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The basics of radio receiver dynamic range performance used for specifying the performance of radio receivers used in radio communications systems.

Abbreviations used in CW operation

Next Generation Beacon hardware platform encompasses both analog and digital modes, i.e. CW FSK and MGM in a mixed mode configuration. The advantage of the mixed mode is that humans can decode the CW FSK by ear and the MGM can be decoded by computers way below what is audible. Therefore the MGM can be used for pre-human-conditions or early warning monitoring.

This versatile broadband amplifier is used in several DX Lab projects.

This resource is an online tutorial focused on setting up the Raspberry Pi for amateur radio applications. It covers the installation and configuration of various software packages tailored for digital communications and protocols, including _Packet Radio_ with Hamlib and Direwolf, as well as data modes like FLDigi and WSJT-X. The guide also details the integration of hardware components such as GPS clocks for time synchronization and real-time clocks for enhanced functionality. Users will find instructions for installing software like GPredict for satellite tracking and GQRX for software-defined radio (SDR) applications. The tutorial emphasizes practical steps, including the use of command-line inputs in the Raspberry Pi OS terminal, and provides troubleshooting tips for common issues such as faulty SD cards or insufficient power supplies. Operators are encouraged to explore various applications, including APRS iGates and WSPR beacons, to enhance their ham radio experience. The material is designed for licensed amateur radio operators with basic knowledge of electronics and computing.

Brugtgrej presents a Danish online classifieds platform specifically for amateur radio operators and electronics enthusiasts. The platform facilitates the buying and selling of used equipment, including transceivers like the Icom IC-7410, various components such as X'TAL FILTER FMT-15A and TRANSISTOR 2SC3019, and accessories like Sadelta microphone capsules and SMA to SMA extenders. Users can post free advertisements for items they wish to sell or acquire, covering categories beyond amateur radio, including antique radios, military radios, and radio tubes. The site lists active advertisements, with 3136 online ads and 167 online users at the time of analysis, indicating a dynamic marketplace. It also features a forum for community interaction, discussing topics like repeater rings on 1297 MHz and FT8 activity. The platform's structure supports both 'Sælges' (for sale) and 'Købes' (wanted) listings across its various sections. Specific items observed include a Miniwatt pentode 4689, various capacitors and coils, and general electronic components, demonstrating the breadth of offerings available to the amateur radio community.

Presents a personal blog, "QSL, maraca!", maintained by Luiz Belem, PY1UR, detailing his amateur radio endeavors. The content includes posts on station setup, operating experiences, and general ham radio topics, reflecting the perspective of an active DXer and contester. The blog serves as a digital logbook and platform for sharing insights with the amateur radio community. Documents PY1UR's participation in various on-air activities, showcasing his QSL card collection and providing narratives behind specific contacts. It offers practical insights into antenna configurations and radio equipment used, demonstrating effective strategies for achieving **DX contacts** and improving station performance. The blog's entries provide a historical record of PY1UR's _amateur radio journey_.

The antenna almost repeat the design of the Car Antenna however instead of aluminum tubes it was used copper wire in plastic insulation in diameter of 2- mm (12 AWG).

IC706_BKT CAT is used to control the transceiver Icom IC-706, IC-706MKII IC-706MKII/G and IC-718 from the personal computer. Works on Windows and is available in free and free donation version

A linear regulated power supply 2A, 20 V designed mainly to get used to soldering and have something usefull as final result.

The details of the spark gap transmitter and its history: how it was invented, developed and used.

There are many many abbreviations used for words on CW, ranging from commonly used abbreviations like B4 for Before or TU for Thank You to very obscure abbreviations known only to the one using them.

Article on propagation basics. The ground wave used for radio communications signal propagation on the long, and medium wave bands for local radio communications

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

PilotMORSE is a great home solution for private pilots or aspiring professionals who want to hone their Morse code skills used to identify VORTACs, localizers, and marker beacons. PilotMORSE takes you through the alphabet with an advanced neural network algorithm that adjusts the pace of presentation based on your responses.

All the essentials about the Dip Meter or Grid Dip Oscillator used for many RF measurements including detecting resonance, locating RF emissions, and making many RF measurements.

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.

Wondering whether human body could be used as an antenna.

An article by microHam about guidelined to eliminate problems caused by RFI

Electronic keyer by pressure sensor. SEN-09673 is used for detecting touch.

Experimental Stations Run by W1TAG WD2XES has been used to study LF antenna design, propagation and communication modes. Signals from WD2XES have been copied as far away as Russia.

Articles on the correct placement of ferrite noise suppressors are common, but little has been written about the different options and where to buy them. This page contains an interesting comparison of several ferrite types used to reduce RFI.

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.

NEC models are used to explore the GR5V and ZS8BKW optimizations. A third optimization is also rediscovered. The effect of fixed lengths of 75 ohm coax are explored. A link to the NEC model is provided.

This circuit stores a morse code message as bits in an EPROM chip, the message controls a relay that keys a CW morse code transmitter. An Arduino processor can also be used in place of this circuit, that eliminates the need to build the circuit and program an EPROM.

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

Approximately 524,475 Brazilian amateur radio operators are cataloged within this resource, offering a comprehensive database for the South American region. Each entry includes geographical coordinates, enabling users to visualize station locations directly within Google Earth. This functionality supports DXers in identifying potential contacts and understanding propagation paths relative to specific Brazilian QTHs. The platform serves as a digital callbook, primarily focused on the Brazilian amateur radio community. It facilitates the lookup of callsigns and associated location data, which is crucial for award tracking, contest planning, and general operational awareness. The integration with mapping services provides a visual dimension to traditional callsign databases, enhancing the utility for operators interested in geographical aspects of radio communication.

The P4 Aruba Callbook, last updated in 2010, serves as a directory for amateur radio operators active from the Caribbean island of Aruba. It meticulously categorizes P4 callsigns into several types: **P41-** for special resident calls valid for one month, **P43-** for permanent resident calls renewable annually, **P49-** for permanent visitor calls also renewable annually, and **P40-** for temporary visitor calls valid for one month, often used in contests. The resource notes that obtaining a permanent visitor callsign requires passing a local examination. The callbook lists numerous specific callsigns, including their QSL routes, operator names, and sometimes addresses or activation dates. For instance, P41A routes via P43A, and P40HQ was used by P43ARC via I2MQP for IARU contests. The entries include both active and Silent Key (SK) operators, with dates of passing where known, such as P43ADA (SK, Sep 2014) and P43JB (SK Jan 2012). This detailed listing assists DXers and contesters in verifying contacts and ensuring proper QSLing for Aruba operations.

The prototype for this amplifier was originally designed for 70cm and was used on the 2004 3B9C Dx-pedition to Rodriguez Island for satellite and EME. It had a noise figure of 0.49dB with an associated gain of 20dB.

Focused on technology to serve emergency response in clackamas county, oregon.

Sort of similar to the one of the 6m omni. Instead of using twin-lead, this design makes use of a more or less regular double bazooka antenna (coaxial dipole). Your attention shall be drawn to the available standart literature, such as Rothammel. In order to "compute" the dimension, Karl Rothammel mentioned that the total length of the dipole shall be 95% of the free-space wavelength. The short-circuit bridges (closing the folded dipole) are to be placed at a distance-fraction being equal to the velocity factor of the coax cable used, which will be 66% using RG-58 or RG174.

Are you confused when it comes to using toroids? The tips given in this article may simplify your next project. Comprehensive article about choosing the proper toroid.

This paper discusses the sources of feed line currents and the methods used to control them.

This is a page to detail how I remotely operate my Elecraft K2 HF transceiver via my home network. The method used should apply to pretty much any amateur transceiver that can be controlled by serial port.

Operating Free DV, the open source digital voice codec for HF, allows any SSB radio to be used for low bit rate digital voice.

An overview about the UHF connectors often referred to as the PL259 plug and SO239 socket used for many RF applications. Limitations, history and soldering properly UHF Connectors

Designer and manufacturer of RF amplifiers used in a variety of custom applications in many diverse industries - from Scientific, Medical, Industrial, and Communications and Broadcast.

This is a standard calculation method that can help you while tuning dipole antennas, by adjusting wire lengths. This method can be used also when you need to add lenght to your wires, and can be additionally used to quarter waves vertical antennas

Ham shack located in a caravan and run by solar power. This page describes VK5SW experience of converting an old, disused and rundown caravan, to a fully functional solar powered Ham Radio shack.

Sound recordings of meteors and things reflecting TV station video carriers , frequencies used are analog TV video carrier frequencies offset by 1 kHz SSB

Grid Calculator allows you to calculate either a grid square locator or the latitude and longitude of a location. Grid Calculator can be used to calculate a Great Circle bearing and distance between two stations in statute miles, nautical miles, and kilometers.

A simple portable dipole antenna for the 40 meter band using a total lenght of 18 meter. It can be used for 80 to 10 meters coverage using a antenna tuner.

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.

Amateur radio operators often document their station activities, equipment, and on-air experiences through personal blogs. These platforms serve as a digital logbook, sharing insights into antenna setups, radio modifications, and DX contacts. Such blogs frequently feature photographs of the shack, descriptions of operating conditions, and reflections on various aspects of the hobby, including contesting or portable operations. The PBG Station Brunei blog provides a glimpse into the amateur radio scene from Southeast Asia. It covers general station updates, local repeater information, and personal reflections on radio operations. The content offers a localized perspective on ham radio activities within Brunei, including details about specific frequencies and equipment used for local communication.

Available worldwide can be used as Arduino Shield or plug it in to you PC , or with a bluetooth adapter connect to Android. With a highly optimized software, KAI200 brings you: a. Antenna analyzer form 1 up to 200 Mhz; b. WSPR transmiter (set up by serial terminal); c. Square Wave Signal generator KAI200 is all you need for your radio whatever it is Yaesu, Icom, Kenwood or Drake and DIY projects.

Community focused organization made up of Amateur Radio Operations from the Gordon County and the North Georgia area.

This guide explores different radio bands that hobbyists use to talk to each other worldwide. It explains how these bands work and what they're used for. From low-frequency to high-frequency bands, each has its own unique features for people who enjoy communicating through radios

The W6JWS 2-meter Repeater Maintenance and Repair Log documents the ongoing upkeep of a 146.745 MHz repeater, specifically addressing modifications to enhance its functionality. It details changes made to ensure the repeater powers up in _PL mode_ and to improve the reliability of touch-tone control, drawing comparisons to similar work performed on the AE6KE repeater. The log also notes a repair to a fused wire in the reverse battery protection circuit after an accidental polarity reversal, highlighting a temporary workaround where a wire was omitted but the system remained operational. The resource includes practical insights from Jeff Liebermann, AE6KS, regarding jumper configurations and programming, with accompanying photos. It provides access to several documents for the Icom RP-1510 repeater, including operating manuals and a schematic for the single logic board version, which differs from the dual-board configuration described in some printed manuals. The log mentions a specific modification to adjust the dropout delay, which was later deemed unnecessary, and references a related project for the AE6KE repeater, aiming to replicate successful modifications on the W6JWS machine, resulting in improved touch-tone reliability and proper PL mode activation.

Article on operating aids and band usage during solar minimun periods. Author tries to explain what can we expect on the HF bands during a solar minimum period and which approach to be used to understand band openings.

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