Antenna System - Midland M ZERO PLUS Manual Del Usaurio

ANTENNA SYSTEM

A mobile antenna system is not limited only to the antenna. The transmission line
as well as the vehicle are important factors in the total antenna system. Therefore,
you must use the correct type of transmission line and mount the antenna securely
in a position that will give you optimal results. Use coaxial cable with an impedance
of 50 Ohms. We suggest type RG 58/U for lengths under 2.5 m or RG 8/U for
longer lengths. Generally speaking, you should keep the length of the transmission
line to a minimum. The above discussion is as important for reception as for the
transmission. If a mismatch exists between the antenna and the receiver, the excel-
lent sensitivity and signal-to-noise radio of the receiver circuit will be defeated.
Suggestions
A few general rules should help you to install any mobile antenna properly.
• Keep it as far as possible from the main bulk of the vehicle.
• During operation, it must be vertical, and rigid enough to remain vertical when
the vehicle or boat is in motion.
• Mount it as far as possible from sources of noise (ignition system, gauges, etc.)
and keep the transmission line away from these noise sources.
• An antenna mounted in a boat requires a good ground connection. This can be
either a metal hull or a ground made of tin-foil or copper sheeting.
This ground should cover an area of at least 1 m2 or more. Be sure the transceiver
also has an adequate ground. There are many types of mobile CB antennas: a full
quarter-wave length whip, a centerloaded whip, top loaded whip and the base loaded
type are typical. A vertically polarized whip antenna is best suited for mobile servi-
ce. It is omnidirectional. If it's the loaded type, you will find it a physically shorter
antenna. But, for greater efficiency the 2.5 m long, full quarter-wave whip is better.
Antenna length is directly related to efficiency.
Generally, the longer it is, the more efficient will be.
There are many possible antenna locations on a car.
Four of the most popular are shown and discussed on the following.
Roof Mount
In this position the antenna radiates equally in all directions. Since the normal 1/2
wavelength whip antenna is too long for roof mounting on a vehicle, the antenna
is shortened and loading coil is used to provide the proper electrical length. Our
fiberglass roof mount is a good durable antenna.
Front Cowl Mount
The radiation pattern is slightly greater in the direction of the rear fender
opposite the side on which the antenna is mounted. However, the front
position offers a number of advantages. The CB antenna can be easily
mounted. It can double as both the CB and the standard auto radio an-
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