Can someone tell me the components in a transmitting tower?

Question

I really need help! My educator told me to explain the function of components in a transmitting tower...well I obviously don't understand what the components are in a transmitting tower, please help!

Answer 1

There is a big difference depending on whether the transmitter is AM (medium wave) broadcast or high frequency broadcast.

For AM, the tower is also the antenna. The guys and base usually have insulators to prevent RF energy from going to ground. At the base are 120 or more radial wires that function as the ground plane. There is a small shed next to the tower which has the ATU (antenna tuning unit) which converts the output from the transmitter to feed the tower.

For FM, Television and mobile radio, the tower is a support structure for the transmitting antenna (s). In this case the tower and guys are usually directly grounded to provide some lightning protection. The tower raises the elevation of the radiating point of the antenna for better reception coverage. HAAT or Height above average terrain, is an important factor in performance distance, combined with transmitted power, ERP or Effective Radiated Power.

In some cases, besides holding the transmitting antenna, the tower may also hold receive antennas for Cell service, or the STL, Studio to Transmitter Link and other auxilliary services.

All of these antennas require feedline, usually heavy coaxial cable or waveguide, to make connection to the equipment located in a building on the ground level.

All tall towers usually have special paint to make for better visibility for aircraft pilots to see, and in some cases have lights for night-time illumination. Very tall tower have daytime lights as well.

Depending on power and height, a security fence to prevent the public from receiving excessive RF exposure may be erected around the base of the tower.