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R175
Compact Receiver
OPERATING INSTRUCTIONS
and trouble-shooting guide
Digital Code Squelch
LECTROSONICS, INC.
Rio Rancho, NM
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INTRODUCTION
The R175 is a fixed frequency, crystal controlled receiver designed for use in public
address applications. A proprietary Digital Code Squelch* is used in the system
design to eliminate squelching problems caused by interference. The compact size
of the receiver permits mounting the receiver almost anywhere. The audio output is
a balanced XLR type, variable in level, to match any type of sound system.
The digital code system provides much more reliable control over the receiver audio
output than a conventional squelch can provide. The matching transmitter generates
a 9-bit code at turn on, and another code at turn off, to open and close the audio
output on the receiver. The squelch on the receiver cannot be opened by anything
other than the specific code it is programmed to receive. This type of squelch
system is even more important when the receiver is connected into an automatic
mixing system.
The R175 circuitry utilizes the latest surface mount technology, with significant
oscillator shielding. Up to four systems can be operated simultaneously in close
proximity in the 169 to 172 MHz band without intermodulation, crosstalk or squelch
problems. The housing is a durable aluminum extrusion with rugged connectors for
lasting reliability.
TABLE OF CONTENTS
INTRODUCTION .................................................................................................. 2
RECEIVER FRONT PANEL ................................................................................. 3
RECEIVER REAR PANEL ................................................................................... 3
SYSTEM SETUP AND OPERATION .................................................................. 4
INDICATOR QUICK REFERENCE ...................................................................... 4
ANTENNA USE AND PLACEMENT ................................................................... 5
TROUBLESHOOTING ......................................................................................... 6
REPLACEMENT PARTS and ACCESSORIES ................................................... 6
SPECIFICATIONS AND FEATURES ................................................................... 7
SERVICE AND REPAIR ....................................................................................... 8
RETURNING UNITS FOR REPAIR ..................................................................... 8
WARRANTY ......................................................................................... Back cover
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Compact Receiver
GRN RED
RED
YEL
RECEIVER FRONT PANEL
-20 and 0dB LEDs - Indicates the modulation (audio level) of the incoming signal - see transmitter manual for proper
adjustment of transmitter “MIC LEVEL” or “GAIN.” The -20 lamp should flicker, or stay lit as you speak into the microphone. The 0dB lamp is a “peak” indicator showing that the audio level in the transmitter is being limited. It is normal
to see an occasional flicker of the 0dB lamp.
OFF-ON Switch - This slide switch turns the power off and on.
POWER LED - Glows when the switch is in the “ON” position and the power source is good, or when the AC adapter
is properly connected. If this LED is very dim or does not light up when the switch is turned on, check the power
source.
CODE LED - Lights when the transmitter is turned on and the internal code in the transmitter matches this particular
receiver. If the receiver is turned on after the transmitter, the code led will not come on. In this case, it will be necessary to turn the transmitter off and back on to enable the receiver. When the carrier signal from the transmitter is too
weak to produce a clean audio signal the receiver will squelch (no audio) but the code lamp will remain lit.
AUDIO LEVEL - This is an attenuator used to regulate the output level of the receiver. When fully counter-clockwise,
the output of the XLR jack on the rear panel will be fully attenuated. When fully clockwise, the output level will be
similar to a high output electret microphone. Intermediate settings are often necessary to ideally match the level with
other equipment.
LECTROSONICS
AUDIO LEVEL
MODULATION
–20
0dB CODE
OFF
ON
DIGITAL CODE
POWER
RECEIVER REAR PANEL
ANTENNA terminal - A standard BNC connector compatible with the supplied antenna.
12 VDC IN - Connect the power supply here - the CH-12 AC adapter is supplied with the receiver for powering the
unit from a 110V AC source. The receiver may also be powered from an 12 to 18 VDC @ 98mA source using the
correct plug (Switchcraft S-760 , 2.1mm coaxial power plug.) The center pin on the receiver jack is positive (+).
AUDIO OUT (standard XLR jack) - This is the audio output that should connect into your sound system. Being such a
common type of connector, many different adapters and cords are available from local audio or electronics dealers in
your area, or from the factory. The pin configuration is:
Pin 1 - shield
Pin 2 - Audio (+)
Pin 3 - Audio (-)
ANTENNA 12V DC IN
Rio Rancho, NM – USA
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AUDIO OUT
2
3
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SYSTEM SETUP AND OPERATION
1) Connect the supplied CH-12 to the power jack on the rear panel.
2) Attach the antenna.
3) Connect the audio cable.
XLR Output: Pin 1 - ground
Pin 2 - audio (+)
Pin 3 - audio (-)
4) Set front panel switch to “ON.” Check to see that the red POWER LED lights up.
5) Adjust transmitter “GAIN.”
This is perhaps the most important step in the set up procedure. (see your transmitter manual for specific
instructions on the proper gain adjustment of your transmitter)
6) Adjust AUDIO LEVEL control according to the type of input on your equipment. The input levels on different
equipment vary which may require that you set the AUDIO LEVEL control in an intermediate position of the
control. Try different settings and listen to the results. If the output of the receiver is too high, you may hear
distortion or a loss of the natural dynamics of the audio signal. If the output is too low, you may hear steady
noise (hiss) along with the audio.
Note: Do not use the transmitter GAIN control to adjust the loudness of your sound system.
INDICATOR QUICK REFERENCE
CODE - This yellow LED lights up when the transmitter is turned on. This indicates that the receiver is getting an
adequate RF signal (carrier) from the transmitter and that the code from the transmitter matches the preset code
embedded in the receiver.
POWER - This red LED lights up when the receiver is properly connected to a power supply and switched on.
-20 and 0dB - The green LED (marked -20) lights up when an audio signal is present at an adequate level to
produce a good signal to noise ratio. The red LED (marked 0dB) lights up when the audio level is being compressed
in the transmitter. An extremely high audio level may also cause distortion.
REVIEW THE TRANSMITTER INSTRUCTION MANUAL FOR PROPER ADJUSTMENT AND SETUP OF THE
TRANSMITTER MIC LEVEL
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Compact Receiver
ANTENNA USE AND PLACEMENT
Connect the antenna to the rear panel jack. Extend the antenna fully if you are using a telescoping type. Position the
antenna so that it is not touching or within 3 or 4 feet of large metal surfaces. It is also good practice to position the
receiver so that there is a direct “line of sight” between the transmitter and the receiver antenna. If the antenna needs
to placed away from the receiver, use a proper external antenna. Use of the supplied whip antenna on the end of a
coax cable with no ground plane is not recommended and may result in poor RF performance.
A wireless transmitter sends a radio signal out in all directions. This signal will often bounce off nearby walls, ceilings,
etc. and a strong reflection can arrive at the receiver antenna along with the direct signal. If the direct and reflected
signals are out of phase with each other a cancellation may occur. The result would be a “dropout.” A dropout
sounds like either audible noise (hiss), or in severe cases, may result in a complete loss of the sound when the
transmitter is positioned in certain locations in the room. A dropout normally sounds like “hum” or “hiss.” Moving the
transmitter even a few inches will change the sound of the hum or hiss, or eliminate it. A dropout situation may be
either better or worse as the crowd fills and/or leaves the room.
In the event that you do encounter a dropout problem, first try moving the receiver/antenna at least 3 or 4 feet from
where it was. This may alleviate the dropout problem. If dropouts are still a problem, try moving the receiver and/or
the antenna to an entirely different location in the room.
Lectrosonics transmitters radiate more power, and the receivers are more sensitive than any other on the market.
This reduces dropouts to an insignificant level. If, however, you do encounter dropouts frequently, call the factory.
There is probably a simple solution.
TRANSMITTER
PHASE
CANCELLATION
REFLECTIVE SURFACE
INDIRECT SIGNAL
DIRECT SIGNAL
LECTROSONICS
DIRECT SIGNAL
RECEIVER
INDIRECT SIGNAL
MULTI-PATH DROPOUT
Rio Rancho, NM – USA
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TROUBLESHOOTING
Before going through the following chart, be sure that you have a good battery in the transmitter. It is important that
you follow these steps in the sequence listed.
SYMPTOM POSSIBLE CAUSE
TRANSMITTER BATTERY LED OFF 1) Battery is inserted backwards.
2) Battery is dead.
RECEIVER CODE LAMP OFF 1) Transmitter not turned on.
2) Transmitter battery is dead.
3) Receiver antenna missing or improperly positioned.
4) Transmitter and receiver not on same frequency. Check
labels on transmitter and receiver.
5) Transmitter and receiver do not have the same internal
code. Check labels on transmitter and receiver.
5) Operating range is too great.
NO SOUND BUT RECEIVER MOD
LEVEL LEDs ARE ON 1) Receiver audio output is disconnected or cable is
defective or mis-wired.
2) Sound system or recorder input is turned down.
DISTORTED SOUND 1) Transmitter gain (MIC LEVEL) is too high. Speak or
sing into the transmitter and check mod level lamps
on the receiver.
2) Receiver output may be mis-matched with the sound
system or recorder input.
3) Excessive wind noise or breath “pops.” Use windscreen
or re-position the microphone.
HISS AND NOISE - AUDIBLE DROPOUTS 1) Transmitter gain (MIC LEVEL) too low.
2) Receiver antenna missing or obstructed.
3) Operating range too great.
EXCESSIVE FEEDBACK 1) Transmitter gain (audio level) too high. Check gain
adjustment and/or reduce receiver output.
2) Microphone too close to speaker system.
3) Microphone too far from the user’s mouth.
REPLACEMENT PARTS and ACCESSORIES
Part No. Description
CH-12 110 Volt AC adapter for receiver
A-185BNC Telescoping, swivel-mount antenna with BNC plug
A-185COAX Remote folded dipole coaxial antenna for VHF receivers
A-170AC Straight whip antenna with BNC plug
A-200 Dipole antenna with dual whips & aluminum base
M119-MICRO Lavalier microphone, omni-directional pattern
M140-MICRO Lavalier microphone, cardioid pattern
M150-MICRO Lavalier microphone, omni-directional pattern with added high
frequency response
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Compact Receiver
SPECIFICATIONS AND FEATURES
Operating Frequencies: 169 to 198 MHz, crystal controlled
RF Sensitivity: -110 dBm for 20 dB Sinad (0.7 uV)
IF Selectivity: 150 kHz interference bandwidth; -30 dB @ ±200 kHz
Squelch Quieting: -109 dB
AM Rejection: Below the noise at all input levels
Modulation Acceptance: ±15 kHz
Third Order Intercept: +5 dBM
Distortion: 0.5% @ 1 kHz, 12 kHz deviation (system)
Signal/Noise Ratio: -90 dB (system)
Audio Outputs: XLR: 200 Ohms bal; 100 mV max.
Antenna Input: BNC; 50 Ohms impedance
Controls: Front panel attennuator controls XLR output; 2 position
power/function switch
Indicators: Red LED for power ON; 2 LEDs for modulation level;
Yellow LED for CODE ON
Power Requirements: Unit accepts 12 to 18 VDC. Polarity protected, standard 2.1mm
coaxial power jack accepts Switchcraft S760 or equivalent plug.
110 Volts AC via CH-12 AC adapter
Power Consumption: 98 mA @ 12 kHz deviation, 72 mA @ idle
Weight: 8.4 oz. without antenna
Dimensions: 1.25 x 3.25 x 5.15 inches
Rio Rancho, NM – USA
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SERVICE AND REPAIR
If your system malfunctions, you should attempt to correct or isolate the trouble before concluding that the equipment
needs repair. Make sure you have followed the setup procedure and operating instructions. Check out the interconnecting cords and then go through the TROUBLE SHOOTING section in the manual
We strongly recommend that you do not try to repair the equipment yourself and do not have the local repair shop
attempt anything other than the simplest repair. If the repair is more complicated than a broken wire or loose connection, send the unit to the factory for repair and service. Don’t attempt to adjust any controls inside the units. Once set
at the factory, the various controls and trimmers do not drift with age or vibration and never require readjustment.
There are no adjustments inside that will make a malfunctioning unit start working.
LECTROSONICS service department is equipped and staffed to quickly repair your equipment. In-warranty repairs
are made at no charge in accordance with the terms of the warranty. Out of warranty repairs are charged at a modest
flat rate plus parts and shipping. Since it takes almost as much time and effort to determine what is wrong as it does
to make the repair, there is a charge for an exact quotation. We will be happy to quote approximate charges by phone
for out of warranty repairs.
RETURNING UNITS FOR REPAIR
You will save yourself time and trouble if you will follow the steps below:
A. DO NOT return equipment to the factory for repair without first contacting us by letter or by phone. We need to
know the nature of the problem, the model number and the serial number of the equipment. We also need a phone
number where you can be reached 8 am to 4 pm (Mountain Standard Time).
B. After receiving your request, we will issue you a return authorization number (R.A.). This number will help speed
your repair through our receiving and repair departments. The return authorization number must be clearly shown on
the outside of the shipping container.
C. Pack the equipment carefully and ship to us, shipping costs prepaid. If necessary, we can provide you with the
proper packing materials. UPS is usually the best way to ship the units. Heavy units should be “double-boxed” for
safe transport.
D. We also strongly recommend that you insure the equipment, since we cannot be responsible for loss of or damage
to equipment that you ship. Of course, we insure the equipment when we ship it back to you.
Mailing address:
Lectrosonics, Inc.
PO Box 15900
Rio Rancho, NM 87174
USA
Shipping address:
Lectrosonics, Inc.
581 Laser Rd.
Rio Rancho, NM 87124
USA
Telephones:
Regular: (505) 892-4501
Toll Free (800) 821-1121
FAX: (505) 892-6243
World Wide Web: http://www.lectrosonics.com Email: sales@lectrosonics.com
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Compact Receiver
Rio Rancho, NM – USA
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LIMITED ONE YEAR WARRANTY
LIMITED ONE YEAR WARRANTY
The equipment is warranted for one year from date of purchase against defects in
materials or workmanship provided it was purchased from an authorized dealer. This
warranty does not cover equipment which has been abused or damaged by careless
handling or shipping. This warranty does not apply to used or demonstrator equipment.
Should any defect develop, Lectrosonics, Inc. will, at our option, repair or replace any
defective parts without charge for either parts or labor. If Lectrosonics, Inc. cannot
correct the defect in your equipment, it will be replaced at no charge with a similar new
item. Lectrosonics, Inc. will pay for the cost of returning your equipment to you.
This warranty applies only to items returned to Lectrosonics, Inc. or an authorized
dealer, shipping costs prepaid, within one year from the date of purchase.
This Limited Warranty is governed by the laws of the State of New Mexico. It states the
entire liablility of Lectrosonics Inc. and the entire remedy of the purchaser for any
breach of warranty as outlined above. NEITHER LECTROSONICS, INC. NOR
ANYONE INVOLVED IN THE PRODUCTION OR DELIVERY OF THE EQUIPMENT
SHALL BE LIABLE FOR ANY INDIRECT, SPECIAL, PUNITIVE, CONSEQUENTIAL,
OR INCIDENTAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE
THIS EQUIPMENT EVEN IF LECTROSONICS, INC. HAS BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES. IN NO EVENT SHALL THE LIABILITY OF
LECTROSONICS, INC. EXCEED THE PURCHASE PRICE OF ANY DEFECTIVE
EQUIPMENT.
This warranty gives you specific legal rights. You may have additional legal rights which
vary from state to state.
LECTROSONICS, INC.
581 LASER ROAD
RIO RANCHO, NM 87124 USA
November 1, 2001
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