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DIY speakers, resources for custom speaker hombrewing

Maintaining vintage Eddystone receivers often presents unique challenges, as detailed by Victor Jenkins in his refurbishment of an EA12, where his deep understanding of RF circuits ensures optimal performance for daily shortwave listening. Similarly, Gerry O’Hara VE7GUH, a prolific contributor to the EUG website and a trustee, meticulously documented his restoration of an Eddystone S830/2, even addressing an unusual instability issue with a follow-up postscript article and YouTube videos demonstrating the fix. His work, along with numerous other articles on the "Restorations" page, showcases a master's approach to bringing vintage sets back to factory specifications or better. Beyond technical restorations, the EUG also shares compelling historical narratives. One such story recounts the discovery of a long-lost 78rpm recording featuring Eddystone Radio Ltd.'s founder, George Stratton Laughton, and other key figures discussing the company's wartime and post-war contributions to shortwave communications. This six-minute BBC production, transcribed into an MP3 file by Peter Carney, offers a rare auditory glimpse into the company's legacy, highlighting its role in supplying equipment to police, ministries, and expatriate British workers. The community aspect thrives through shared experiences, like Roger Trickett's anecdote about his Eddystone EC10, which has been continuously powered for 50 of its 54 years, traveling across continents and enduring various modifications. Another intriguing account from Roy GM4VKI details the "S640 Identity Crisis," where a seemingly standard S640 receiver turned out to be a masterfully engineered 80/20-meter SSB transceiver built into the original chassis by GI3ZX, showcasing incredible ingenuity from a bygone era of amateur radio.

A Kenwood TM-D710A microphone (Model MC-59) is producing crackling and intermittent, poor audio so John took a peak inside to have a look around.

Kenwood TS-950SDX ESSB audio mods by voodoo labs

Displays a placeholder page indicating the upcoming launch of a personal website for F5MSU Bruno. The content briefly notes the operator's interests, including amateur radio, genealogy, and motorcycling. While the site is not yet active, it provides contact information for inquiries regarding the future content. The page is presented in French, catering to a European audience interested in personal profiles of ham radio operators and their diverse hobbies. The resource is categorized under Ham Radio/Personal Pages/Europe, suggesting an intent to share DXing, contesting, and general operator profiles.

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

NEScaf: A Switched Capacitive Audio Filter

KF6SPI Technical blog, audio, hifi, car and ham radio topics

The _Touch CPO_ circuit offers a unique method for Morse Code practice, eliminating the need for a physical key. It leverages the versatile IC555 timer, configured as an astable multivibrator, to generate an audio tone. Users can adjust the tone's frequency by manipulating a 100 K variable resistor connected between pins 7 and 6 of the IC555, providing flexibility in the practice experience. Volume control is achieved via a 10 K variable resistor, while a 1 K Ohms preset at pin 4 of the IC555 allows for fine-tuning the touch plate's sensitivity. The design connects the touch plate to the base of a BC147B transistor, a configuration noted for its flexibility regarding the length of wire between the transistor and the touch plate. The author's prototype successfully used a 9 cm wire with a 3 x 6 cm aluminum plate. This project also suggests an alternative application as a touch-operated doorbell, demonstrating the circuit's adaptability. The design emphasizes simplicity and ease of construction, making it accessible for hams interested in DIY electronics.

Listen to Ingham County Michigan Public Safety, County Sheriff, Police and Fire

How-to decode and Display APRS Packets from WebSDR Audio using linux computer

A 12V powered, 4x15 Watt quad audio amplifier

RTTY transmissions with audio boards, can be transmitted either in FSK or AFSK mode. Learn differences between this two different modes by IK3QAR

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.

Weak Signal Audio 160m, choosing a headphone for weak signals reception

An excellent guide on choosing external audio equalizers by K3DAV

The Vintage Radio and Phonograph Society (VRPS) is a non-profit historical organization, incorporated in Texas, serving enthusiasts in the Dallas-Fort Worth area and surrounding regions. Its core mission revolves around the **preservation** and **restoration** of antique radios and phonographs, fostering a community for those with a general interest in early wireless technology and vintage audio equipment. The society actively supports the new radio/TV museum in Kilgore, TX, demonstrating its commitment to broader historical preservation efforts. Members engage in activities such as "Show and Tell" days, where they bring items for discussion, and participate in an annual convention. Events like the Spring Auction and the 2026 VRPS Convention, scheduled for October 23-25 at the Grapevine Convention Center, provide opportunities for members to connect, share knowledge, and acquire vintage pieces. The organization also highlights related events, such as the Houston Vintage Radio Association's 2026 convention.

A basic article on audio cables, electrical wiring, cable lenght, data cables.

Amateur Television (ATV) operations involve transmitting and receiving live or recorded video and audio signals over amateur radio frequencies. Unlike narrow-band modes, ATV utilizes a wider bandwidth to convey video information, often requiring specialized transceivers, antennas, and signal processing equipment. This mode allows hams to share visual content, demonstrate projects, or conduct video conferences, typically on VHF, UHF, and microwave bands due to the bandwidth requirements. The SwissATV resource focuses on the technical aspects and community engagement surrounding ATV within Switzerland. It covers topics relevant to setting up ATV stations, understanding signal propagation at higher frequencies, and participating in local ATV activities. The site serves as a central point for Swiss ATV operators to exchange knowledge and coordinate transmissions, fostering the growth of this specialized amateur radio mode.

When one starts in amateur television, one begins with a small simple transmitter and a small camera. But very quickly, one needs to transmit audio signals with the pictures, then comes a second camera

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 web site dedicated to the voodoo audio crew, a group of ESSB enthusiasts

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

Schematic diagram of a two tone audio oscillator by VK3YE

Delta Electronics Manufacturing, a global manufacturer, specializes in _RF connectors_, adapters, and cable assemblies, providing custom interconnect solutions with superior performance. Their Advanced Vertically Integrated (AVI) global facilities emphasize efficiency, quality, flexibility, and cost control across their product lines. The company serves diverse industries, including broadcast and audio, test and measurement, military, aerospace, and public safety communications. For instance, Delta supplies RF interfaces for military aircraft, satellite launch vehicles, and missiles, maintaining a long-standing QPL supplier status. Their field-tested RF interconnects are also crucial for two-way radios, base station equipment, and antenna systems in public safety applications, ensuring reliable performance in critical communication infrastructure. Delta's solutions extend to commercial aircraft and semiconductor manufacturing, where their RF interconnects power etch equipment, deposition equipment, and chip testing systems worldwide.

Troop I, Region 2 - Live Audio Feed Web Player

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

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

Article and video showing a technique to straighten Microbore copper pipe that is useful in antenna construction. This technique has been implemented to build a Quadrifiliar Helix antenna.

A homebrew project about a bluetooth interface to connect a transceiver to an audio headset.

JTAlert provides several audio and Visual alerts for WSJT-X & JTDX software. JTAlert generate audio and visual alerts for several alert conditions, logs automatically to several ham radio log books software like hrd dxkeeper,log4om, interoperates with web services and it supports dxlab suite.

Xggcomms specialise in producing cost effective, high quality CAT and Audio interfaces for Icom and Yaesu Amateur Radio Equipment. Our interfaces are fully compatible with a large range of CAT and Digital Mode control software.

This article shows how to make a mains filter that can be extremely effective in reducing and in some cases eliminating completely EMC from the electricity supplying your shack

The program sends morse code audio via sound card and can be used under Windows in Danish only

Extended Single SideBand is any SSB transmission that exceeds the audio bandwidth of common 2.9kHz SSB J3E modes by essb.us

Live police radio feed from Gippsland Police Region 5 Division Q1 and Q2. Victoria Australia

Remote Ham Radio via WebRTC Audio Raspberry Pi 3. Stream Transceiver Audio to and from the remote station though a Browser using WebRTC.

All about RTTY, including audio samples, rtty software, video exaples and rtty related links

An article by CT1BOH about recording amateur radio contests. Recording contests is a great tool to detect problems and improve operating efficiency

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.

The online Morse code translator and decoder provides functionality for converting plain text into Morse code and decoding Morse code back into text. Users can input text directly into a designated box for translation to Morse, with the tool ignoring characters that lack a Morse equivalent. Conversely, Morse code can be entered using periods for dots and minus signs for dashes, requiring a single space to separate letters and a forward slash to delineate words. The interface also supports direct Morse input via a button, where a half-second pause separates letters and a 1.5-second pause separates words. The resource details the historical context of Morse code, noting its invention by _Samuel F.B. Morse_ in the 1830s for telegraphy, and its continued use by amateur radio operators for recreational purposes and emergency signaling, such as the **SOS distress signal**. Guidance on learning Morse code suggests using online translators for practice and listening to amateur radio transmissions. The tool offers an audio playback feature for translated Morse, allowing users to hear the code at various words per minute (WPM) settings. It also includes a visual chart to aid in memorizing the dot and dash sequences for the alphabet.

Police Live Audio Feed from Elko City USA

How to improve performance of your audio using a home made speech processor. In this article the author describes how to make your own speech processor providing a PCB foil pattern and with a 60mm x 60mm board.

Article with answers to common questions as what cable types to user, cable length, how to join ends.

West Fire and Police - Live Audio Feed Virginia

W3FPR fixed level AF output fot the Elecraft K2

The BikeLoop antenna project details the construction of a double magnetic loop antenna optimized for VLF frequencies, specifically around 136 kHz. This innovative design incorporates two orthogonal loops, which significantly enhance reception capabilities. Key construction hints include utilizing lightweight bicycle rims for the antenna structure, making it easy to transport and set up in various locations. The document provides valuable mathematical and electrical insights into the antenna's performance, alongside practical reception tests conducted in the Italian Alps, showcasing its effectiveness in capturing various VLF signals, including Sferics and FSK transmissions. Proper setup is crucial for optimal performance. The project emphasizes the importance of grounding and avoiding interference from nearby electrical sources. The reception tests revealed the antenna's ability to capture a range of signals, demonstrating its practical application for enthusiasts interested in VLF reception and antenna experimentation. Overall, the BikeLoop serves as an excellent starting point for those looking to explore the world of VLF frequencies and enhance their antenna-building skills.

Technical Comments about Transmitter Intermodulation, Distortion, and ESSB (or Hi Fi Wide Fi SSB) audio or over equalization by W8JI

Documents S21RC's construction of an impedance transformer harness for a VHF/UHF cross yagi, utilizing 20m of _RG179_ cable. Details the creation of a DIY RF sampler with a -50dB sampling output, primarily for measuring HF radio PA section output with a Spectrum Analyzer, also applicable for _Pure Signal_ transmission. Chronicles the deployment of a 200m long beverage antenna for the _S21DX IOTA_ operation in 2022, positioned 2m above ground. Discusses the construction of a 3-element short beam for 10m to replace a previous 2-element antenna, with assistance from S21DW. Provides guidance on operating cheap _PA-70_ and _PA-100_ type Chinese SSPAs using IRF530 MOSFETs, emphasizing the necessity of a final LPF. Outlines the design and construction of a fully isolated interface for radio-to-computer connections, supporting various digital modes with isolated ground, audio transformers for IN/OUT, optical isolation for CAT/CIV, and isolated PTT/COS lines. Includes a log of software updates, such as the _HMI/TFT for NX8048K070_ and _2.1.14 Lite_ release with bug fixes for PEP hold and gradual watt decay.

Amplitude Modulation (AM) is essentially a mixing process where the audio modulating signal is mixed with the radio frequency carrier