Lectrosonics CR170 User Manual

CR170

VHF MINIATURE RECEIVER

OPERATING INSTRUCTIONS

and trouble-shooting guide

LECTROSONICS, INC.

Rio Rancho, NM

INTRODUCTION

Thank you for selecting the Lectrosonics FREEDOMIKE system.
The FREEDOMIKE CR170 receiver represents over 80 years of combined experience in the design of RF and

audio devices and sets new standards for RF performance and flexibility. The CR170 receiver design is the result
of surveying the needs of professional video producers, audio visual coordinators, and many others in the industry.
Numerous conversations with dealers and end-users have established the parameters for the design.

The CR170 is designed for professional users who demand outstanding performance and flexibility. It is the ideal
choice for use with video recording equipment or as an "add-on" wireless receiver for almost any type of sound
equipment.

TABLE OF CONTENTS

INTRODUCTION .......................................... 1

GENERAL TECHNICAL DESCRIPTION .......................... 2

RECEIVER FRONT PANEL ................................... 3

RECEIVER REAR PANEL .................................... 4

ANTENNA USE AND PLACEMENT ............................. 5

OPERATING INSTRUCTIONS ................................. 6

TROUBLESHOOTING GUIDE ................................. 7

REPLACEMENT PARTS and ACCESSORIES ..................... 7

SERVICE AND REPAIR ..................................... 8

RETURNING UNITS FOR REPAIR ............................. 8

SPECIFICATIONS AND FEATURES ............................ 9

WARRANTY ........................................ Back cover

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GENERAL TECHNICAL DESCRIPTION

The CR170 receiver employs a two stage, crystal controlled oscillator, individually trimmed to the exact operating
frequency, to ensure that the frequency will not drift. This eliminates the need for "tuning" adjustments each time
the receiver is used. Numerous frequencies are available from 150 MHz through 216 MHz.

High Q toroidal filters in the RF and IF stages reject interfering adjacent signals and provide over 100 dB of image
rejection. Dual gate MOS FET semi-conductors in the RF amplifier and mixer provide excellent sensitivity and
resistance to RF overload.

The audio section contains a noise reduction "compandor" to suppress audible noise (hiss) without impairing the
natural dynamics of the audio signal. A 6-pole active filter in the audio path eliminates all supersonic and subsonic
noise in order to increase the compandor tracking accuracy in weak signal conditions. A time delayed, correlation
squelch system is employed in the CR170. This circuit is highly stable and never needs adjustment by the user.

A recessed level control knob adjusts the audio output from microphone level to line level. Since the audio input
level requirements vary from one VCR or sound system to another, this control is continuously variable which
allows the receiver audio output to be perfectly matched to the audio input of any type of recording or PA
equipment.

The receiver may be powered from an internal 9 Volt battery, external 12 Volt DC or from 110 Volts AC using the
supplied charger. The battery compartment will accept any brand of 9 Volt alkaline or lithium battery. A unique,
floating polarity barrier prevents inserting the battery backward and will automatically adjust itself to accommodate
varies lengths of batteries.

The CR170 receiver is compatible with all Lectrosonics 185 series high band transmitters.

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RECEIVER FRONT PANEL

OFF/ON

A slide switch which turns the power on and off.

POWER

An LED that glows when the OFF/ON switch is in the "ON" position and the battery is good, or when the AC
adapter or external power source is properly connected. If this lamp is very dim or does not light up when the
switch is turned on, check the external power source or replace the battery. Use only ALKALINE or LITHIUM
batteries.

RF

An LED which lights when the companion transmitter is turned on and there is sufficient signal for good receiver
operation. Internal circuits monitor both signal level and interference levels and decide if the transmitted signal is
strong and "clean" enough for satisfactory operation. If not, the RF lamp will go out and the receiver will "squelch",
shutting off the sound output. This action is automatic and requires no user adjustment.

MODULATION

Two LEDs which continuously monitor the modulation (audio level) of the received signal from the transmitter and
are used when making initial adjustment to the transmitter.

LEVEL

An output attenuator used to regulate the output audio level of the receiver. When adjusted fully counter-clockwise
to the "MIC" position, the output of the mini jack on the front panel will be the same as from a typical microphone.
When adjusted fully clockwise to the "LINE" position, the output level will be at a normal 0dB line level.
Intermediate settings are sometimes necessary due to the variations in different input compressors and ALC
(automatic level control) circuits on different VCR’s and audio inputs.

AUDIO OUTPUT JACK

A mini-phone jack that connects to your VCR, camcorder or sound system. It is a standard 3.5mm jack which is
used on most industrial video equipment. A male-to-male patch cord is supplied with the receiver to connect the
receiver output to the same type of mini-jack on the external equipment. This is a common type of connector used
on many different adapters and cords available from your local audio or electronics dealers, or from Lectrosonics.

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