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K8CU builds a classic 1967 QST semiconductor project during the 40th anniversary year of the original project publication.

This page describes an cheap RF signal source, a portable micro beacon, using a low cost temperature controlled crystal oscillator

The essentials of the parabolic reflector or dish antenna and its theory and design for high performance applications such as satellite transmission and reception as well as microwave links.

Microwaves articles, The Technology Voice of the Wireless World , need registration to access

Examines the Icom IC-2100H 2-meter mobile transceiver, detailing its operational characteristics and user experience. The review highlights the clear, easy-to-read display with internal labels, the button-filled microphone's functionality, and the rig's physical construction, including its weighty heat-sink and lack of a cooling fan. It also discusses memory programming, the unique amber-to-green backlight color options, and the radio's performance against _intermodulation_ in urban environments, noting it performs "pretty darn good" compared to other rigs. The analysis delves into a significant low-voltage cutoff problem, where the microphone ceases to function below approximately **12.6 VDC**, rendering the radio receive-only or causing it to stick in transmit. The author describes testing the voltage cutoff, observing it fluctuate from _12.38 VDC_ to 12.69 VDC. An update from Icom involved a "factory update" to the CPU's control code, which is strongly recommended for early-serial number units to prevent operational failure in low-power emergency scenarios.

RF-and Microwave Coaxial switches and relays

This is a prototype of the WA4DSY 56KB RF modem. It is intended for use on amateur packet radio networks. The modem generates RF in the 28 to 30 mhz range and requires and linear transverter to convert the signal to a UHF or microwave ham band

Application for the Apple Macintosh computer that provides a CW contesting interface for the popular MacLoggerDX loggging software. FKeyer runs on MacOS X and uses an external keyer such as the MicroHam CW keyer.

Enhanced SSB Audio (ESSB) is a specialized operating mode that extends the capabilities of traditional Single Sideband (SSB) voice transmissions. This presentation by K4QKY delves into the technical aspects of ESSB, discussing its advantages and the ongoing debates within the ham radio community regarding audio quality and bandwidth usage. ESSB aims to provide clearer and more natural-sounding audio, which can enhance the overall communication experience for operators. The presentation covers various topics, including microphone selection, audio processing techniques, and the importance of proper equalization. It also addresses the controversies surrounding ESSB, such as the potential for interference and the debate over whether it strays too far from traditional SSB practices. By understanding these elements, amateur radio operators can make informed decisions about their audio setups and contribute to discussions about the future of SSB operations.

Modelling an horizontal Loop antenna at 3.5 MHz

Microwave general web site by G3PHO

Electro-Voice Model 664 (EV 664) cardioid microphone, wiring diagram, pictures and data sheet

Dish antenna and its theory and design for high performance applications such as satellite transmission and reception as well as microwave links. Parabolic Reflector Antenna: Dish Antenna The parabolic reflector antenna which is often called the dish antenna provides an antenna solution applicable for VHF and above where high gain and directivity are needed for all type of radio communications and radio reception.

Satellites and Oscar 40, Microwave and ATV

Cloudlog is a web-based amateur radio logging application built with PHP and MySQL, supporting station logging activities from HF to microwave. It integrates with companion tools for CAT control and automation, offering a flexible solution for managing QSO data. The application provides a self-hosted platform for amateur radio operators to maintain their logbooks, facilitating interaction with various ham radio operations. Its open-source nature allows for community contributions and customization, enhancing its utility for diverse operating preferences. Originally started by Peter, **2E0SQL**, Cloudlog was designed to enable simple interaction with the Ham Radio Deluxe logbook using MySQL.

Low signal, noise-high AC gain preamplifier

A hombrew QRP transceiver for 40 meter band with many pictures, circuit and sound recording of some QSOs made with this Rig consisting of 5 transistor and one chip.

Draw static response time of an audio system. Originally intended for loudspeakers tests, is also a great tool for looking at microphone equalisation.

Kenwood Ibérica's online presence details their extensive product line, including the NEXEDGE NXDN and DMR digital radio systems, alongside traditional analog offerings. The site categorizes transceivers by mode, such as HF / Todo Modo (All Mode), and portable/mobile VHF/UHF units, catering to various amateur radio operating preferences. This includes specific accessories like batteries, chargers, microphones, and programming cables, essential for maintaining and customizing radio equipment. The Spanish portal also highlights Kenwood's broader electronics portfolio, extending beyond amateur radio. This encompasses car electronics, featuring navigation and multimedia systems, as well as marine receivers and speakers. The product range covers everything from CD and CD-less car receivers to power amplifiers and DashCam/RearCam solutions, demonstrating the brand's diverse market reach. Beyond communications gear, the site presents home audio systems, including all-in-one receivers and portable party speakers. This breadth of offerings underscores Kenwood's long-standing presence in both the consumer electronics and two-way radio sectors, providing a centralized resource for product information and support.

The HotPaw Morse Code Decoder application for macOS processes audio input to transcribe Morse code characters into text. It presents both an audio spectrum graph and a tone amplitude graph, which aid in configuring a narrow band audio filter. Operators can set the audio filter for tone frequencies between 400 and 1600 Hz, optimizing reception for various CW signals. The software offers user-configurable settings, including WPM dot/dash speed detection, a noise threshold level, and the option to use Farnsworth timing for inter-character spacing. The Morse code WPM detection automatically adapts from approximately 8 to 40 WPM, with a lock feature for the estimated speed. A High Speed WPM Mode is available for code speeds ranging from 40 to 80 WPM, catering to faster CW operators. The application's decoding performance is influenced by signal level, signal-to-noise ratio, frequency and WPM stability, keying quality, and proper configuration, with an initial learning phase required for WPM estimation to stabilize. An external microphone or line-in may be necessary for optimal performance on some MacBook models to mitigate fan noise or room reverberations. Version 1.4.4, updated on November 11, 2021, includes compatibility improvements for newer macOS releases. The developer, Ronald Nicholson of HotPaw Productions, does not collect any user data from the application.

This web article by VK3BLG details the construction of an experimental 70cm (432 MHz) circularly polarized patch antenna, intended for satellite communication. The resource provides dimensions, feed point specifications, and impedance matching considerations for a single patch element, with discussion extending to array configurations for circular polarization. Construction involves a copper patch element on a dielectric substrate, fed via a coaxial cable. The design is based on information derived from AO-40 satellite antenna specifications, focusing on achieving circular polarization for satellite reception. The article includes specific dimensions for the patch and feed points, along with impedance values. Validation is implied through on-air satellite reception reports, with initial signal reports of **1 S-point above noise** for AO-40 beacons using a grid reflector, improving to **3-4 S-points above noise** with a 2-turn helical feed. The author references a _NanoVNA_ for impedance measurements and discusses the relationship between slot and dipole antennas in the context of patch design. DXZone Focus: Web Article | 70cm Patch Antenna | On-Air Satellite Reception | Circular Polarization

Shows which beacon is currently transmitting on the selected radio band Displays information about transmitting beacon Informs about direction and bearing from users position towards transmitting beacon

The decibel (dB) is a logarithmic unit used to measure sound level, widely applied in electronics, signals, and communication to describe power, sound pressure, voltage, or intensity ratios. For instance, a 3 dB increase signifies a doubling of power, while a 10 dB increase represents a tenfold power multiplication. Sound pressure level is calculated as 20 log (p2/p1) dB, reflecting the square relationship between power and pressure. Standard reference levels, such as 20 micropascals for sound pressure in air, establish absolute dB values, where 0 dB corresponds to the reference level, not an absence of sound. Human hearing sensitivity varies with frequency, necessitating A and C weighting filters (dBA, dBC) in sound meters to approximate the ear's response. The phon unit relates to dB via psychophysically measured frequency response, with 1 kHz readings being identical. The sone unit quantifies perceived loudness, where 1 sone equals 40 phons, and a 10 dB increase above 40 phons roughly doubles perceived loudness. In radio, dBi measures antenna gain relative to an isotropic radiator, crucial for anisotropic radiation patterns.

Japanese electronic parts online shop offer a wide range of products, from microchip pic to leds and batteries to any kind of connectors

A good reference site for antique radio, bakelite paskon plastinc decription, microphones picture and antique radio gallery

PIC micro controller based frequency counter with LCD readout

Millimeterwave/Microwave transmission lines and components, Cryogenic temperature application transmission cables and systems, Permittivity(Dielectric rate) and Permeabillity measurement systems, Antennas, Radar systems

The North East Weak Signal Group (N.E.W.S.) website serves as the digital hub for an ARRL-affiliated regional club dedicated to _weak signal_ work across the VHF, UHF, and SHF spectrum, from 50 MHz up to light. It provides essential information for members and prospective enthusiasts, including the club's constitution and by-laws, details on officers and the board of directors, and a calendar of meetings and events. The site also features an application for membership, information on dues, and a membership roster, fostering a sense of community among its over 100 members. A significant feature of the site is its extensive archive of conference papers, including proceedings from the _Eastern VHF/UHF/Microwave Conference_ dating back to 2009. These papers cover a wide array of technical topics relevant to weak signal operations. The site also lists _50 MHz Beacons_ and _144 MHz and up Beacons_, along with links to other VHF and above resources, providing practical tools and knowledge for operators interested in pushing the boundaries of amateur radio communication.

Boom Microphone Headsets for use on amateur transceivers- assembled and kit form.

Ham radio shop for APRS digipeaters WX3in1, RPTC, GSM devices, SDR software defined radio producrsa, APRS trackers and GPS Receivers based in Poland

A family of small size QRP SSB transceivers for the 15 MHz. Includes a cigarette pocket size QRP transceiver and a larger shirt-pocket transceiver.

70 MHz transverter, 4m band, by G3XBM

Accurate frequency measurement is crucial for amateur radio operators, particularly when building or troubleshooting transceivers and test equipment. This resource details the construction of a _PIC microcontroller_-based frequency counter, providing a practical solution for precise frequency display. The design incorporates an LCD readout, offering clear visual feedback of measured frequencies. The counter can operate as a standalone unit, useful for general bench testing, or be integrated directly into a receiver. Its built-in offset functionality allows for seamless integration, enabling the display of the received signal frequency rather than the intermediate frequency. The project focuses on accessible components and construction techniques, making it suitable for homebrew enthusiasts. Key features include a measurement range up to **50 MHz** and a compact form factor.

Loop Antenna Basics and Regulatory Compliance for Short-Range Radio

tk3 is open source software designed for the ICOM IC-R3 receiver. Though tk3 is intended chiefly for Linux, MacOS X, and BSD users, it will work on Microsoft Windows too.

XLT Communications two way radio accessory manufacturer, microphones, headsets, belt clips, earpieces, radio cases

Australia's largest range of Electronic Kits & Components In Stock for the Radio Experimenter, ATV, microwaves, HF Band pass filters

Graph of the frequency response of some of the legendary microphones favoured by radio hams

The ÖVSV website provides extensive resources for Austrian radio amateurs, including details on its nine **Landesverbände** (regional sections) and the Austrian Military Radio Society (AMRS). It features information on licensing, legal frameworks, and **band plans** for both HF and VHF/UHF operations. The site also covers various amateur radio activities such as contests (HF, VHF/Microwave, Alpe-Adria, SOTA, ARDF), technical projects like WRAN, and educational content explaining what amateur radio is and how to become a licensed operator. Recent news items highlight events like the "Laa Funk '26" exhibition, the "OE5XLM" club station's participation in the CQ WW Contest, and the "International Marconi Day 2026" activation by "OE26M" from Küniglberg. The site lists upcoming events, including a 160m OE-Aktivitätsrunde, a seminar on Baluns/Ununs, and various club meetings and flea markets. Membership is facilitated through regional sections, and the site emphasizes amateur radio's role in independent communication during crises.

A simple home made desk microphone project that can be fitted into a small plastic project box

Provides technology and solutions for the electronic test and measurement, optical, rf and microwave, wireless, wired, telecommunications. Make Frequency Counters, Antenna and spectrum analyzers, power meters, signal generators

A 200 kHz bandwidth digital transmission system for image transfer in the Amateur Service is under development, specifically targeting VHF allocations. John B. Stephensen, KD6OZH, leads this project under an FCC Special Temporary Authority (STA) valid until September 10, 2006, authorizing emissions up to 200 kHz bandwidth in the 50.3-50.8 MHz segment. Current regulations typically limit bandwidths to 20 kHz on VHF amateur bands, making this STA crucial for testing wideband digital modes. The modem, a modified **OFDM** (Orthogonal Frequency Division Multiplexed) unit, was initially tested on the 70-cm band. It splits a high-rate data stream into multiple low-rate subcarriers to mitigate multipath echoes. The system uses a DCP-1 card with a Xilinx XC3S400 FPGA and Oki Semiconductor ML67Q5003 microcontroller. The transmitter, located at 36d 46m 30s N, 119d 46m 22s W, generates 150 WPEP into an 8 dBi gain vertical antenna, while the mobile receiver uses a Ham-stick. Three data formats for 50, 100, and 200 kHz channels are being tested, with encoded data rates of 96, 192, and 384 kbps. Verilog code for the VHF OFDM modem is 95% simulated, with modifications from the UHF version including increased filter coefficient precision and a change from Ungerboeck **TCM** to BICM for improved performance over fading paths. Final tests will involve one-way over-the-air measurements of bit error rates and coverage area.

A complete guide to undestand and know how electret condensor microphone elements works by K3DAV

K8GP web site, home of the Grid Pirates Contest Group.

CAT decoded Band decoder, remote Antenna switch

Manufacture of microwave directional, omni directional, sector and multisector antennas with horizontal polarization for ISM band 2,4 GHz

tk7 is open source software designed for the ICOM IC-Q7 walkie-talkie. Though tk7 is intended chiefly for Linux, MacOS X, and BSD users, it will work on Microsoft Windows too.

Microhams is a dynamic organization of hams in the Puget Sound area. The club includes a broad range of people from our local tech industry who participate in just about every aspect of our hobby.

About basics of the horn antenna used for many rf microwave antenna applications.

The .64 wavelength antenna is presented as a single-element design offering superior gain, specifically noted for achieving at least 0.8 dB/d more gain towards the horizon compared to a 5/8 wave element. The discussion emphasizes identifying specific hardware revisions, defining clear operating goals for various signal paths like receiving, transmitting, and data, and establishing a baseline measurement before any modifications. This methodical approach ensures accurate assessment of antenna performance. Practical application involves a structured testing methodology where only one variable is altered at a time to ensure valid comparisons. The article suggests exploring related technical paths, referencing components like the R820T Rafael Micro and Mirics MSI3101 SDR USB Dongle, and encourages a holistic view of the radio system from antenna to operator. This systematic process helps hams optimize their antenna systems for improved DXing and contesting.