MODEL UA870 UHF ACTIVE DIRECTIONAL ANTENNA
The Shure UA870 is an active UHF wireless directional
antenna designed for use with the Shure UHF Wireless Sys-
tem. It features a log periodic dipole array. When compared
to an omnidirectional 1/2-wave antenna, the cardioid pattern
provided by the UA870 offers enhanced reception of the de-
sired coverage area and greater rejection of RF signals out-
side the coverage area.
To compensate for coaxial cable signal loss, the UA870
has an on-board amplifier that offers user selectable 3 or 10
dB gain. The gain setting is indicated by two LEDs. Remote
12 Vdc power for the antenna amplifier is provided by a
Shure U4 Receiver or a Shure UA840 Antenna Distribution
System through the connecting coaxial cable.
The UA870 can be mounted on a microphone stand,
suspended from the ceiling, or mounted to a wall using the
integrated swivel adapter bracket. The UA870 is weather re-
sistant for use outdoors. For best diversity performance, use
two UA870 antennas.
INSTALLATION INSTRUCTIONS
1.
Determine the length of cable required to connect the
UA870 Antenna to the U4 Receiver or UA840 Antenna
Distribution System.
IMPORTANT: Always use low-loss 50 ohm cable, such as
RG-8X or equivalent. Shure UA825 7.6 m (25 ft.) or
UA850 15.2 m (50 ft.) cables are recommended.
2.
Set the gain switch to the appropriate setting. If you are
using coaxial cables up to 7.6 m (25 ft.) long, select the
3 dB position. If using cables 7.6 m (25 ft.) or longer, se-
lect the 10 dB position. To access the gain switch, re-
move the cover of the preamplifier box (printed side) by
unscrewing the four screws at each corner. Gain set-
tings are marked on the pc board inside.
NOTE: The UA870 gain control is factory preset at the
10 dB position.
3.
Connect one end of the antenna cable to the UA870.
Then mount the antenna so that it points toward the in-
tended coverage area. See Figure 1.
4.
Connect the other end of the antenna cable to the U4
Receiver or UA840 Antenna Distribution System. The
gain LED on the UA870 illuminates to verify that power
is being provided to the antenna.
IMPORTANT: Always perform a “walk around” test to
verify coverage before using a wireless system during a
speech or performance. Experiment with antenna place-
ment to find the optimum location for the UA870.
FIGURE 1
NOTE: For additional technical assistance, call the
Shure Customer Service Department at 1-800-434-3350. In
Europe, phone 49-7131-72140.
Model UA870 UHF Active Directional Antenna
User Guide
Shure Brothers Incorporated
222 Hartrey Avenue
Evanston IL 60202-3696 U.S.A.
E
1997, Shure Brothers Incorporated
Printed in U.S.A.
27A8629 (QJ)
www.audiovias.com
Product Information
