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.
Note: The antenna will not operate without 10-15 V DC bias. This is required even at -6 dB and 0 dB ("passive") gain settings.
To maintain top performance for 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.
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.
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.|
Use the following guidelines when mounting antennas:
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.
The gain setting should only be used to compensate for the calculated cable signal loss. Additional signal gain does not mean better RF performance. Too much gain actually reduces reception range and the number of available channels. This is because Shure receivers are optimized to deliver the best performance when the sum of signal gain and cable loss equals 0 dB. Additional gain just amplifies everything in the RF range—including interference and ambient RF noise. It cannot selectively increase the signal from the transmitter.
To calculate the required gain setting, obtain the cable manufacturer's specification for signal loss. The rated loss usually varies with RF frequency in addition to cable length.
Multiply the per 100 feet rating of the cable by cable length to determine signal loss, and add gain as necessary to compensate. For example: a 50 ft. cable with rated loss of -12dB per 100 ft. would calculate as (-12dB/100)*50 = -6dB and require +6dB of gain for a sum total of 0 dB loss.
For more information, visit http://www.shure.com
10 to 15 V DC bias from coaxial connection, 75 mA
3 dB Beam Width
±1 dB, Switchable
+12 dB, +6 dB, 0 dB, −6 dB
RF overload LED does not operate for passive gain settings
|UA874||316 x 359 x 36 mm (H x W x D)|
|UA874X||224 x 234 x 36 mm (H x W x D)|
|UA874XA||224 x 234 x 36 mm (H x W x D)|
|UA874Z||224 x 234 x 36 mm (H x W x D)|
|UA874||317 g (11.2 oz.)|
|UA874X||213 g (7.5 oz.)|
|UA874XA||213 g (7.5 oz.)|
|UA874Z||213 g (7.5 oz.)|
−18°C (0°F) to 63°C (145°F)
−29°C (-20°F) to 74°C (165°F)
This product meets the Essential Requirements of all relevant European directives and is eligible for CE marking.
The CE Declaration of Conformity can be obtained from: www.shure.com/europe/compliance
Authorized European representative:
Shure Europe GmbH
Headquarters Europe, Middle East & Africa
Department: EMEA Approval
75031 Eppingen, Germany
Phone: 49-7262-92 49 0
Fax: 49-7262-92 49 11 4
|Protective zipper pouch||WA874ZP|