What are harmonics?

What is a harmonic? A harmonic of a particular frequency (the fundamental frequency F) is a frequency that is an integer multiple of the first one. For example: if f = 125 MHz, the harmonics would … Read More

70 centimetres

The 70-Centimeter Band: Everything You Need to Know

The 70-centimeter band is a popular UHF band. Equipment Single-band equipment for 70cm is rare, but many dual-band transceivers are available that operate on both 2 meters and 70cm. Available gear includes base stations, mobile units and HTs. … Read More


TVI: Everything You Need to Know

What is TVI? Simply, TVI is the interference of TV reception by transmissions from another source. In ham radio, we are specifically talking about transmissions from an amateur station, although it is not uncommon for … Read More


Radio Modes: Everything You Need to Know

The term mode has varying meanings, according to the context, but the most common are permitted modes in amateur licensing. Waves have three characteristics that can be changed, Amplitude, Frequency and Phase. A mode is … Read More

Oscillator Design

Oscillator Design: Everything You Need to Know

Fundamentals An oscillator is an electronic circuit designed to produce either audio or radio frequency signals. These will generally have sinusoidal waveform, but other wave shapes such as square and sawtooth are possible. In radio … Read More


here are multiple systems in use for identifying location (QTH) using zones or grid squares. Zone systems A number of systems exist to divide the world into zones and regions. In some cases, the divisions and … Read More


What Is A Filter?

A filter is an electric circuit (often called a network) that allows certain frequencies to pass but rejects (attenuates) other unwanted frequencies.In general, filters are one of four types – Lowpass, Highpass and Bandpass (Notch) … Read More