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Learn about the LinHT handheld SDR radio, an open-source, Linux-based project that is shaking up the ham radio and SDR communities. This guide is perfect for hams new to digital voice and interested in exploring experimental radio platforms. Discover what sets LinHT apart from traditional handheld radios, how it leverages SDR technology and Linux operating system, and why it's generating buzz in the ham radio landscape. Dive into the world of software-defined handheld radios with this beginner-friendly overview.

The TangerineSDR is a Modular Software Defined Radio Project with the following objectives, Development of SDR radios that allow experimentation, provide support to unaffiliated other groups, to provide hardware modularity, to allow varying performance, To allow users to experiment with differing configurations.

Monitoring radio communications through web-accessible Software Defined Radios (SDRs) has become a popular facet of the hobby, and Receiverbook serves as a centralized directory for locating these remote assets. The platform aggregates listings for both **OpenWebRX+** and **KiwiSDR** installations, providing a gateway to a diverse array of frequencies and operating modes. My own experience with similar directories highlights their utility for casual listening, DXing, and even troubleshooting local RFI by comparing signals across different geographic locations. The directory details specific receiver locations, from Bedford, England, to Marahau, New Zealand, and Berlin, Germany. Each entry often specifies the supported frequency ranges, which can span LF, MF, HF, VHF, and UHF bands, including dedicated segments like 80m, 40m, 2m, and 70cm. Many listings explicitly note support for HAM radio, broadcast services, and public two-way radio, making it a versatile tool for various listening interests. Beyond general frequency coverage, some entries provide granular details about the underlying hardware, such as the **SDRPlay RSP1A** or RTL-SDR Blog V3, and even the antenna types employed, like the Sirio Gain-Master. This level of detail is invaluable for serious SWLs and hams looking to understand the capabilities and limitations of a particular remote receiver before tuning in.

Integrating a _Software Defined Radio_ (SDR) into an existing ham radio setup involves connecting it with a standard transceiver (TRX), power amplifier (PA), and antennas. The core component is a splitter box that facilitates the connection between the TRX and the SDR, allowing for simultaneous operation without modifying existing equipment. In receive mode, the splitter ties the antenna inputs of both the TRX and a direct conversion receiver (DC RX) together. During transmission, the DC RX input is grounded via a fast telecom relay controlled by the transceiver's -SEND signal, incorporating a 10ms delay for safety. The splitter box includes a 3.7 dB input attenuator for impedance matching and acts as a protective fuse for the DC RX input. Ground loops are mitigated using common mode balun transformers, while the DC RX input is insulated with a broadband transformer. An audio switch box complements the setup, enabling users to listen to either the main transceiver, the SDR output, or both simultaneously. This configuration ensures noise immunity and safety, with the splitter housed in a screened box made from PCB material. On-air tests, such as the CQ WW 160m CW DX Contest, demonstrate the system's effectiveness, showcasing the SDR's ability to handle crowded band conditions with superior selectivity and dynamic range. The SDR's narrow bandwidth filters and waterfall display provide significant advantages, allowing operators to detect weak signals amidst strong interference. The integration of SDR with conventional radios offers enhanced operational flexibility and performance in challenging environments.

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.

Quisk is a Software Defined Radio (SDR) and is the software that controls my receiver and transmitter. Quisk can control the HiQSDR, Hermes-Lite hardware, SoftRock hardware, SDR-IQ by RfSpace

This page, authored by VU2ESE, delves into the sBitx, a Software-Defined Radio (SDR) designed for homebrewers. The content covers the hybrid SDR circuit, software, user interface, hacking/modifying the sBitx, performance, and more. It explores the various components of the sBitx, including the exciter, filters, amplifiers, digital circuit, and modems. The page aims to provide information and guidance for hams interested in building their own SDR. Readers will learn about the capabilities, features, and adaptability of the sBitx, making it a valuable resource for DIY radio enthusiasts.

This page explores the world of Software Defined Radios (SDRs) in the context of amateur radio. It discusses how SDRs have revolutionized the hobby by reducing costs and enabling remote operation. The article provides ideas for projects and experiments that hams can undertake with SDR technology, highlighting the educational and experimental opportunities it offers. It also mentions specific examples of SDR projects like the Stoke on Trent SDR and SDR.HU. The content is aimed at amateur radio operators looking to explore and harness the potential of SDRs in their stations.

The RTL-SDR tuner dongle is a popular tool for amateur radio enthusiasts, transforming a $10 device into a wide-band software-defined radio. This guide outlines using the RTL-SDR as a full-band pan-adapter for conventional receivers, focusing on hardware setup and software integration with HDSDR. Future sections will address RTL-SDR performance compared to native receivers, enhancing digital mode operations with virtual serial ports and audio cables.

Demonstrates the application of Software-Defined Radios (SDRs) as effective tools for conducting Radio Frequency Interference (RFI) site surveys. The resource details the methodology for capturing and analyzing RFI, specifically focusing on the 80-meter band over a 24-hour period. It outlines the setup of an SDR-based survey tool, utilizing software like _S-Meter Lite_ and _Spectrum Lab_ to visualize and quantify noise sources. The article emphasizes the SDR's wideband capabilities, which allow for comprehensive identification and documentation of RFI across broad frequency ranges, crucial for effective mitigation strategies. The analysis presents practical results, illustrating how continuous monitoring can reveal intermittent RFI sources that might otherwise go undetected. For instance, the survey identified noise peaks exceeding **S9+20dB** on 80 meters during specific hours, correlating with local appliance usage. The methodology provides a repeatable process for hams to characterize their local noise floor, enabling targeted RFI suppression efforts and improving weak-signal reception, particularly for DXing and contesting.

The ZL1WTT resource details an experimental software-based Digital Amateur Television (DATV) system, demonstrating the multiplexing of up to six standard-definition (SD) and one high-definition (HD) channel utilizing _h264 compression_. The author encountered peak data rates reaching 32 Mbit/s, necessitating a shift to Freeview and Sky settings (22.5M Sym/s 3/4FEC) to manage bandwidth. The setup employs four networked computers, with a laptop functioning as the multiplexer to re-code PIDs for various inputs, including looped MPEG2 playlists, MPEG2 encoder card input from a VCR, satellite feeds, and an off-air UHF receiver. The system highlights the inherent flexibility of the DVB transport stream, supporting diverse formats such as MPG2, h264, AC3, and AAC. A significant advantage of this software-defined approach is the absence of video quality degradation from stored MPEG2 files to the displayed output, coupled with the ease of reconfiguring settings for MPEG2 encoder cards (e.g., size, bit-rate, frame rate, video input, coding format) and satellite receiver cards (e.g., frequency, LNB volts, symbol rate, FEC). The author also discusses the development of a new graphical user interface (GUI) using _Gambas_ for Linux, aiming to simplify configuration for this DATV project. Specific hardware components mentioned include Hauppauge WinTV PVR-150 and Nova-S plus cards, with a focus on optimizing analog video input via Y/C (S-video) to minimize frequency roll-off. The resource also provides insights into data rates for HD (1080i) content, recommending 8 to 12 Mb/s for optimal performance. Software utilized includes _Ubuntu Studio 10.04_, WinFF, VLC, and TMPGEnc Editor, underscoring the project's reliance on open-source tools and a foundational understanding of LAN networks and DVB transport streams.

PortFlux provides a software-defined virtual serial cable solution for Windows operating systems, specifically supporting x64 and ARM64 architectures. It facilitates the creation of paired virtual COM ports, allowing two distinct applications to communicate as if connected by a physical null-modem cable. The utility is designed to bridge data streams between software requiring serial port access, such as logging programs, rig control applications, or digital mode clients, without the need for physical hardware interfaces. This software addresses the common challenge of connecting multiple ham radio applications that each demand exclusive access to a single physical serial port. By establishing virtual pairs, PortFlux enables simultaneous operation of, for instance, a contest logger and a digital mode program, both interacting with a single transceiver via a shared virtual link. The GitHub repository includes source code, offering transparency and the potential for community contributions or custom modifications.

The LY4A DX Reminder application monitors five distinct DX cluster sources—DXScape, DXSummit, DXHeat, PSK Reporter, and Reverse Beacon—to alert amateur radio operators when a specific call sign appears. It supports a wide range of bands from 160 meters to 70 centimeters, including 60m, 6m, 2m, and 70cm, accommodating **CW**, SSB, FT8, FT4, and RTTY modes. The software operates in the background, checking clusters at user-defined intervals of 1, 5, 10, or 30 minutes, and persists across device restarts. Alarm functionality is robust, activating even if the mobile device is silenced, by utilizing the alarm channel and illuminating the locked screen. On desktop platforms, notifications remain active in the system tray. Users can directly manage alarms—stopping, snoozing, or deleting them—from the notification interface, enhancing operational flexibility during DX pursuits. Available in 15 languages, including English, Italian, German, and Spanish, the application is provided free of charge and without advertisements. It offers optional donation support for continued development. Installation instructions are detailed for Android, Windows 10/11 (64-bit), and macOS 12+, addressing common system security prompts for unsigned applications.

This guide details how to set up an OpenWebRX software defined radio (SDR) receiver using an RTL-SDR V4 dongle on a Raspberry Pi or similar small computer. The resulting SDR receiver is accessible via a web interface, featuring a live waterfall display and demodulation for AM, FM, SSB, and CW. It can be configured for public sharing or private network use. The RTL-SDR V4 dongle offers direct sampling improvements for HF, a tuning range of approximately 500 kHz to 1.7 GHz (covering HF, VHF, UHF, and microwave amateur allocations), improved front-end filtering, and a built-in software-switchable bias tee. The guide covers two installation methods for OpenWebRX: using an official Raspberry Pi image or a Docker installation. It also provides recommendations for Raspberry Pi models (3/3B+, 4, Zero 2 W), antenna and placement tips, and troubleshooting common issues. OpenWebRX is an open-source, browser-based SDR software package.