Antenna use and placement, Multi-path dropout, Reflective surface – Lectrosonics UDR200c User Manual

Page 17: Wireless diversity receiver, Transmitter receiver

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17

Wireless Diversity Receiver

Rio Rancho, NM – USA

DI

RECT SI

GNAL

INDI

RECT SI

GNAL

MULTI-PATH DROPOUT

TRANSMITTER

RECEIVER

DIRECT SIGNAL

INDIRECT SIGNAL

PHASE
CANCELLATION

REFLECTIVE SURFACE

OPTI

BLEND

OPTI

BLEND

TX AUDIO LEVEL dB

RF LEVEL

RF LEVEL

LECTROSONICS

FREQ

SELECT

POWER

MONITOR

MODE

MENU

6 1 5 . 1

T X : B 3

T V 2 3

ANTENNA USE AND PLACEMENT

When using a remote antenna with this receiver, position the
antennas at least three or four feet apart and so that they are
not within 3 or 4 feet of large metal surfaces. If this is not
possible, try to position the antennas so that they are as far
away from the metal surface as is practical. It is also good to
position the receiver so that there is a direct “line of sight”
between the transmitter and the receiver antenna. In situa-
tions where the operating range is less than about 100 feet,
the antenna positioning is much less critical. The antennas
can also be configured with one whip mounted directly onto
the rear panel of the UDR200C receiver, and the other one
mounted remotely.

A wireless transmitter sends a radio signal out in all directions.
This signal will often bounce off nearby walls, ceilings, etc. and
a strong reflection can arrive at the receiver antenna along
with the direct signal. If the direct and reflected signals are out
of phase with each other a cancellation may occur. The result
would be a “dropout.” A dropout sounds like either audible
noise (hiss), or in severe cases, may result in a complete loss
of the carrier and the sound when the transmitter is positioned
in certain locations in the room. A dropout normally sounds

like “hiss” or a “swishing” sound. Moving the transmitter even
a few inches will change the sound of the hum or hiss, or
eliminate it. A dropout situation may be either better or worse
as the crowd fills and/or leaves the room, or when the transmit-
ter or receiver is operated in a different location.

The UDR200C receiver offers a sophisticated diversity design
which overcomes dropout problems in almost any imaginable
situation. In the event, however, that you do encounter a
dropout problem, first try moving the antenna at least 3 or 4
feet from where it was. This may alleviate the dropout problem
on that antenna. If dropouts are still a problem, try moving the
antenna to an entirely different location in the room or moving
the antennas in closer to the transmitter location. By observ-
ing the OPTI-BLEND LEDs on the front panel, you can deter-
mine which antenna is suffering weak signals.

Lectrosonics transmitters radiate power very efficiently, and
the receivers are very sensitive. This reduces dropouts to an
insignificant level. If, however, you do encounter dropouts
frequently, call the factory or consult your dealer. There is
probably a simple solution.

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