Lectronics Venue 2-941, Руководство по установке, Страница: 23 / 32

Digital Hybrid Wireless ® Modular Receiver System
Rio Rancho, NM, USA
23
Antennas
Use and Placement
The Venue 2 mainframe is designed for rack mounting.
Although it can be operated with two whip antennas, it
is best to use remote antennas such as the SNA600 or
ALP Series for optimum reception. Position the remote
antennas at least three or four feet apart and not within
three or four 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 them so that there is a direct “line of
sight” between the transmitter and the receiver anten-
nas.
In situations where the operating range is less than
about 100 feet, the antenna positioning is much less
critical. The length and type of cabling between anten-
nas and the system, however, is critical. Long cable
runs can experience significant signal loss. Lectroson-
ics offers in-line RF amplifiers to compensate for this
signal loss. Contact your dealer or the factory for more
information.
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’s antennas along with the direct signal. If the
direct and reflected signals are out of phase with each
other and similar in strength, a cancellation or “drop-
out” may occur. A dropout can sound like audible noise
(hiss, swishing or a “shhht” sound), or in severe cases,
may result in a complete loss of both the carrier and the
sound. Moving the transmitter even a few inches can
change the sound of the dropout, or may even eliminate
it. A dropout situation also may be either better or worse
as a crowd fills or leaves the room.
The receiver offers two different diversity reception
methods which overcome most dropout problems. In the
event, however, that you do encounter a dropout prob-
lem, first try moving one of the remote antennas at least
three or four feet from its current location. If dropouts
are still a problem, try moving the antennas to entirely
different locations.
Lectrosonics transmitters radiate power very efficiently,
and the receivers are very sensitive, which reduces
dropouts to an insignificant level. If, however, you do en-
counter dropouts frequently, call the factory or consult
your dealer. There is probably a simple solution.
Using Remote Antennas
Remote antennas can be placed at a distance from
the receiver to optimize reception. To overcome loss
in long coaxial cable runs, a Lectrosonics UFM Series
inline RF filter/amp should be positioned at the far
end of the coaxial cable, close to the antenna.
With the amplifier in this position, gain is applied
ahead of the loss to maximize the signal to noise ratio
of the antenna system.
NOTE: It is best practice to enable this DC
power ONLY when a UFM remote amplifier or
active antenna is used. Some antennas may
present a short to the power supply. While the
power supply is fused and it is unlikely that
damage would occur, it is always best to disable
the DC when it is not in use.