I thought I would put pen to paper and explain some of the basic terms used in Television Reception. Caravanners need to understand because their results will be impacted by their ability to understand a few basics. It is the prime driver in accepting poorer results because it seems too complicated.
It is only seeming that way because the language of the industry is not understood. So, let us have a go. I would appreciate any feedback you have to offer.
Antenna -- It is a device that collects energy from the air. The energy is known as Radio Frequencies, and it is a wave. An antenna is designed to collect the wanted frequencies efficiently. Homeowners generally have 5 different frequencies. The caravanner has to be able to collect approx. 40 different frequencies.
Frequency - Every network sends their pictures out on a unique frequency which changes from place to place. Each frequency has a unique wavelength. example 7 Network in the capital cities is about 1Metre long. The network Prime in Bendigo the wavelength would be 800mm long. So, frequency of the wanted Television channels in Australia means the wave that travels through the air to your antenna can be anything from 400mm to 2Metre long and everything in between.
Wave - Take your garden hose and flick it. It will appear like a snake going up and down. If you could see the wave this is what it that they would look like.
Transmitter - Throw a stone into a pool of water and watch the energy ripple outwards from the point that the stone entered the water. A transmitter does exactly the same thing except it is a frequency. In other words, it is precise, and it is an exact length. They come in various sizes. Big, medium, and small types and the term used is Effective Radiated Power
Polarity - The angle the signal is transmitter See Horizontal and Vertical below.
Horizontal - This is a radio wave that is travelling perpendicular to the ground.
Vertical - This is a radio wave that is travelling 90 degrees to the ground.
Directional - This relates to a transmitter and the way that it is transmitting the frequency. In this case it is in the exact direction.
Omni-directional - This means the signal is transmitted in a 360-degree arc. This assumes there are no physical things in the way. Antennas promoted this way are never totally 360 degrees.
VHF - Very High Frequency Any channel between 6 and 12 or 176mhz and 220
MHz
UHF - Ultra High Frequency Any channel between 28 and 51 or 526mhz and 635mhz
RF signal Energy that travels through the air and is of a known length.
Sally Garden
Founder and CEO.
Commentaires