Redback C 8890B User manual

REDBACK®UHF Band Diversity Wireless Microphone System
®
Operating Instructions
REDBACK® C 8890B 700 Ch UHF Band Diversity Wireless Mic System
700 CHANNEL UHF BAND
TRUE DIVERSITY WIRELESS
MICROPHONE SYSTEM

REDBACK® C 8890B 700 Channel UHF Band Diversity Wireless Mic System
Congratulations on purchasing a REDBACK PLL synthesized true diversity wireless microphone system. The UHF band wireless
microphone and receiver are the latest generation high quality audio systems. The PLL synthesized diversity wireless
microphone system operates on UHF band frequency (540-570MHz) with 700 selectable channels. Please read this instruction
manual completely before operating the system. These instructions cover the transmitters, and receiver model C 8890B. The
receiver unit is used with compatible 700 channel handheld (C 8892B) and lavalier (C 8893B) transmitters.
System Features:
• Operates on UHF band frequency range 540-570MHz with PLL synthesized control.
• Auto-scan function to easily find an interference free channel.
• Preset channel groups allow up to 8 transmitters and receivers with the use of the autoscan function, up to 12 transmitters
can be used in the same location.
• PLL (Phase Locked Loop) synthesized wireless microphone system with 700 selectable frequencies
making it easy to choose non-interference channels.
• Excellent reception system ensures super high sensitivity, and a high signal to noise ratio.
• Units are supplied with SMT assembled PCB modules ensuring high reliability and easy serviceability.
• High dynamic range handheld microphone for all vocal applications.
• Lapel microphone that minimises static pickup resulting in very low noise.
Receiver Features:
• 12V DC Power supply (supplied)
• 1/2 19” size case with power and RF indicators. Rack ears available for mounting one or two systems into
19” rack equipment.
• Removable aerials making the unit suitable for portable or fixed installations. Aerials are fitted with BNC connectors.
• Includes in-built power supply for antenna booster.
Receiver Specifications:
Carrier Frequency Range: ............................................................................................................ UHF band 540-570MHz
Frequency Stability: ............................................................................................ ±0.005% with PLL synthesized controlled
S/N Ratio: .................................................................................................................................. Over 94dB, at 60dB/μV
Image and Spurious Rejection: .............................................................................................................. 80 dB minimum
Receiving Sensitivity: .................................................................................................... 10uV over 80dB/uV antenna input
Selectivity: .......................................................................................................................................................... >50dB
Dynamic Range: ................................................................................................................................................ >100dB
Modulation Mode: ......................................................................................................................................................FM
IF Frequency: ................................................................................................................ 1st : 243.95MHz 2nd: 10.7MHz
Service Area: ............................................................................................................................ 100m in ideal conditions
AF Response: ................................................................................................................................ 80Hz to 16kHz(±3dB)
T.H.D.: ..................................................................................................................................Less than 1% (at 1kHz)
Receiver Audio Output: .................................................................. Unbalanced: max. 775mV (0dB=0.775V) at 5KΩLoad
Balanced: max. 1V (0dB=1V) at 5KΩLoad
Receiver Power Supply: ............................................................................................................................ DC 12 Adapter
Transmitter Specifications (transmitters sold separately):
Carrier Frequency Range: ............................................................................................................ UHF band 540-570MHz
RF Power Output: ...................................................................................................................................... 10mW (max.)
Spurious Emission: .............................................................................................. More than 60dB below carrier frequency
Frequency Stability: .................................................................................. Within ±0.005% with PLL synthesised controlled
Maximum Deviation: .................................................................................................. ±48kHz within limiting compressor
Microphone Capsule: .............................................................................................. Uni-directional condenser microphone
Operating Voltage: .................................................................................................... DC1.5Vx2 AA (UM-3) or rechargeable
Current Consumption: ........................................................................................................ Approx 120mA ± 10mA(max.)
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REDBACK® C 8890B 700 Channel UHF Band Diversity Wireless Mic System
1. Power: To switch on, press and hold power switch until display can be seen.
2. ▲ Button: Used to select mode, and search channel forwards.
3. SYNC: Press this button when synchronising the receiver and transmitter frequency. See SYNC Mode (Page 7) for
operation description.
4. Set Button: See ‘Channel Selection Modes’ (Pages 4-6) section for more information on this button’s operation.
5. LCD: Displays the channel number, frequency level, RF & AF signal strength, and mode.
6. GP: Indicates the preset group number, eg. P1, P2 etc.
7. CH: Indicates the preset channel number eg. C1 C2 etc.
8. CH: Indicates the channel number, from 001 to 700.
9 FREQ: Indicates the frequency.
10. RF Level Indicators: 5-segment meter illuminates to indicate RF signal strength. If no LEDs illuminate then the
unit is not receiving a signal.
11. AF Level Indicators: 5-segment meter illuminates to indicate audio signal strength. If no LEDs illuminate then the
unit is not receiving an audio signal.
12. MANUAL: This mode allows you to select your own interference free channels.
13. SCAN: This mode scans for an interference free channel and selects one automatically.
14. PRESET: This mode selects an interference-free channel from preset-groups. There are 4 preset groups. In each
group there are 8 preset channels (see Table 1). This allows up to 8 systems to be used simultaneously.
15. Volume Control: Use this rotary control to adjust the receiver output level to match the input sensitivity of an audio
mixer or an amplifier.
16. Antenna Input Connector: BNC-type connectors provide connection to the supplied antennas or to coaxial cable
used with an antenna divider, antenna boosters or remote antennas.
17. Balanced Output: 3-pin XLR connector provides balanced low-impedance output.
18. Unbalanced Output: Unbalanced 6.3mm mono jack audio output for connecting to a line point.
19. Mic/Line Switch: Use this to adjust output (XLR balanced connector and 6.35mm unbalanced phone jack) for
microphone (-20dB) or line-level (0dB).
20. Squelch: Use the squelch to adjust the output level to suppress noise. The higher the squelch control, the lower
the sensitivity of the receiver and smaller the service area of the system. Set the squelch to minimum before
turning the receiver on. If you have unwanted noise increase the squelch control until the noise disappears.
21. DC IN: DC Input connector for the included 12V DC power supply.
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Figure 1: Front and Rear Panel views

REDBACK® C 8890B 700 Channel UHF Band Diversity Wireless Mic System
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Connection:
1. Connect the cable, one end to the balanced or unbalanced output jack of the receiver, the other end to the mic mixing
input of amplifier, audio mixer etc.
2. For best results set the output volume control at about three quarter level and adjust mixer / amplifier level to suit.
3. The squelch level is adjustable by the rotary pot at the back of the unit. Adjust the squelch level to prevent
external noise. Note: setting the squelch high (towards max) will reduce the range of the system.
4. When the receiver is not in use disconnect from the mains power.
CHANNEL SELECTION MODES:
The receiver operates in three channel selection modes.
Manual Channel Selection:
This mode allows you to manually select interference free channels. Table 1 shows the frequencies available. If two
transmitters are being used in the same area, ensure the selected frequencies are at least 10 channel spaces apart.
This reduces interference.
Use the ▲button to select the MANUAL mode so
that the ‘MANUAL’ marker appears on the LCD
display.
Press the SET button for two seconds until the
‘MUTE’ marker appears on the receiver’s LCD
display, and when the frequency and channel data
start flashing, then release the button.
Use the ▲button to select the frequency. Hold the
up arrow button to fast forward through all available
frequencies until a suitable frequency is found.
Press the SET button to lock the setting or let the
selected channel and frequency values keep
flashing five times, until they lock into that setting.

REDBACK® C 8890B 700 Channel UHF Band Diversity Wireless Mic System
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Scan Channel Selection:
This mode automatically searches for an interference free channel.
Note: Have the transmitter 1m from the receiver when using this function.
Use the ▲button to select the SCAN mode so that
the ‘SCAN’ marker appears on the LCD display.
Press the SET button for two seconds until the
‘MUTE’ marker appears on the receiver’s LCD
display, and when the frequency and channel data
start flashing, then release the button.
Use the ▲button to allow the unit to scan for a
vacant or unused frequency. Press the up arrow
button to initiate each frequency channel search
– no need to hold button.
Press the SET button to lock the setting or let the
selected channel and frequency values keep
flashing five times, until they lock into that setting.

REDBACK® C 8890B 700 Channel UHF Band Diversity Wireless Mic System
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Use the ▲button to select the PRESET mode so
that the ‘PRESET marker appears on the LCD
display.
Press the SET button for two seconds until the ‘MUTE’ marker
appears on the receiver’s LCD display, and when the
frequency and channel data start flashing, then release the
button.
There are four preset groups each with eight preset channels.
Press the up arrow button to select a preset group.
Preset Channel Selection:
This mode is used when multiple C 8890B systems are used in the same area. Each receiver is setup to use PRESET mode. This
allows each receiver to select a channel in one of four preset groups. Within each preset group is eight selectable channels. See
Table 1 for a list of frequencies within each preset group. Once configured, up to eight transmitters and receivers may be used in
the same location without interference. If more than eight frequencies are required, once a group of eight is selected, go to
autoscan mode and continue to set frequencies nine through twelve.
If interference occurs within the selected preset group, try switching to the next preset group. If all groups exhibit interference,
use manual or auto scan mode to find a suitable channel.
Press the SET button to lock the setting or let the
selected channel and frequency values keep
flashing five times, until they lock into that setting.
Press and hold the ▲button to scroll through the
channel numbers in order to select a preset
frequency channel..
Press the SET button again to change to the
channel selection zone within the chosen preset
group.

REDBACK® C 8890B 700 Channel UHF Band Diversity Wireless Mic System
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SYNC Mode:
Select the SYNC mode to quick match the interference-free channel on the receiver with Handheld Mic/Bodypack.
First use one of the other modes to select an interference-free channel.
When using SYNC function, the distance from the receiver and transmitter should be within one metre.
1M
SYNC
Press and hold the SYNC button on the Handheld
Mic/Bodypack. The ‘SYNC’ marker will start
flashing on the receiver LCD display.
Keep pressing the SYNC button on the Handheld
Mic/Bodypack. Then press the SYNC button on the
receiver at the same time.
When the ‘SYNC’ marker disappears from the LCD
display and the RF signal shows up, it will lock the
setting and memorize the channel. Now the
Receiver and the handheld units are paired.

REDBACK® C 8890B 700 Channel UHF Band Diversity Wireless Mic System
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Handheld Transmitter Features:
• High sensitivity unidirectional dynamic capsule reduces unwanted handling noise to a minimum
• Special noise absorption design which eliminates switch shock and handling noise.
• PLL synthesised control.
• Accepts two AA batteries (not supplied).
• Low battery LED indicator.
1. Grille: Protects the microphone capsule and helps
reduce breath sounds and wind noise.
2. LCD: Displays channel number & battery level.
3. Power ON/OFF Switch
4. Battery Compartment
5. SYNC button: For frequency pairing with receiver.
6. Battery Cover
7. Colour Clip: This colour clip helps to identify the
frequency for multi-channel systems operation.
8. Anti Roll Ring: Prevents microphone from rolling
when placed on furniture.
Operation: (See Fig 2.)
1. Unscrew to open the battery compartment.
2. Insert two AA Size 1.5V batteries into the battery holder according to polarity (+) and (-) indicators marked on the battery
housing. The transmitter accepts dry cell batteries or rechargeable batteries.
3. Replace battery cover.
4. Push and hold the power switch until the LCD illuminates to switch on. The LCD shows channel number and battery status.
5. To change channel/frequency, press the SYNC button and synchronise the receiver and transmitter frequency. See SYNC
Mode for operation description.
6. To switch off, press and hold the power button until the LCD displays ‘OFF’.
7. Remove the batteries from the unit if it is not to be used for a long time. This will prevent damage to the unit that a defective
leaking battery may cause.
PLEASE NOTE: ALL TRANSMITTERS ARE SOLD SEPARATELY
1
2
5
6 4
7
3
8
Figure 2: Handheld Microphone Transmitter C 8892B

REDBACK® C 8890B 700 Channel UHF Band Diversity Wireless Mic System
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Beltpack Microphone:
A range of microphones and pickups are available for the belt pack transmitter including tie clip mic, lecture type headset,
aerobics type headset and guitar. The belt pack microphone is equipped with a line/mic switch.
1. Power ON/OFF Switch
2. Mini XLR Connector: For microphone or guitar pick-up.
3. Antenna: Permanently connected, helical antenna.
4. LCD: Displays channel number and battery power level.
5. SYNC: For frequency pairing with the receiver.
6. Mic/Line Selector: This switch sets the audio input either to microphone level or line level.
7. Gain: This rotary control adjusts the input audio level of the transmitter. The gain adjustment range is 10dB.
8. Mic Unit: Pictured with the C 8893B lapel.
9. Tie Clip: To clip on the tie or lapel for free-movement.
10. Cable: With mini XLR connector cable to connect the transmitter.
11. Battery Compartment
Figure 3: Beltpack Microphone Transmitter C 8893B
Operation: (See Fig 3.)
1. Slide open the battery compartment.
2. Insert two AA Size 1.5V batteries into the battery holder according to polarity (+) and (-) indicators marked on the battery
housing. The transmitter accepts dry cell batteries or rechargeable batteries.
3. Replace battery cover.
4. Connect the microphone or guitar pick-up to the unit.
5. For microphone set the mic/line switch to mic. For guitar input set to line.
6. To switch on, push the power switch until the LCD illuminates. The LCD shows channel number and battery status.
7. To change channel/frequency, Press the SYNC button and synchronise the receiver and transmitter frequency. See SYNC
Mode for operation description.
8. Adjust gain to optimum level. If the unit overdrives reduce gain.
9. To switch off, press and hold the power button until the LCD displays ‘OFF’.
10. Remove the batteries from the unit if it is not to be used for a long time. This will prevent damage to the unit that a defective
leaking battery may cause.

3 Pin XLR Lead
AMPLIFIER
SPEAKER
Mic IN Line IN
AUDIO MIXER
WIRELESS
RECEIVER
Line OUT
Fig 4. Wireless Receiver Connection Via Mic In
REDBACK® C 8890B 700 Channel UHF Band Diversity Wireless Mic System
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AMPLIFIER
SPEAKER
Mic IN Line IN
AUDIO MIXER
WIRELESS
RECEIVER
Line OUT
6.35mm Stereo jack Lead
Fig 5. Wireless Receiver Connection Via Line In
Figure 6: The unit may be 19” rack mounted individually, shown in (A). Or side by side
with an additional receiver, shown in (B).
A. B.

REDBACK® C 8890B 700 Channel UHF Band Diversity Wireless Mic System
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Note: TWO OR MORE WIRELESS MICROPHONES WHICH TRANSMIT AT THE SAME FREQUENCY CAN NOT BE
USED IN THE SAME LOCATION.
WHEN TWO OR MORE WIRELESS MICROPHONES (HANDHELD AND/OR LAVALIER) ARE USED IN THE SAME
LOCATION ENSURE THAT 10 OR MORE CHANNEL SPACES ARE BETWEEN EACH SELECTED FREQUENCY SO
THAT INTERFERENCE DOES NOT OCCUR.
If interference still occurs (which is due to harmonics) select another frequency. TABLE 1 shows 4 groups of 8
frequencies which may be used together in the same area. ALTERNATIVELY USE THE SCAN FUNCTION.
TROUBLESHOOTING:
Signal dropouts and noise may be suddenly encountered by interruption from outside if there is too long a distance between
microphone and receiver, or battery power is low. In such a case, adjust receiver antenna or change battery.
No Sound Output • Check the transmitter and receiver power supply and switch.
• Check that the transmitter and receiver are tuned to the same frequency.
• Check that the audio amplifier or mixer is switched on and that the receiver
output is connected.
• Check whether transmitter is too far away from receiver or SQUELCH control
set too high.
• Check whether transmitter or receiver is located too close to a metal object or there are
obstructions between transmitter and receiver.
Sound Interference • When using two or more microphone sets simultaneously, ensure that the chosen
frequencies do not interfere (see Table 1 for frequency guide).
• Check for interference from other devices - wireless microphones, TV, radio etc.
• Improve antenna location.
Distortion • Check the receiver volume level is not set too high.
• Check for interference from other devices - wireless microphones, TV, radio etc.
PRECAUTIONS:
* Avoid extremely dirty or dusty environments.
* Avoid use in areas where extremely high humidity is present.
* Do not drop the microphone on a hard concrete floor, nor strike the microphone head front with fist or fingers,
nor blow strongly into the microphone head front.
* Remove the battery in microphone if not in use for a long time. This will prevent damage that a defective
"leaking" battery may cause.
DESIGN AND SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE.
TABLE 1: 540-570MHz
CH GROUP 1 CH GROUP 2 CH GROUP 3 CH GROUP 4
CH 1 2540.075 18 540.875 32 541.575 65 543.225
CH 2 47 542.325 113 545.625 95 544.725 182 549.075
CH 3 162 548.075 133 546.625 308 553.575 323 554.075
CH 4 245 551.475 204 550.125 350 554.975 447 558.225
CH 5 399 556.625 264 552.125 378 555.925 504 560.175
CH 6 554 562.675 488 559.575 426 557.525 529 561.425
CH 7 608 565.375 647 567.325 542 562.075 572 563.575
CH 8 631 566.525 661 568.025 679 568.925 698 569.875

REDBACK® C 8890B 700 Channel UHF Band Diversity Wireless Mic System
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For long distance requirements or special or difficult applications such as stadiums, auditoriums, shopping centres, a range of
accessories are available to increase transmission distance or to reduce drop outs.
These include:
C 8841 or C8841A Ceiling mount antenna
C 8842 or C8842A Vertical mount antenna booster
C 8843 or C8843A Mounting bracket to suit C 8842 antenna booster
In addition to the above, for multiple system installations a range of accessories are available to aid cabling and installation.
These include:
C 8844 or C8844A Antenna splitter / combiner
C 8846 or C8846A Antenna divider
For further information on these and technical help please contact your nearest Redback dealer or consult the product manuals
for the above.
The detachable antenna is
highly recommended for
long-distance purposes, such
as in a stadium or in an
auditorium.
Antenna Booster
UHF Antenna
Antenna
Mounting
Bracket
The antenna booster is
designed for long distance
receiving applications,
eg. if the distance exceeds
30M.

REDBACK® C 8890B 700 Channel UHF Band Diversity Wireless Mic System
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REDBACK® C 8890B 700 Channel UHF Band Diversity Wireless Mic System

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REDBACK® C 8890B 700 Ch UHF Band Diversity Wireless Mic System

REDBACK® C 8890B 700 Ch UHF Band Diversity Wireless Mic System
Page 16 Revision 12042012
The Distributors warrants this product for 12 months from date of purchase from its resellers to the consumer. If
this item is part of an installation or another product, please contact the installer or supplier for your warranty.
During the warranty period, we undertake to repair or replace your product at no charge if found to be defective
due to a manufacturing fault. The warranty excludes damage by misuse or incorrect installation (i.e. failure to
install and operate device according to specifications in the supplied instruction manual), neglect, shipping
accident, or no fault found, nor by use in a way or manner not intended by the supplier.
For repair or service please contact your PLACE OF PURCHASE.
It is at manufacturer discretion as to whether the goods will be repaired or replaced (whilst under warranty);
and as to whether identical goods will be used to replace the item due to changes of models / products.
Note: Under no circumstances should you attempt to repair the device yourself or via a non-authorised service
centre, as this will invalidate the warranty!
Our goods come with guarantees that cannot be excluded under the Australian Consumer Law. You are entitled to
a replacement or refund for a major failure and for compensation for any other reasonably foreseeable loss or
damage. You are also entitled to have the goods repaired or replaced if the goods fail to be of acceptable quality
and the failure does not amount to a major failure.