Search results

Antennas manufacturer based in Germany produce portable and wire HF VHF antennas

Litchfield County New Milford Connecticut Harwinton Warren Watertown Waterbury Washington

The RFzero is a multi function signal platform developed for radio amateurs who wants to extend the Arduino skills in combination with RF. The RFzero board is largely compatible with the Arduino Zero and Arduino M0 boards, however, it has been carefully designed for flexible use in RF applications and with attention to the frequency spectrum and stability performance.

An article edited and published by Michael Mandeville on correlation of sunspot peaks and global events, like recessions or human conflicts. This document include solar cycle charts since Solar Cycle 1749-1751

The Central Scotland FM Group has provided and is responsible for maintaining many of the repeaters now operating in West, South-West, Central and East Scotland.

Experimenting OCF and dipole wire antennas over house roof. Effects of roofs on wire antennas

Arizona contest club for big guns, little pistols and cap guns, from experienced to new contesters.

The Cheshire County DX Amateur Radio Club - or CCDX ARC - Has been around for well over a decade. The longest running club ever in this area.

Spanish ham radio chat

Lake county races/ares, volunteer auxillary communications group working under lake county emergency management agency. offical skywarn site for lake county. VE testing and radio clases offered. not-for profit 501(c)3

NS8O portable generators

Rock-n-rescue the source for safety and rescue equipment focused on delivering the best equipment for climbing, water fire and search rescue

Comparing many antennas for 50 MHz band

Blog site for various home brew projects including antennas, power dividers etc

CRAM - Club Centro Radioaficionados Montevideo, CX1CCC, Montevideo, Uruguay

As FT8, JT65 and JT9 are a time synchronized protocol, one soon discovers that an accurate PC clock is very important. If your workstation time is off it can cause you to send when no one is listening, or to listen when no one is sending.

Havering and district Amateur radio club based in Hornchurch, Essex

Manufactures automatic mixers, analog and DSP signal processors, room combining and matrix mixers, and audio test equipment for just about any customer application.

Demonstrates the fundamental principles for connecting a personal computer to a ham radio transceiver, specifically for utilizing sound card-based digital mode software like those in the MM Hamsoft suite. It details the basic hardware setup, emphasizing the use of shielded leads and proper audio routing from the radio's output to the sound card's input, and from the sound card's output to the radio's microphone or data input. The resource highlights the critical need for transmit attenuation, suggesting a 100:1 voltage divider to prevent overdriving the transmitter's audio stage, and mentions the optional addition of ferrite beads and decoupling capacitors for RFI mitigation. The guide also points to external resources for more detailed pin-outs and interface schematics, such as a specific QSL.net page, and recommends consulting the help files within MM Hamsoft programs for interfacing specifics. It underscores that while the process is straightforward, understanding the audio level management and proper cabling is key to successful operation. The author, VE5KC, provides practical advice drawn from common issues encountered by operators setting up digital mode stations.

Information on so-35 satellite

Setting up the necessary Software for the Softrock 6.1 is a bit tricky, images and screenshots hopefully bring some light into the dark

General information page including contest scores, station pictures

South Bay Amateur Radio Club

A CW sidetone bypass for the NESCAF audio filter, a small and low cost circuit that works great.

A cavity filter, often a critical component in _duplexer_ designs, functions as a sharply tuned resonant circuit, allowing only specific frequencies to pass while attenuating others. These filters are essential for maintaining signal integrity in environments where multiple transmitters and receivers operate simultaneously on closely spaced frequencies, such as in repeater stations. The article details how these filters, sometimes referred to as _notch filters_, achieve high Q factors, which are crucial for their performance. Understanding the principles of cavity filters is fundamental for any amateur radio operator involved in repeater operation or designing custom RF front-ends. The discussion covers the basic circuitry and operational characteristics that enable these devices to provide significant isolation, often achieving **-80 dB** or more between transmit and receive paths. This level of isolation is vital for preventing receiver desensitization and intermodulation distortion. Properly tuned cavity filters ensure that a repeater can transmit and receive simultaneously on different frequencies without self-interference, a common challenge in VHF/UHF operations.

Antenna Authority Inc. offers a wide assortment of directional, wideband antennas and other equipment specifically engineered for radio direction finding (DFing) and geolocation applications. Their product line includes _log periodic_, _cavity-backed spirals_, and _Yagi_ antennas, alongside covert antenna solutions for various operational requirements. The company emphasizes its expertise in designing and manufacturing specialized antennas for both overt and covert operations. Beyond standard offerings, Antenna Authority Inc. provides custom design services to meet specific client needs, focusing on tailored RF directional products. Their capabilities extend to developing antennas for vehicles and optimizing their operational performance in diverse scenarios. The firm is located at 3381 W. County Line Road, Douglasville, Ga. 30135-1145. Ferrel Bentley is associated with Antenna Authority Inc., which has been operating since at least 2005, as indicated by the copyright notice.

Specialized in manufacturing measurement instruments for more than 25 years. Clamp meter, digital multimeter, analog panel meter, thermometer, and led panel meter

Ham-Spirit.de amateur radio classifieds from germany

The Radio Amateur Megacycle Society

An ARRL affiliated club with many members who are interested in public and emergency service. The membership supports ARRL, ARES, CERT, RACES, NTS and Skywarn.

1500 watts PEP SSB is the power handling capability of the MFJ-989C HF Antenna Tuner, a popular choice among amateur radio operators. Users have shared a wide range of experiences, with some praising its durability and performance over decades of use, while others criticize its build quality and accuracy. The tuner features a built-in dummy load, SWR-wattmeter, and a balun for balanced line feeders, making it versatile for various antenna setups. However, discrepancies in RF power readings and SWR measurements have been noted, with some users finding the dual scale meter to be off by about 20% compared to a Bird wattmeter. Long-term users report that the MFJ-989C performs well with proper antenna setups, but caution against tuning at high power without initial adjustments at lower power levels. Some have experienced issues such as arcing when exceeding 400 watts, while others have had no problems even at higher power levels. The roller inductor and capacitors are functional, though some users have had to perform maintenance like tightening screws or cleaning components to ensure reliable operation. Despite mixed reviews, the MFJ-989C remains in production, suggesting continued demand. It's a tuner that requires careful handling and possibly some DIY fixes to achieve optimal performance.

The Caribbean Contesting Consortium is a contest club dedicated to fun, international friendship, and advancement of the contesting art through superior operating technique and maximum application of technology.

The New England QRP NESCAF Kit Switched Capacitor Audio Filter by N5ESE

This document has been produced by examining the data going into and coming out of the TH-D7 HT from Kenwood.

The CQ World Wide DX Contest records document top scores, with the Multi-Multi SSB category showing CN8WW achieving **78,170,508 points** in 2000. These records span from 1948 to 2025, categorizing results by region, operating class (e.g., Single Operator High Power, Low Power, QRP, Assisted), and specific bands like 10M, 15M, 20M, 40M, 80M, and 160M. For instance, EF8R (E77DX) holds the All-Band High Power SSB record with **25,747,775 points** in 2025. Each entry includes the callsign (with operator callsign in parentheses for guest ops), year of operation, and total score. The _CQ WW DX Contest_ also features records for the RTTY and VHF contests, alongside the main SSB and CW categories. QRP records demonstrate significant achievements, such as P40W (W2GD) with 5,097,780 points in the All-Band SSB QRP category in 2000. Multi-Two and Multi-Single categories are also detailed, providing a comprehensive overview of competitive performance.

White Tower DX Team DX peditions and contests team from Greece

Review of the X1M HF QRP trasceiver by VE3FAL

CBS is a program that produces statistical data from a Cabrillo file by K5KA and CBSW windows version by N6TV

Electronic and RF components for the hobbyist

The first interactive map of amateur radio repeaters and more updated in REAL TIME.

Ham radio site with personal info, search facilities and some links pages

Low Country Amateur Radio Club Summerville, South Carolina 147.060+ / 147.030

Printer in Poland, now provide T-shirts, CAP with Call sign, dust cover for yaesu, icom, kenwood, elecraft transceivers, acom amplifiers and more. QSL printing has been dismissed

In portuguese by PY4ZBZ

Signal generatos, oscillators, direct and indirect synthesizers, exciters custom oscillators

News/Projects for Amateur Radio

BCHF 14.316 MHz Broadcasters HF NET where radio/tv broadcasters-engineers meet 2300 UTC Sunday's