echolink

Echolink

Introduction Echolink is a VOIP (Voice Over IP) application that allows amateurs to connect to one another using the internet. It is similar to IRLP but allows users to connect via either radio or computer. … Read More

Screwdriver antenna

Screwdriver antenna

A screwdriver antenna is a vertical antenna with a remotely-adjustable center-loading coil. Intended for mobile operation, it may be adjusted to cover any band from 10m to 75m. The antenna takes its name from the use of a … Read More

QSL

QSL

QSL means either “do you confirm receipt of my transmission” or “I confirm receipt of your transmission”. It can also mean “please send me a QSL card”. QSL is a Q-code. QSL Cards A QSL card … Read More

QRN

QRN

Strictly speaking, QRN means “noise from natural sources” as opposed to QRM which means “man-made noise”. The abbreviation QRN is often used in general terms to mean any noise that interferes with the propagation or … Read More

QRSS

QRSS

QRSS is a CW mode in which the receiver bandwidth is drastically reduced and the rate at which code is sent is slowed beyond that which would normally be readable by ear. It is named for QRS, … Read More

Resistance

Resistance and Resistivity Resistance (R) is the measure of how much an object – a resistor – opposes the flow of electric current. The resistance of an object is measured in Ohms (<math>\Omega</math>) Resistivity (<math>\Rho</math>) is a measure of … Read More

Gain

Gain

What is Gain? Gain compared to a half wave dipole – dBD The gain of an antenna is the relative increase in radiation at the maximum point expressed as a value in decibels (dB) above a standard. … Read More

Propagation

Propagation

Radio wave propagation largely depends on atmospheric conditions, the band and power used to operate the radio equipment. Ground waves are “line of sight” communication. Atmospheric conditions come into play when transmitting between ham radio stations that are farther away … Read More

RadioPC Interfaces

Radio/PC Interfaces

There are many brands of interface available to connect a PC to an amateur radio transceiver. Often home-brew interfaces are used. They all do essentially the same thing. They key the radio to transmit, pass … Read More

Semiconductor

Semiconductor

Structure of Atoms The simplest model of atomic structure has each atom is made up of a nucleus containing Protons and Neutrons, with electrons, circling the nucleus at various energy levels (layers). Each layer can only hold a … Read More