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CW Morse Nano QRP and Micro Keys. CW Morse PCB Keys. Morse Keyers

Microwave Filter Company is a leader in the design, development and manufacture of high quality passive electronic filter products in the 5 Hz to 50 GHz frequency spectrum.

SNASharp is a free software application designed to work with scalar network analyzers compatible with NWT software from DL4JAL. It is used to measure and analyze the scattering parameters (S-parameters) of microwave devices. Provide several measurements and analysis tools including Smith chart, Polar plot, S-parameter tables, Transmission line calculator

This tutorial provides detailed instructions for constructing a DIY magnetic loop antenna, ideal for amateur radio operators seeking efficient short wave communication. The design features a remote tuning system utilizing an Arduino and RC servo, making it suitable for indoor use where larger antennas cannot be installed. Magnetic loop antennas are compact and can operate effectively in confined spaces, but they do require careful handling due to the high voltages and currents they generate during operation. Users should possess the necessary technical skills to implement this project safely. The tutorial includes a comprehensive overview of the antenna's theory, specifications, and mechanical design. It outlines the components needed, including a Soviet-made variable capacitor and a digital RC servo for tuning. Safety precautions are emphasized, as the antenna can produce several kilovolts of voltage and high currents. The project is not certified for safety, and users are advised to proceed at their own risk. The tutorial also provides diagrams and explanations of the antenna's operation, making it a valuable resource for both beginners and experienced operators looking to enhance their setup.

This practical, hands-on article offers a valuable journey through balun construction for portable antenna systems. The author skillfully navigates from theoretical debates to practical implementation, providing a well-documented DIY process using RG316 micro coax and an FT114-43 toroid core. The step-by-step instructions, complemented by photographs, make this complex technical project accessible to hobbyists. Particularly impressive is the author's focus on lightweight design (just 173 grams) for SOTA field operations. While the final antenna requires minor tuning adjustments, the successful field test during the Pirate Contest demonstrates the effectiveness of this approach. An excellent resource that transforms theory into practical application for ham radio operators.

This is basic instructions for homemade 4G Antenna working on 2600 MHz UMTS featuring 13 14 dBi gain. This antenna is desigend to resonate on microwave frequencies in two segments from 2500 to 2570 MHz for Uplink, and from 2620 to 2690 MHz for Downlink.

A data converter for the Tandy WM918 weather station. The Weather APRS data converter project aims to create an interface to interpret data from the popular Tandy WM918 weather station and format it for transmission over packet radio. The South East Radio Group in South Australia has established a network of these weather stations to provide amateurs with regularly updated weather data. However, the WM918's data output is not structured for APRS weather reporting. This project describes a solution using a PIC microcontroller to convert the WM918 data into APRS-compatible strings that can be sent as beacons or connected packets. The interface offers features like position/positionless data, connected/beacon modes, and metric/imperial units. The goal is to create an interconnected weather reporting system for amateur radio operators

Open Two Radio Switching Protocol Antenna Selector on ATMEL ATmega8 microcontroller

Miniature PIC microcontroller based keyer kit with convenient modes. The kit includes PCB, componets, knob and ready programmed PIC microcontroller. Author make available from his web site Circuit diagram, Component layout,List of components and downloadable Software

This interface is perfect to operate the ICOM IC706 MKIIg with a pc-headset,in VOX or with PTT.

The Specan is actually a very simple but robustly built receiver. it is, in essence, a double conversion superhet receiver with 112 Mhz and 12 Mhz Intermediate frequencies. The first mixer uses an Si570 as the local oscillator. The Ardiuno that controls the Specan is a very flexible microcontroller board that you can program in simple C language

The 8m ISM band, a unique frequency range between 10m and 6m, holds potential for amateur radio enthusiasts, yet it remains largely unallocated. This spectrum offers fertile ground for research and self-training. The author's experience with low-power transmissions and WSPR testing highlights the band's capabilities and the need for a narrow, speech-free amateur allocation to encourage experimentation. Discover the world of 8m ISM radio exploration and its future possibilities.

This Arduino project explores long-range RF communication using EBYTE E32 1W LoRa modules (either E32-915T30D or E32-900T30D) paired with ESP32 microcontrollers featuring OLED displays. The setup leverages the modules' Semtech SX1276 chip with amplifier to achieve up to 1W transmission power—significantly more than the chip alone provides. Unlike other LoRa implementations, these modules include a microcontroller that simplifies interface through UART rather than SPI. The documented implementation includes proper wiring between components and Arduino code that configures the module, displays received messages on the OLED screen, and transmits messages every two seconds while keeping power consumption manageable.

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.

Horn Antenna - The energy of the beam when slowly transform into radiation, the losses are reduced and the focussing of the beam improves. A Horn antenna may be considered as a flared out wave guide, by which the directivity is improved and the diffraction is reduced. One of the first horn antennas was constructed in 1897 by Bengali-Indian radio researcher Jagadish Chandra Bose in his pioneering experiments with microwaves. The modern horn antenna was invented independently in 1938 by Wilmer Barrow and G. C. Southworth. This Horn model antenna is suitable employed in the UHF or SHF radio bands. Making this horn model antenna it will be easy for a beginner to make if it works in the 10GHz frequency, because small dimensions so it is not so difficult and also offers gain up to 25dBi.

Many low-power SSB rigs and kits lack dedicated speech processor circuitry, although most modern HF rigs include it. Speech processing is crucial for low-power SSB to overcome QRM. This simple, low-cost circuit integrates a microphone element and can be housed in a defunct desk mike. It features a feedback amplifier, audio preamplifier, and adjustable speech compression control

Nuts & Volts, founded in 1980, began as an advertising-based newsprint and evolved into a leading electronics magazine. A major shift came in 1992, introducing content-rich articles, columns, and DIY projects, cementing its role for hobbyists and professionals. Reformatted in 2003 to standard magazine size, it now averages 100 full-color pages on high-quality paper. Celebrating 40 years, Nuts & Volts remains the longest-running U.S. electronics publication, with loyal readers and advertisers since the 1980s. Its diverse topics span robotics, circuit design, automation, microcontrollers, and more, appealing to all skill levels.

The PicoFox is a versatile fox transmitter for 2-meter ham radio operators, built around the RP2040 microcontroller. With open-source hardware and software, it can be customized to suit your needs, from APRS to other digital modes. This fully assembled transmitter comes with a rechargeable battery and antenna, ready for use. The design allows for easy addition of features like sensors or interactivity. Modulation is handled in software for smooth FM output, with ample CPU, flash, and GPIO available. Configure your PicoFox by connecting it to a computer via USB and adjusting settings in a text file. Explore the possibilities of this innovative transmitter for your amateur radio projects.

Single-sideband (SSB) radio enhances spectral efficiency but poses challenges with audio intelligibility, particularly in noisy conditions. A microphone audio compressor addresses these issues by dynamically managing the audio signal’s dynamic range. It amplifies quiet sounds and attenuates loud ones, ensuring consistent audio levels for improved clarity. Benefits include increased intelligibility, higher average power, and reduced spurious emissions. While essential for optimal SSB performance, careful parameter adjustment is crucial to balance natural sound quality and effective communication across various operating modes.

Manufacturer of 50MHz, 70MHz, 144MHz, 222MHz, 432MHz, 900MHz or 1.2GHz transverters and VHF UHF amplifiers

This blog post documents the author's journey building an APRS micromodem for amateur radio applications. Using an open-source design by LY2EN, the author assembled a cost-effective Terminal Node Controller (TNC) with SMD components, an Arduino Nano, and a JDY-31 Bluetooth module. The construction process included PCB fabrication, careful component soldering, microcontroller programming, and Bluetooth configuration. A custom 3D-printed case protected the completed device. Field testing in Romania showed the device functioned with a Baofeng UV-5R radio, though antenna limitations affected performance. The entire project demonstrates an affordable DIY alternative to commercial APRS trackers.

Noise-canceling electret condenser microphones (ECMs) are ideal for compact, battery-powered devices due to their small size, low power consumption, and high sensitivity. These microphones, used in conjunction with active noise cancellation circuitry, significantly reduce ambient noise, creating a more peaceful listening experience by combining and processing signals from multiple microphones.

This page provides a detailed guide on how to receive WWVB 60 KHz time signals using the Everset ES100 module with an Arduino Due microcontroller. It explains the background of time standards and the significance of WWV radio stations in maintaining these standards. The content is useful for ham radio operators interested in time synchronization, scientific research, navigation, and radio communications. The article is written by Keith Greiner, who shares his project inspired by his passion for the subject. For more projects by the author, visit the provided links.

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.

Let this microprocessor controlled MFJ Contest Voice KeyerTM call CQ, send your call and do contest exchanges for you in your own natural voice

Learn how to build a simple transmitter called the 'Easy Ten' that can be easily heard at a distance of 10 miles using a random length wire antenna thrown into a tree. This article focuses on working with frequencies in the 3.5 and 7 MHz range without the need for complex setups like coax lines or baluns. The author shares their experience of making contacts across the Pacific Ocean and the United States using just one watt of output power and simple antennas. Discover how to optimize signal output using a homemade level meter made from a DC microameter and a germanium diode.

Direct conversion receivers (DCR) are gaining renewed interest due to advancements in semiconductor technologies and their suitability for integration in compact, low-cost, multi-standard applications. Unlike traditional superheterodyne receivers, DCR eliminates image frequencies and bulky off-chip filters but introduces challenges like DC offsets, nonlinearity, and noise issues. This tutorial explores DCR's historical development, compares it with other receiver architectures, and addresses its inherent obstacles. DCR's potential for integration and compatibility with software-defined radio highlights its role in modern communication systems despite its technical complexities.

An **Arduino LC Meter** provides an accessible solution for precisely measuring inductance and capacitance values, crucial for RF circuit design, filter tuning, and troubleshooting in amateur radio applications. This project details the construction of a low-cost, accurate instrument using readily available components, making it an attractive alternative to commercial units for hams and electronics enthusiasts. The build process involves assembling a resonant circuit, integrating an Arduino microcontroller for frequency measurement, and displaying results on an LCD. Key components include an Arduino Uno, a 16x2 LCD, a 74HC14 Schmitt trigger inverter, and a few passive components. The design leverages the Arduino's processing power to calculate L and C values from resonant frequency shifts. Calibration procedures are outlined to ensure measurement accuracy, which is vital for critical RF work. The project includes schematics, a parts list, and the necessary Arduino code, enabling hams to construct a functional LC meter for their workbench.

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.

Getting started with Aircraft scatter, defined as the process of scatter radio waves of the body of a traveling aircraft in order to enhance the distance possible to bridge on VHF, UHF and microwaves. The ACS path, Equipment requirement and Operating techniques

The article explores the concepts of return loss, VSWR, and S11 within the context of microwave engineering, highlighting the confusion arising from their definitions. It clarifies that these parameters, while seemingly distinct, fundamentally describe the same phenomenon related to wave reflection and transmission in microwave circuits. The discussion emphasizes the historical context and mathematical relationships among these terms, revealing that their interpretation can vary significantly across different engineering disciplines. Ultimately, it advocates for a pragmatic approach to using these parameters based on familiarity rather than strict definitions.

This tutorial demonstrates how to charge laptops or tablets, like the Microsoft Surface, using off-grid 12-volt batteries typically used for ham radio gear. The guide highlights the importance of selecting a reliable USB-C PD adapter, recommending a 15V, 60W minimum with 5–20V, 3–5A capability. Featured tools include a 100W USB-C adapter and a USB multimeter for monitoring power usage. The video also explores the compact, efficient Power Queen 50Ah LiFePO4 battery for portable power solutions.

This page provides a detailed guide on how to build your own radioless Allstar node for ham radio operators. It includes information on power supply, components needed, wiring instructions, and tips to avoid common issues like ground loop hums. The author shares personal experiences and recommendations for specific components like microphones, audio amps, and sound fobs. Whether you're a beginner or experienced ham radio operator, this DIY project can help you set up a cost-effective and functional Allstar node for communication purposes.

This project presents a compact QRP SWR meter featuring a 0.96" OLED display (128x64 pixels) for high-contrast visibility, updated with software fixes for display compatibility, improved low-power performance, and support for ATtiny45/85 microprocessors. A 1.3" OLED version accommodates visibility needs. Designed for HF QRP transmitters (3-15W), it uses a Breune coupler with germanium diodes for accurate SWR measurement. Powered by a AAA battery, the meter offers a standalone solution for impedance matching, with a 3D-printed enclosure enhancing portability.

The DIY Power Meter project utilizes the _INA226_ high-side power monitoring chip, paired with an ATtiny85 microcontroller, to measure voltage, current, and power, displaying the results on a 128x32 OLED screen. The INA226 communicates via an I2C interface and is programmed with a calibration factor based on the shunt resistance and current register LSB. The project is designed to handle a maximum current of 500mA using a 0.16ohm shunt resistor, which can be adjusted to a 0.2ohm resistor, reducing the full-scale current range to 409mA with a resolution of **12.5uA**. The shunt resistor dissipates only 33mW at maximum current, making 1/4 watt resistors suitable for the setup. The PowerMeter.ino sketch configures the shunt resistance and maximum design current, automatically calculating the calibration factor. The project can be prototyped on a breadboard using an Arduino Uno, employing the Wire library for INA226 and OLED communication, and the u8g2lib library for the OLED display. For the ATtiny85 version, the Adafruit-TinyWireM and Tiny4kOLED libraries are used. The power meter is independently powered by a 3V CR2032 cell, with power switching options including manual switches or DC switched jacks. The low-side n-channel MOSFET switch configuration is tested but introduces voltage drop issues, making manual switching a more reliable option until a suitable DC switched jack is found. DXZone Technical Profile: INA226 | ATtiny85 | OLED Display | Power Meter

This project outlines a simple Lead Acid/SLA battery monitor, designed to alert users when battery voltage falls below 10.6V. The monitor, based on a PIC16F1827 microcontroller, checks the voltage of up to five batteries and triggers an alarm if any drop too low. The system operates in various modes, including self-test, monitoring, and alarm. This updated version improves upon the original 1999 design, offering a more modern microcontroller and extended functionality for workshop use, with minimal impact on battery charge.

This excel workbook addresses the issue of power loss in transmission lines with complex characteristic impedance ZoZo​. It illustrates the discrepancy between actual loss (0.35 dB) and matched line loss (0.6 dB) using a simplified example, highlighting potential software tool limitations. The RF Feedline Power-Loss Calculator provides accurate end-to-end loss assessments for both microwave and RF applications. This tool is suitable for engineers and students and is compatible with Windows versions of Excel 2016 or later, though it is not compatible with Macintosh systems.

A versatile digital VFO design utilizing the Silicon Labs Si5351a oscillator chip and Nokia 5110/3310 graphics LCD display, operating from 1-160MHz with dual VFO capability. This microcontroller-based system, powered by an ATmega328 processor, features rotary encoder tuning, selectable step sizes, RIT control, and comprehensive band memory functions. Drawing less than 40mA at 3.3V, it significantly improves upon previous DDS designs' power consumption while offering advanced features like S-meter display, VFO lock, and programmable BFO/CIO offsets. The design achieves flexible functionality through simple hardware implementation and efficient software architecture, making it particularly suitable for QRP and portable amateur radio applications.

MyWaveRecorder is a lightweight utility designed to capture and save any audio played on your computer. Whether it’s sounds generated by programs like CW_PLAYER, WX_PLAYER, MyWaveRecorder itself, your microphone, your sound card, or even streaming audio from the internet, this tool records them all with a single click.

The YIG Tuned Oscillator (YTO) is the only direct signal source to provide multi octave tuning bandwidths in excess of 10 GHz. Common tuning ranges are from 2-10 GHz, 8-18 GHz and 10-20 GHz. YTO is are also known for their superior phase noise and exceptional tuning linearity.

Detecting stray RF voltages on station grounds, chassis, and interconnecting cables is crucial for preventing program and hardware failures in the shack. This article details the construction and application of an LED RF V-probe, which offers significantly higher sensitivity compared to conventional neon lamp indicators. The probe leverages two specific properties of modern red LEDs: their ability to glow at microampere currents and their rectification capability at frequencies up to tens of megahertz. The design features a simple circuit with two LEDs, allowing for indication of both positive and negative RF voltage half-waves. The minimum detectable RF voltage is approximately 2 V, a substantial improvement over the 40-60 V threshold of neon bulbs. The resource illustrates the probe's physical construction on a PCB and provides a direct comparison demonstrating its superior sensitivity in detecting RF fields near a coil. Two operational modes are described: a non-contact mode for high RF voltages (above 15-20 V) and a direct-contact mode for measuring lower RF voltages, with a safety caution for the latter. Practical examples show the probe's use in analyzing RF voltage distribution across a radio station setup at 1.84 MHz and 24.9 MHz, revealing insights into common-mode current issues and the effectiveness of mitigation strategies like adding radials.

2023 September DXPedition Chuuk, F.S.M QRV on September 18-21, 2023 from Weno Island, Chuuk, Federated States of Micronesia. On 160-6m, CW/SSB/RTTY/FM (29MHz)/FT8. V6Z, V63Z, V6AAA, V6WW, V6C, V63FM, V63OS,V63VB,V63SX

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.

Details the construction and performance of a phase-controlled receiving array, specifically a **MicroSWA** variant, optimized for QRP low band fox hunting on 40M and 80M. The resource documents the author's iterative design process, addressing significant regional noise challenges encountered during 0100-0230 UTC fox hunt periods. Initial experiments involved a director wire on a 40M vertical, yielding limited improvement, prompting a shift towards advanced null-steering techniques. The project leverages concepts from Victor Misek’s "The Beverage Antenna Handbook" and Dallas Lankford’s extensive work on phased receiving antennas for urban lots. A key modification involved integrating a new passive phase control box and a push-pull **Norton common base preamp** using 2N5109 transistors, designed for high third-order intercept performance to maintain weak signal integrity amidst strong adjacent signals. The system incorporates Faraday-shielded transformers with RG174 primaries on -75 ferrite cores, housed in ABS plastic pipe. Performance tests confirmed the MicroSWA's ability to produce deep, steerable nulls, achieving approximately 30 dB noise reduction on 160M, 80M, and 40M. This enabled detection of QRP signals undetectable on conventional transmit antennas. The final unit includes front panel controls, a 10-11 dB preamp, and a robust power conditioner, demonstrating effective noise mitigation for challenging low band QRP operations.

The project aims to create a remote control system for the VK5RSE beacons located near Millicent, South Australia. The beacons on 144.550, 432.550, and 1296.550 MHz can interfere with nearby amateur radio operations, particularly for EME work on 1296 MHz. The remote control system uses a DTMF decoder and PIC microcontroller to allow turning the beacons on and off individually or in combination. The system is housed in a diecast box and powered from 5-8V. The password-protected control allows authorized users to manage the beacon operations remotely, helping mitigate interference issues for local amateurs.

This online project documentation details the construction of a hands-free microphone interface unit designed for _mobile_ amateur radio operation. The curriculum covers the integration of electret microphone elements with amateur radio transceivers, specifically addressing **VHF** band communication. It outlines the circuitry for a switch box that provides an interface between various radio models and microphone types. The guide specifies the inclusion of a **1750 Hz** tone-burst generator for accessing amateur radio repeaters, an operational protocol for many VHF systems. Design considerations include the reduction of ambient vehicle noise through an adjustable audio input level control. The project provides schematics and wiring diagrams for connecting the interface unit to specific amateur radio transceivers, including the Yaesu FT-817. It addresses the selection and adaptation of readily available electret microphone and earpiece assemblies, initially sourced from mobile phone accessories, and later from dedicated headset units. The design incorporates a control mechanism for radio functions, enabling hands-free operation during _mobile_ excursions. Circuit details cover power supply considerations for the electret microphone and signal routing for both transmit audio and received audio monitoring. The documentation specifies component selection for the switch box, ensuring compatibility with common amateur radio microphone input impedances and output levels. This includes considerations for PTT line switching and audio path isolation. DXZone Focus: Online Project Documentation | Hands-Free Mobile Microphone Interface | Electret Microphone Integration | 1750 Hz Tone-Burst Generation

The W6PQL 23cm Beacon Project describes a **1296 MHz** beacon designed for microwave propagation studies and equipment testing, capable of 30 watts output. It utilizes a PIC 16F628A microcontroller to generate CW and FSK keying for a crystal oscillator, followed by a series of frequency doublers and triplers to reach the target frequency. The final power amplification stage employs a Mitsubishi M57762 module, providing a robust 10-watt RF output. The design emphasizes stability and reliability for continuous operation, with the microcontroller code, written in assembly, provided for customization of the beacon's callsign and message. Originally located in CM97am and aimed at 140 true, the beacon used four 4-foot Yagis stacked vertically for a total ERP of 3kW. The article includes schematics, parts lists, and construction notes to guide builders, along with antenna pattern measurements. Although the beacon itself is no longer in service as of August 2010, the detailed documentation remains a valuable reference for amateur radio operators interested in building similar **microwave** projects or understanding beacon operation.

This online construction guide details the assembly of a signal generator specifically for the **13cm band** (2.4 GHz). The curriculum focuses on the integration of a Voltage Controlled Oscillator (VCO), specifically the ROS-2400, to produce a stable RF signal. The resource outlines the necessary components for frequency generation and output, including the use of a Mini-Circuits MMIC amplifier for signal conditioning. The construction protocol involves configuring the ROS-2400 VCO to operate within the 2.3 GHz to 2.45 GHz range, ensuring frequency coverage for amateur radio _microwave experimentation_. The guide specifies the output power level, approximately 70mW, directly from the MMIC stage, indicating its application as a low-power instrumentation source rather than a transmit-capable device. This project provides a practical example of constructing a dedicated test instrument for microwave frequency measurements and system alignment on the **13cm band**. DXZone Focus: Construction Guide | 13cm Signal Generator | VCO Integration | Microwave Experimentation