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RadioMasterList, a comprehensive receiver and transceiver directory. Performances and specifications for every radio set

This article will explain a few of the ways author use an external SDR and Linrad to enhance his K3 experience. Linrad is one of many available SDR receiver programs. The same could be done with any radio that lets you access its IF frequency output. Article from NCJ Nov Dec 2019

K3AS.com Home Page, Discover SSTV, See K3AS SSTV CAM, Live SSTV Images Received by my Station, View My Station Equipment.

Using Spectrum Lab for the reception of VLF natural radio

An improved version of the audio interface commonly used to connect a computer soundcard to a transceiver\'s receive and transmit audio circuits

A schematic diagram of a homemade direct conversion receiver for 30 meters band

Nearly half of all reception problems are due to deficiencies or faults in the television receiver, the aerial lead or the aerial. This article will help you to check whether the problem you are having is due to one of these causes.

One-Cubic-Inch Direct-Conversion Receiver

High Performance Communications Receiver AKA, The Progressive Receiver

HamAlert let you receive Push,SMS,Email notifications for Cluster,RBN,SOTAwatch spots, with customizable filtering based on many criteria including DXCC, SOTA and WWFF references, CQ zones

CATSync V1.30 integrates OpenWebRX support, expanding its capability to synchronize a local amateur radio transceiver's CAT control with a broader range of public WebSDR receivers. The software facilitates real-time frequency tracking, allowing the operator to adjust their physical rig's VFO and observe the connected WebSDR instantly follow the tuned frequency. This functionality is crucial for remote listening, signal comparison, and verifying propagation conditions across different geographic locations using a familiar hardware interface. The application supports both the classical WebSDR interface and KiwiSDR platforms, providing a consistent control experience across various online SDR deployments. It bridges the gap between local station operation and the vast network of globally distributed software-defined radios, offering a practical tool for DXers and contesters. CATSync is designed for Windows and Linux environments, with Android compatibility noted, making it accessible to a wide user base seeking to leverage WebSDR resources with their existing station setup.

Presents the full owner's manual for the _Drake R-4C_ communications receiver, specifically a late version edition. This resource outlines the comprehensive operational instructions, covering everything from initial setup and tuning to advanced features and controls. Hams can reference detailed diagrams and explanations for proper signal reception across various amateur bands. The manual includes critical information for alignment procedures, ensuring the receiver performs to its optimal specifications. It details the steps required for calibrating the internal circuitry, which is essential for maintaining sensitivity and selectivity over time. My experience with vintage Drake gear confirms the value of these original documents for accurate adjustments. Furthermore, the document provides insights into troubleshooting common issues and performing routine maintenance. It serves as an authoritative guide for anyone operating or servicing this classic piece of amateur radio equipment, helping to preserve its functionality for years of DXing and ragchewing.

The equipment shown on this page comprises a basic G3WDG transmit and receive system with the addition of a 1W Qualcomm amplifier.

tk150 experimental Software for the Standard VR-150 Receiver

A tutorial on how to setup a receiver capable to decode SSTV signals with a small RaspberryPi version 2 and a RTL-SDR dongle. The author explains how to install the needed software to interface the RTL-SDR and a step by step guide to install the QSSTV software used to decode the signals.

Tuned circuits for Progressive Receivers

In order to determine total distance that a transmission may be received by two elevated antennas, we must add together the radio horizon distance of both antennas.

Homemade RF limiter project, to protect the K3 receiver front-end for high radiofrequency based on the original KD9SV project.

Build a SPDT coaxial relay that can be used as a main Transmit/Receive relay or an A-B switch to select between two different 6m antennas

Sixty-meter repeaters typically use a 1 MHz frequency separation between input and output, while 2-meter repeaters commonly employ a **600 kHz** split and 70-centimeter repeaters use a **5 MHz** offset. This article details the fundamental technical principles of amateur voice repeaters, explaining how they extend VHF/UHF communication range by receiving on one frequency and simultaneously retransmitting on another. It covers essential components such as receivers, transmitters, filters, and antennas, often situated on elevated locations for optimal coverage. The resource delves into the critical challenge of _desensing_—where the repeater's strong transmit signal overpowers its own receiver—and the engineering solutions employed, including antenna separation and the use of high-Q cavity filters. It also explores various control and timing systems, from basic squelch activation to more sophisticated microcontroller-based boards that manage functions like voice identification, time-out timers, and fault protection. Different access methods are discussed, including open access, toneburst, CTCSS subtone, and DTMF, each offering distinct advantages for managing repeater usage and mitigating interference. Furthermore, the article examines repeater linking, both conventional RF methods and modern internet-based solutions, highlighting how linking expands coverage and promotes activity across multiple repeaters or bands. It introduces less common repeater types such as 'parrot' repeaters, which use a single frequency and digital voice recording, and linear translators, capable of relaying multiple signals and modes simultaneously across different bands, often found in amateur satellites.

Microprocessor based interface designed receives a signal from a Morse key, processes it, and re-transmits it to the radio. A microprocessor in the circuit is pre-programmed with a proprietary algorithm which makes a number of measurements and adjustments to the less percise human generated code.

Producers of custom name tags, luggage tags, club badges, Employee Name Tags, Special Event Badges, but also Comtech Amateur Radio Television Transmitters and Receivers D480 filters, Video cameras and accessories.

An SDR project, MDSR modulator-demodulator software radio, made using an inexpensive converter and a pc. MDSR has a transceiver and a receiver converters.

A homemade interface for any android device, allow to receive and trasmitt SSTV PSK RTTY from an android tablet based on the DD7LP original project include demo of a sample DIY kit.

Developing operational amateur radio equipment for the 134 GHz band presents significant technical challenges, particularly in frequency generation and stability. This resource details the construction of a 134 GHz system, outlining its architecture with separate transmit (Tx) and receive (Rx) modules, each employing a local oscillator (LO) and RF head units. The system utilizes a dual Flann 50 GHz lens-type horn antenna configuration for optimal signal coupling. The transmit path incorporates an LMX2541 synthesizer chip operating at approximately 2.8 GHz, referenced by a 10 MHz double-oven Morion OCXO for exceptional stability. This signal is multiplied through a series of stages (X4, then X2) to generate a 22.4 GHz signal, which subsequently drives a dual series diode multiplier to produce the final X6 signal for 134 GHz operation. The receive side features an anti-parallel diode mixer coupled to a 144 MHz transceiver via a preamplifier, ensuring effective downconversion. Operational mode is CW, achieved by keying a multiplier stage. The project includes images of the Tx and Rx head units and describes a successful 3.5 km test with G8ACE, demonstrating stable signal tones due to PLLs locked to OCXOs at both ends, confirming the system's robust performance.

This article describes the construction of a high performance transmitter and receiver for SSB (voice) communication covering the 14MHz (20 meters) high frequency amateur radio band with output range 15 to 20 watts and a top audio sound quality both on transmit and receive.

A very simple experimental short wave radio receiver. This is basically just a crystal radio with two stages of transistor amplification afterwards made with scrap components.

Receivers and transmitters by Collins , Drake , Hallicrafters , Hammarlund , National Receivers

A microprocessor based interface designed to go between a standard Morse code key and a radio transmitter. The circuit receives a signal from the key, processes it, and re-transmits it to the radio.

This project is a USB Audio, Serial and PTT interface for rigs that does not directly support digital modes provided by applications such as FLDIGI, WSJT-X and JS8CALL. Plug these interface devices into your Windows or Linux laptop or Raspbian Raspberry Pi and you can send and receive digital tones to/from your rig and automate the frequency and mode control and PTT control.

Barest of bones APRS RF position reporter using a Raspberry Pi B+, USB GPS receiver, Baofeng UV-5R, and a mono 3.5mm audio cable between the Pi and the radio

KiwiSDR Software-defined receiver at Bjargtangar Iceland covering HF Bands

Technical details of the Drake R-4C receiver

Vintage radio and scientific apparatus by john jenkins, include antique radios, Horn Loudspeakers, Vacuum Tubes, A.C. Receivers

Modified 80cm Offset Dish for 2.4 GHz Satellite Reception. This 50-ohm impedance antenna allows, when connected to 2.4GHz preamplifier and downconverter, to receive Amateur satellites with 2.4GHz transponders such as AO-40.

How to build a complete Single-Sideband amateur radio transceiver from scratch. Article published on hackaday dot com includes an introduction to radio architectures, ssb receivers and tramsitter

FHD22 radio-relay transmitter and receiver by F4DAY

Key details about the superhet or superheterodyne radio reeiver: basic overview; how it works; applications; design notes, all you need to know.

Picture gallery of SSTV images received by DU1IVT Thelma

N-channel scalable coherent receiver that employs the RTL-SDR technology in order to create inexpensive multi-channel receiving systems.

Since 2011, crkits offer radio kits that you cannot find on eBay or AliExpress. Includes HT-1A 20/40m Dual Band CW Transceiver Kit, D4D DSB Transceiver Kit for Digital Mode, R3500D ARDF Receiver, CW Transceiver Kit

This FM wireless mike can transmit voice signals to any FM Radio receiver 100 meters away.

Presented is a historical collection of short-wave listening (SWL) QSL cards, primarily from the late 1930s and early 1940s, offering a glimpse into early international broadcasting and the technical pursuits of SWL operators like Les Miles during that era. The resource showcases specific QSLs from stations such as _Broadcasting Corporation of Japan_, _XGOY - The Central Broadcasting Administration_ in Chungking, China, and _Australian broadcasting ship, Kanimbla VK9MI_, each with reception dates and frequencies like 11.90MHz or 9.525MHz. It highlights the self-sufficiency of SWL enthusiasts who constructed and maintained their own radio and test equipment, evoking the sensory experience of vintage valve receivers. The collection provides concrete examples of international broadcast stations active before and during World War II, including _2RO3 - Rome_ and _WRUL - World Wide Broadcasting Foundation_ from Boston. Each QSL entry details the station, location, reception date, and often the frequency, such as 9.63MHz or 11.26MHz, allowing for historical verification of broadcast schedules. The resource also briefly mentions the operational details of the _VK9MI_ offshore radio station, directing readers to further information on its history. This compilation serves as a tangible record of global radio communication during a pivotal historical period.

A 0-30 MHz step attenuator, constructed from switchable Pi attenuation pads, provides a practical tool for evaluating receiver sensitivity and calibrating S-meters. The design utilizes readily available 5% tolerance resistors, with values derived from paralleled components to achieve specific attenuation steps. A schematic (Fig 1) illustrates the circuit, including PCB pad shielding, while a table details required and actual resistor values, along with percentage differences. Measurements of voltage input versus output at various frequencies are used to calculate dB attenuation, presented in a graph (Fig 4). The resource includes formulas for determining output voltage from a known input and a comprehensive 0-40 dB voltage multiplier table, which is crucial for precise signal level management. The project also references external attenuator calculators and equations for further study. Photos (1-3) provide visual guidance for the assembled unit, showing bottom, top, and front views. The project emphasizes the use of **Pi attenuation pads** and **receiver sensitivity** evaluation, offering a hands-on approach to RF signal management.

The first EME history was written in 1944 when first EME echoes were received on 564 MHz by German Wurzmann radar according to the article by Dr. Ing. W. Stepp.

Do you want to see how your FT8 signals are being received in the other parts of the globe?

The ICOM IC-R72E a neat compact communications receiver. Coverage: LW, MW, SW (0.1- 30.0 MHz continuous) discontinued in 1998

Bi-Directional 2.4 GHz One Watt Amplifier With Receive Pre-Amplifier. This will show you how to add a bi-directional, 2.4 GHz amplifier to your Proxim Symphony for under $100

This Return Loss Bridge has been designed to characterize the input impedance of a receive strip, and the output impedance of a transmit strip

Drake R-4 Receiver manual