Lectrosonics UDR200b - Manual (Page 15)

Wireless Diversity Receiver
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 UDR200B 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 “drop-out.” A drop-out 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 drop-out 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 elimi­
nate it. A drop-out situation may be either better or worse as
the crowd fills and/or leaves the room, or when the transmitter
or receiver is operated in a different location.
The UDR200B receiver offers a sophisticated diversity design
which overcomes drop-out 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 drop-out prob­
lem on that antenna. If drop-outs are still a problem, try mov­
ing the antenna to an entirely different location in the room or
moving the antennas in closer to the transmitter location. By
observing the OPTI-BLEND LEDs on the front panel, you can
determine which antenna is suffering weak signals.
Lectrosonics transmitters radiate power very efficiently, and
the receivers are very sensitive. This reduces drop-outs to an
insignificant level. If, however, you do encounter drop-outs
frequently, call the factory or consult your dealer. There is
probably a simple solution.
REFLECTIVE SURFACE
DIRECT SIGNAL
TRANSMITTER
DIRECT SIGNAL
INDIRECT SIGNAL
PHASE
CANCELLATION
ANT A
A
500 250 100 50 25 10 5 1uV 2 1mV OPTI BLEND
500 250 100 50 25 10 5 1uV 2 1mV OPTI BLEND
B
LIM 0 -6 -12 -18 -24 -30 -36 -42 -48
TX AUDIO LEVEL dB RF LEVEL
RF LEVEL
LECTROSONICS
FREQ
SELECT
POWER
MONITOR MODE
A B
DIVERSITY
MENU
6 1 5 . 1 T X : B 3 T V 2 3
RECEIVER
MULTI-PATH DROPOUT
AT ANTENNA B
Rio Rancho, NM – USA 15