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General Description
The Shure UA874 uses a log periodic dipole array to offer enhanced reception
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.
Features
• Low-noise signal amplifier compensates for insertion loss in coaxial cable
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 antenna cables:
UA874Z
Active Directional Antenna
• 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
Note:The antenna will not operatewithout 10-15 V DC bias. This is required
even at -6 dB and 0 dB ("passive") gain settings.
• 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.
Selecting Antenna Cables
Use 50 ohm low-loss coaxial cable, such as RG-8U. Shure offers pre-terminated antenna cables ranging from 6 to 100 feet.
NOTE:When ordering cables from Shure, select the low-loss "Z" models
(available for longer cables) when using frequency bands above 1000 MHz.
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.
Caution: There may be a small RF dropout when changing the gain setting.
1/4©2017 Shure Incorporated
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Shure IncorporatedUA874Z Active Directional Antenna
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 lower the antenna gain setting.
NOTE:RF Overload LED does not operate for passive gain settings (−6 dB or 0 dB).
④ BNC Connector
Connect to a receiver 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 one wavelength (two feet) apart.
• Position antennas so there is nothing obstructing a line of sight to the transmitter (including the audience).
• Keep antennas away from 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 "trouble spots" and ask presenters or performers to avoid those areas.
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