Three-Element Hex Beam Project, 40m Wire Antennas Comparison, 9:1 Balun and Unun, Building a new lithium battery, Dx-peditions365 App, Tripod Platform and Bi-Quad Antenna Mount, Band Decoder Arduino,
Technical Reference/Filters This article explores the nuanced design challenges of Band Pass Filters (BPF) in radio receivers, balancing low insertion loss, high stop band rejection, and narrow bandwidth. The focus is on the "Series-Trap, Shunt-C" topology, resonator count impact, and meticulous layout design for superior stop band performance across various frequency bands
Operating Modes/Mobile Detailing a Yaesu FT-857 and ATAS-120 installation in a 1997 Toyota Tacoma, the author used Polar Plot to map signal strength. Using a hand truck with a laptop, FT-817, and an Iron Horse antenna, they circled a chalk-outlined 100-foot diameter, revealing potential nulls towards the truck's rear and through the cab, offering insights into antenna performance.
Antennas/End-Fed/End Fed Half Wave Antenna 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.
Technical Reference/Audio 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.
Performance of 49:1 Ferrite Core Transformers, Variations on a Dipole, Yaesu FTDX101D QST Review, GP Antenna for 1296 MHz, Repair of an FT-1000 MP Mark V , Cloverleaf Antenna, CWvox
Radio Equipment/HF Transceivers/Icom IC-7300 Despite the model limitations, such as a single TXRX antenna connector, the author shares a reversible modification involving a coax relay for enhanced functionality, demonstrating the transceiver's adaptability and customization potential.
Antennas/End-Fed Intrigued by a German OM positive experience with a 20m delta loop, the author replicated the design, noting its favorable 50-ohm impedance compared to their 40m version. Testing against a vertical EFHW, the delta loop excelled within EU but lagged at longer distances. Despite needing more testing, the user leaned towards the EFHW for its overall performance and practicality.
Aluminium Push Up Mast , Yaesu FT-710 QST Review, FT-710 Yaesu official web site, Short introduction to D-STAR, ICOM IC-7100 Review , Troubleshooting Data Mode Problems, Fix FT-757GXII blank display
Technical Reference/Audio Inspired by Heathkit, author aimed to enhance his Yaesu FT-817 with audio and RF processing. Design goals included a compact enclosure, PCB simplicity, matching jacks, a visual meter, and a built-in signal generator. Despite challenges in finding a suitable compressor IC for a 5V DC mic jack, he chose the Analog Devices SSM2165/2166 series. Prototyping with a solderless breadboard, author planned a PCB layout for its versatile performance in communication use.
Radio Equipment/HF Transceivers/Yaesu FT-857 After owning the second-hand radio for a few months, it developed a sense wire failure, limiting output to 20 watts. Yaesu support advised the owner, an Electrical Engineer, to investigate. The issue was traced to a blown digital transistor, Q1032. Yaesu provided free replacements, revealing intricate internal components during the repair.
Technical Reference/Morse Code Decoder The CW typewriter is a compact adapter board that transforms Morse code into ASCII characters using an Iambic key. It connects to a computer via USB, emulating the keyboard. The device features inputs for Iambic keying and a WPM speed potentiometer, and outputs for a key and a speaker for side tone. The device can be used with various software and online typing games for practice, offering a unique and interactive way to learn and use Morse code.
IC-R20 by Icom. Wideband Receiver Professional radioreceiver, allow double receiver, from HF to Microwave, digital recorde, DTCS, Memories and 11 hours countinuous reception.
Technical Reference/Arduino/Morse Code An Arduino-Based Solution for 5-35 WPM Signals. Explore the circuit, controls, and setup of this innovative device designed by Allen Baker (KG4JJH). Decode Morse code efficiently, providing a valuable tool for operators, from novices to veterans, and offering a hands-on experience with Arduino technology.