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Cellular Telephone Antenna Tower
29 January 2007
Throughout Canada and USA


Credits:
Ken Lyons

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Cell phones communicate via airwaves so they must be in range of an antenna such as this one. The antennas shaped liked rectangles are used to communicate with the cell phones. Their signals are then transmitted to the equipment in the building at the base of the tower. They are processed and combined with the signals with other cell phones and sent back up the tower to the large round dish antenna for transmission to the switching office. Cell towers without the round dish antennas have their equipment linked to the switching office by cable.

When a cell phone is turned on it searches for a signal which is transmitted from a nearby antenna, antennas are arranged in adjacent cells so that none is more than about 10 km from each other. As a user moves, his phone will always handed off to the antenna that provides the best signal.

It's interesting to note that the round dish antennas transmit microwaves, this is about all that is left for microwave transmission since the long haul microwave systems have been replaced by fibre-optic transmission.