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CwGet v2.55 is a software application for amateur radio operators designed to decode Morse code (CW) signals into text using a standard computer sound card, eliminating the need for specialized hardware. The program features a customizable interface with a spectrum display for visualizing signal frequencies and peaks, an oscillogram for monitoring signal presence and setting detection thresholds, and a received symbols window for displaying decoded text. Key functionalities include Automatic Frequency Control (AFC) to lock onto signals, adjustable FIR and IIR filters for noise reduction, and a burst filter to mitigate short noise impulses. It also supports automatic CW speed detection, multiple character sets, and the ability to record and replay received audio. Integration with logging software like AALog is facilitated through double-click word transfer, and transceiver frequency control is possible via the Omni-Rig interface, allowing for automatic tuning of the radio's VFO or RIT. The multi-channel decoder feature can simultaneously decode up to five strong signals within a 1600 Hz bandwidth, displayed in a separate Multi-RX Window with an adjustable squelch. CwGet also offers the capability to decode signals from pre-recorded WAVE files and can function as a narrow-band sound DSP filter for aural decoding. This is a commercial version and it has been tested on latest MS Winows versions.

Demonstrates the construction of a **remote antenna tuner** utilizing a standard radio-controlled (RC) servo mechanism to adjust a variable capacitor. The design focuses on enabling remote tuning for narrow-bandwidth antennas, specifically mentioning frame and packing crate antennas, from within the shack. It covers the mechanical arrangement for integrating the servo with a capacitor and provides a circuit diagram for a control unit that generates the necessary 0.5mS to 1.5mS pulse-width modulation (PWM) signals to drive the servo's 180-degree rotation. This setup was successfully tested with up to 20 watts RF power without arcing or adverse effects on the servo, though tuning was performed at 1 watt for VSWR readings. The resource highlights the use of inexpensive, readily available components, such as Futaba servos, and details critical considerations like power supply decoupling with a 47uF capacitor to prevent unintended servo movement upon power-off. The system provides a practical solution for optimizing antenna performance for specific frequencies without manual adjustment at the antenna itself.

SSTV program for the Linux platform with several functions written by ON1MH Johan. QSSTV is a Linux-based program for receiving and transmitting SSTV (Slow Scan Television) and HAMDRM (Digital SSTV) signals, compatible with MMSSTV and EasyPal. Key features include support for narrow band SSTV modes, gallery functionality for viewing received/transmitted images, repeater capabilities for both SSTV and DRM modes, PulseAudio direct interface, and CAT radio control. The software includes waterfall visualization, hybrid mode operation, and template editing features. QSSTV requires Qt5 and several other libraries for compilation, and operates with a three-window interface for receive, transmit, and gallery functions.

Free windows comprehensive tool for Finite Impulse Response (FIR) filter design

Power connectors, power cables, coax cables, wires, batteries fuses and holders and tools

A system designed to automatically tune small transmitting magnetic loop antennas, particularly beneficial for **contest operations** where rapid frequency changes are common. The core of the system involves a PC-based control application, AutoCap, written in C#, which monitors antenna SWR via an external meter and commands a motor interface to adjust the loop's variable capacitor. The software is compatible with Windows and Linux via the Mono framework, offering a graphical user interface for monitoring system status, SWR, power, and motor commands. Key components include one or more magnetic loop antennas equipped with DC or stepper motors for capacitor adjustment, an SWR meter with data output (such as the Telepost LP-100A or a homebrew serial/USB SWR meter), the AutoCap PC software, and a motor interface. The most effective motor interface utilizes an **Arduino-based controller** with custom firmware, providing precise control over both simple DC motors and stepper motors, and supporting features like motor braking for finer adjustments. The system allows for configurable SWR thresholds, pulse widths, and motor effort settings to optimize tuning speed and resolution. Optional radio integration provides frequency hints, enabling the algorithm to learn the relationship between motor actions and resonant frequency, thereby speeding up initial tuning responses. The software also supports antenna profiles, allowing operators to save and recall specific configurations for different loops, including accumulated frequency hint data.

CLOVER-2000 is a faster version of CLOVER (about four times faster) that uses eight tone pulses, each of which is 250 Hz wide, spaced at 250-Hz centers, contained within a 2 kHz bandwidth between 500 and 2,500 Hz

ScopeIIR: an Infinite Impulse Response (IIR) digital filter design tool for Windows. It designs high-order IIR filters based on analog filter prototypes, and can design lowpass, highpass, bandpass, and bandstop filters.

Demonstrates the _RoMac Automatic CW Identifier 2012_ software, a Windows application designed to automate station identification and provide a tuning pulser. It can send CW identification via a sound card's audio output or by keying a radio's manual CW jack using a serial port's DTR line. The software also supports CAT commands for various Kenwood, Yaesu, Flex, and Elecraft radios, enabling automatic mode and frequency changes for ID transmission. It integrates with USB audio-capable radios like the Icom 7300 and Yaesu FT-991, simplifying connectivity with a single USB cable. The application features a fully programmable interface, adjustable CW speed from **5 to 35 WPM**, and ID intervals from **5 to 30 minutes**. The integrated "Pulse Tuner" function allows for safe amplifier and antenna tuner adjustments by sending short audio tones or rapid CW keying, with an adjustable duty cycle from 1% to 100%. It offers compatibility with a wide range of transceivers and amplifiers, and a schematic for a basic sound card interface is included for users without existing setups.

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.

The problem originates by improper TXOUT-to-RF timing (RF transmission exists still after a TX-EN prohibition), combined by too long decay of their CW pulses.

RF amplifier products from NP Technologies, Inc. encompass a wide array of specialized designs, including highly linear Class A broadband amplifiers, crucial for maintaining signal integrity across various frequencies. Their portfolio also features cell band amplifiers, specifically engineered for cellular communication infrastructure, and pulse amplifiers, which are vital in applications requiring high-power, short-duration signal bursts. The company's manufacturing capabilities extend to AM and FM broadcast amplifiers, supporting radio transmission systems, and military VHF amplifiers, designed to meet rigorous defense specifications for robust and reliable communications. NP Technologies, Inc. emphasizes comprehensive development, design, manufacturing, and testing processes for all its RF amplifier offerings. This integrated approach ensures that each product, from initial concept to final deployment, adheres to stringent performance and reliability standards. The company's expertise in these areas allows for the creation of custom solutions tailored to specific client requirements, addressing complex RF challenges in diverse operational environments. Their product range demonstrates a commitment to serving multiple sectors, including commercial broadcasting, telecommunications, and defense. The focus on specialized amplifier types underscores their technical depth in RF engineering.

Tabor electronics produces high-end function generator, universal counters/timers, synthesizers, pulse, function and arbitrary waveform. Frequency counters

Design, develop, test and manufacture a wide range of Amplifier products including highly linear class A Broad Band, Cell Band, Pulse, AM & FM broadcast and Military VHF

High power, UHF, L-band, S-band, C-band, microwave frequency amplifier and oscillator devices, pulsed, CW, fixed-tuned, or tunable devices in the range of 600 MHz to 2000 MHz

Encode/decode On-Off audio pulses for remote control of projects

Mitigating impulse-type noise, a common challenge in the **HF radio spectrum**, often requires specialized processing before the signal reaches the transceiver's receiver stages. The NR-1 addresses this by functioning as an RF interference removal device, specifically a noise blanker, targeting transient noise sources. Its operational range extends from 1.6 MHz to beyond 70 MHz, making it suitable for various amateur radio bands and general shortwave listening applications. Unlike QRM eliminators or X-phasers, the NR-1 does not require a separate noise antenna for its operation, simplifying its integration into existing station setups. The device's design focuses on wideband performance, allowing its use both within and outside the allocated amateur radio frequencies. Documentation detailing its operation is available, providing insights into its technical specifications and deployment. This unit is a hardware product, conceptualized and implemented by SV3ORA.

Sending and receiving text with Morse code light pulses across the room is a fun and cheap project you can do on a Raspberry Pi or Arduino or any other microcontroller. This post explains how I did it, and how you can do it too.

Analyzing 433 MHz radio signals from common wireless devices, such as temperature sensors and remote controls, involves understanding **On-Off Keying (OOK)** modulation. This resource details the process of capturing these signals using a Software Defined Radio (SDR) like Gqrx and then visually inspecting the captured audio data in a sound editor such as Audacity. It differentiates between **Pulse Width Modulation (PWM)** and Pulse Position Modulation (PPM) encoding schemes, illustrating how to identify and decode binary data by eye based on pulse and gap durations. The article provides a step-by-step walkthrough for decoding a wireless thermometer's data, correlating bit patterns with known temperature, humidity, and channel values. It also demonstrates decoding an RF remote control's button presses, highlighting the constant and varying parts of the transmitted packets. The content further introduces automated decoding using tools like RTL_433, explaining its capabilities in parsing various device protocols and showing how to interpret its output, including modulation type and decoded data. Specific examples include analyzing Prologue sensor protocol specifications from RTL_433's source code and noting common operating frequencies like 433.92 MHz in Europe and 915 MHz in the US.

Ferrite E-cores offer a practical solution for constructing baluns, especially when connectors are already mounted on cables. These cores, commonly used in mass-produced pulse transformers, allow for multiple turns without dismounting connectors, making them ideal for control and power supply cables. The material of E-cores is generally suitable for common mode baluns up to 15 MHz, providing a cost-effective option for amateur radio operators. E-cores can often be sourced from old switch-mode power supplies, adding to their appeal for those looking to utilize existing resources. A notable example involves a balun on a USB cable using a Ferroxcube E 32x16x9, 3F3 core with four turns, secured by three cable ties. This setup demonstrates the ease of construction and stability achievable with E-cores. Another example features a balun with eight turns of shielded cable with RCA connectors on the same core, achieving 140 uH inductance at low frequencies. The impedance plot for this configuration is measured between the shield ends, illustrating the effectiveness of E-cores in practical applications. The article includes detailed figures and descriptions, providing valuable insights into the construction and application of baluns using ferrite E-cores. These examples serve as a guide for amateur radio enthusiasts looking to enhance their setups with cost-effective and efficient solutions.

TFilter is a free online tool for designing linear phase, optimal, equiripple finite impulse response (FIR) digital filters. It utilizes the Parks-McClellan algorithm implemented in JavaScript. Users can specify the sampling frequency, desired number of taps, passbands, and stopbands to generate a filter. An example configuration is provided for easy testing.

KISS703 is a 703 Hz narrowband digital mode for amateur radio, designed for simple, low-power operation without computers. A 500 Hz pilot tone ensures frequency alignment, replaced by unique tones for 37 symbols (letters, numbers, space). Built from common discrete components, it draws about 40 mA at 12 V, ideal for SOTA/IOTA use. The receiver uses amplification, wave shaping, and a pulse-counting frequency meter for manual decoding via a calibrated meter. Transmitter and receiver calibration involves marking meter positions for each tone, enabling fully self-contained messaging with minimal hardware in portable or fixed operations.

The NR-1, conceived and implemented by SV3ORA, functions as an **antenna noise blanker** to suppress impulse noise before it reaches the receiver. This device is explicitly not a QRM-eliminator or X-phaser, and it operates without requiring a separate antenna. Its primary goal is to improve receiver performance by reducing annoying noise. Documentation includes a comprehensive manual detailing its operation, alongside several videos demonstrating its functionality. The NR-1 is available for purchase directly from Elisys via their online shop. Numerous radio amateurs have reviewed the NR-1, with Pavel OK7PM highlighting significant improvements in receiver **dynamic range**. Further insights are available in an article published in the Greek magazine SVnea and through various reviews posted on eham.net.