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• Make your own 40/80 Dipole - Make your own dipole for 40 and 80 meters band, assembling standard product parts like 40 meter traps, the 1:1 balun and insulators
  [ Hits: 125 | Votes: 0 | Rating: 0 ]

• TEFV Terminated End Fed Vee Antenna - The Terminated End Fed Vee Antenna (TEFV) is a travelling wave antenna with constant current distribution. Unlike traditional resonant antennas, TEFV operates without standing waves, using a terminating resistor for broadband efficiency. With a combination of vertical and horizontal polarization, it offers wide bandwidth from 1.8 MHz to 30 MHz, eliminating the need for a tuner. Key components include a 9:1 unun transformer and a 500-ohm terminating resistor. Grounding and counterpoise enhance performance, and it can handle power losses of up to 30%. TEFV provides an effective, versatile antenna solution for amateur radio and broadcast applications.
  [ Hits: 187 | Votes: 2 | Rating: 6.5 ]

• Tuning OCF L-Dipoles - The behavior of a straight dipole and its L-form is examined in terms of impedance and SWR. By adjusting the feed point or bending angle, impedance variation is observed. Impedance shifts symmetrically as the feed point deviates, leading to recommendations for optimal ratios. Model simulations aid in understanding and fine-tuning, crucial for achieving a 50 Ohm match. Practical tuning guidelines ensure efficient antenna performance.
  [ Hits: 29 | Votes: 0 | Rating: 0 ]

• Countries with CEPT Licence - A document that includes a list of all countries implementing CEPT licence, with detailed information on licence types like standard CEPT, CEPT Novice and HAREC. A full list of frequencies, and call signs schemas to be used by foreign operators, compiled by Hans Schwarz, DK5JI
  [ Hits: 177 | Votes: 3 | Rating: 9 ]

• Frequency Accuracy and Stability of WWV and WWVH - Measuring the Frequency Accuracy and Stability of WWV and WWVH by Michael A. Lombardi. An examination of just how accurate these frequency standard stations are.
  [ Hits: 81 | Votes: 0 | Rating: 0 ]

• M17 digital radio protocol for data and voice - M17 is a community of open source developers and radio enthusiasts. We are building understandable systems in support of the hackers and experimenters' history of ham radio. M17 is developing open source hardware, software, and offers a complete digital radio protocol for data and voice, made by and for amateur radio operators. M17 voice mode uses the free and open Codec 2 voice encoder.
  [ Hits: 56 | Votes: 17 | Rating: 9.47 ]

• Exploring the Spectrum From HF to UHF Frequencies - During radio's early days, high frequencies were under 30 MHz due to technical limitations. As understanding grew, components improved, allowing for higher frequencies like VHF and UHF up to 3 GHz. The HF band's long wavelengths provide unique propagation challenges influenced by solar activity. VHF and UHF bands face diffraction and reflection issues but offer diverse applications, from amateur radio to 5G and GPS technologies.
  [ Hits: 77 | Votes: 0 | Rating: 0 ]
• Mastering HF Communication: Decoding Space Weather Data - The article enlightens radio amateurs on utilizing real-time space weather data to optimize HF communication. Navigating through Hp30 index, MUF, f0F2, and eSFI metrics, it explains their significance in band selection and propagation forecasting. With essential links and practical insights, enthusiasts learn to discern optimal conditions for high-band DX, low-band DX, and NVIS operations. The author's observations and antenna optimization tips enrich understanding for effective HF operations.
  [ Hits: 68 | Votes: 0 | Rating: 0 ]

• IC705 GoBox: A Portable Windows-Based Solution for All-Digital Modes - This project details the creation of a portable GoBox housing an IC705, Windows 11 PC, and Bluetooth microphone. The robust setup, enclosed in a weatherproof Hofbauer Explorer Case, ensures stability and functionality for QRP and emergency radio activities. The aluminum-mounted devices minimize RF interference, and a built-in LifePO4 battery powers the 10.1 TFT touch LED monitor, providing approximately 12 hours of use in receive mode. With a focus on grab-and-go versatility, this GoBox stands as an efficient solution for outdoor ham radio operations.
  [ Hits: 96 | Votes: 0 | Rating: 0 ]

• FT 1000MP MK V and Keyclicks - YaesuFT1000MK V stands out with improved close-spaced SSB transmit performance, reversing a trend seen in other modern radios. Featuring a class-A mode, it offers clean HV finals when kept out of ALC. However, two significant flaws persist: the noise blanker causes receiver IM distortion, and the transmitter lacks wave-shaping on CW, resulting in pronounced keyclicks. Preliminary tests reveal strong keyclicks +1kHz and -1kHz, prompting a combined modification to address both issues.
  [ Hits: 31 | Votes: 0 | Rating: 0 ]

• MSF radio time signal - The MSF radio signal is a dedicated standard-frequency and time broadcast that provides an accurate and reliable source of UK civil time. It is available 24 hours a day across the whole of the UK and beyond. The signal operates on a frequency of 60 kHz and carries a time and date code that can be received and decoded by a wide range of readily-available radio-controlled clocks.
  [ Hits: 50 | Votes: 1 | Rating: 10 ]
• Radio Station WWV - NIST radio station WWV broadcasts time and frequency information 24 hours per day, 7 days per week to millions of listeners worldwide. WWV is located near Fort Collins, Colorado, about 100 kilometers north of Denver. The broadcast information includes time announcements, standard time intervals, standard frequencies, UT1 time corrections, a BCD time code, and geophysical alerts
  [ Hits: 52 | Votes: 1 | Rating: 10 ]

• ITU Synergizing AI and Radiocommunications for Smarter Connectivity - Explore the pivotal role of artificial intelligence in advancing emerging radio technologies, facilitating ubiquitous connectivity essential for sustainable development, the digital economy, and the Internet of Things, guided by ITU's harmonized regulations and standards.
  [ Hits: 12 | Votes: 0 | Rating: 0 ]
• AI Projections for Ham Radio Modes in 2023-2025 - In an innovative analysis, Michael G7VJR employs NeuralProphet to predict ham radio modes' usage trends. The AI model, leveraging deep learning, forecasts a steady FT8 dominance, with slight declines in CW and Phone activities. This approach simplifies statistical predictions, showcasing the power of AI in understanding complex patterns and facilitating insightful time series projections. Access the freely available Club Log data for continuous exploration.
  [ Hits: 55 | Votes: 0 | Rating: 0 ]

• Smart SO2R Antenna Switcher: A DIY Solution - 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.
  [ Hits: 152 | Votes: 0 | Rating: 0 ]

• Understanding Impacts of 75-ohm Devices in 50-ohm Systems - This article explores the implications of using 75-ohm devices, common in TV setups, within 50-ohm systems. While mismatched cables and connectors may lead to minimal consequences in receive-only setups, potential losses and reduced isolation in splitters and taps are examined. The article concludes that, for general applications, inexpensive TV-type components can offer reasonable performance with some trade-offs
  [ Hits: 149 | Votes: 2 | Rating: 9.5 ]

• Adapting Standard Headset Mic for Yaesu FT-8900 - Explore the process of creating a custom adapter for the Yaesu FT-8900 radio with a non-standard mic port. The article guides users through understanding the reversed pin-out of the RJ-12 connector on the 8900, providing a detailed circuit for adapting the voltage for electret-based mics. With a list of required parts and construction tips, this DIY project ensures seamless compatibility with standard electric headset mics.
  [ Hits: 45 | Votes: 1 | Rating: 1 ]

• JBOT QRP linear amplifier - JBOT stands for Just a Bunch of Transistors. It is a simple, stable and easy to build 5 watts linear amplifier build out of a bunch of ordinary low power NPN transistors.
  [ Hits: 83 | Votes: 0 | Rating: 0 ]

• Simple 2-tone generator - A simple 2-tone-generator for testing the linearity of SSB transmitters. This device is as simple as useful. With 2 transistors and an oscilloscope, it is fairly easy to test the linearity of your SSB transmitter. The 2-tone-method is a standardized test method that can be used to determine the maximum output and the amplification characteristics of a sideband transmitter.
  [ Hits: 111 | Votes: 0 | Rating: 0 ]

• Innovative 2m to HF Converter - Ulrich L. Rohde N1UL conceived an outstanding 2m to HF receiving converter with specific requirements, including 144-148MHz to 28-32MHz coverage, low noise, high IP3, and a unique modular design. The design decisions emphasize modularity, absence of preselection, stability, and a passive mixer, showcasing Rohde's distinctive approach.
  [ Hits: 94 | Votes: 0 | Rating: 0 ]

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