Tag radio repeater

Radio Repeater


A Radio Repeater is a device that boosts communication range.

Repeaters receive a weak signal and retransmit it.

By retransmitting the signal at a higher power, further range is enabled.

Another reason to use repeaters, is obstacles.

Obstacles include both natural and manmade structures.

Examples of natural obstacles include hills and mountains.

Examples of mademade obstacles include buildings and bridges.

Obstacles matter to radio signals.

Basically they block or attenuate radio signals.

Attenuation means reduces the power of the signal.

Reducing the power of the signal, reduces communications range.

A classic use of a radio repeater is to overcome a hill.

Hills will block radio signals above 30 MHz.

Radio signals above 30Mhz are normally known as ‘line of sight’.

The term ‘line of sight’ is slightly misleading, as signals will pass through a building.

Therefore you don’t actually have to be able to see a clear path between transmitting and receiving radio.

However hills block radio waves, so a hilltop repeater overcomes this.

Placing a repeater on a hill allows signals to be received from one side of the hill, and boosted to both sides of the hill.

This is because the repeater antenna is physically above the top of the hill.

What is a Radio Repeater

A radio repeater is basically a radio receiver, and a radio transmitter in one unit.

The receiver part receives a radio signal from a walkie talkie or mobile two way radio on one frequency,  and then re-broadcasts it out again on another frequency.

The point of a Radio Repeater system is to increase the broadcast range.  For example a handheld walkie talkie may only have a range of a few miles, and is fairly line of sight.

With a repeater the fairly weak signal from a handheld walkie talkie (5 watts on VHF for professional equipment) is re-transmitted at maybe 25 watts of  RF power. Thus the signal can be heard further away.

Repeaters are also useful when there are hills in between two radios wishing to communicate, as is the case at the relatively high frequencies that private business radios operate on. As the signals are mainly line of sight, a repeater located on top of the hill can receive the signal from one radio, and re-transmit it, which can be received by the radio on the other side of the hill.