Shure UA874 Manual De Instrucciones página 3

Active Directional Antenna
General Description
The Shure UA874 uses a log periodic dipole array to offer enhanced re-
ception when directed toward the desired coverage area. An integrated
amplifier and four gain settings compensate for varying degrees of coaxial
cable signal loss. The UA874 can be mounted on a microphone stand,
suspended from the ceiling, or mounted to a wall using the integrated
swivel adapter bracket.
Features
• Low-noise signal amplifier compensates for insertion loss in coaxial
cable
• Compatible with Shure wireless receivers and antenna distribution
systems that provide 10–15 V DC bias
• Integrated threaded adapter mounts easily to microphone stands
• Four-position gain selector switch
• Shure quality, ruggedness, and reliability
Installation
• Connect the antenna to the receiver or distribution system using
Shure antenna cables (or any 50 ohm, low-loss coaxial cable, such as
RG-8U).
• The antenna only operates with receivers or distribution systems that
provide 10–15 V DC bias.
• Lower the gain setting for short cable runs, or increase gain for longer
runs. Note that the quality of the cable, not just the length, contributes to
signal loss. A lighter-grade 50 foot cable may require more gain than a
100 foot, low-loss cable. Contact the cable manufacturer for cable loss
specifications.
• Direct the antenna toward the intended coverage area.
• Do not use this antenna for transmitting (such as with PSM transmitters)
Cable Maintenance
To maintain top performance for UA825, UA850 or UA8100 antenna
cables:
• Avoid sharp bends or kinks in the cables.
• Do not deform cables with makeshift clamps, such as bending a nail
over the cable.
• Do not use in permanent outdoor installations.
• Do not expose to extreme moisture.
Antenna Cables from Shure
Shure offers the following pre-terminated antenna cables:
Length Type
6 foot RG58
10 foot RG58
25 foot RG8X
50 foot RG213
100 foot RG213
Model No.
UA806
PA725
UA825
UA850
UA8100
Interface
① Gain Switch
Adjust the four-position gain switch to compensate for the calculated
cable loss, based on the length and type of cable.
② Gain Mode LED
Indicates the current gain switch setting.
③ RF Overload LED
Indicates a strong RF signal that is overloading the antenna amplifier,
which results in distortion or poor performance. Increase the distance
between the antenna and transmitter, or set the antenna to a passive
gain setting.
NOTE: RF Overload LED does not operate for passive gain settings
(−6 dB or 0 dB).
④ BNC Connector
Connect to a reciever or antenna combiner with RF inputs that supply
10–15 V DC bias.
Antenna Placement
Use the following guidelines when mounting antennas:
• Antennas and receivers must be from the same band.
• Mount antennas at least four feet apart.
• Position antennas so there is nothing obstructing a line of sight to the
transmitter (including the audience).
• Keep antennas away from large metal objects.
Important: Always perform a "walk around" test to verify coverage before
using a wireless system during a speech or performance. Experiment with
antenna placement to find the optimum location. If necessary, mark "trou-
ble spots" and ask presenters or performers to avoid those areas.
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