Jensen HEAVY DUTY JHD3000 - Manual (Page 7)

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AM AND FM RECEPTION IN A MOBILE
ENVIRONMENT
Although you may be familiar with both AM and FM reception in your home,
you will experience notable differences in reception while driving.Both AM and
FM provide excellent listening enjoyment and supply the diversified entertain-
ment necessary to relieve the boredom of hours behind the wheel. FM recep-
tion, although unique in its characteristics while driving, provides a different
listening experience compared to that of AM. The few reception inconveniences
common to FM are compensated by the rich sound quality of its wide frequency
response and stereo effect.Your new AM/FM radio has been built to the strictest
engineering standards available today and through quality components and con-
struction will provide maximum performance under all conditions. A few minutes
reading this section will enable you to obtain the most from the unit and answer
your questions about the differences between mobile AM and FM
reception.
SOME FACTS ABOUT AM AND FM RECEPTION
1.RECEPTION IN TUNNELS: Although you will lose AM reception when driving
through tunnels and large bridges, it is common to continue to receive FM re-
ception under the same conditions.
2.THE NUMBER OF STATIONS IN YOUR AREA: Depending on your location,
you may find that you can receive a greater number of AM stations in your area
than FM stations. In most urban and suburban areas, the numbers of AM and
FM stations are comparable.
3.RECEPTION DURING STORMS: Local electrical thunderstorm activity often
produces sharp static sound when listening to AM stations although you will find
that FM is unaffected.
4.ELECTRICAL INTERFERENCE: When listening to AM stations, you may exper-
ience some buzzing sounds or static when passing roadsidz electric power lines
which do not interfere with FM reception. Conversely,FM reception may be affect-
ed by electrical noise from passing cars and trucks while AM reception is not
affected.
5.FM RECEPTION RANGE: FM reception range is usually limited to about 50 miles
from the broadcast station. FM signals radiate straight out from the broadcast
antenna. They do not follow the earth's curve and are not reflected back to the
earth by the atmosphere, resulting in "line-of-sight"reception range.
6.AM RECEPTION RANGE: AM stations can often be received hundreds of
miles from the broadcast station. AM signals follow the earth's curve and are
easily reflected back to earth by the atmosphere. Therefore an AM signal may
be more easily received far from the broadcast station antenna than an FM
signal.
FM RECEPTION WHILE YOU ARE DRIVING
Since FM signals become weaker as you drive further from the broadcast sta-
tion, you may experience flutter, noisy reception and fading in the poor signal
fringe areas. Through the use of advanced circuitry in this radio,the Fringe
Area has been greatly reduced, providing a larger reception range.Even with
this improved circuitry however, eventually the FM signal will become too weak
to provide quality reception. When this occurs, it is best to change to a stronger
local FM station. Although FM signals are not reflected by the atmosphere, they
are easily reflcted by solid objects. This characteristic of FM signals can produce
two different reception possibilities. First, an FM signal can "bounce" between
tall buildings resulting in reception in areas where AM reception is not possible.
Second, the same effect can result in the loss of an FM signal if a large obstruc-
tion such as a mountain or building is located between you and the FM broad-
casting antenna so that it blocks the signals. In such cases, it is possible to
have poor FM reception even if you are not far from the broadcasting station.
AM AND FM RECEPTION IN A MOBILE ENVIRONMENT FM RECEPTION WHILE YOU ARE DRIVING