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MI-2 MULTIPATH/TUNING INDICATOR

GENERAL DESCRIPTION

The Mclntosh MI-2 Multipath/Tuning Indi-

cator is designed to be used with an FM tuner

to detect and display multipath reception.

Multipath reception is the result of a reflected

signal arriving at the tuner antenna slightly

later than the direct signal. By rotating or

repositioning your FM antenna it is possible

to reduce the multipath reception. The MI-2

Multipath/Tuning Indicator makes it easy to

know when the FM antenna is oriented for

the best reception of any station.

Multipath reception degrades FM tuner

performance in several ways:

1) Usually there is an increase in back-

ground noise level.

2) Distortion is often heard in the pro-

gram signal.

3) Stereo separation may be reduced.

4) The stereo effect may be completely

lost.

5) Stereo indicators may fail to function,

or function erratically.

Figure 1. FM Tuner Antenna Receiving

Direct and Reflected Signals

To show multipath reception the MI-2 dis-

plays instantaneous signal strength versus

frequency deviation. Signal strength is shown

as vertical deflection of the indicator display

beam. Frequency deviation is shown as hori-

zontal deflection. Multipath reception ap-

pears as a peak or a valley in the MI-2 dis-

play. See Figure 2.

To overcome multipath reception it is

usually necessary to orient the tuner antenna

to receive the FM signal by only one predom-

inant path. Rotating a directional antenna is

very effective at correcting multipath recep-

tion. In a metropolitan area where a simple

antenna such as a dipole is used reposition-

ing the antenna will achieve the same result.

1

DIRECT

SIGNAL

REFLECTED

SIGNALS

1 2 3 4 5 6 7 ... 17 18

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