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

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.

Tuned circuits for Progressive Receivers

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.

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.

tk150 experimental Software for the Standard VR-150 Receiver

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.

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

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.

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.

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

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

Tune into this SDR receiver located near Krizevci, Croatia with 0-2 MHz, 60-80 meters band and 40-49 meters band

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

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

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.

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

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.

Sending the Audio from the Receiver to the Recorder, from the Recorder to the EQ, and sending the Audio from the EQ or Recorder to the Transmitter

Technical details of the Drake R-4C receiver

FHD22 radio-relay transmitter and receiver by F4DAY

Learn how to build a QRP digital transceiver with Arduino, based on a project by Burkhard Kainka. This article covers the development process, including the source code, modifications made, and the addition of an OLED display for a more professional look. Discover the inner workings of the transceiver, from the receiver to the oscillator, and how components like the CD2003 are utilized. Explore the schematic design, the use of a PLL module Si5351A controlled by Arduino nano, and more. Ideal for hams looking to create their own digital transceiver for amateur radio operations.

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

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

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

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

Low-frequency (LF) radio time signals, operating primarily in the 40–80 kHz range, are broadcast by national physics laboratories for precise clock synchronization. Transmitters like **JJY** (40 kHz, 50 kW; 60 kHz, 50 kW), RTZ (50 kHz, 10 kW ERP), MSF (60 kHz, 15 kW ERP), WWVB (60 kHz, 50 kW ERP), RBU (66.66 kHz, 10 kW), and DCF77 (77.5 kHz, 50 kW) cover vast geographic areas, often several hundred to thousands of kilometers. LF signals offer distinct propagation advantages over higher-band transmissions such as GPS. Their long wavelengths (3–6 km) enable effective diffraction around obstacles like mountains and buildings. The ionosphere and ground act as a waveguide, eliminating the need for line-of-sight and allowing a single powerful station to cover extensive regions. Ground wave propagation minimizes ionospheric variability effects on transmission delay, and signals penetrate most building walls effectively. Robust and low-cost receivers, often priced at 20–30 USD/EUR, are widely used in radio clocks. These receivers typically comprise a tuned ferrite core antenna, a receiver IC (e.g., Atmel T4227, U4223B, MAS1016) for amplification and AM detection, and a microcontroller for decoding the time signal and phase-locking a local clock. Specific components for DCF77, MSF, and WWVB are readily available from vendors like HKW Elektronik and Ultralink.

Drake R-4 Receiver manual

A complete review of the Ten-Tec RX340 all mode HF receiver

Selecting a portable QRP transceiver for field operations or SOTA activations often involves weighing trade-offs between size, power output, and feature sets. This article directly compares the _Elecraft KX2_ and the _Yaesu FT-818_, two popular choices among QRP operators. It examines key specifications such as receiver sensitivity, transmit power levels, and battery life, providing practical insights into their on-air performance. The comparison delves into user interface differences, discussing the ergonomics of controls, display readability, and menu navigation for each rig. It also touches upon integrated features like internal antenna tuners and digital mode capabilities, which are crucial for efficient portable operation. The author shares personal experiences with both transceivers, highlighting their respective strengths and weaknesses in real-world scenarios. Specific attention is given to the form factor and weight, critical considerations for backpackers and those operating from remote locations. The article concludes with a summary of which transceiver might be better suited for different operating preferences.

This is a compact three transistor regenerative general coverage receiver with fixed feedback. The sensitivity and selectivity is relative good, especially on the LF and MW bands, as can be expected with this simple design.

Gimme Five reloaded, a compact 5 band QRP SSB transceiver in SMD technology. This unit covers 5 bands within the amateur radio spectrum (3.5, 7, 14, 21 and 28 MHz). Receiver is a single conversion unit with an interfrequency of 9 MHz. Transmitter uses 5 stages and has got a power level of 10 watts PEP output.

On December 12, 1901, Guglielmo Marconi successfully received the first transatlantic wireless communication, a Morse code "S" (three dots), at 04:30 GMT. This article details the setup for this groundbreaking experiment, noting Marconi's receiver in St. John’s, Newfoundland, Canada, utilized a _coherer_ and an antenna elevated by balloons and kites. The transmitting station at Poldhu, Cornwall, England, featured twenty-four 200-foot ships' masts and a 25-kilowatt alternator. The resource explains how this contact disproved contemporary beliefs about radio wave limitations due to Earth's curvature, later understood through _ionospheric propagation_. It frames Marconi's achievement as the "very first DX" in amateur radio terms, defining DX as telegraphic shorthand for distance and _DXing_ as the hobby of receiving distant signals. The article also provides external links for further reading on Marconi's experiments and the science behind transatlantic radio signal reception.

Homemade receiver for 80 meters band. The receiver works very well (in fact better than some of its successors), especially the AGC makes listening to 80m QSOs a real pleasure. Sensitivity is not cutting-edge, but on a full-size short-wave antenna it is by fare sensitive enough.

This is a WebSDR receiver, located in Friedrichshafen, Germany (at Lake Constance) using a multiband dipol and a FUNCube Dongle Pro+.

A review of the Chinese version of uSDX USDR HF QRP Transceiver. Author made an extensive review of receiver and transmitter features.

Listen to HF communications via the KiwiSDR online receiver located in Badgad IRAQ locator LM23fh. This web receiver is running a MLA 30+ antenna and can be tuned easily on all HF bands from 10 to 80 meters.

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.

Amateur Packet Reporting System (APRS) operations often require compact, reliable solutions for transmitting position data, particularly for mobile or portable stations. This resource details the construction of the _Tiny Track-I_, a transmit-only APRS tracker designed for straightforward integration with a VHF radio and a Global Positioning System (GPS) receiver. It enables hams to broadcast their location without the complexity of a full-duplex TNC. The project outlines the printed circuit board (PCB) layout and schematic, based on an original design by N6BG, with a personal PCB drawing by SV1BSX. It includes specific component placement and notes an additional 10uF/10V capacitor (C5) for improved IC voltage decoupling, a modification not present in the original N6BG diagram. The unit connects to a computer or GPS via a DB9 female connector. This tracker is ideal for basic position reporting, offering a simple and effective way to participate in APRS networks. Its small footprint makes it suitable for vehicle installations or field deployments where space is limited, providing a **reliable 9600 baud** data stream for location updates.

VHF-UHF receiver covers from 25 to 800 and 900 to 2000 MHz in the following modes: AM, AM-W, FM, FM-W, FM-N, USB and LSB

The _RTL-SDR V4_ dongle offers a tuning range from approximately 500 kHz to 1.7 GHz, encompassing HF, VHF, UHF, and microwave amateur allocations, with direct sampling improvements for HF reception. This guide outlines two primary installation methods for _OpenWebRX_ on a Raspberry Pi: utilizing an official Raspberry Pi image or employing a Docker installation. It also provides specific recommendations for Raspberry Pi models such as the 3/3B+, 4, and Zero 2 W, alongside practical advice for antenna selection and placement to optimize reception. _OpenWebRX_ is an open-source, browser-based SDR software package that facilitates web-accessible radio reception. The setup results in a receiver featuring a live waterfall display and demodulation capabilities for AM, FM, SSB, and CW modes. This configuration can be deployed for public access or restricted to a private network, depending on the operator's preference. Further sections address common troubleshooting scenarios and offer tips for mitigating noise, ensuring a stable and effective SDR listening station. The _RTL-SDR V4_ also integrates improved front-end filtering and a software-switchable bias tee, enhancing its utility for various amateur radio applications.

A software defined receiver located in Tuscany Italy with a Windom antenna convering HF bands

A detailed review of the Icom IC-R75 30 kHz -6 0 MHz Receiver first introduced in 1999

Operating in a Single Operator Two Radios (SO2R) setup, especially with beverage antennas, often exposes the receiving radio's front-end to significant RF energy from the transmitting radio. This resource details a practical, homebrew receiver protection circuit designed to mitigate this risk. The core of the design involves a non-inductive 2W 22 Ohm carbon composition resistor in series with the RX antenna line, followed by two stacks of four fast-switching diodes (e.g., _1N914_) configured in opposite polarizations. This arrangement effectively clamps the incoming voltage to approximately 2.8 V peak-to-peak, safeguarding sensitive receiver input components. The series resistor plays a crucial role by absorbing excess power, preventing the diodes from exceeding their current ratings and potentially failing open, which would leave the receiver unprotected. The author, _N4KG_, measured up to 50 watts of coupled power between 80M slopers on the same tower, highlighting the necessity of such protection. The design is presented as a cost-effective solution to prevent damage to receiver input transformers, with the author noting successful protection of a receiver even after a resistor showed signs of overheating. This simple circuit can be integrated via a transverter plug, offering a robust defense against high RF input.

Manufacturer of software definded radio receivers, antenna switches, preselectors, antenna splitters based in Italy and USA

If your 756 has lots of noise with crackles and sweeping heterodynes, especially noticeable on AM, it may be due to a faulty electrolytic capacitor in the noise-blanker circuit

Homebrew Antennas, Transmitters, Receivers, Converters, Keyers and SWR/RF Current Indicators with photographs an excellent blog with many projects by VU2NAN

If You are using a separate receive antennas then you need a good protection circuit to eliminate the possibility of blowing out the receiver front-end while using these auxiliary receive antennas specially on low bands.

Stand Alone Software Defined Radio, direct sampling receiver from 30 kHz to 1700.00MHz continuous frequency range, LAN interface for remote access

Crystal receivers are radio receivers that work without a power supply or batteries. Gallery of some crystal radio projects