Pollution

From Pretoria Wireless Project

Overview

In terms of radio use, can indicate the amount of excess radio energe emitted by and antenna, that is not absorbed by antennae or other obstructions, and may cause interference with other radio equipment.

This interference usually manifests in reduced signal reception with other radio equipment. In essence, when a transmitter is 'polluting' it is transmitting more radio energe than needed. This causes reduced signal quality in other devices, especially those operating on similiar frequencies. Sufficiently strong signal though, can interfere with all radio equipment.

Often, in order to combat this reduced signal quality, the other radio equipment operators increase the strength of their transmittions, which increase the overall pollution, which lead to more and more people increasing their transmition strentgh, and so on. In areas with a lot of radio activity

The effect is similar to standing in a crowded room, with dozens of people shouting to the person next to him in order to be heard above the din, but there being so much noise that nobody can actually hear each other. If each person were to whisper to his neighbour, everybody would be able to talk to his neighbour.

Best Practice

The legal limit for 2.4GHz transmisions in 100mW ( milli Watt ). Commercial wifi equipment stay within these limits. Exceeding that limit can result in a fine, or confescation of the equipment. Also, interfering with millitary radio equiment is a serious offence. You might get shot.

Or bombed.

We're not joking. Stay within legal limits and frequencies.

Do not use amplifiers for the transmision signal, as this would exceed the 100mW level. Avoid the use of omni directional antennas as they broadcast signal in all directions. directional antennas focus the transmision in the desired dection, making sure you signal goes to the people you are trying to reach, with less of it interfereing with your neighbour.

Also, because directional antennas focus the signal, less power is needed to reach the intended recipients.