Search results

Operating the _Icom IC-746_ HF/VHF transceiver often presents specific technical questions, and this resource compiles a comprehensive Frequently Asked Questions (FAQ) document in an ASCII text format. It details common inquiries and solutions related to the rig's functionality, accessories, and potential modifications. The content is structured into distinct sections addressing general information, power supplies, antennas, microphones, keyers, amplifiers, TNC integration, and optional IF filters. The FAQ provides practical guidance on topics such as configuring the internal automatic antenna tuning unit (ATU), selecting appropriate power supplies, and understanding microphone pin-outs. It also delves into advanced subjects like computer control via CI-V, wiring for PSK31 operation, and troubleshooting common issues like low S-meter readings on 2m FM or loose tuning shafts. Specific questions cover the installation of optional IF filters, comparing Inrad versus Icom filters, and optimizing filter combinations for various modes. Furthermore, the document outlines various hardware and firmware modifications, including those for increasing monitor volume, replacing LCD driver transistors, and implementing a "poor man's TCXO." It even touches upon untested modifications, such as replacing PIN diodes in the demodulator. The FAQ also lists manual errata and discrepancies, offering a robust knowledge base for IC-746 owners seeking to optimize their station or resolve operational challenges.

Consumer solar power products, portable solar panels maker, Solar Mini Panels & Control Electronics.

Understanding the operational impact of Broadband over Power Line (BPL) on amateur radio communications is crucial for any radio amateur, especially given the potential for significant radio frequency interference (RFI). This ARRL tutorial delves into the technical aspects of BPL, explaining how the technology operates by transmitting data over existing electrical power lines, which can inadvertently radiate broadband noise across various amateur bands. My own field experience, particularly on the lower HF bands, has often involved tracking down noise sources that exhibit characteristics consistent with BPL emissions, making this a pertinent topic for maintaining clear receive conditions. The resource further details the specific FCC rules and regulations implemented to restrict BPL deployment. These regulations aim to protect licensed radio services, including amateur radio, from harmful interference. It outlines the technical standards and operational limitations imposed on BPL systems to minimize their impact on the electromagnetic spectrum, a critical aspect for contesters and DXers alike. For those engaged in RFI mitigation, the tutorial provides a foundational understanding of the regulatory framework that can be leveraged when addressing BPL-related interference issues. It serves as a valuable reference for hams seeking to comprehend the technical challenges and regulatory solutions surrounding this pervasive noise source.

Dedicated to the design, manufacturing, technical support, and delivery of innovative and cost effective power solutions for worldwide applications. AC/DC switching power supplies and DC/DC converters.

The KnightLites QRP Association is a world wide fellowship of low power (QRP) amateur radio communications enthusiasts founded in 1996, and is coordinated through the efforts of a small group of radio amateurs located in the Research Triangle region of North Carolina in the United States.

This article describes an alternative to water as the cooling liquid for amateur radio vacuum tube power amplifiers. This cooling system is designed for adequate vacuum tube cooling, reasonable cost, and very low maintenance. By K8CU

Broadband over power lines (BPL) is a technique for transmission of high speed data (broadband Internet) over powerlines. Access BPL technology injects radio frequency energy into powerlines which were not designed for transmission of radio frequency energy, and leak substantial energy that causes interference to radiocommunications service

New and used test equipment, oscilloscope, spectrum analyzers, multimeters, signal generators, power supplies, network and signal analyzers and more

Supplier and exporter of generator, diesel generator, petrol generator, industrial generator, silent generator, power generator, electricity generator, gas generator, air cooled generator, gensets 1kva, 2kva, 5kva, 10kva, 50kva, 100kva, 250kva

Two cheap CMOS ICs and a few transistors was all that was required to rebuild an elderly TTL automatic morse keyer into a low current lightweight battery powered iambic morse keyer.

Article on evaluating HF Power amplifiers and review of popular PA by K0BG

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.

KD5FX, 20 through 6 meters, QRP to full legal power, lightweight, easy to carry

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

DragonOS is a linux distribution dedicate to Software Defined Radio. It leverages the portability, security, and power of Lubuntu Linux as a delivery package and operating environment for a pre-installed suite of the most powerful and accessible open source SDR software. DragonOS has verified support for a range of inexpensive and powerful SDR hardware, including RTL-SDR, HackRF One, LimeSDR, BladeRF, and many others.

All remotely controlled HF mobile antennas require some sort of device to power the motor. Hints on setting up a ham radio mobile antenna by k0bg

KB9AMG's Top WSPR Spots presents a focused online tool for monitoring **2-way WSPR reports**, specifically detailing propagation data from February 2026 through March 2026. This resource aggregates _WSPRnet_ data, allowing radio amateurs to observe weak signal propagation conditions across various bands. The interface is straightforward, presenting callsigns, frequencies, signal-to-noise ratios, and distances for each reported contact, which is crucial for understanding current band openings and signal paths. The utility of this WSPR spotter lies in its ability to quickly visualize global propagation. Users can identify active stations and assess signal viability over long distances, with reports often showing contacts spanning thousands of kilometers. For instance, a typical WSPR report might indicate a signal from Europe reaching North America with a _SNR_ of -25 dB, demonstrating effective low-power communication. This data is invaluable for planning DX operations or evaluating antenna performance under actual propagation conditions.

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.

A project of a linear regulated for low noise power supply 16v, 10A

Vapex Tech offers over **150 different battery products** tailored for diverse applications, including specific models for Icom, Kenwood, and Yaesu handheld transceivers. The product catalog details specifications for NiMH, LiPo, and LiFePO4 chemistries, providing crucial data on voltage, capacity, and discharge rates. Customers can browse by application, such as _Airsoft Batteries_ or _Model Control Batteries_, or directly by consumer battery types like AA and AAA cells. The resource presents a structured e-commerce platform where users can filter products by category, view detailed item descriptions, and proceed with online purchases. Each product listing includes high-resolution images and key technical parameters, enabling informed selection for specific radio equipment. Operational hours are clearly stated as 9am-5pm Mon-Fri and 9am-12pm Sat, with contact information including a sales email and phone number for direct inquiries. The site also features a "Latest News" section, indicating ongoing updates regarding product availability or company information.

A 600W 1.8 MHz to 54 MHz power linear amplifier made using rugged MRF300 transistors featuring output power between 580W and 750W depending on band, power supply: 48V, 18A typical, 20A max

This online project guide details the construction of a homebrew boom microphone system. It details the assembly of a microphone shell from a 3/4" PVC pipe section and an end cap, requiring a drilled hole for a snug fit of the electret or condenser mic element. The internal wiring schematic specifies a **2.2 K** resistor and a **47 uF** polar capacitor for signal conditioning, with a circuit diagram provided for integration with IC-706 series transceivers. The guide outlines the use of CAT-5 cable for internal connections, incorporating strain relief at the rear of the mic shell, and an inline 3.5 mm jack to facilitate an external _PTT_ line, designed for a foot-mounted switch. Further construction involves fabricating a microphone shock mount from a 2-inch PVC connector, detailing the creation of four "fingers" and the insertion of screw-eyes for attaching elastic bands, which are twisted 180 degrees for tensioning and vibration isolation. A foam wind screen is also incorporated into the microphone assembly, secured with adhesive. The boom arm itself is repurposed from an articulated architect lamp, with the original lamp assembly converted into a **60 watt** resistive load for testing power sources. Microphone cabling is secured to the boom arm using wire ties, ensuring sufficient slack at hinge points to maintain articulation. The boom base is mounted to a bookshelf, requiring specific positioning to achieve proper microphone placement in front of the operator. Performance evaluation of the microphone system is conducted through on-air audio signal reports from other amateur radio operators. DXZone Focus: Online Project Guide | Boom Microphone Construction | Electret Mic Element | PTT Line

A home made 50 MHz KW power amplifier project with picture and PCB schematic by W6PQL

A manufacturer of standby and prime power generator sets for industrial, telecommunication, commercial, small business, mobile and residential applications.

Mods.dk collection of Ameritron ALS-600 power amplifier

The 160-meter amateur radio band, spanning 1.8 to 2 MHz, was historically the lowest frequency amateur allocation until the introduction of the 630-meter and 2200-meter bands. ITU Region 1 allocates 1.81–2 MHz, while other regions use 1.8–2 MHz. This band, often called "Top Band" or "Gentleman's Band," was established by the International Radiotelegraph Conference in Washington, D.C., on October 4, 1927, with an initial allocation of 1.715–2 MHz. Effective operation on 160 meters presents significant challenges due to the large antenna sizes required; a quarter-wavelength monopole is over 130 feet, and horizontal dipoles need similar heights. Propagation is typically local during the day, but long-distance contacts are common at night, especially around sunrise and sunset, and during solar minimums. The band experienced a resurgence after the LORAN-A system was phased out in North America in December 1980, leading to the removal of power restrictions.

Resources for custom battery chargers and power supplies from powerstream

137.7 kHz QRSS beacon exciter is described, utilizing a single chip for operation on the 2200m amateur band. The design focuses on simplicity and efficiency for weak signal applications, providing a compact solution for generating QRSS signals. This project targets the DX portion of the band, enabling long-distance communication with minimal power output. The resource details the construction and functionality of the **QRSS beacon**, emphasizing its **low-power operation** and suitability for experimental amateur radio. It provides insights into the circuit's architecture and potential for integration into existing station setups. The design aims to offer a practical and accessible entry point for amateurs interested in weak signal modes on the LF/MF bands.

Electroswitch Electronic Products specializes in the design and manufacture of various switch types, including rotary, toggle, pushbutton, and rocker switches, as well as encoders and indicator lights. The company provides commercial and MIL-spec compliant components, detailing features such as spring return, push/pull to turn, adjustable stop, concentric shaft, and keylock configurations for their rotary switch lines. Specific product series like the M5-series enclosed frame rotary switches are highlighted, demonstrating their engineering capabilities. The resource offers a Rotary Switch Configurator to assist customers in selecting appropriate components based on application requirements. It categorizes switches by construction, such as enclosed frame, open frame, military grade, sealed, subminiature, blade, and power options for rotary switches. Toggle switches are presented in miniature, full-size, military grade, and sealed variants, while pushbutton switches include ultra-miniature, miniature, standard, and sealed types. Further product details cover rocker switches in subminiature, miniature, and sealed configurations, alongside thumb switches. Encoder offerings include magnetic and mechanical types with options like concentric shafts and push-to-turn functionality. Indicator lights are available for both commercial rectangular panel mount and MIL-spec applications, featuring configurations such as Press-to-Test, Watertight, EMI Shielded, and Dimmable options.

This unit uses four capacitors, only two of which are variables, and a single tapped coil. It is built in a die-cast box, and has been tested up to 80W input power on 70MHz by G4CJZ

How to interface the Icom IC-7300 to RF Power amplifiers. Menu settings, cable connections and recommendations on how to avodi common errors that could even damage either the amplifier or the IC-7300

A synthesized 2.3 GHz Amateur Television (ATV) transmitter design, conceived by Ian G6TVJ, is presented, targeting broadcast-quality video performance on the 13cm band and extending up to 2.6 GHz. The core of the design utilizes a commercial Z-comm Voltage Controlled Oscillator (VCO) that tunes from 2.2-2.7 GHz, providing a +10 dBm output and simplifying RF alignment. This VCO's stability, originally intended for narrowband applications, readily accepts high-frequency video modulation, contributing to the transmitter's robust performance. The exciter stage, incorporating a Mini Circuits VNA 25 MMIC amplifier, boosts the signal to +16dBm, while a Plessey SP4982 prescaler divides the output frequency for the synthesizer. The synthesizer employs a Motorola MC145151 CMOS parallel IC, favored over the common Plessey SP5060 for its superior video modulation characteristics and ease of programming without microprocessors. This choice addresses issues like LF tilt and distorted field syncs often seen with SP5060 designs, particularly when operating through repeaters or over long distances. The MC145151 divides the signal further, enabling precise frequency stepping, with programming handled by EPROMs for channel selection and LED display. The loop filter network, critical for video integrity, was developed through experimentation to prevent the PLL from reacting to video modulation, ensuring a clean transmitted picture. The transmitter incorporates a Down East Microwave commercial power amplifier module, delivering approximately 1.6W output, driven by the exciter through a 3dB attenuator. Construction involves surface-mount SHF components on micro-strip lines etched onto double-sided fiberglass board, housed within a tinplate box. The design boasts no AC coupling in the video path, preserving low-frequency response, a common failing in other ATV transmitters. Performance tests with a 50Hz square wave revealed no LF distortion, and a calibrated "Pulse & Bar" signal showed a near 100% HF response, demonstrating its capability for high-quality ATV transmissions.

Power meters

Essentially, a choke balun is designed to 'divorce' your antenna from the feed line. if your feed line is coaxial cable then you don't want it to be part of your antenna. you want to be able to deliver all your power to the radiator itself, i.e. 'the antenna'. a choke balun does this admirably

1.5 dB of matched line loss can be calculated for a given transmission line using this online tool, which employs a model calibrated from empirical data. The calculator allows radio amateurs to input specific transmission line types, such as _RG-8_ or _RG-58_, and then determine the expected signal attenuation. This is crucial for optimizing antenna system efficiency and understanding power delivery to the radiating element, especially for HF and VHF operations where feedline losses can significantly impact performance. Beyond matched loss, the calculator also provides an estimate for mismatched loss if the Standing Wave Ratio (SWR) is specified. This feature helps operators quantify the additional power loss due to impedance discontinuities between the transceiver, feedline, and antenna, which is a common concern in amateur radio installations. Accurate loss calculations are vital for effective station design and for predicting actual radiated power. The tool's utility extends to various operating scenarios, from fixed station setups to portable deployments, aiding in the selection of appropriate feedline lengths and types to minimize signal degradation. Understanding these losses is a fundamental aspect of maximizing the effectiveness of any amateur radio antenna system.

A nice review of the Acom 1000 HF and 6 meter RFpower amplifier by Acom in Dutch and with online google translation available. Includes pictures and notes of the popular amplifier by Acom.

A 102-inch vertical whip, commonly a CB antenna, forms the core of this low-profile 10-meter antenna design, optimized for the 28 MHz band. The construction details specify three 8-foot radials made from scrap wire, connected to a common point. This simple yet effective setup is designed for ease of construction and deployment, making it accessible for operators with limited space or materials. The design emphasizes using readily available components, including PVC pipe for the mast and a SO-239 connector for the feedline, ensuring a straightforward build process for a resonant quarter-wave vertical. Field results indicate that this antenna provides good performance for local and DX contacts on 10 meters, despite its compact footprint. The author, N8WRL, shares practical insights into its construction and tuning, highlighting its suitability for temporary or permanent installations where a full-sized antenna might be impractical. Comparisons to more complex designs suggest that this low-profile vertical offers a respectable signal-to-noise ratio and effective radiated power for its size, proving that simple designs can yield satisfying on-air results.

Amplifiers, filters, attenuators, mixers, PLL, switches and frequency dividers, signal generators, power detectors, transimpedance amplifiers, variable gain amplifiers and more

This article shows how to power an amateur radio station from solar power using four kits that have been designed to work together in a modular way, each kit provides a unique function.

SPX Communication Technologies, operating under the TCI International brand, presents a range of radio frequency (RF) solutions primarily for government, defense, and commercial sectors. The offerings include advanced systems for spectrum monitoring, communications intelligence (COMINT), and high-frequency (HF) and medium-frequency (MF) broadcasting and communication antenna systems. Specific product lines encompass _Blackbird_ COMINT systems, _Scout_ spectrum monitoring receivers, and various antenna arrays designed for robust performance in challenging RF environments. The resource details the capabilities of these systems, such as wideband signal detection, direction finding (DF), and signal analysis, crucial for intelligence gathering and regulatory compliance. It also highlights the engineering behind their antenna designs, which are optimized for specific frequency ranges and operational requirements, including high-power broadcast applications and secure military communications. The information presented emphasizes the integration of hardware and software for comprehensive RF situational awareness. The company's focus on empowering partners to "Command the Spectrum" underscores its commitment to delivering critical tools for signal interception, analysis, and management across diverse operational landscapes.

Technical specifications and details of the Yaesu FL-2100B HF Power Amplifier

Mobile RFI, often manifesting as persistent noise in the receiver even with the antenna disconnected, frequently originates from the vehicle's power supply system. This guide details systematic troubleshooting steps, beginning with isolating the radio from the car's 12-volt supply to confirm the power system as the noise source. It emphasizes the critical importance of drawing power directly from the battery using **heavy gauge wire**, bypassing the fuse block to leverage the battery's natural capacitance for RFI suppression and ensuring a solid RF ground. Proper routing of power lines through the firewall is also covered, advocating for dedicated grommeted holes to prevent inductive coupling from other wiring harnesses. The article stresses the necessity of fusing both positive and negative leads from the battery, a crucial safety measure to prevent damage to the rig and mitigate high-current risks should the battery's engine block ground become compromised during service. Addressing **alternator whine**, a common high-pitched noise that varies with engine speed, the resource suggests checking battery connections and the alternator-to-battery harness for looseness or corrosion. It also mentions the utility of adding an external RF noise suppression capacitor in parallel with the alternator's internal capacitor for enhanced filtering, and the effectiveness of commercially available in-line power supply filters.

Pictures of a homemade monoband linear amplifier for 160m band powered by 3 x QB5/1750

Maxdao: offer you 7/16, N coaxial connectors, jumper cables, feeder clamps and grouding kits, surge arresters & brackets, wall entries and microwave components used in base tower, power dividers, couplers

A keyed piezo beeper, connected to the microphone jack of a HT, appeared feasible as a ready-made MCW generator.

Battery-powered monitor designed to provide an audible indication of keying for those whose rigs lack a CW sidetone

Windows PC control program for the Icom IC-7300 transceiver. Power-on and Power-off by software BktNetInterface for JTDX and WSJT-X, audio recording, memory management, cw keyer management, Interface for other software

By Floyd Sense K8AC

The CQ World Wide DX Contest records page details the highest scores achieved in the CQ WW DX Contest across various categories and years. It systematically lists records for both SSB and CW modes, segmenting results by entry class such as Multi-Multi, Multi-Two, Multi-Single High, Multi-Single Low, Single Operator High Power, Single Operator Low Power, Single Operator QRP, Single Operator Assisted High, Single Operator Assisted Low, and Single Operator Assisted QRP. Each record entry specifies the callsign, the operator's callsign in parentheses if different, the year of operation, and the total score achieved. The data is further broken down by individual amateur radio bands, including 160m, 80m, 40m, 20m, 15m, and 10m, allowing for granular analysis of performance within specific frequency segments. The page also includes records for the "ALL" band category, representing cumulative scores across all operational bands. The presented records span from 1948 to 2025, providing a historical perspective on contest performance. This resource also references other CQ contests like CQ WPX, CQ WW RTTY, CQ WPX RTTY, CQ 160, CQ VHF, and WW DIGI, indicating a broader context of contest record keeping. It explicitly states that late logs are not included in the records, ensuring data integrity. The page is maintained by the World Wide Radio Operators Foundation, Inc.

The WB5RVZ Genesis Radio G40 build log documents the construction of a 5W QRP 40m SDR transceiver kit, detailing each phase of assembly from power supply to RF filtering. It provides specific component lists, parts placement diagrams, and testing procedures for stages like the local oscillator, Tayloe detector, and RX op-amps. The resource highlights discrepancies between documentation versions and offers practical advice for builders, including a "virtual build" approach to preemptively address potential ambiguities in component identification and placement. It also addresses a specific "VK6IC Fix" for early board revisions, involving trace cuts and jumper wires for improved performance. The build log presents measured voltages and expected current consumption for various stages, such as the 4.9-5.0 Vdc on the 5V rail and under 100mA for RX current. It outlines critical adjustments like image rejection tuning, a common procedure for direct conversion receivers. The resource also includes practical tips for handling components like the 2N3866 transistor and its heatsink, emphasizing pre-assembly. It details the winding of two 1.45 uH toroidal inductors on T50-6 cores with 17 turns of #20 AWG wire, crucial for the RF path.