Lectrosonics UDR195 - Manual (Page 12)

ANTENNA USE AND PLACEMENT
There are two remote antenna assemblies included with this receiver. Position the antennas at least three or four feet apart at
VHF frequencies 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 situations where the operating range is less than
about 50 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 DR195 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 eliminate 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 DR195 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 problem on that antenna. If drop-outs 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 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.
DIREC
T SIGN
AL
IND
IRE
CT
SIG
NA
L
DIRECT SIGNAL
INDIRECT SIGNAL
MULTI-PATH DROPOUT
TRANSMITTER
RECEIVER
PHASE
CANCELLATION
REFLECTIVE SURFACE
Figure 4 - Drop-outs
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