras, PDAs, and cellular phones, alongside specialized batteries for Nextel radios. The focus is on providing reliable power sources for critical portable electronics.

Homebrew Tubes/LDMOS amplifiers, Antenna, accessories, adventures in 9Q, DX, UN missions, Contests, and more.

This WebSDR, hosted at Goonhilly Earth Station in Cornwall, enables you to listen to the Qatar OSCAR-100 Narrow band transponder onboard the Es'hail-2 satellite.

Using portable generators during emergencies or at field day site, using batteries and how to recharge them, using solar panels.

Dedicated to the advancement and promotion of amateur radio, Rome, Ga.

T93Y WEB page with details from Contest DXpeditions to Cyprus and United Arab Emirates

DXA Hoboken, Belgium

13,8 v / 1 A power supplies using the UA78 series by ON6MU