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Designed for the FT-817, this audio speech compressor, centered on the Analog Devices SSM2165, offers a 40 dB compression range, enhancing signal power. Built externally with the SMD version to preserve warranty, the circuit interfaces smoothly with electret microphones. Testing shows a 6 dB average power increase. Adaptable to rigs with electret microphones, it maintains unity gain and 40 dB compression.

PH0NO conducted field tests comparing a mobile antenna (DX-UHV) to an end-fed half-wave wire. Results on 20m showed the end-fed wire outperforming the mobile antenna, with a significant difference in signal strength. On 40m, the end-fed wire surpassed the mobile antenna in spots and reach. While the mobile antenna is more practical, the end-fed wire offers superior performance. Further testing is planned.

The article discusses the use of SDR# (SDR SHARP) software for SDR receivers, highlighting its Band Plan feature that visually represents RF spectrum allocations. The author modified SDR# to display detailed IARU HF band plans, creating three XML files for different IARU regions. These files include various operational modes and specific frequency allocations. Despite potential errors, the modifications aim to enhance the usability of SDR# for ham radio operators. The article includes references and download links for the XML files and IARU band plans.

This presentation on antennas is a practical guide for amateur radio operators. The key takeaway is that the best antenna for your station depends on your constraints and goals. There is no magic solution and buying a wire antenna is not recommended as it might be expensive and not as effective. The presentation covers different antenna types including dipoles, verticals, Yagis and loop antennas. Important factors to consider when choosing an antenna include SWR, feeder types, and whether you need a balun. The author emphasizes that ATUs don’t improve a poor antenna and advises against obsessing over SWR readings.

This project builds into a box into which you plug a Morse Code Key. Using the Morse Key creates realistic sounds so you can judge how well you Send. A great tool for beginners to improve Morse sending skills before going on-air

This article focus on the radiation angle of vertical antennas and the fundamentals of electromagnetic wave propagation. The calculation of antenna length at 145 MHz is followed by an explanation of electromagnetic wave speed and the link between wavelength, frequency, and velocity. Author discusses the 5/8th wave vertical antenna, namely its performance and the influence of radiation angle on signal transmission. Figures and analogies demonstrate how different antenna types produce distinct radiation patterns. This highlights the importance of selecting the right antenna for a certain purpose, such as local traffic or dxing. The article discusses a variety of factors that affect antenna performance, including SWR, propagation conditions, and equipment dependability

Medium power BMU (Base Matching Unit) intended for 42 foot to 48 foot vertical, sloper, or Inverted-L antennas.

Learn how to choose the right portable antennas for backpacking as a ham radio operator. Find out the factors to consider, including weight, performance, and reliability. Understand the trade-offs involved in selecting the best antenna for your needs, based on the purpose of your trip and distance to be covered. Discover different options available and how they can help you make contacts while on the go. Get insights into one ham radio operator's portable antenna kit and the factors that influenced their choices. Explore the importance of band selection and adaptability in creating a successful antenna system for backpacking adventures.

MorsePractice is a Java application originally written by Martin Minow (K6MAM) as an aid to learning Morse code. With morse practice you can select the digits you want the app to be transmitted. Additionally can be selected a random phrase, or random QSO.

How to use a small USB DJ controller to remote control the Kenwood TS-590s

This article is from the book Ham Radio For Dummies and features some tips for portable amateur radio operations, on Field Day or generic outdoor operation, like selecting the proper antenna and portable power.

A detailed guide presents a simple 2-element quad antenna for 2m, offering ease of construction, portability, and efficient performance across the 144-148 MHz band. The design allows quick disassembly for storage and features adjustable polarization, making it ideal for various applications, including transmitter hunting and SSB operations.

Practical Wireless is a doing magazine focusing on the practical and constructional side of amateur radio and appeals to all ages. Written by expert authors and contributors, Practical Wireless reflects developments in the technology, participants, activities and licensing framework of the hobby.

The RTL-SDR tuner dongle is a popular tool for amateur radio enthusiasts, transforming a $10 device into a wide-band software-defined radio. This guide outlines using the RTL-SDR as a full-band pan-adapter for conventional receivers, focusing on hardware setup and software integration with HDSDR. Future sections will address RTL-SDR performance compared to native receivers, enhancing digital mode operations with virtual serial ports and audio cables.

The 1/4 wavelength vertical antenna project, initially designed for 20 meters, has evolved into a versatile portable solution covering 10 through 60 meters. K0BXB details its construction, emphasizing a bottom-loaded design with a tapped loading coil and four 10-foot counterpoise wires. The author shares personal experiences and field results, including **18 QSOs** during a park activation on 17m and 30m with 10 watts, and a **2,435-mile** contact with a contest station in Bonaire on 20m using 5 watts. Comparisons are drawn to commercial offerings like the _Wolf River Coils TIA_ and _QRPGuys Triband Vertical_, highlighting the DIY antenna's small footprint, light weight, and ease of tuning for POTA activations. The resource includes insights into using test equipment such as the _NanoVNA_ for SWR optimization and discusses various radiator lengths, from 17-foot wire to a 102-inch whip, demonstrating adaptability for different portable setups. Construction tips cover coil winding, tap placement, and connecting feedlines and radials using common components.

A collection of morse telegraph and radio items

Chavdar Levkov, LZ1AQ, presents an experimental comparison of small wideband magnetic loops, building on his previous work on wideband active small magnetic loop antennas. His research focuses on increasing loop sensitivity by maximizing the short-circuit current, which is directly tied to the "loop factor" M = A/L, where A is the equivalent loop area and L is its inductance. Levkov's methodology involves reducing inductance and increasing area through parallel or coplanar crossed (CC) configurations, comparing these designs against a reference single quad loop of 1 m2 area. Experimental verification included testing three distinct loop types: a simple quad loop, two coplanar crossed (CC) loops, and eight parallel loops, all designed to have a total geometric area of 1 m2. Measurements were conducted at 1.8, 3.5, 7, and 10 MHz using a small transmitter 270 meters away, with a Perseus direct sampling receiver for precise signal level assessment. The results consistently showed that CC loops, particularly Loop 5 (two CC circular loops with 1.44 m2 total area), yielded significantly higher currents, up to 9.1 dB over the reference loop at 3.5 MHz, validating M as a reliable predictor of loop sensitivity. Numerical simulations using MMANA further corroborated the experimental findings, demonstrating an almost perfect correlation between the calculated M factor and the induced loop current for 15 different loop models. Levkov concludes that CC loops offer superior sensitivity for a given loop area, while parallel loops are advantageous for minimizing physical volume. Practical recommendations suggest using loops with an M factor greater than 0.5 uA/pT for quiet rural environments, and he provides a spreadsheet tool, WLoop_calc.xls, to aid in optimizing loop configurations for specific operational needs.

In his POTA activation, WK4DS experimented with radials for hamstick antennas. Despite sun and RF noise challenges, successful connections were made. Surprisingly, tuned radials proved unnecessary, simplifying setup. Hamsticks demonstrated versatility across frequencies. Increased power improved signal quality, sparking his curiosity for further exploration in radio technology.

Effective suppression of harmonics and parasitic radiation from HF transmitters is crucial, especially with the increasing sensitivity of VHF/UHF radio channels to interference. This project details a hybrid low-pass filter (LPF) designed to operate across the HF bands up to 51 MHz, making it suitable for 6-meter band operations while providing deep VHF/UHF suppression. The design addresses the challenge of modern interference landscapes, where even microvolt-level signals can disrupt wireless sensors and other simple VHF/UHF receivers. The filter utilizes a single elliptic link, combining high cutoff steepness with robust suppression in the hundreds of megahertz range. A key feature is the use of only two standard capacitor values, simplifying construction and component sourcing. The article provides a detailed schematic, performance characteristics, and _RFSim99_ model file, demonstrating a reflection coefficient S11 below 0.017 (VSWR < 1.03) across 1-51 MHz, ensuring minimal degradation to the antenna system. Construction notes include coil winding specifications and capacitor selection guidance, with recommendations for _FR-4_ assembly. Two capacitor sets are presented, with the first variant recommended for its lower RF current demands, keeping currents below 3 A at 1 kW passing power at 51 MHz. Fine-tuning involves adjusting frameless coils, with considerations for capacitor tolerance and high-frequency capacitance measurement accuracy.

This page offers a tool for hams to design vertical antennas for portable use on different HF/VHF/UHF bands. Vertical antennas provide omni-directional transmission and reception, making them ideal for DX contacts. By adjusting the antenna's dimensions and viewing radiation patterns and VSWR charts, hams can optimize performance in various terrains. The tool also accounts for the impact of sloping ground on elevation radiation patterns. Perfect for hams looking to enhance their portable radio setups and improve long-distance communication.

Examining the demographic shifts within amateur radio, particularly concerning **radiosport** participation, this resource analyzes survey data from the National Contest Journal (NCJ) and two regional ARRL surveys. It focuses on the relationship between age and engagement in contesting, presenting findings that suggest older amateur radio operators tend to participate in more contests annually. The author, a spatial demographer, details the methodology, including data consolidation, georeferencing, and statistical analysis performed in collaboration with Dr. Scott Wright K0MD, covering ARRL November Sweepstakes participants from 2000 to 2020. The analysis also addresses the limitations inherent in using voluntary response samples rather than random samples, which may influence the generalizability of the results. Furthermore, the resource investigates the preferred sources of contest information among different age groups, noting that older contesters frequently rely on traditional publications like the NCJ, while younger participants show a preference for online platforms. This demographic review provides insights into the evolving landscape of **amateur radio contesting** and the generational differences in information consumption.

Discover a comprehensive solution for mapping Australian ham radio entities using data from the ACMA Public Register. This tool, developed in Delphi 7, generates KML files for Google Earth, showcasing repeaters, beacons, and operators across different prefixes. While respecting privacy regulations, the files provide valuable insights into the amateur radio landscape.

When new to the 2-meter FM transceiver, securing a quiet frequency for chatter seems straightforward, but it's essential to navigate FCC rules and band plans effectively. Even though frequency allocations are consistent above 50 MHz for Technician licenses, adherence to specific segments within the 2m band—ranging from 144 MHz to 148 MHz—is crucial. This includes respecting designations for different modes like CW, SSB, and FM to prevent interference, particularly with satellites and exotic modes like EME. Understanding and following the structured band plans not only ensures legal compliance but also optimizes frequency use and minimizes disruptions in the amateur radio community.

This project details an automatic roger beep circuit for VHF/UHF contests. Built around a Microchip PIC microcontroller, the design detects PTT (Push-To-Talk) activation and generates a brief tone upon release, mimicking a "roger beep" to signal the end of transmission. The circuit utilizes readily available components and includes downloadable resources for PCB layout and firmware.

This article explains the trick of how to shorten and lengthen pairs of radials to make a 2-band ground plane antenna. Included is a "Table of Multi-Band Possibilities" covering the range of 6 to 40 meters.

In 2004, Carl Luetzelschwab, K9LA, wrote a guide on using W6ELProp for radio wave propagation predictions. This tutorial, translated for broader accessibility, explains initial setup, configuration, and daily use. It emphasizes using mean solar index values for accuracy, helping users effectively predict and interpret propagation for improved amateur radio operations.

Delta loop antennas, particularly the 30 meter variant, offer unique advantages in terms of vertical polarization and omni-directional coverage. The construction process detailed by VE3VN highlights common mechanical and electrical challenges faced by amateur radio operators. Key design considerations include minimizing interaction with existing contest band antennas, achieving low elevation angles for DX chasing, and ensuring the antenna remains off the ground for agricultural clearance. The article provides specific measurements, such as the loop's height and feed point impedance, which are critical for optimizing performance. The use of NEC modeling software illustrates the importance of accurate resonance calculations, revealing how proximity to the tower affects both pattern and impedance. This practical account serves as a resource for hams looking to build effective antennas while navigating typical construction hurdles.

This **PDF report** documents a _maritime mobile_ DXpedition operating from the _Southern Ocean_ near Antarctica, detailing antenna deployment strategies on a sailing vessel. It addresses power management systems for remote operations and propagation characteristics specific to polar regions on **20m and 40m** bands. Operational strategies include managing high-density pileups using split frequency operation and maintaining signal integrity during periods of high aurora activity. Equipment considerations cover specific transceiver models like the Icom IC-7300, antenna types optimized for marine vessel installation, and battery power systems for extended periods without shore power. The resource also examines the use of satellite communication for real-time log uploads and QSL confirmation from remote locations, and discusses mitigating signal degradation from ice accumulation on antennas. DXZone Focus: PDF report | Maritime Mobile DXpedition | Polar Propagation | Split Frequency Operation

The ICOM IC-705, a popular QRP transceiver for portable operations, often presents unique challenges for field deployment. This resource details practical solutions for common portable setup issues, particularly for _Parks on the Air_ (POTA) activations. It describes a custom bracket for connecting antennas to the IC-705 through a backpack's antenna flap, utilizing a BNC female-to-female chassis mount connector to mitigate cable tangles. The author shares experiences with a DIY magnetic loop antenna, noting its ease of tuning with the IC-705 and successful CW contacts on 40 and 20 meters over distances exceeding **1000 miles**. Another modification presented is a strain relief solution for the microphone cord, replacing the standard spring clip with an easier-to-attach method. The page also mentions using a _Wolf River Parks antenna_ for POTA activations and references the QRPGuys DS-1 antenna as another portable option. Firmware updates and integration with an LDG Z11-Pro II auto-tuner are also discussed.

The CW keyer with memories, inspired by SOTA activities, features three on-the-fly programmable memories for hands-free operation during logging or specific calls. Designed for low power consumption, it uses AAA batteries and an Arduino Mini, optimized for minimal energy use with a sleep function. The compact design fits in a small TEKO box, with a printed circuit board for easy assembly. The keyer includes customizable software for various CW modes and settings, programmable via paddles and command mode. It's an efficient, portable solution for amateur radio enthusiasts seeking enhanced CW functionality.

This page delves into the early history of radio and television, exploring the fascinating personalities and inventions that shaped the industry between 1870 and 1929. The author reflects on the pioneering work of figures like Thomas Edison, Guglielmo Marconi, and Nikola Tesla, highlighting the challenges and innovations that defined the golden age of radio. With a focus on a specific project involving a one tube AM radio, this article offers insights into the evolution of radio technology and its enduring impact on society. Ideal for hams and radio enthusiasts interested in the roots of modern communication.

This page showcases the use of ChatGPT for quickly creating a prototype application that maps out individual QSOs from a CZML map. The author details the process of using ChatGPT to generate code that positions and frames a Cesium Ion map based on data from a czml file. The page includes links to the original map, the prototype app, a video demonstration, and the mapped QSOs output. The content is aimed at hams interested in experimenting with AI tools for ham radio applications.

This article provides a comprehensive introduction to the decibel (dB), its logarithmic nature, and its applications in power, voltage, and antenna gain calculations. It explains how dB simplifies comparisons in electronics, telecommunications, and audio perception. The author clarifies key mathematical concepts, including power ratios, voltage doubling, and absolute levels like dBm and dBV. The discussion on S-units and antenna system gain is particularly relevant for radio amateurs. Overall, this is an informative and well-structured guide to understanding and applying decibels in technical fields.

Guide to constructing an effective antenna for 50MHz. Inspired by a design from Martin DK7ZB, the article emphasizes the importance of precise measurements and quality materials. With a 2.20m boom and careful assembly, the antenna promises excellent performance, resilience, and cost-effectiveness, making it ideal for six meter band operations.

The ICOM IC-745 is a durable 1980s HF transceiver, ideal for enthusiasts who enjoy restoration. While lacking modern serial control, it supports digital modes with modifications like sound card connections and frequency stabilization. Enhancements like an RTL-SDR panadapter can also be added, making it a versatile and valuable radio for contemporary use.

This resource details the construction and performance of a compact broadband magnetic loop antenna designed for portable receiving applications with devices like the _ATS MiniRadio_. The antenna utilizes approximately 3 meters of 0.5–1 mm copper wire wound in two turns on a rhomboidal wooden frame, measuring 50 cm by 70 cm. It connects via a modified 9:1 unun, where the primary center tap is isolated from ground to improve common-mode noise rejection. The design provides untuned operation across a frequency range from the longwave band up to approximately 25 MHz. Performance characteristics include observable directivity for noise suppression and the ability to connect directly to a radio or via a 50 coaxial cable for remote operation. The article specifies the unun's 3:1 turns ratio and its SMA output for connectivity. The methodology focuses on practical construction and observed reception quality.

This paper by Leif Asbrink (SM 5 BSZ) presents a practical approach to designing very high gain Yagi antennas, focusing on the "brute force" optimization method. The method, described in a previous article, ensures convergence independent of initial guesses. The paper provides detailed tables of element lengths and positions for Yagi antennas optimized for 144.1 MHz with a 50-ohm feed point impedance, aiming for minimal losses and high accuracy in comparisons.

This PDF document discusses the setup and operation of UHF vertical dipole phased stack antennas for hams. It covers the advantages, principles, and practical aspects of using this type of antenna configuration. The document is a useful resource for amateur radio operators looking to improve their UHF station setup with phased array antennas.

VE1ZAC's analysis details the performance of **MFJ927** and **SGC239** autotuners with portable HF vertical antennas, specifically comparing 31 ft and 43 ft configurations. The resource originated from challenges encountered during a Maritime QSO Party roving operation, necessitating a lightweight and easily deployable antenna system. Target bands for the contest included 80, 40, 20, 15, and 10 meters, with a maximum power handling of 100 W CW. The author utilized a 30-foot carbon fiber push-up pole to support a vertical wire element, noting its 2 lb weight and reliability. EZNEC modeling was employed to predict performance, showing favorable results for a 30-foot vertical with elevated radials, particularly on 40 and 20 meters. Feedpoint impedance measurements, taken with an AIM4170C, are presented for various HF bands, both with and without a 41-foot RG6 stub designed to reduce reactance on 80 and 20 meters. The stub significantly improved matching on these bands, easing the tuner's workload. Operational tests revealed issues with the MFJ927's reliability during contest setup, leading to reliance on the K3's internal tuner. The SGC239, tested post-contest, performed flawlessly. A detailed side-by-side comparison covers mechanical aspects, connection options, power bias, impedance range, board quality, and documentation. Modifications to the MFJ927, including a new aluminum case, white paint for heat reduction, and upgraded impedance-measuring resistors, are also described.

This page by ARCTICPEAK provides a calculator for determining ERP and EIRP (Effective radiated power and effective isotropic radiated power). The tool is designed to help hams calculate and understand the power radiated by their radio equipment. The content is useful for ham radio operators who want to optimize their transmission power and comply with regulations. LA8OKA Martin has created this resource to assist hams in accurately measuring their radio signals.

A modern, free online study tool for US amateur radio exams. It provides current NCVEC question pools for all license classes (Technician, General, and Extra). Features include a smart practice mode that tracks your weak areas and provides detailed explanations to help you pass faster.

Examines the historical context of amateur radio, specifically focusing on Guglielmo Marconi's pioneering wireless transatlantic signal reception at Signal Hill, Newfoundland, in 1901. It describes the operation of a contemporary remote radio station at Signal Hill, utilizing the special event call sign _VD1M_ issued by Innovation, Science and Economic Development Canada. The content recounts a specific contact from Signal Hill, reporting a signal strength of 5 by 9 to a station in Sarnia, Ontario, which received the signal at 3 by 3. The narrative also introduces the concept of 'Marconi chasers' who endeavor to replicate historical transmission methods. Further, the resource discusses general amateur radio operating procedures, the evolution of the hobby, and its critical role in emergency communications, citing examples from hurricanes _Irma_ and _Maria_ in 2017 and the conflict in Ukraine in 2022.

This article About Noise offers a clear, non-mathematical explanation of noise in telecommunications, making it accessible to radio amateurs. It categorizes noise into fundamental and intermodulation types, detailing sources like thermal, shot, and cosmic noise. The article effectively highlights noise impact on receivers and introduces key metrics like Noise Figure and Signal-to-Noise Ratio (SNR). While comprehensive, it remains digestible, balancing technical depth with simplicity. A great resource for understanding radio noise fundamentals without complex equations, though a more detailed discussion on mitigation techniques would further enhance its value.

This page by Arctic Peak provides a detailed explanation on how to use quarter-wave transmission lines as impedance transformers in ham radio antenna work. It explains how to match impedance values by connecting them with a λ/4 transmission line. The page also offers guidance on constructing your own transmission lines with specific impedance requirements, along with a calculator to determine the quarter wave length based on velocity factor and frequency. Useful for hams looking to optimize antenna performance and match transmission line impedance effectively.

AA9PW offers free practice exams for all three US license classes plus international licenses like Canadian and Australian. The site generates random tests from the current question pools, simulating the actual exam experience. You can choose between online exams or printable PDF versions for offline study. The site maintains a simple, no-frills interface that loads quickly even on slow connections. Practice tests provide immediate feedback with score reports highlighting areas needing improvement.

The page features a spreadsheet that calculates power in watt and dBm based on voltage and impedance, power in dBm with a given power and impedance, voltage in millivolts with a given power and impedance, and more. It also converts between millivolt, microvolt, volt, watt, and milliwatt. Useful for hams looking to accurately calculate power and voltage values for radio equipment. Last updated in December 2014.

The article describes ongoing issues with a new TS590s transceiver, including intermittent reception and transmission failures. After a repair diagnosed as a "Control Unit interruption," the problem persisted. The author discovered the cause was a poorly crimped CN601 connector on the Control Unit board, leading to signal loss when moved. Soldering the connector resolved the issue. Similar problems reported by other users suggest a potential defect in the cables, pointing to a possible manufacturing issue.

This article explores the historical importance of clandestine radio stations in Algeria's fight for independence. It discusses the power of radio as a tool for communication and public opinion shaping. The content delves into the impact of underground radio stations in times of crisis and their role in achieving power, revolution, independence, or democracy. The article reflects on the evolution of radio in Algeria throughout the 20th century and its adaptation to societal changes. It provides insights into the significant events witnessed by Algerian radio and the influence of clandestine broadcasting in the country's history.

QSL cards remain the preferred method for confirming QSOs, especially when received free via bureau. They capture the personality of the station operator and offer varied designs. Proper sorting by country and correct card dimensions are crucial for efficiency. Despite modern alternatives, QSL cards retain their charm, but ensuring compliance with bureau requirements and understanding international practices is essential.

Tracing the foundational work of Guglielmo Marconi, this article details his early laboratory experiments in 1895, where he successfully transmitted wireless signals over 1.5 miles. It highlights his 1896 patent for a wireless telegraphy system in England and subsequent demonstrations, including signal transmissions up to 6.4 km (4 miles) on Salisbury Plain and nearly 14.5 km (9 miles) across the Bristol Channel. Marconi's work built upon the mathematical theories of _James Clerk Maxwell_ and the experimental results of _Heinrich Hertz_, proving the practical feasibility of radio communication. The resource further chronicles the formation of The Wireless Telegraph & Signal Company Limited in 1897 and Marconi's relentless efforts to popularize radiotelegraphy. A significant milestone was the 1901 transatlantic reception of the Morse code letter "S" from Poldhu, Cornwall, at St. John's, Newfoundland, using a kite-supported wire antenna, defying contemporary mathematical predictions about Earth's curvature limiting range. This achievement underscored the global potential of radio. The article also touches upon Marconi's later discoveries, such as the "daytime effect" concerning atmospheric reflection of radio waves, and his 1902 patent for a magnetic detector, which became a standard wireless receiver. His contributions earned him a Nobel Prize in 1909.