RECEIVER GAIN
The rear-panel receiver OUTPUT can be adjusted using
the MICROPHONE OUTPUT LEVEL Control. In this way,
the wireless system output can be made identical to that
of a conventional wired microphone, avoiding extreme
d i f f e r e n c e s i n i n p u t l e v e l s e t t i n g s . T u r n i n g t h e
M I C R O P H O N E O U T P U T L E V E L C o n t r o l c o u n t e r -
clockwise decreases the output level, and turning it
clockwise increases the output.
OPERATION
1. T u r n o n t h e t r a n s m i t t e r a n d r e c e i v e r P O W E R
Switches.
2.
Make sure the transmitter MIC ON/OFF Switch is on.
3. Talk into the microphone (or play the connected
musical instrument) and observe the receiver display
for proper audio and RF indications.
4.
Continue talking or playing and move around the per-
forming area. In each area, observe the receiver
displays and make sure the RF signal strength is
adequate.
Normal operation is shown by steady illumination of
the green RF SIGNAL LED on the Shure W20R receiver,
or by illumination of at least one green LED of the RF
SIGNAL LEVEL display on the W25DR receiver. Weak
signals are evidenced by intermittent operation of the
W20R LED and by illumination of the lower LEDs on the
W25DR.
In most cases, the problem of weak RF signal strength
is also indicated by audible evidence:
signal dropout,
either continuous or intermittent, or noisy, distorted
operation. The condition is generally caused by poor
antenna location, RF signal blocking, or operation
b e y o n d t h e s y s t e m c a p a b i l i t y . R e f e r t o t h e
Troubleshooting section of the receiver manual for
remedies.
Feedback-the annoying howl or squeal heard in the
s o u n d s y s t e m - i s a s m u c h a p r o b l e m i n w i r e l e s s
microphones as in wired mics. Checking microphone
operation throughout the performing area will probably
uncover any locations that are prone to audio feedback.
If the problem cannot be solved by a slight lowering of
the receiver output level or the associated amplifier gain,
relocation of the speakers or possibly professional
equalization of the sound system is recommended.
IMPORTANT
Every
wireless microphone installation is a unique
situation, and can present a variety of problems.
N e v e r a t t e m p t a l i v e p e r f o r m a n c e w i t h o u t a
“walkthrough” first. And if major changes (fur-
niture,
s c e n e r y , e t c . ) w e r e m a d e s i n c e t h e
walkthrough,
c h e c k t h e w i r e l e s s m i c r o p h o n e
operation again.
SPECIFICATIONS
RF Power Output
50 mW maximum; 30 mW typical
Modulation
54F3 ± 12 kHz deviation, 50 µsec pre-emphasis
Modulation Limiter
Internal compressor
Input Impedance
Actual: 16k (20k dc), pin 4 wired to pin 3 for WL83
microphone; 91k, pin 4 open for microphone or instru-
ment pickup
Gain Switch
High position . . . . . . .
0.0065 Vrms required for
100% modulation
Low position . . . . . . . . . 0 . 0 6 5 V r m s r e q u i r e d f o r
100% modulation
Gain Adjustment Range
Low Position . . . . . . . . . . . . . . . . . . . . . . 20 dB
High Position . . . . . . . . . . . . . . . . . . . . . . . 30 dB
Antenna
Attached, 305 mm (12 in.), omnidirectional, flexible
wire
Power
Battery Type . . . . . . . 9 - v o l t a l k a l i n e ( N E D A
1604A); 8.4-volt nicad op-
tional
Battery Life . . . . . . . . . . 6 to 8 hours typical
(alkaline); 1.5 to 2 hours
typical (8.4-volt nicad; per
charge)
Current Drain . . . . . . . . 35 mA typical
Dimensions
102 mm H x 69.8 mm W x 25.4 mm D (4 in. x 2-3/4 in. x 1
in.) (not including antenna, controls and belt clip)
Weight
113 grams (4 oz); 170 grams (6 oz) with battery
ANTENNA
The transmitter antenna is a permanently attached,
flexible wire, 1/4-wave antenna. It has an omnidirectional
pickup pattern (equally effective in all directions) and is
designed to operate in a vertically polarized mode. This
means that the antenna should hang downward during
operation; coiling or wadding it to minimize visibility will
reduce the system’s operating distance.
BATTERIES
Careful transmitter battery selection, installation, use
a n d c a r e w i l l h e l p a v o i d p r o b l e m s i n w i r e l e s s
microphone use. The most dependable, long-lived bat-
teries at this time are the manganese-alkaline, or
alkaline, types. In addition to offering the longest ex-
pected operating life, they are commonly available.
One small word of caution about alkaline batteries:
they are not all the same size. Make certain the battery
you buy will make contact inside the battery compart-
ment.
Nickel-cadmium (nicad) batteries can save money
through their rechargeability, but the tradeoff is in
shorter expected life per charge. In addition, forgetting
to recharge can be disastrous.
Another major consideration in nicads is that of
operating voltage. The “heavy-duty” 8.4-volt nicads are
satisfactory for transmitter use, but the “9-volt-size”
nicads commonly found in stores are only 7.2 volts and
will not provide satisfactory wireless performance.
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