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A Low Power Indoor Portable HF Antenna by N5ESE

Amateur radio kits. Makers of the WinKeyer, their goal is to keep homebrewing and kit building alive.

Another general tutorial on BPL

Getting started on RTTY contesting. A PDF by ED Muns, presented at CTU conterst university, about amateur radio RTTY Contesting

The _Sci.Electronics FAQ: Repair: RFI/EMI Info_ document, authored by Daniel 9V1ZV, provides a detailed analysis of computer-generated RFI/EMI, focusing on its impact on radio reception. It identifies common RFI sources such as CPU clock rates (e.g., 4.77 MHz to 80 MHz), video card oscillators (e.g., 14.316 MHz), and even keyboard microprocessors, all of which generate square-wave harmonics across HF and L-VHF regions. The resource outlines a systematic procedure for pinpointing RFI origins, including disconnecting peripherals and using a portable AM/SW receiver with a ferrite rod antenna to localize strong interference sources. The document categorizes RFI mitigation into shielding, filtering, and design problems, offering practical solutions for each. It recommends applying conductive sprays like _EMI-LAC_ or _EMV-LACK_ to plastic casings of radios, monitors, and CPUs to create effective Faraday cages, emphasizing proper grounding and avoiding short circuits. For filtering, the guide suggests using line filters, ferrite beads, and toroids on power and data lines, and small value capacitors (e.g., 0.01 uF for serial/parallel, 100 pF for video) to shunt RFI to ground. It also discusses the use of bandpass, high-pass, low-pass, and notch filters on the receiver front-end or antenna feed to combat specific in-band noise.

Demonstrates the design and functionality of _uLog_, a Windows-based logging application for amateur radio operators. The resource details its core purpose as an easy-to-use logbook, emphasizing its streamlined interface that provides only the basic fields necessary for efficient QSO entry. It positions _uLog_ as a practical alternative to more complex logging software, catering to operators who prefer simplicity and speed in their logging workflow without an abundance of advanced features. The application's utility is highlighted by its focus on fundamental logging tasks, distinguishing it from comprehensive contest loggers or DX cluster clients. While not explicitly comparing it to other specific software, the description implies its niche for everyday logging rather than specialized operating events. Its design philosophy prioritizes quick data input, making it suitable for casual operating or for those who desire a minimalist approach to maintaining their station log.

MS Excel document that allows you to plot SWR, resistance, reactance, impedance magnitude and angle and more from a variety of sources

Rules of CQ World Wide RTTY Contest. The CQ World Wide RTTY DX Contest take place last full week-end of September, inviting amateur radio operators globally to connect across various CQ zones and countries. Participants will operate on five designated bands: 3.5, 7, 14, 21, and 28 MHz, exchanging RST reports and zone numbers. Scoring is based on QSO points multiplied by zone, country, and QTH multipliers. The contest encourages innovation in operating strategies while adhering to established rules to ensure fair competition among entrants.

A homemade GPS for TM-D710 using a Telit Jupiter JN3 GPS unit

A 2x3-foot laminated world map product is detailed, offering customization for amateur radio operators. Each map features two distinct views: one centered on the operator's specific station location and another precisely centered on its _antipode_. Countries are clearly labeled, complemented by a tabular listing of all countries. The map integrates a standard latitude/longitude grid alongside concentric circles that delineate distance increments radiating outward from the operator's QTH. Personalization includes the operator's name, callsign, and location printed directly on the map. This custom mapping service provides a unique visual aid for DXing and propagation analysis, allowing operators to quickly ascertain beam headings and distances from their station. The dual-view presentation, particularly the antipodal centering, offers a practical reference for understanding long-path propagation and identifying potential DX opportunities. The inclusion of distance circles and personalized station data makes it a tailored tool for daily operating and contest planning, distinct from generic world maps.

RadioReference.com page dedicated to the Drake TR-7 HF transceiver

Tape measurement yagi. The longest part is 530 mm, easy fit to your backpack. Very easy and fast deploy. Great for SOTA and portable operation. Can be used in horizontal or vertical polarization. Based on DK7ZB design

NFDXA On-Line Eritrea DXpedition Log

How to calculate range for a VHF antenna with a simple formula and how to increase VHF coverage.

Marshall G. Emm, N1FN, meticulously examines iambic keying, dissecting its historical introduction in the late 1950s with transistorized electronic keyers and its purported advantages. The resource defines keying systems, electronic keyers, and various paddle types, including single-lever and dual-lever paddles, clarifying the distinction between iambic keyers and the iambic sending technique itself. It details the two main types of squeeze keying: true squeeze for alternating dot-dash strings and character insertion for specific elements within a character. N1FN critically evaluates the actual efficiency gains of iambic keying, referencing Chuck Adams, K7QO's, keystroke analysis. While a straight key to bug transition yields a 34.1% reduction and a bug to non-iambic keyer offers 16.1%, iambic keying provides only an 11% theoretical improvement. However, considering typical QSO text and Morse code's inherent optimization for common letters, the practical efficiency gain is estimated at a modest 4-6%. The article also highlights how iambic keying's reliance on precise timing gates can impose a speed limit, making it less effective above 40 WPM, where many operators revert to non-iambic methods or single-lever paddles.

This is a QST Article published in January 1982 by W1FB D. Demaw and HH Beverage and is a complete review of the original article published in 1922, which updates and reivew the beverage antenna theory and developlment, explaining the antenna design of transformers and gives accurate reports on antenna general performance.

VQSpot is a simple utility program developed for sending DX-Spots automatically when QSO are logged into VQLog

The South Alabama Radio Club is located in Covington County, Alabama in grid square EM61

Current info on DX, special events, awards, FIRAC

An overview of coax cable often called coaxial feeder or RF cable, used to feed antennas and deliver radio frequency power from one point to another

Chart that present results of impedance measurements made on a variety of common-mode choke implementations across the frequency range 1MHz to 30MHz by G3TXQ

A free PDF from NASA about cubesat. Basic Concepts and Processes for First-Time CubeSat Developers. A great introduction document dedicated to Cubseat developers.

Gao engineering offers a wide range of affordable, popular and reliable rfid products, dsp, arm and other microprocessor evm and development boards, ides, universal programmers, emulators, dsp learning systems, micro-network terminals, test and measurement products for engineers.

Sense The Right Way To Go With The HANDI-Finder

SW Radio Africa is the independent voice of Zimbabwe broadcasting on the short wave

New and refurbished test and measurement instruments

The Rochester VHF Group, the oldest VHF-Oriented club in the World

Technical supplement manual of the Yaesu FT-8800R in english

Designed to handle audio signal interfacing as well as transmit/receive switching Reviewed by Steve Ford, WB8IM

Somalia

Radio Interferences, QRN, or noise, information by W8JI

Linux for shortwave and amateur radio monitoring. Supports popular SDR hardware and online streaming from KiwiSDR, WebSDR, and Spyserver sites. Articles about using Linux with your SDR devices.Skywave Linux, an innovative operating system, leverages cutting-edge technology for seamless access to radio signals globally. Ideal for regions with limited internet access, it effortlessly connects to a network of SDR servers, offering high-performance SDR operation without the need for extensive hardware. With pre-installed and configured SDR software, Skywave Linux simplifies signal discovery and operation for all users.

Some things I've discovered about learning and operating CW by Chris Kantarjiev K6DBG

Designing a beacon keyer that transmit the relative output power along to call sign.

dogparkSDR is a native Macintosh visual radio display and interactive control software for any Flex Radio Systems

Changing band selector to a Kenwood TL-922 power amplifier by IW1PUR in italian

Article on setting up a shotened beverage antenna with picture and setup notes by VE1ZAC

A 2 elements delta loop antenna for 14 MHz with a MMana simulation file, dimensions, pictures of this aluminium tube based delta loop antenna, and matching system details.

Civilianized and Militarized HF antenna systems for Portable, Base, Mobile, Manpack. Antenna manufacturer based in MO USA

Heathkit SB220 refurbishing by PA5CA

Handcrafted Accessories for the shack by W2ENY includes Full range headphones with a mic, computer interfaces, mic ptt adapters

WinXXDataConverter is a Windows GUI application that will convert files between the various formats used by Win92, Win93, Win95, and Win96.

Tips and tricks to start working Meteorscatter with WSJT. Author: PE1AHX

How can the current "flowing" out of the top of a mobile loading coil be greater than the current "flowing" into the bottom of the coil?

Operating a ham station often involves encountering radio frequency interference (RFI), RF feedback, or RF burns, which are frequently misattributed to poor equipment grounding. This resource meticulously dissects these assumptions, asserting that RF grounds on the operating desk often merely mask more significant system flaws. It identifies five primary causes for RF problems, including antenna system design flaws, proximity of the antenna to the operating position, DC power supply ground loops, equipment design defects, and poorly installed connectors or defective cables. The content emphasizes that issues like "hot cabinets" or changes in SWR when connecting a ground indicate substantial RF flowing over wiring or cabinets, a phenomenon known as common-mode current. The article provides detailed explanations of common-mode current generation, particularly from single-wire fed antennas like longwires, random wires, and OCF dipoles, which inherently present high levels of RF in the shack. It also illustrates how vertical antennas, lacking a perfect ground system, can excite feed lines with significant common-mode current. Through simulations, the author demonstrates how a dipole without a proper _balun_ can cause RF problems at the operating desk, showing current patterns and voltage distributions on feed line shields. The discussion extends to the proper application of _RF isolators_ and _ferrite beads_, clarifying their role in modifying common-mode impedance on cable shields and cautioning against their use as a band-aid for fundamental system defects. The resource advocates for correcting the actual source of RF problems, such as antenna system issues or poor connector mounting, rather than relying on internal shack grounding or isolators. It highlights that properly functioning two-conductor feed lines, like coaxial or open-wire lines, should result in minimal RF levels at the operating position, even without a desk RF ground. The author shares personal experience, noting that his stations since the late 1970s have operated without RF grounds at the desks, relying instead on proper antenna system design and feed line integrity.

The Microsniffer is a fully autoranging VHF or UHF sniffer which has been designed for those who are foxhunting on a budget.

The Indianapolis Police Scanner on Broadcastify allows users to listen to live police radio transmissions from Indianapolis. The website provides access to emergency communications and public safety broadcasts.

Serving Columbia and Greene Counties of New York State

This R.F. current meter was developed to assist in measuring line currents in balance feed lines as used in the All Band HF Antenna.

The Short Mountain Repeater Club (W4YXA) maintains an open repeater operating at 146.910 MHz using a negative offset (146.310 MHz). The repeater is located about 60 miles SSE of Nashville, Tennessee