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Modification to an old cellular phone base station modules, with a fairly reduced output power (10 watts or so), the stock power amplifier modules will cover the 2.3 GHz and 2.4 GHz amateur radio bands.

Building an End-Fed Half-Wave (EFHW) antenna from a kit, as detailed by Frank Bontenbal, PA2DKW, with process photos by Bob Inderbitzen, NQ1R, offers a practical approach for hams. This specific kit, a collaboration between ARRL and HF Kits, targets 10, 15, 20, and 40 meters, making it a versatile option for HF operations. Unlike a center-fed dipole, the EFHW is a half-wavelength antenna fed at one end, which simplifies deployment, particularly for portable use. The construction guide meticulously outlines the assembly of the 49:1 impedance matching network, crucial for transforming the antenna's high impedance (around 2,500 Ohms) to a transceiver-friendly 50 Ohms. Steps include preparing the enclosure by drilling holes for the coaxial connector and antenna connections, followed by the precise winding of enameled copper wire onto a toroid to create the transformer. The guide emphasizes careful insulation removal and soldering for reliable connections. Final assembly involves integrating a 100 pF capacitor for higher band compensation, soldering the transformer's primary and secondary sides, and conducting SWR tests with a 2K7 resistor or a half-wavelength wire. The document also provides examples of wire lengths for different bands, such as 16 feet for 10 meters or 66 feet for 40 meters, demonstrating the transformer's adaptability for various half-wavelength configurations.

The MiniPA Linear Amplifier for HF page discusses the popularity of QRP for HF among ham radio operators, such as those using the Yaesu FT818 or low power SDR transceivers. It explores the use of cheap kits from eBay or Chinese suppliers to build a 70-100W SSB amplifier using IRF530 MOSFET transistors. The article provides a review of the MiniPA design, including its features, components, and assembly process. It also highlights the importance of using a heatsink and forced air cooling for optimal performance. This page is useful for hams looking to enhance their HF rig with a budget-friendly amplifier.

The Panther Amateur Radio Club is the student run radio club on Pitt's campus. The club's repeater sits 535 feet above the campus on top of the Cathedral of Learning.

The Steampunk-styled air cannon sending tennis balls flying at 500 mph!

GB3SH, the Southampton and South Hampshire 2m repeater

This project revisits a minimalist software-defined radio (SDR) receiver built using a Raspberry Pi Pico, now optimized for simplicity and affordability. Designed for breadboard assembly with through-hole components, the receiver covers 0–30MHz, supporting CW, SSB, AM, and FM modes with an OLED display and spectrum scope. Key improvements include enhanced frequency accuracy, reduced op-amp saturation, and lower-cost components. Powered by three AAA batteries, it delivers standalone operation for global signal reception. Ideal for hobbyists, the design fosters experimentation and is documented with firmware and schematics available online.

An article on amplitude modulation (AM) operation on VHF bands.

Review of the excellent ICOM IC-R8600 Wide Band SDR communications receiver. Featuring Direct Sampling SDR below 30 MHz Hybrid Superhet / SDR above 30 MHz.

Online antenna parts store, providing many accessories for amateur radio antenna homebrewing. Boom joiners, aluminium parts, elements clamps, filters, ferrites, fasteners, plasti caps, dipole elements. Based in UL

A home made battery charger 110-220 v AC providing from 1.25-24 v DC Adjustable at 8 Amps output power, with Short Circuit Protection Over Load and over charge Protection.

In this survey some practical experiences were written down, that might become handy in case you are contemplating purchasing such an amplifier.

NPR (New Packet Radio) is a custom amateur radio digital protocol, designed by F4HDK to transport bidirectional IP trafic over radio links on the 70cm band. This IP protocol is optimized for point-to-multipoint topology, with the help of managed-TDMA. Bitrate is up to 500kbps. Home Made modem has a built-in ethernet port to connect to PC. To boost power a DMR amplifier is required to reach 20W. This project is an extension of HSMM - Hamnet - AREDN networks

The **Nilex Morse Tutor** is an HTML5 web application designed to teach Morse code reception, adapting to user proficiency by adding new characters as readiness is detected. It prioritizes practice on less familiar letters, numbers, symbols, words, and phrases, while minimizing repetition of already mastered elements. The program offers multiple learning orders, including "Q7ZG..." (Ward/Jim's), "KMRS..." (PU5EPX/Koch), "KMUR..." (lcwo.net), "AENT..." (CWops CW Academy), "TEAN..." (Stephen C Phillips), "ANET..." (Vic VE3YT), and "ETI5..." (Ham Whisperer), alongside an alphabetical option. Users can customize the learning experience by enabling or disabling automatic progression, and selecting specific content categories such as numbers, symbols, words, phrases, QSO bits, Ham Radio Bands, X+Y=Z math, and units. Audio settings are adjustable for volume, speed (WPM), tone frequency, and keyshape/keying envelope, allowing for a personalized auditory environment. The interface provides visual feedback with blue bars indicating practice emphasis and gray bars for reserved characters, with clickable bars for manual character selection. Developed by "Nosey" Nick Waterman, VA3NNW, this tutor is based on earlier versions by Jim Wilson and a 1977 QST article. A significant October 2019 rewrite incorporated a new WebAudio sound library by AwesomeAidenW, improving offline functionality and mobile support. The content library was expanded to include 3000 top Google words, 2284+ General Service List words, ISO country codes, capital cities, US states, Canadian provinces, UK counties, common names, periodic table elements, quotes, Q-codes, electronic components, ham abbreviations, and example call signs. The software is distributed under the GNU GPL V2 license.

How to easily receive and decode CubeSat telemetry

2m 70cm 23cm Low noise Amplifiers, 3 Low noise amplifiers Outdoor unit with DB6NT parts completed.

Learn how to design and analyze a folded trifilar antenna for the 80-meter band. Based on a description from RAF antennas between 1940 and 1970, this article provides step-by-step guidance on modeling the antenna, calculating resonance frequency, adjusting dimensions, and verifying performance. Perfect for hams looking to improve their antenna setup for better transmission and reception on the 80M band.

Amateur radio courses teach that in amplitude modulation, sidebands arise. This can be proven mathematically, and nowadays with an SDR one can easily see them.

Nuand bladeRF 2.0 Software Defined Radio (SDR) 47MHz to 6GHz, 2x2MIMO, 61.44MHz sampling

Coil64 (Coil32) is a versatile tool for calculating single-layer inductance coils used in various electronics, such as matching circuits and amplifiers. The online calculator enables users to estimate the number of turns, winding dimensions, and select the appropriate wire type for home-brewed RF inductors. It employs Bob Weaver's equation, factoring in wire corrections, and allows for the calculation of Q-factor and self-capacitance. Coil64 is compatible across multiple platforms, including Windows, Linux, Mac-OS, and Android.

Since 2012, the RTL-SDR is the simple and cheap way to give Software-Defined Radio a try. For about 25 euro you get a receiver covering much of the VHF and UHF range, and by either adding an upconverter, or using the direct sampling option, also the HF bands. They are so cheap because they are mass-produced as DVB-T receivers.

Due to the nature of PSK it is imperative that you maintain a very clean signal. In this page you will find examples of a clean PSK signal and one with excessive splatter, and a short guide on how to properly adjust your transmitter to assure a clean trace

A simple 2-tone-generator for testing the linearity of SSB transmitters. This device is as simple as useful. With 2 transistors and an oscilloscope, it is fairly easy to test the linearity of your SSB transmitter. The 2-tone-method is a standardized test method that can be used to determine the maximum output and the amplification characteristics of a sideband transmitter.

his article explores the construction of a PL519 tube amplifier, utilizing Ulrich L. Rohde N1UL's insights. Focusing on a modest 25W continuous output, the design ensures robustness with forced air cooling. The detailed breakdown covers input matching, screen grid voltage generation, bias adjustment, anode power supply, heater power supply, and monitoring circuitry, providing valuable guidance for ham radio enthusiasts.

Notes, hints and tips on starting with morse code, how to approach learning the code, how and when to get on the air, learning and using abreviations, common Q-Codes and a sample morse code QSO.

KB3IFH Full Color quality QSL & Eyeball cards. Free custom design & imaging scanning, based in Hampstead, MD USA

Here are some hints and tips for construction of a good preamp for satellite work.

This PA has been designed by Sergey EX8MLE and uses three Mitsubishi RD100HHF1 FETs, Frequency Range 70 to 72 MHz

Over 15 amateur radio bands, from 160m to 70cm, are supported by the _DXTRON_ web cluster, providing real-time DX spotting information. This service integrates directly with the _QRZCQ_ API, allowing users to monitor activity across various modes including CW, Phone, Digi, RTTY, SSTV, and SAT. DXTRON displays critical spot data such as timestamp, spotter callsign, frequency, mode, DX call, and remarks, along with geographical details like Grid, DXCC, ITU, CQ zone, continent, and country. Developed by _DO5SSB_, DXTRON v1.42 offers a user-friendly interface for filtering spots by band and mode, catering to both casual DXers and serious contesters. The platform is designed for accessibility, providing a clear overview of current propagation conditions and active stations worldwide. This web cluster is a practical tool for hams seeking to identify rare DX, track contest activity, or simply observe band conditions. Its reliance on the QRZCQ API ensures a consistent flow of up-to-date spotting data, making it a reliable resource for real-time operational awareness.

This article explores the conventional wisdom about antenna height in amateur radio operations, challenging the common belief that "higher is always better." Through practical examples and computer modeling, it examines how low-height antennas like Beverage antennas, VP2E, and End-Fed Half Wave (EFHW) configurations can perform effectively in various scenarios. The analysis includes radiation patterns and efficiency considerations for antennas at different heights, particularly focusing on portable operations. The article demonstrates that while height affects antenna performance, lower installations can still provide practical and efficient solutions for specific applications, especially in portable and QRP operations.

Removing disturbing RFI from the Behringer HA400 Headphone Amplifier, using ferrites and capacitors soldered in the main circuit board of the small amplifier.

A picture gallery of a home-brew RF Power amplifier made with 3CX3000

This project explores the construction and performance of an Alford Loop antenna as an alternative to a round loop. The Alford Loop, symmetrically fed at opposite corners, behaves like a small loop despite its larger size. Built using PVC pipes and secured with tire wraps, the antenna integrates an LZ1AQ active amplifier for optimal performance. With deep nulls in its horizontal radiation pattern and improved resonance characteristics, this design has significantly outperformed previous active antennas in reception quality.

Amateur radio blog about Homebrew equipment,ham radio antennas, satellites, QO-100 operations, rf amplifiers, 2m ldmos amplifier, 70cm ldmos amplifier, 23cm ldmos amplifier

This is a power amplifier project for a RF 600W 1.8 MHz to 70 MHz linear amplifier including a Low Pass Filter. Projects includes schematics, pictures, PCD design, fans details, note on PA ferrite chokes and assembling instructions

A large collection of morse keys classified by country with samples from all over the world

eHam reviews of the Alpha 87A RF power amplifier

This page by Lajos Hoss, HA8HL, provides a detailed guide on how to build a simple direct receiver using FT8QRP CAT control support. The author shares his experience in making QSOs with FT8, WSPR, and JT65 modes during the Covid-19 lockdown. Modifications to the VFO, transmitter design using BD329 transistor Class A amplifier, and the challenges faced in achieving clean output signals within legal limits. This project is interesting for those hams that are interested in experimenting with DIY transmitter projects and understanding CAT control support for various amateur radio modes.

Optimizing a QRZ.com page involves adding essential callsign data, ensuring correct _Maidenhead Gridsquare_ and DXCC information in the Detail tab, and populating the Biography section with relevant station details. Operators should include their operating conditions, specific country references like WAB square, club affiliations, and detailed QSL information, specifying preferences for electronic confirmations (e.g., _LoTW_, Clublog) and paper QSLs (direct, bureau, SASE). The guide emphasizes the importance of accurate data for electronic logging software integration, which fetches Gridsquare, DXCC, and CQ/ITU zones to populate contact logs correctly. Further enhancements include leveraging the QRZ.com photo gallery for images and setting a primary image that logging software like _Log4OM_ can display. Advanced customization involves embedding external services via HTML source code. Examples include integrating HamAlert for DX Cluster spots, Clublog for log searches and Online QSL Requesting (OQRS), and Parks on the Air (POTA) statistics widgets from WD4DAN. Additionally, live weather information from Weather&Radar and solar data banners from HamQSL can be embedded, providing real-time environmental context for visitors to the QRZ page. These embedded tools require creating accounts on respective platforms and often involve copying specific source code snippets into the QRZ biography's HTML editor, ensuring callsign placeholders are updated.

Open source code to add CQ Zone, ITU Zone and Maidenhead Locator to your leaflet maps.

FTDX-9000MP + HDSDR + Ham Radio Deluxe. An IF Based Direct Sampling Panoramic Adapter for the Yaesu FTDX-9000

TFilter is a free online tool for designing linear phase, optimal, equiripple finite impulse response (FIR) digital filters. It utilizes the Parks-McClellan algorithm implemented in JavaScript. Users can specify the sampling frequency, desired number of taps, passbands, and stopbands to generate a filter. An example configuration is provided for easy testing.

Showcasing German engineering, ANjo Antennen develops and manufactures a diverse portfolio of amateur radio and commercial antenna products. Their offerings span a wide frequency range from 1.8 MHz to 3000 MHz, emphasizing electrical and mechanical precision for longevity. The company actively participates in events like FUNK.TAG Kassel, providing opportunities for direct engagement and order pickup. ANjo's product line includes high-performance **Yagi antennas** optimized for Tropo and EME, along with multi-stacked Quad antennas designed for contest operations, featuring wide horizontal and narrow vertical beamwidths. They also produce circularly polarized satellite antennas, some with switchable LHCP/RHCP, leveraging their commercial satellite antenna expertise. Beyond amateur applications, ANjo provides flexible, custom antenna solutions for commercial sectors such as BOS, EMC measurements, and telemetry. Their commitment to quality is evident in the Premium-Line antennas, which utilize **1.4301 (V2A) stainless steel** for mast clamps and connectors, ensuring durability and corrosion resistance. They also offer end-fed HF multiband wire antennas, known for their compact footprint and discreet installation.

World Radiosport Team Championship, Germany July 12-16 2018

Hostilog, developed by DF1LX using Python 3.5 and PyQT5, is a logging application designed for high-speed QSO data entry, achieving rates of 300–400 QSOs per hour from handwritten logbooks. The software prioritizes keyboard input, minimizing mouse usage for efficiency. It incorporates a cluster window with RegEx filtering capabilities and facilitates UDP transfer of QSO data to _DXkeeper_ from the _DXLab Suite_. The program supports basic rig control via _Hamlib_, with configuration examples provided for radios like the TS-590S using `rigctld`. Hostilog can process 50,000-line ADIF files in under 10 seconds and includes features for combining and sorting ADIF data. While primarily a Windows application, it runs under _WINE_ on Linux, with specific notes on Ubuntu compatibility. Recent updates, including a version from August 28, 2024, address bugs and improve UI, with documentation available in both German and English.

JBOT stands for Just a Bunch of Transistors. It is a simple, stable and easy to build 5 watts linear amplifier build out of a bunch of ordinary low power NPN transistors.

The *SPACE* Amateur Radio over Internet Protocol (RoIP) system offers public audio transmissions from NASA Mission Control and astronauts, primarily for educational purposes. This service streams NASA public media sources, including *Artemis II* and the ISS public audio channel 2 feed, which predominantly features English communications. Astronaut activities on the ISS typically occur between 0700 UTC and 19:00 UTC, with transmissions most common during early mornings USA time, alongside special events such as launches or spacewalks. Users can connect to the live stream via EchoLink to the *SPACE* conference, via IRLP to the 0100 experimental reflector, or via Allstar to node 516221. EchoLink connections utilize the GSM CODEC, while IRLP and other connections default to uncompressed or u-law CODEC. The service notes that long periods of silence are common, and NASA audio sources can be periodically unavailable or noisy. Daily recordings of these transmissions are published at space.rfnet.link/recordings/, available as .ogg audio files for direct playback or .m3u8 playlist files for network streaming in applications like VLC. Each playlist file provides a list of timestamped audio transmissions, allowing users to review specific segments of interest.

Method, Units of Measure, and the Dipole Standard of Reference. This article helps in understanding where does beam gain come from in directional aerials like in example Yagi antennas.

After a storm damaged the antenna, W6AER replaced it with a pre-made capacitance hat from DX Engineering. Using hose clamps and conductive grease, he ensured durability. Experimenting with radials and a coil, he aimed for better performance and resilience.

Arduino/ATtiny Based (Ham Radio) ICOM CIV to Yaesu BCD Band Decoder. Build a ICOM CIV to Yaesu BCD Band to automatically band switch the Yaesu Quadra Amplifier.