KCBS Transmitter

This is the base of tower three. The building to the right is the tuning shack or dog house. The feed line coming from the phasor for tower three terminates inside and feeds what is called an ATU. The purpose of the ATU is too match the tower to the feed line in order to get maximum power to the tower. The building also contains AC power for tower lights and other goodies. The tower sits on a concrete base about eight feet tall. On top of the base is a insulator that keeps the tower from being shorted to ground. On the left side you can see one small pipe coming off the tower and one going to the bottom of the insulator. These are ball gaps to short lightning to ground. It looks like they short the tower to ground but there is a small gap between the balls on the end of each pipe. The air between the balls acts like an insulator at 50,000 watts but if lightning strikes the tower the energy is sufficient to arc across the ball gaps and short the lightning to ground. This protects the ATU, feed lines, transmitters and phasor. Lightning can really do a lot of damage if it is not shorted by the ball gaps. On the right side of the tower are two loops at 90 degrees to each other. This is a Austin ring transformer. It supplies AC power to the tower to light the tower lights. The two loops do not touch and therefore do not short the tower to ground. Around the base of the tower, supported by the wood frame, is part of the antenna ground system. It is called a counterpoise and connects to the antenna ground system. The ground system consists of 120 wires buried in the ground radiating out in a circular pattern around each tower. The ground wires act like a mirror to the tower in the ground and help improve the signal in the coverage area. Each tower base is surrounded by a fence to protect anyone who comes out in the field and prevent premature bar-b-queing of the cows (assuming of course that you have cows that can climb an eight foot tall concrete base. Hey, it could happen).

Normally, towers stand nice and straight. But sometimes things don't quite work out that way........

Updated 10/22/98