Antenna System; Mobile Antennas - Midland Alan 100Plus B Manual De Instrucciones

ANTENNA SYSTEM

A mobile antenna system is not limited to the antenna only. 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 it is for the transmission.
If a mismatch exists between the antenna and the receiver, the excellent sen-
sivity and signal-to-noise radio of the receiver circuit will be defeated.

MOBILE ANTENNAS

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 m
sceiver 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.
› A vertically polarized whip antenna is best suited for mobile service. It is
omni-directional.
› If it's the loaded type, you will find it a phisically 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.
There are many possible antenna locations on a car. Four of the most com-
mon are shown and discussed on the following.
Roof Mount - In this position the antenna radiates equally in all directions.
Since the normal 1/4 wavelength whip antenna is too long for roof mounting
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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 ea-
sily mounted. It can double as both the CB and the standard auto radio anten-
na by employng a two-way coupler. Ask about our complete line of antennas.
Rear Deck Mount - The radiation pattern is stronger in the direction of the
front fender opposite the side on which the antenna is mounted. In this posi-
tion you can use a full quarter-wave antenna or a shorter loaded whip. Here
you might consider one of the full 2.5 meters whips.
Bumper Mount - The antenna radiates in a pattern directly in front of and
to the rear of the vehicle, with maximum radiation directly away from the
vehicle, in a horizontal plane. Despite its fairly irregular pattern, a bumper-
mounted full-length whip antenna will normally give the best results. Remo-
ving the antenna is simple and will leave no holes in the car.
2 or more. Be sure the tran-
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