SHURE UA874WB

The Shure UA874WB is an active directional antenna for professional wireless microphone systems. It uses a log periodic dipole array (LPDA) to improve reception when aimed at the coverage area, compared with a standard 1/2-wave omnidirectional antenna. An integrated amplifier with four gain settings compensates for coaxial-cable loss.

Key Features

• UA874WB wideband variant: RF range 470-900 MHz (not UA874US 470-698 MHz, UA874E 470-790 MHz, or the 900 MHz / 1.2-1.8 GHz UA874X/Z models)
• Log periodic dipole array with 7.5 dBi on-axis antenna gain and 70° (3 dB) beam width
• Four-position gain switch: +12 dB, +6 dB, 0 dB, −6 dB (±1 dB)
• Requires 10-15 V DC bias on the coaxial feed (75 mA), even at 0 dB and −6 dB
• BNC female, 50 Ω; RF overload LED (does not operate in the passive 0 / −6 dB settings)
• Integrated threaded swivel adapter for microphone-stand, wall or ceiling mounting

Placement and cabling

Connect the antenna to a Shure wireless receiver or antenna distribution system that supplies 10-15 V DC bias, using 50 Ω low-loss coaxial cable (for example RG-8U). Shure states that the antenna will not operate without that bias. Direct the antenna toward the coverage area, keep a line of sight to the transmitters, and mount antennas at least one wavelength (two feet) apart. Do not use the UA874 for transmitting, in permanent outdoor installations, or where it is exposed to extreme moisture.

Gain

Set gain only to offset calculated cable loss. Shure receivers are specified to perform best when the sum of antenna gain and cable loss is 0 dB; extra gain also amplifies interference and ambient RF. Use the lowest setting that gives a solid RF meter reading. The −6 dB setting is described for short runs (25 ft or less) with less than 100 ft between transmitter and antenna. If the RF overload LED lights, increase distance or reduce gain.

Specifications

Figures below are from the Shure UA874 User Guide (en-US). Only the UA874WB frequency row is used for RF range. Electrical, pattern and gain figures are series specifications in that same table. Dimensions and weight are listed in the guide under UA874 (not a separate WB line); they are not mixed with the compact UA874X / UA874XA / UA874Z body.

RF and electrical (UA874WB)

Source: Shure UA874 User Guide (en-US), Specifications. RF Frequency Range row UA874WB 470-900 MHz only. Other UA874 SKU frequency rows in that table are not used.

Model	UA874WB
RF frequency range	470-900 MHz
Connector	BNC, female
Impedance	50 Ω
Power requirements	10 to 15 V DC bias from the coaxial connection, 75 mA
Reception pattern	3 dB beam width, 70 degrees
Third-order overload intercept point (OIP3)	> 30 dBm
Antenna gain (on axis)	7.5 dBi
Signal gain	±1 dB, switchable: +12 dB, +6 dB, 0 dB, −6 dB
RF overload LED threshold	−5 dBm (LED does not operate at 0 dB or −6 dB)

Mechanical and environment

Source: Shure UA874 User Guide (en-US), Specifications, Dimensions and Weight rows labelled UA874 (316 × 359 × 36 mm / 317 g). Compact UA874X / XA / Z dimensions are omitted. Operating/storage temperatures are series figures from the same page.

Dimensions (H × W × D)	316 × 359 × 36 mm (UA874 body in this guide)
Weight	317 g (11.2 oz) (UA874 body in this guide)
Operating temperature range	−18 °C (0 °F) to 63 °C (145 °F)
Storage temperature range	−29 °C (−20 °F) to 74 °C (165 °F)
Mounting	Integrated threaded swivel adapter (microphone stand, wall or ceiling)
Optional accessory	WA874ZP protective zipper pouch

Datasheets

Public manufacturer documents (link only - this does not add a downloads module):

• Shure UA874 User Guide (en-US, PDF)
• Shure UA874 User Guide (en-US, HTML)