20 W HF Power Amplifier, Tri-Band VHF/UHF Antenna Design, Building The Fox-in-a-Box, Aircraft Scatter ACS, Airplane scattering, Taking a look at the 900 MHz band, Thevenin equivalent calculator,

Antennas/Feed Lines/Choke
This is a small collection of K9YC info and my experiences. Problems by feed lines of 1/2 lambda length. CMCs in transmitting and receiving systems. Antenna unbalance, Maximal allowed power, Choke winding tips.

Propagation/Sporadic E
Recent researches seem to support the hypothesis that Sporadic E propagation could be connected to presence of thunderstorms.

HF DXView Propagation Map, HF EFHW Antenna Antenna Tuner, A Morse Code Practice Oscillator, URE WebCluster, MSF radio time signal, Morse Code Practice Oscillator, CW Key-to-Rig Switch Box,

Propagation/Sunspots
The estimated international sunspot number (EISN) is a daily value obtained by a simple average over available sunspot counts from prompt stations in the SILSO network.

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

28 MHz Antenna Project, K1FM Mini Magnetic Loop, Portable 40m CW Transceiver , AircraftScatterSharp, 3B7M St Brandon DXPedition, HD8M Galapagos,

Antennas/Receiving
This page is a project for a small loop antenna for reception of short wave broadcasting. It is in Portuguese and contains pictures and schematics to build your own antenna

Antennas/Feed Lines/Choke
This article is an attempt to shed some light on this misunderstood component, covering topics like why you need a common mode coke, what it does, what properties it should have, ho to build one and how to measure its performance.

Radio Equipment/HF Transceivers/Yaesu FT-817
If your FT-817 has stopped powering up from the internal battery but works from external power, then maybe the internal battery fuse has blown. There is a small PCB mounted fuse to protect the battery and radio. This fuse can blow, if it does your radio will not work from battery power. This page will describe how to test the fuse and describe how to make a repair.

Software/Databases
This script queries the QRZ.com callsign database and returns the result to the command line. A XML subscription plan with QRZ.com is required for full functionality. QRZ.com callsign data query script written in Bash

Antennas/30M
This article describes the construction of a 9,50 m long dipole for the 30 m band (10.1 MHz to 10.15 MHz). It was designed to be mounted ca. 6 m above ground inside an attic. The calculations were performed by OE1MEW

Antennas/Yagi
This article describes the phases for the construction of a Yagi antenna. The calculations of the parameters are made using 4NEC2 software. This type of antenna is used for transmissions and receptions of electromagnetic waves. The project shown here refers to the frequency of 433.92 MHz.

Countries with CEPT Licence, BG2FX Amateur Radios, JBOT QRP linear amplifier, RF Inductor Calculator, DCF77 , JJY, 9X5RU Rwanda,

The ID-50 is a compact VHF/UHF dual bander with both D-STAR and FM dual modes. Connecting to the D-STAR network, you can call a friend in another city, or other regions around the world with the ID-50. Smart functions such as Band Scope and Picture Sharing function enhance your QSO experience.

IC-R20 by Icom. Wideband Receiver Professional radioreceiver, allow double receiver, from HF to Microwave, digital recorde, DTCS, Memories and 11 hours countinuous reception.

Technical Reference/Radio Frequency Interference/Noise Reduction
If RF noise threatens to take your hobby away, this could be probably a good solution to reduce or even eliminate RF Noise.

Technical Reference/Batteries
A free educational website offering hands-on battery information. The tutorials evaluate the advantages and limitations of diverse battery chemistries, advise on best choices, and suggest ways to extend life.

Ham Radio/Clubs/Europe/UK/Southern England
Mid Sussex ARS is an RSGB-affiliated club and meets at its headquarters in Burgess Hill on the 2nd and 4th Friday of each month. They organize various activities ranging from talks by members or guest speakers, evenings on the air using their shack's latest SDR equipment, training evenings and used equipment sales. As well as scheduled club nights, they run many outdoor activities throughout the year, including direction-finding contests, town days, social evenings and Special Event Stations. They even have their own free online training academy!

Operating Modes/Portable Operations
This article is from the book Ham Radio For Dummies and features some tips for portable amateur radio operations, on Field Day or generic outdoor operation, like selecting the proper antenna and portable power.