TABLE OF CONTENTS K. Blair Benson
L. H. Hoke, Jr., L. E. Donovan, J. D. Knox, D. E. Manners, W. G. Miller, R. J. Peffer, J. G. Zahnen, U. L. Rohde
The antenna system is one of the most important circuit elements in the reception of television signals. The ultimate quality of the picture and sound depends primarily on how well the antenna system is able to capture the signal radiated by the transmitting antenna of the broadcast station and to feed it, with minimum loss or distortion, through a transmission line to the tuner of the receiver.
In urban and residential areas near the television station antenna, where strong signals are present, a compact set-top telescoping rod or rabbit ears for VHF and a single loop for UHF usually are quite adequate. The somewhat reduced signal strength in suburban and rural areas generally requires a multielement roof-mounted antenna with a shielded 75 ? coaxial transmission line to feed the signal to the receiver.
Fringe areas, where the signal level is substantially lower, usually require a more complicated, highly directional antenna, frequently on a tower, to produce an even marginal signal level. The longer transmission line in such installations may dictate the use of an all-channel low-noise preamplifier at the antenna to compensate for the loss of signal level in the line.
Antennas have a number of key characteristics that define their ability to receive energy from a radiated field. These are as follows:
