Lectrosonics SRc-941 Instruction Manual

SRc-941

Camera Slot Dual UHF Receiver

Featuring

Digital Hybrid Wireless® Technology

INSTRUCTION MANUAL

U.S. Patent 7,225,135

Quick Start Summary

The following checklist includes the minimum required
settings to start using the receiver.

• Install either a battery sled or camera slot adapter
kit (see pages 6-9).

• Connect power to the receiver (see pages 9-10, 13)

• Set the DIVMODE for single or dual channel opera­tion (see pages 17, 19).

• Set the COMPAT (compatibility) mode for the trans­mitters to be used (see page 20).

• Find clear operating frequencies for one or both
receivers (see pages 19 and 22).

• Set transmitters on the matching frequencies (see
transmitter manual).

• Verify transmitters are set to the same compatibility
mode as the receiver (see transmitter manual).

• Adjust transmitter input gain to match voice level
and mic position (see transmitter manual).

• Adjust receiver output level as needed for the
camera or mixer input level desired (see LEVEL on
page 19 and MIXTRIM/MIXMODE and TONE on
page 21).

IMPORTANT:

Performance will be degraded if

FREQ.

WARNING

Receiver 2 is set 4.2 to 4.8 MHz higher
than Receiver 1. The LCD will also flash
this message periodically.

Fill in for your records:

Serial Number:

Purchase Date:

Rio Rancho, NM, USA
www.lectrosonics.com

SRc-941 Dual Receiver

Table of Contents

General Technical Description .............................................. 3

IF Amplifiers and SAW Filters ............................................... 4

Digital Pulse Counting Detector ............................................ 4

DSP-Based Pilot Tone ........................................................... 4

SmartSquelch
SmartDiversity

Turn On and Turn Off Delays................................................. 4

Test Tone ............................................................................... 4

LCD Display .......................................................................... 5

Smart Noise Reduction (SmartNR

Front Panel Controls and Functions ..................................... 6

Audio Outputs ....................................................................... 6

LCD Screen .......................................................................... 6

MENU/SELECT Button ......................................................... 6

PWR/BACK Button ............................................................... 6

IR (Infrared) Sync ................................................................... 6

UP/DOWN Arrow Buttons ..................................................... 6

Rear Panel Adapters............................................................... 6

Camera Slot Adapter KIts ..................................................... 7

Adapters for Stand-Alone Use .............................................. 7

Installing Adapters ................................................................ 8

Installing Rear Panel Adapters.............................................. 8

Replacement Screw Kits ....................................................... 8

Battery Adapters ................................................................... 9

Installing the SRBATTSLED .................................................. 9

SR9VBP 9 Volt Battery Adapter .......................................... 10

SRSLEEVE mounting adapter ............................................ 10

SRHARDWARE mounting adapter kit ................................. 10

Audio Output Cables and Connectors ................................. 12

External Power Cables ........................................................ 12

Mounting and Orientation .................................................... 13

AMJ Rev. A Jointed Antenna ............................................... 13

PCA900 Printed Circuit Antenna ......................................... 14

LCD Main Window................................................................. 15

Navigating the LCD .............................................................. 16

Main Window ....................................................................... 17

Frequency Screen ............................................................... 17

Setup Screens .................................................................... 17

Locking and Unlocking the Front Panel Controls ................ 17

LCD Backlight Setup ........................................................... 17

Battery Timer Reset ............................................................ 17

Menu Item Descriptions ...................................................... 18

Front Panel Shortcuts ......................................................... 20

Scanning for Clear Frequencies ......................................... 21

Scan Window ...................................................................... 21

Zoom View Window ............................................................. 21

Frequency Coordination ...................................................... 22

Multi-channel Checkout ....................................................... 22

Specifications and Features ................................................ 23

FCC Notice ......................................................................... 23

Troubleshooting .................................................................... 24

Service and Repair ............................................................... 26

Returning Units for Repair .................................................. 26

™ ......................................................................................................................... 4

™ ........................................................................................................................ 4

™

) .................................... 5

Digital Hybrid Wireless

®

The Lectrosonics Digital Hybrid Wireless® uses innova­tive technology to combine the advantages of digital
audio with the advantages of analog RF transmission.
The result delivers the superior sound quality of a digital
system and the excellent range of an analog system.

A proprietary algorithm encodes the digital audio infor­mation into an analog format which can be transmitted
in a robust manner over an analog FM wireless link. The
receiver employs state-of-the-art filters, RF amplifiers,
mixers and detector to capture the encoded signal and
a DSP recovers the original digital audio.

This digital/analog hybrid technique has some very
beneficial properties. Because the information being
transmitted is digitally encoded, immunity to noise is
much higher than what a compandor can offer. Because
the encoded audio is sent in analog format, spectral
and power efficiency and operating range are not com­promised.

Under weak RF conditions, the received signal de­grades gracefully, like an analog system, delivering
as much usable audio as possible at maximum range.
Since the audio is free of compandor artifacts, pumping
and breathing problems are also greatly reduced.

2

LECTROSONICS, INC.

General Technical Description

Ant 1

243.950 MHz

Ant

Detector

2

SRC-941 DUAL RECEIVER

SRC-941 DUAL RECEIVER

UHF Digital Hybrid Wireless

®

SAW

BPF

2

SAW

BPF

LNA Splitter

RECEIVER 1

RECEIVER 2

LNA Splitter

Keypad

To both PLL

To phase switches

+3.3V

V Reg

Power

RF BLOCK DIAGRAM

Phase

Shifter

Phase

Shifter

LCD

display

µP

Memory

On/O

Audio 1
Audio 2

DC-DC

conv

–5V

(from RF PCB)

Fuse

Ref xtal

DSP

+5V

µP

Codec

Mixer

SAW

BPF

High Side

Injection

12 MHz

Ref.

Osc.

High Side
Injection

SAW
BPF

Mixer

AUDIO BLOCK DIAGRAM

DAC

DC-DC

conv

Osc

sync

DC-DC

conv

248.450 MHz

IF Amp

1st

VCO

1st

VCO

IF Amp

Audio amps

+3.3V

DC-DC

conv

+1.6V

PLL

PLL

SAW

BPF

248.800 MHz

2nd

VCO

µP

2nd

VCO

244.200 MHz

SAW

BPF

µP

digital

atten

+30V

High Side

Injection

High Side

Injection

Digital pot

Digital pot

Rx IC

350 kHz

BPF

Rx IC

250 kHz

BPF

CH 1

µP

polarity

CH 2

+5V

+5V

audio switch

+5V

+5V

audio switch

Diode

protected

outputs

Pulse

Detector

Pulse

Detector

5k

5k

5k

5k

Audio

Amp &

Filter

Audio

Amp &

Filter

50

50

50

50

Audio 1

Window
Detector

RSSI

RSSI

Window

Audio

+

Hi

Com

Lo

–

3

2

1

4

5

+

Hi

Com

Lo

–

The design consists of two separate receivers built into
a single, ultra compact housing with interchangeable
adapters for video camera wireless receiver slots and
stand-alone use. Digital Hybrid Wireless® technology
provides superb, compandor-free audio quality and
compatibility with other wireless systems. The RF per­formance is extremely stable over a very wide tempera­ture range, making the receiver perfectly suited to the
rough environmental conditions in field production.

The front panel features a menu-driven LCD interface
and four membrane switches used to view and alter set­tings. Audio outputs are provided on the rear panel for
camera slots or other audio devices.

A built-in spectrum analyzer scans across the tuning
range of the receiver to simplify finding clear operating
frequencies.

The dual receiver architecture allows two different types
of diversity reception:

Rio Rancho, NM

Osc

sync

SmartDiversity™ allows each receiver to run indepen-

dently to provide two separate audio channels. The
algorithm analyzes both the incoming RF level and the
rate of change in RF level to determine the optimum
timing for antenna phase switching. The system also
employs “opportunistic switching” to analyze and then
latch the phase in the best position during brief squelch
activity.

Ratio Diversity blends the audio outputs of both receiv­ers in a seamless manner to produce a single audio
output. A panning circuit blends more signal from the re­ceiver with the stronger RF signal over a wide RF level
range to anticipate and eliminate dropouts long before
they occur. When a good RF signal is present at both
receivers and the audio is blended equally, the signal­to-noise ratio is increased by 3 dB.

3

SRc-941 Dual Receiver

IF Amplifiers and SAW Filters

The first IF stage employs two SAW (surface acoustic
wave) filters. The use of two filters significantly increas­es the depth of filtering while preserving sharp skirts,
constant group delay, and narrow bandwidth. Though
expensive, this special type of filter allows primary filter­ing as early as possible, at as high a frequency as pos­sible, before high gain is applied, to deliver maximum
image rejection. These filters are made of quartz, and
they are very temperature stable.

In receiver 1, the signal is converted to 248.450 MHz
in the first mixer stage, then passed through two SAW
filters. After the SAW filters, the signal is converted to
350 kHz and then the majority of the gain is applied.

In receiver 2, the same conversions take place at differ­ent frequencies: first to 243.950 MHz, then to 250 kHz.

Digital Pulse Counting Detector

Following the IF section, the receiver uses an elegantly
simple, yet highly effective digital pulse counting de­tector to demodulate the FM signal and generate the
audio, rather than a conventional quadrature detector.
This unusual design eliminates thermal drift, improves
AM rejection, and provides very low audio distortion.
The output of the detector is fed to the microprocessor
where a window detector is employed as part of the
squelch system.

DSP-Based Pilot Tone

The Digital Hybrid system design uses a DSP generat­ed ultrasonic pilot tone to reliably mute the audio when
no RF carrier is present. The pilot tone must be present
in conjunction with a usable RF signal before the audio
output will be enabled. A unique pilot tone is generated
every 100 kHz across the tuning ranges of the 941 MHz
system. This alleviates erroneous squelch activity in
multichannel systems where a pilot tone signal can ap­pear in the wrong receiver via IM (intermodulation).

The 941 MHz models can tune in either 25 kHz or 100
kHz steps, and the pilot tones increment in 100 kHz
steps. The systems are never operated within 100kHz
spacing, so the pilot tone is the same for all four ad­jacent frequencies in each 100 kHz increment. For
example, 959.300, 959.325, 959.350 and 959.375 all
have the same pilot tone.

SmartSquelch

A DSP-based algorithm called SmartSquelchTM optimizes
the receiver performance in very weak signal conditions.
The RF level and supersonic noise in the audio are con­tinuously monitored to determine the appropriate noise
reduction needed and the point at which squelch (com­plete muting of the audio) is necessary.

As the RF level decreases and supersonic noise in the
signal begins to increase, a variable knee, high frequency
roll-off filter is applied to suppress high frequency noise.
The filtering action moves in and out smoothly to avoid
abrupt changes that could be audible. When the RF signal
becomes so weak that the receiver can no longer deliver
usable audio, the squelch will activate.

SmartDiversity

Microprocessor controlled antenna phase combin­ing is used for diversity reception. When the incoming
RF level drops to a certain point, the phase (polarity)
of one antenna is reversed and the resulting level is
compared with the one in the previous state. If the level
has increased, the phase is retained. If the level has
decreased, the phase is reversed back to the previous
state.

The logic behind this design is based upon the fact that
two antennas mixed in phase will deliver a stronger
signal than either antenna by itself. If the antennas are
spaced more than a few inches apart, the signals arriv­ing at them will be non-correlated (diverse), to effec­tively deal with multi-path dropouts.

™

™

Turn On and Turn Off Delays

A brief delay is applied when the receiver is powered up
or down to prevent audible noise such as a thump, pop,
click or other transient noise.

Test Tone

To assist in matching the audio levels of equipment con­nected to the receiver, a 1 kHz audio test tone genera­tor is provided, with an output level adjustable from -50
to +5 dBu in 1 dB increments.

The tone simulates the audio output with a steady sig­nal at full modulation, making it easy to adjust the level
to precisely match the optimal level for the connected
device and maximize the signal to noise ratio of the
system.

4

LECTROSONICS, INC.

LCD Display

Setup and monitoring is done through the LCD display
on the control panel. The built-in backlight for view­ing in dimly lit environments can be set to remain on
for 30 seconds, 5 minutes or to remain on constantly.
The characters and background on the display can be
inverted as desired for easy viewing in brightly or dimly
lit environments.

Smart Noise Reduction (SmartNR™)

Note: The SmartNR setting is user selectable only in
the Digital Hybrid compatibility mode. In other modes,
noise reduction is applied in such a way as to emulate
the original analog system as accurately as possible
and is not user adjustable.

The wide dynamic range of digital hybrid technology,
combined with flat response to 20 kHz, makes it pos­sible to hear the -120 dBV noise floor in the mic pre­amp, or the (usually) greater noise from the microphone
itself. To put this in perspective, the noise generated
by the recommended 4k bias resistor of many electret
lavaliere mics is –119 dBV and the noise level of the mi­crophone’s electronics is even higher. In order to reduce
this noise the receiver is equipped with a “smart” noise
reduction algorithm called SmartNRTM, which removes
hiss without sacrificing audio high frequency response.

SmartNR
the audio signal that fit a statistical profile for random­ness or “electronic hiss.” Because it is much more than
a sophisticated variable low pass filter, the transparency
of the audio signal is preserved. Desired high frequency
signals having some coherence are not affected, such
as speech sibilance and tones.

SmartNRTM algorithm has three modes, selectable
from a user setup screen. The optimal setting for each
application is subjective and is normally selected while
simply listening.

• OFF defeats noise reduction and complete trans-

• NORMAL applies enough noise reduction to re-

• FULL applies enough noise reduction to remove

TM

works by attenuating only those portions of

parency is preserved. All signals presented to the
transmitter’s analog front end, including any faint
microphone hiss, will be faithfully reproduced at the
receiver output.

move most of the hiss from the microphone preamp
and some of the hiss from lavaliere microphones.
The noise reduction benefit is significant in this
position, yet the degree of transparency maintained
is exceptional.

most of the hiss from nearly any signal source
of reasonable quality and some high frequency
environmental noise, assuming the input gain is set
properly at the transmitter.

UHF Digital Hybrid Wireless

®

Rio Rancho, NM

5

SRc-941 Dual Receiver

Front Panel Controls and Functions

Receiver 1 Receiver 2

MENU/SELECT

Button

UP Button

POWER/BACK

Button

IR Sync Port

Audio Outputs

Audio outputs and the power inlet are located on the
rear panel, accessed by a variety of different adapters.

LCD Screen

A backlit, graphics-type LCD is used to set up and
monitor the receiver. The Main Window shown above is
used during normal operation, to display RF and audio
levels, transmitter battery status, pilot tone status and
diversity activity for both receivers.

MENU/SELECT Button

This button is used to select menu items and enter
setup screens during setup.

PWR/BACK Button

Press the PWR/BACK switch to turn the power on.
Press and hold it until the display goes blank to turn
power off. It also functions as a “back” button while navi­gating the various menus and setup screens to return to
the previous screen or menu item.

The firmware “remembers” whether the receiver was
turned on or off after power is disconnected, and it
returns to that state when power is restored. This allows
the receiver to power up and down as the camera or
external supply is turned on and off.

Press the PWR/BACK button from the Main Window to
briefly display the external power voltage.

DOWN Button

Rear Panel Adapters

Several different panel adapters are available to config­ure the receiver for use with popular camera slots and
for stand-alone use. The adapters are retained by two
screws through the side panel of the housing, making
them easy to install.

Power and audio connections are made through mating
connectors on the adapter and receiver main circuit
boards.

IR (Infrared) Sync

An IR Sync Port is used for quick setup with transmit­ters that offer this feature. Settings for frequency, step
size, compatibility mode and talk back are transferred
from receiver to transmitter via the IR ports.

UP/DOWN Arrow Buttons

The UP and DOWN arrow buttons are used to select
various options and adjust values in the setup screens,
and provide secondary functions such as locking out
the panel to guard against accidental changes.

6

LECTROSONICS, INC.

UHF Digital Hybrid Wireless

JMP-1

1

2

RX ON (REMOTE)

UART TX

UART RX

UART TX

UART RX

CH1 AUDIO (+) OUT (HOT)

DB-25

EXTERNAL POWER GND

CH1 AUDIO (+) OUT (HOT)

CH1 AUDIO (–) OUT (COLD)

CH1 AUDIO (–) OUT (COLD)

EXTERNAL POWER GND

RX ON (REMOTE)

CH1 AUDIO GND (SHIELD)

CH1 AUDIO GND (SHIELD)

CH2 AUDIO (+) OUT (HOT)

CH2 AUDIO (+) OUT (HOT)

CH1 AUDIO GND (SHIELD)

CH1 AUDIO GND (SHIELD)

CH2 AUDIO (–) OUT (COLD)

CH2 AUDIO (–) OUT (COLD)

®

Camera Slot Adapter KIts

SRSUPER

Adapter kit for
Unislot® camera
slots such as those
provided on Ikega­mi® and Panasonic®
cameras, as well as
the SL-6 by Sound
Devices®.* Includes
bezel, hardware and
rear panel DB25
connector wired for
power and audio
connections.

Adapters for Stand-Alone Use

SREXT

For stand-alone use,
this kit includes a
rear panel with two
TA3 male jacks for
the balanced out­puts and a power
jack with a locking
connector. Trim the
power cable to the
desired length.

SRSNY

* UniSlot® is a trademark of Ikegami Tsushinki Co., Ltd.

®

Ikegami
Panasonic
Sony

Sound Devices

is a registered trademark of Ikegami Tsushinki Co., Ltd.

®

is a registered trademark of Matsushita Electric Industrial Co., Ltd.

®

is a registered trademark of Sony Kabushiki Kaisha TA Sony Corporation.

®

is a registered trademark of Sound Devices, LLC.

Rio Rancho, NM

Adapter kit for
Sony® camera
slots,* includes be­zel, hardware and
rear panel DB15
connector wired for
power and audio
connections.

SRHARNESS

Ideal for use in por­table “bag systems.”
Two balanced output
cables and the power
cable are 6 feet long.
Cut the cables to the
desired length and
terminate as needed.

7

SRc-941 Dual Receiver

Installing Adapters

SRSUPER Adapter

Thread two short
screws through the
recessed tabs on the
adapter and slide
it onto the receiver
housing. Thread two
short screws through
the tabs on the
receiver flange as
shown.

On the opposite
side, thread two long
screws through the
tabs on the receiver
flange, then align
them with the tabs
on the adapter.

Slide the adapter
up and tighten the
retaining screws
to secure it to the
receiver flange.

The four lower
screws attach to the
camera body.

Installing Rear Panel Adapters

Installation of the rear panel output/power adapters is
the same for all models.

Panels are held in
place by two phil­lips head screws
on the sides of the
housing.

Connections
between the panel
and main circuit
board are made
via miniature mat­ing connectors.

Align the mating
connectors and
slide the panel
straight into the
housing until the
screw holes align
with the housing.

Replacement Screw Kits

SRSNYSCREWKIT

Contains:
5 - #28863 (smaller mid-length)
5 - #28864 (larger mid-length)

5 - #28869 (shortest)*

* For Housing

SRSNY Adapter

Two different types of screws are used to attach the
receiver flange and the adapter.

Thread the smaller, thin head screws through the
adapter and into the camera body.

Upper screws with thicker
heads secure the receiver

to the adapter.

Lower screws with thinner

heads secure the adapter

to the camera body.

NOTE: If you are having difficulty inserting the
receiver into the camera slot, try mounting the blue
adapter plate to the camera first, then inserting the
receiver.

SRUNISCREWKIT

Contains:
3 - #28862 (longest)
5 - #28864 (mid-length)
3 - #28869 (shortest)*

* For Housing

8

LECTROSONICS, INC.

UHF Digital Hybrid Wireless

®

Battery Adapters

Battery sled adapters configure the receiver for stand­alone use or to provide battery backup power. Several
options are available:

• SRBATTSLEDTOP

• SRBATTSLEDBOTTOM

• SR9VBP (inserts into the SLED adapters)

SRBATTSLEDTOP

SRBATTSLEDBOTTOM

The battery sled adapters accept L and M type video
camera rechargeable batteries and the optional
SR9VBP 9 volt battery case.

Installing the SRBATTSLED

Orient the battery sled so that the PCB connectors will
mate when the sled is inserted.

PCB

connectors

Slide the battery sled adapter into the end of the SR
and gently seat it into place with the rear panel flush
with the housing.

L or M type video

camera batteries

mount directly onto

the battery sled

SR9VBP

battery

case for

two 9 volt

batteries

The battery sled adapters do not include charging
circuitry. Batteries must be charged with their respective
chargers. The adapters include an integral circuit that
automatically selects between the battery and the exter­nal source, whichever delivers the highest voltage.

Install and tighten the two side panel and two top panel
screws as indicated by the arrows.

Spare
screw

Battery retaining clips.

Battery Life

• The SR receiver operating time with a NP-F570
slim L series battery at full charge is approximately
12 hours.

• Battery life with two Energizer 9 volt alkaline batter­ies in the optional adapter is approximately 5 hours.

• Two LiPolymer 9 volt rechargeable batteries will op­erate the SR for approximately 6 hours. The operat­ing time will typically decrease over the useful life of
a rechargeable battery.

Rio Rancho, NM

9

SRc-941 Dual Receiver

SR9VBP 9 Volt Battery Adapter

This optional adapter is mounted onto the battery sled
for use as the primary power source or as a battery
backup for an external power supply. The housing and
door are constructed of machined aluminum.

Slide the latch plate in the center of the door outward
and swing the door open for access to two 9 volt battery
compartments. Polarity barriers in each battery com­partment protect against inserting the battery back­wards. The circuitry is also protected electrically.

A pressure plate on the battery door compresses the
battery contacts to maintain a solid connection with
the batteries.

SRSLEEVE mounting adapter

This sleeve is supplied with Velcro swatches for mount­ing an SR Series receiver on a flat surface of camera,
cart, rack, etc. The sleeve is sized and lined for a snug
fit in a vertical or horizontal position.

SRHARDWARE mounting adapter kit

Bracket

P/N 26739

Cold shoe

Thumb nut

P/N P1241-1

Long pan

head screw

P/N 28876

Jam nut

P/N 28898

Short pan

head screw

P/N 28898

Retaining pins

P/N 28865

For a vertical mounting, attach the right angle bracket to
the bottom of the sleeve.

mounting foot

P/N 26752

Washer

P/N 28912

Hex Key

P/N 35931

The mechanical and electrical connections are the
same as the rechargeable video camera batteries.

CAUTION: DO NOT
CONNECT TO A
BATTERY CHARGER.

USE ONLY TWO SAME
TYPE BATTERIES.

10

1/4-20

insert nut

Long pan

head screw

P/N 28873

Attach retaining

pin to keep bracket

from rotating

Retaining pin

opening

1/4-20 clinch

pressnut

The bracket provides
two different mount­ing nuts. The stan­dard pressnut is used
to attach the sleeve.
The tensioning (clinch
type) pressnut is used
to attach the cold
shoe mounting foot.

LECTROSONICS, INC.

UHF Digital Hybrid Wireless

®

Attach the bracket to the sleeve with the long pan head
screw into the standard pressnut. The retaining pin fits
into the opening in the bracket. Attach the cold shoe
mounting foot to the tensioning nut and rotate it to orient
the receiver as desired.

Standard
pressnut

Retaining

pin

For horizontal mounting, insert the cold shoe foot into
the clinch nut in the sleeve. Rotate the foot to the de­sired postion, then tighten the jam nut to lock it in place.

Use a wrench to thread the stud in about 1 - 2
turns, then rotate it to orient the receiver control
panel in the desired direction.

Cold shoe

foot into

clinch

pressnut

The clinch nuts in the foot and housing apply friction to
the threads to allow the foot to be rotated to the de­sired position, with the jam nut locking it in place. Use
a wrench to rotate the foot, then tighten the jam nut to
prevent the foot from rotating.

Clinch pressnut in bracket and sleeve

Washer

Jam nut

Thumb nut

Cold shoe foot

Tighten the jam nut to prevent the foot from rotating

The SRSLEEVE, SRBATTSLED and SRHARDWARE
used together provide a versatile, stand-alone receiver
(battery shown for illustration only; not sold by
Lectrosonics.)

Rio Rancho, NM

11

SRc-941 Dual Receiver

Audio Output Cables and Connectors

MCSRPT

12 inch long TA3 female to
stripped and tinned wires
for balanced output.

PIN 1: Shield
PIN 2: Audio (+) white
PIN 3: Audio (-) green

MCSRXLR

12 inch long TA3 female to
XLR male 3-pin for balanced
output.

PIN 1: Shield
PIN 2: Audio (+)
PIN 3: Audio (-)

MCSRTRS

Male 3.5 mm TRS plug
to two female TA3 (mini
XLR) connectors for
dual channel use.

External Power Supply

DCR15/4AU

Power supply with a standard C14 inlet and locking
LZR coaxial output connector; 100-240 VAC in, 15 VDC
regulated output; 4A max.

External Power Cables

21747

Locking LZR style plug
to stripped and tinned;
6 feet long.

21746

Locking LZR style plug
to stripped and tinned;
12 inches long.

PS200

Hirose 7-4 pin to LZR
type locking plug, 12”
long.

2142 5

6 ft. long power cord; coaxial to stripped & tinned leads.
Coaxial plug: ID-.080”; OD-.218”; Depth- .5”.

.475”

.375” O.D.

21472

6 ft. long power cord; coaxial to stripped & tinned leads.
Right angle coaxial plug: ID-.075”; OD-.218”; Depth­.375”

.375”

.375” O.D.

21586

DC16A Pigtail power cable, LZR stripped & tinned.
Thread lock collar.

.35”

12

LECTROSONICS, INC.

UHF Digital Hybrid Wireless

®

Mounting and Orientation

A variety of accessories are available to enable various
mounting options. For maximum operating range, the
antennas should be vertical and above the camera and
other equipment. The AMJ Rev. A antenna is jointed so
the whips can be oriented vertically regardless of the
orientation of the receiver.

Maximum sensitivity is perpendicular to the whip, so
an ideal setup is shown in Fig. 1 and Fig. 2 where the
receiver is mounted in either a vertical or horizontal
position with the whips oriented vertically.

Fig. 3 depicts the receiver and antenna whips oriented
horizontally, which places the null of the receiver an­tenna pattern pointing toward the transmitter. The result,
of course, is a weak signal entering the receiver.

Fig. 4 depicts the worst setup where the nulls in both
receiver and transmitter patterns face one another.

The transmitter antenna whips can point upward as
shown in these diagrams, but they will work just as well
with the whip pointing downward. Mount the transmitter
so that the whip is vertical and not in direct contact with
the wearer’s body or metallic objects in clothing and
costuming.

AMJ Rev. A Jointed
Antenna

The AMJ-944 Rev. A antenna is a general purpose
design with a hinged joint that pivots in both directions
for positioning the whip at any desired angle. The pivot
allows the whips to be oriented vertically regardless of
the mounting position of the receiver.

The hinged joint pivots in both directions

Rx

Rx

Rx

Fig. 1

STRONG

SIGNAL

Tx

Fig. 2

STRONG

SIGNAL

Tx

Fig. 3

WEAK

SIGNAL

Tx

Fig. 4

Rx

WEAKEST

SIGNAL

Rio Rancho, NM

Tx

13

SRc-941 Dual Receiver

PCA900 Printed Circuit
Antenna

This antenna is typically used when the receiver is
mounted in a somewhat fixed position such as on a
sound cart. The pickup pattern is a circular horizontal
pattern with a subtle forward lobe due to the built-in
reflector. The antenna is connected with standard 50
ohm coaxial cable.

The antenna pattern is essentially the same as a dipole,
so mounting it with the elements oriented vertically
provides circular coverage.

The antenna pattern provides about 3.7 dB of gain,
which makes it ideal for use with a passive splitter to
feed two receivers. This is one example of using a split­ter to feed two receivers.

PCA900

COAXIAL

CABLE

ZSC24

SPLITTER

A “bendable” mounting strap is included that allows
vertical orientation on a variety of surfaces. Several
other adapters are also available for temporary or fixed
installations.

STRONG

SIGNAL

ANTENNA ORIENTATION

WEAK

SIGNAL

Tx

Tx

Use Lectrosonics P/N 21770 BNC (F) to SMA (M) adapter;
Pomona P/N 4290

The PCA900 and whip antennas
both have a toroidal shaped pattern.
Viewed from the side, a cross section
of the pattern can be visualized.

WEAK

SIGNAL

The elements of both antennas
should be parallel to each other for
maximum signal strength. When they
are perpendicular or above one an­other, the signal weakens significantly.

Tx

14

LECTROSONICS, INC.

LCD Main Window

Receiver 1 Receiver 2

Diversity

Activity

Transmitter

Battery Level

UHF Digital Hybrid Wireless

NOTE: When the RATIO DIVERSITY mode is
selected, both receivers are combined to pick up
the same transmitter, so the Main Window will
display a single audio channel.

®

RF Levels Audio Level

Pilot Tone

Indicator

The Main Window displays information concerning
the condition of the pilot tone, antenna phase, RF and
audio signal levels and battery conditions for both the
receiver and the associated transmitter.

Icon

Description

Pilot Tone Indicator

A steady “P” icon will be displayed when a pilot tone from the transmitter is present. The icon will
flash if no pilot tone is detected and will change to a small “b” if the pilot tone has been bypassed.
To bypass or enable the pilot tone on Receiver 1, hold MENU/SEL button and press the UP button
briefly. To bypass or enable the pilot tone on Receiver 2, hold MENU/SEL and press the DOWN but­ton briefly. Bypassing the pilot tone also disables the squelch, regardless of which compatibility mode
has been selected.

Channel Mute

The audio output can be muted on Receiver 1 by holding the MENU/SEL button and holding the UP
button for about a second or more. Receiver 2 can be muted by holding MENU/SEL and then hold­ing the DOWN button. The same buttons toggle the mute status off. An “M” will appear on the screen
when a channel is muted. In ratio diversity mode, the UP button is used and a signal M appears.

Antenna Phase Indicator

This antenna icon is displayed when the SWITCHING DIVERSITY mode is selected. As the antenna
phase is switched, the symbol will flip vertically.

Receiver 1

RF Level

Receiver 2

RF Level

Audio

Level

Transmitter

Battery Level

Pressing the MENU/SEL button accesses the menus
and screens for setting up the receiver and searching
for clear frequency channels.

RF Level

This icon changes in size vertically to indicate the strength of the incoming RF signal.

Audio Levels

One icon is used in the SWITCHED DIVERSITY mode and the other when RATIO DIVERSITY is
selected. The icon changes in size horizontally to indicate the audio level (modulation) of the signal
received from the transmitter. The icon display will change to a solid rectangular block when the audio
signal is being limited in the transmitter.

Battery Levels

A battery icon is displayed on the LCD to indicate the transmitter battery condition. The receiver will
receive a periodic battery status from the transmitter and update the icon in a “fuel guage” manner. In
the example at left, the icon indicates about “half full.” When other COMPAT modes are selected, this
area of the LCD will be blank.

If selected in the TXBAT setup screen, a transmitter battery timer is available. It accumulates hours
and minutes whenever the transmitter is turned on, and retains the accumulated time even when the
receiver is off. The icon represents a digital clock readout (rotated 90 degrees clockwise) and in this
example is indicating 4 minutes.

To reset the battery timer, change the selection in TXBAT to something other than a timer
mode, then back to the desired mode.

Rio Rancho, NM

15

SRc-941 Dual Receiver

SETUP

(item)

1

01

941.600

27A

953.700

MENU

BACK

BACK

MENU

Receiver 1

Pilot Tone

ON\OFF

Hold MENU and

hold DOWN for

1 sec. or more

Hold MENU

and hold UP

for 1 sec. or

more

Mute Audio on

Receiver 1

Mute Audio on

Receiver 2

Press

UP/DOWN

to select

MENU

BACK

Setup Screen

Main Window

Receiver 1

Receiver 2

Press UP/DOWN to
change frequency

Press UP/DOWN to change frequency

When DIVMODE is set to RATIO the
frequency screen will look like this.

Receiver 2

Pilot Tone

ON/OFF

Hold MENU and

press UP

momentarily

Hold MENU and

press DOWN

momentarily

941

:

941

:

Press

UP/DOWN

to adjust

RECEIVER 1

00

00

00

RECEIVER 2

SEL

BACK

SEL

SEL

LEVEL LEVEL

00

BACK

LEVEL

SETUP

UP

R

941

:

01

941.600

Ratio
Mode

Block

Freq hex code

Freq MHz

SEL

BACK

DEFAULT

SETUP

Ratio

Switched

RESET– –

DEFAULT

Press
DOWN to
continue

SURE?

ARE YOU

Press

MENU/SEL

to reset

DOWN

SEL

BACK

SMARTUNE

SETUP

UP

DOWN

SEL

BACK

IR SYNC

SETUP

UP

SEL

BACK

SEL

SCANNING

STOPS

Press
SEL to
select

receiver

Press

UP/DOWN

to scroll

frequency

Press both

UP and

DOWN to

ZOOM

Press

UP/DOWN to

scroll

frequency

DOWN

25

BACK

BACK

SCAN

SETUP

UP

DIVMOD

RATIO

Press

UP/DOWN

to select

DOWN

SEL

BACK

DIVMODE

SETUP

UP

DOWN

SEL

BACK

TALKBACK

SETUP

UP

SEL

BACK

COMPAT

RECEIVER 1

Press

UP/DOWN

to select
receiver

COMPAT

SETUP

DOWN

SEL

BACK

RECEIVER 1

RECEIVER 2

TUNING

u

NOR

Press

SEL to

select

receiver

DOWN

UP

DOWN

SEL

BACK

STEPSIZE

SETUP

UP

DOWN

SEL

BACK

RECEIVER 1

RECEIVER 2

SmtNR

FUL

NOR

Press

SEL to

select

receiver

SmtNR

N/A

OFF

SmtNR

SETUP

UP

DOWN

PHASE

SETUP

SEL

BACK

PHASE

PHASE

RECEIVER 1

RECEIVER 2

Press

UP/DOWN

to select

Press

SEL to

select

receiver

+

+

UP

TXBAT

SETUP

SEL

BACK

TXBAT

TXBAT

RECEIVER 1

Press

UP/DOWN

to select

Press
SEL to
select

receiver

9V

AA

AA

9V

DOWN

TONE

SETUP

SEL
BACK

TONE?

RECEIVER 1

RECEIVER 2

Press

UP/DOWN

to select

Press

SEL to

select

receiver

00+05

Tone will be enabled
when level is set with
the UP/DOWN buttons

TONE?

00+05

LVL 1K

RECEIVER 1

00+05

BACK

TUNING

SETUP

TUNE

SMART

1

BAND

TX

1

B1

Press

UP/DOWN

to select

band

Press

MENU/SEL

to start

scanning

SYNC

OK

1

Press

DOWN to IR

sync TX 1

Press

MENU/SEL

to continue

Follow

prompts to

scan and set

up TX 2

SYNC

1
2

Press UP to sync TX 1

Press DOWN to sync TX 2

TALKBACK

OFF

Press

UP/DOWN

to select

1

2

NU HYBR

Press
MENU/SEL
to highlight

mode

COMPAT

RECEIVER 2

IFB SER

Press

UP/DOWN

to select

mode

Press

UP/DOWN

to select

mode

STEPSIZE

100

25

Press
MENU/SEL
to highlight

receiver

Press

UP/DOWN

to select
step size

Press

UP/DOWN

to select

mode

MIXMODE

SETUP

SEL

BACK

MIXMODE

Press
UP/DOWN

to select

MIXBOTH

DOWN

UP

UP

STEPSIZE

100

25

TUNING

v

NOR

DOWN

DOWN

UP

DOWN

UP

MIXTRIM

SETUP

SEL

BACK

MIXTRIM

00

MIXTRIM

00

+05

Press

UP/DOWN

to select

value

00

Press

SEL to

select

receiver

8A

941

8A

941

SCANNING

BEGINS

8A

941

Navigating the LCD

16

NOTE: The Main Window will
look like this when the RATIO
DIV mode is selected.

NOTE: An error message will appear if a setting on the
transmitter cannot be enabled by the SYNC procedure.

NOTE: N/A will appear if the COMPAT mode is
set to IFB SER since there is no noise reduction
available in the IFB mode.

NOTE: To reset the timer, set the TXBAT mode to anything
other than 9VT or AAT, then back to the desired mode.

NOTE: This setting does not appear
when the MIXMODE is set to DIRECT.

NOTE: Press the BACK
button from the Main
Window to briefly display
the external power
supply voltage, and
the transmitter battery
voltages.

NOTE: Fewer screens are
shown when DIVMODE is
set to RATIO.

LECTROSONICS, INC.

UHF Digital Hybrid Wireless

®

Main Window

The appearance of the LCD Main Window will change
according to which diversity mode is selected:

• SWITCH (2-channel mode) splits the screen to
indicate activity and levels on both receivers and
transmitters.

• RATIO combines the audio outputs of both receiv-
ers to deliver a single audio channel.

With the DIV MODE set to
SWITCH, two audio channels will
be displayed.

With the DIV MODE set to RATIO,
a single audio channel will be
displayed.

Frequency Screen

Receiver

Band

1 941 : 29
945 . 600

Freq in MHz

to 945.600 MHz. The frequency can also be set accord­ing to the hex code, which is usually easier to remem­ber. Lectrosonics transmitters with LCD interfaces allow
frequency to be set in MHz or hex settings.

Press the UP and DOWN buttons to change the fre­quency of the receiver. When the tuning mode is set to
NORMAL, the UP and DOWN buttons tune in single
channel increments. In the group tuning modes, the UP
and DOWN buttons step through the frequencies stored
in the particular group. Refer to the menu items named
TUNING and GROUP TUNING MODES for details.

SHORTCUT: Hold the MENU/SEL button in while
pressing the UP or DOWN arrow to jump in 16 channel
increments (1.6 MHz steps).

Freq in

hex

Press MENU/SEL from the
Main Window once for Receiv­er 1 and twice for Receiver 2.
The selected receiver is
shown in the upper left corner
of the LCD.

In this example, the screen
denotes that receiver 1 is set

Setup Screens

From the Main Window, press MENU/SEL three times
to enter the setup screens. Press UP and/or DOWN to
scroll through the available items and press MENU/SEL
to enter the desired screen. For those items that allow
separate settings for each receiver, press MENU/SEL
repeatedly to toggle back and forth between Receiver 1
and Receiver 2, then press the UP and DOWN buttons
to select the value or option. Press BACK one or more
times to store the setting and return to the previous
screen.

Locking and Unlocking the
Front Panel Controls

The front panel controls can be LOCKED to prevent
accidental changes being made during operation and
handling.

Note: Whether locked or unlocked, the state persists
even when the unit is turned off.

From the Main Window, press and hold the UP and
DOWN arrows at the same time and observe the
display. The current state is displayed as LOCKED or

UNLOCKED, and numerals appear as a 3, 2, 1 or 1,
2, 3 countdown takes place. When the countdown is

complete the state is reversed and the new state is
displayed.

LCD Backlight Setup

With the power on, simultaneously press the UP but­ton AND the POWER/BACK button. The unit will then
display the Backlight Options screen. Use the UP and
DOWN arrows to select the desired backlight operating
mode.

BKLIGHT

DOWN

UP

BKLIGHT

30 SEC

DOWN

UP

BKLIGHT

5 MIN

DOWN

UP

BKLIGHT

OFF

Remains on

ON

Dims after 30 seconds

Dims after 5 minutes

Backlight turns OFF
and Remains OFF

Battery Timer Reset

Navigate to TXBAT in the menus and select anything
other than AAT or 9VT. Then set it back to the timer
setting that matches the batteries you are using in the
transmitter. There is no need to exit the setup screen.
The timer will be reset when you select a non-timer
mode.

Rio Rancho, NM

17

SRc-941 Dual Receiver

Menu Item Descriptions

LEVEL

This setup screen displays the audio output level of the
receiver in dBu when the transmitter is fully modulated.
Press the MENU/SEL button to toggle between receiver
1 and receiver 2. Use the UP or DOWN buttons to
change the level. Range is from -50 to +5 dBu in 1 dB
steps. Press the BACK button to leave this screen.

The output levels at the two jacks may be set indepen­dently, regardless of the diversity mode setting.

DEFAULT

Restores the factory default settings.

SMARTUNE

The receiver will scan through its tuning bandwidth and
automatically find clear frequencies. The newly found
frequency will be displayed and can then be sent to the
matching transmitter via the IR link, or be set manually.

Note: Pressing BACK during an active scan will restore
the operating frequency to what it was set at pre-scan.

When the DIVMODE is set to SWITCHED, there are
two different frequencies that can be discovered, so the
LCD screens will prompt you through the procedure for
one receiver, then continue to repeat the process for
the other receiver. When the DIVMODE is set to RATIO,
there is only one frequency to be found.

The sample screens below are for the SWITCHED
mode. Similar screens appear for the RATIO mode, but
there is only one frequency to be discovered.

Navigate to the SMARTUNE screen
and press MENU/SEL.

SMART

TUNE

TX 1
BAND

OK

SYNC

NOTE: If the transmitter does not have an IR
port, set the frequency selected by SMARTUNE
on it manually. Then press MENU/SEL on the
receiver to continue.

TUNE RX2
NOW? YES

IS TX1
ON? NO

1

941

1

The scan will cover the full tuning
bandwidth, or only one of the three.
Use the UP and DOWN arrows to
select.

After the scanning is complete,
the LCD will prompt to transfer
the frequency to the matching
transmitter via the IR port. Press
the DOWN arrow to start the
transfer.

After leaving the SYNC screen,
the LCD will ask about setting up
the other receiver. Use the UP and
DOWN arrows to toggle YES/NO
then press MENU/SEL.

Make sure the TX 1 transmitter is
on (the one just set in the previous
screen), then use the UP and DOWN
arrows to a YES answer and press
MENU/SEL.

IR SYNC

Navigate to this menu item to manually initiate the IR
sync transfer. Hold the IR ports on the transmitter and
receiver facing each other a foot or two apart and press
the UP arrow for channel 1 or the DOWN arrow for
channel 2. Watch for a confirmation on the transmitter
LCD to verify the settings were correctly transferred. If
one or both settings could not be enabled on the trans­mitter, an error message will appear on its screen.

SCAN

Follow the procedure detailed in the subsequent section
entitled Scanning for Clear Frequencies for instruc­tions on finding clear channels manually.

DIVMODE

The SWITCH diversity mode (dual channel mode) al­lows the two internal receivers to operate independently
on different frequencies and settings with two different
transmitters. Diversity reception uses an antenna phase
switching technique on each receiver. When this mode
is selected, the setup screens will prompt you to select
the receiver to be adjusted.

The RATIO mode combines the two internal receiv-
ers to pick up the same transmitter and mix their audio
outputs in a ratio panning mode. In this mode, the setup
screen for frequency will prompt you for a single value
which will automatically be set for both receivers.

TALKBACK

This is a special function that re-directs the audio output
of the transmitter in use to the channel 2 output when
a button is pressed on the transmitter. The normal use
is to provide a “com” channel so the person using the
transmitter can have a direct line to the crew or produc­tion staff that is not sent to the program output. The
HHa hand held transmitter provides a programmable
switch on the housing that can be configured for this
function.

Programmable button

As long as the button
is held in, the audio
will appear at the
channel 2 output.

Button

(none)
Mute
Ta lkBk

When the button is
released, the audio
output will switch
back to channel 1.

To enable this mode,

simply select Talk­back in the menu and use the UP and DOWN arrow
buttons to turn the function on. The mode must also be
enabled on the transmitter.

Talkback works the same way in either the SWITCHED
or RATIO diversity modes, but ONLY works in the NU
HYPR compatibility mode.

NOTE: When Talkback is enabled, only receiver 1 and
a blinking TB will appear in the Main Window.

18

LECTROSONICS, INC.

UHF Digital Hybrid Wireless

®

COMPAT

The IFB SER compatibility mode allows the receiver to
be used with Lectrosonics wireless IFB transmitters in
the same frequency band that may be available in the
future.

NU HYBR NU HYBR (new) ETSI compliant Digital Hybrid Wireless

IFB SER IFB transmitters in IFB mode

TUNING

In addition to the NOR (normal) mode, this screen also
allows selection of two user programmable frequency
groups (Groups u and v).

• NOR allows selection of all frequencies that the
receiver picks up. Each press of the UP or DOWN
button will step in 100 or 25 kHz increments to the
next frequency.

• u, v allow up to 16 user-selected frequencies to
be stored in each group. Each press of the UP or
DOWN button will step to the next stored frequency
in the group.

NOTE: The TUNING setup screen only selects the
tuning mode (NORMAL or Group Tuning). Frequencies
are chosen through the frequency setup screens as
shown below.

Receiver Block Frequency

941

1

v

945.600

Tuning

group

If the selected frequency is not in the tuning group, the
tuning group indicator will blink.

1

v

945.600

NOTE: When a tuning group is selected, the available
frequency selections will be limited to those that are in
the tuning group.

In a compatibility mode other than HYBRID, no battery
telemetry information is available, so the TXBAT setup
screen offers only two choices:

• --- (no timer) - Display no transmitter battery status
in the main window.

• TIM - Monitor the transmitter battery status with the
battery timer in the LCD Main Window.

Frequency

941

29

in MHz

29

in hex

When any tuning mode

other than NOR is

selected, the frequency

screen will include the

selected tuning group

number.

®

USING THE GROUP TUNING MODES

Press MENU to select receiver 1 or 2.

941

1

v

945.600

The group letter in the display will blink if the selected
frequency is not included in the group.

1

v

When no frequencies are stored in groups u and v, the
UP and DOWN buttons will function the same as in the
NOR mode.

When only one frequency is stored in group u or v, the
UP and DOWN buttons will not change the frequency. In
this case, hold the MENU/SEL button in and then press
UP or DOWN to scroll to the desired frequency.

To add a frequency to tuning either group u or v, Select
the desired frequency, then hold the MENU/SEL button
in and then hold the UP or DOWN button in until the
letter stops blinking.

To delete a stored frequency, select it with the UP and
DOWN buttons, then hold the MENU/SEL button in,
then hold the UP or DOWN button in until the letter
starts blinking.

STEPSIZE

Selects the frequency increment on each receiver to 25
kHz or 100 kHz.

SmtNR

This setup screen is available only in the Digital Hybrid
COMPAT (compatibility) mode. Select the desired mode
while listening to the audio to of one of three choices:

• OFF provides no noise reduction for complete
transparency, which is useful in controlled environ­ments with very little high frequency noise such as
an indoor motion picture production set.

• NOR (normal) applies a moderate amount of noise
reduction to noticeably reduce hiss from subtle
sources such as electret microphones.

• FULL is very similar to the Lectrosonics noise
reduction system used for many years in legacy
analog systems. Hiss from electret microphones
and some environmental HF noise are suppressed.

PHASE

This setup screen allows the audio output polarity to be
inverted to match other microphones or audio sources.

29

941

29

945.600

When a tuning group is

selected, a letter will appear

next to the frequency.

The letter will blink when

a frequency outside of the

tuning group is selected.

NOTE: To reset the timer, set the TXBAT mode to
anything other than 9VT or AAT, then back to the
desired mode.

Rio Rancho, NM

19

SRc-941 Dual Receiver

RECEIVER 2

TXBAT

Select the type of battery being used in the transmitter
to improve the accuracy of the battery monitor.

• 9V - Transmitter uses a 9V alkaline battery.

• 9VL - Transmitter uses a 9V lithium battery (not
rechargeable).

• 9VT - Transmitter uses a 9V battery of any type.
Monitor its status with the timer in the LCD Main
Window. This is the best choice when using a re­chargeable battery in the transmitter.

• AA - Transmitter uses a AA alkaline battery.

• AAL - Transmitter uses a AA lithium battery (not
rechargeable).

• AAT - Transmitter uses an alkaline, lithium or re­chargeable AA battery. This is the best choice when
using a rechargeable battery in the transmitter.

MIXTRIM and MIXMODE

When set to the SWITCHED (dual channel mode),
special options are available to allow the audio from the
receivers to be mixed to either one or both audio output
channels.

The MIXMODE setting determines which audio signal
appears at which output channel:

• MIXBOTH mixes the audio and delivers the mix to
both output channels.

• MIXTO 1 mixes the audio and delivers the mix to
output channel 1.

• MIXTO 2 mixes the audio and delivers the mix to
output channel 2.

• DIRECT keeps the audio separated and delivers
receiver 1 audio to output channel 1, and receiver 2
audio to output channel 2.

The MIXTRIM setting applies attenuation up to 20dB in
1 dB steps to adjust the ratio of the two audio signals in
the mix. This adjustment takes effect only when a mix
mode is selected. If the MIXMODE is set to DIRECT,
the MIXTRIM option will not be available.

TONE

The TONE setup screen enables an audio test tone at
the receiver output for precise level matching with other
equipment. The first screen prompts you to press the
UP or DOWN button to enable the tone at the receiver
output. Press MENU/SEL to toggle between receivers.

TONE?

00+05

The first screen prompts you to
press the UP or DOWN button to
start the tone.

Once the UP or DOWN button is pressed, a 1 kHz tone
is enabled, and its level can be adjusted with additional
presses on the UP or DOWN buttons.

The level set here will be retained in the regular operat­ing mode. It will supersede the setting made in the
LEVEL setup screen. The test tone has 1% distortion
and is intended for confirmation of output levels only. To
stop the tone and exit the test tone screen, press the
BACK button.

Front Panel Shortcuts

A convenient shortcut is available from any setup
screen that displays the two receiver selection options
next to each other, such as the LEVELS and STEPSIZE
screens. Once the value has been set on one receiver,
the same value can be copied to the other receiver with
a simple button push combination.

Hold the MENU/SEL button and press the DOWN arrow
to copy the value set on receiver 1 to receiver 2. Hold
MENU/SEL and press UP to copy the value set on
receiver 2 to receiver 1.

LEVEL LEVEL

+05

NOTE: It does not matter which receiver is selected
(highlighted).

00 00

Hold MENU and

press UP arrow

00

IMPORTANT: The output level of each receiver
is adjusted with the LEVEL setup screen, which
is hardware-based, so it affects the output level
regardless of which mix mode is selected. MIXTRIM
then applies attenuation to that level setting resulting in
the final level delivered to the output channel. It is good
practice to set the output LEVEL of both receivers

to the same value when using a mix mode.

When a MIXMODE is selected, each audio signal is au­tomatically attenuated by 6 dB prior to the mixing. This
is done to avoid overload and potential distortion since
mixing increases the level by 6 dB.

20

LECTROSONICS, INC.

Scanning for Clear Frequencies

Scan Window Zoom View Window

UHF Digital Hybrid Wireless

®

Previously tuned

frequency

RF activity level

Spectrum scanning with the receiver itself is the best
way to find clear operating frequencies, since it will
reveal all RF signals present in the receiver, including
those generated by IM (intermodulation).

First, turn off all of the transmitters you intend to use
with the receiver.

Navigate to the SETUP/SCAN screen and press the
MENU/SEL button to start the scanner. The display will
switch to the Scan Window (see illustration above) and
start scanning immediately. Allow the receiver to scan
across the entire tuning range at least once, then press
the MENU/SEL button to stop the scanning.

Scroll through the screen with the UP and DOWN but­tons and find a frequency where no RF signals (or in
the worst case, only very weak RF signals) are present.
Press the PWR/BACK button to set the receiver to this
new frequency.

Press both the UP and DOWN buttons at the same
time to switch to the Zoom View Window (see illustra­tion above). In this view, the cursor remains fixed in the
center of the screen and the background scrolls behind
it. The frequency can be stepped up and down in 100
kHz increments using the UP and DOWN arrow buttons.

When the receiver is configured for SWITCHED diver­sity (dual channel mode), two cursors will appear when
the scanning is stopped. Press MENU/SEL to toggle
between the two receivers. The cursor for the selected
receiver will be a dashed rather than solid line. Select
each receiver and use the UP and DOWN buttons to
locate a frequency with no (or very weak) RF activity.

Freq in

hex

941

Dashed line (cursor)

shows the currently

selected receiver

Block

B2

Press both UP and

DOWN arrows on

control panel to switch

to the Zoom View

Press the BACK

button to return

to the Scan View

Window

Cursor (center bar)

Block

941

8E

Freq in

hex

Keep the frequencies of the two receivers at least 700
kHz apart to minimize de-sensing (short range) issues.
This spacing is a “worst case” approximation assum­ing the transmitters are about 25 feet from the receiver
antennas.

Data gathered during a scan is stored until it is inten­tionally erased or the power is turned off. Previous
data will remain and subsequent scans can be made
to search for additional signals or to accumulate higher
peaks.

To clear the scan memory and screens, press the back
button several times to return to the Main Window, then
press and hold the PWR/BACK button briefly. As soon
as Powering off... appears on the display, release the
button. The receiver will remain turned on, and the scan
data will be erased.

Set your transmitter to the same frequency as shown on
the receiver display, turn the transmitter on and verify
that a strong RF signal is present.

It is always good practice to go through the Multi-chan-
nel Checkout procedure detailed on the following page.

Rio Rancho, NM

21

SRc-941 Dual Receiver

Frequency Coordination

IM (intermodulation) is a process of two or more RF
signals mixing in any stage in the transmitter or receiver
that generates another RF signal. If this new signal
happens to land on a carrier, IF or oscillator frequency
you may have interference problems that affect range
or audio quality. The possible combinations also include
odd and even order harmonics of the carriers.

Feel free to contact the factory if you need help in coor­dinating frequencies. A specialized computer program is
used to perform thousands of calculations and identify
various interfering signals. Potential problems and trou­ble areas can be identified in advance, and proposed
new frequencies or other solutions can be suggested.
This service is offered to authorized Lectrosonics deal­ers and other customers who are using Lectrosonics®
wireless microphone and wireless IFB systems.

Even with thorough analysis, interference can still be
present from local sources that cannot be predicted in
advance. This makes it mandatory to check out a multi­channel system before the production or use begins.

Multi-channel Checkout

IM (intermodulation) and crosstalk increases as the
distance between transmitters and receiver decreases.
In order to conduct a valid checkout of multi-channel
compatibility using the procedure shown here, it is best
to adhere to the following guidelines:

• 4 to 5 feet between transmitters

• 20 to 25 feet between transmitters and receiver
antennas

• Receiver antennas not touching one another

If the distances are less than this, IM will be exagger­ated and not likely to be realistic. If the distances are
greater than this, IM products that could occur during
actual use that may not show up in the checkout proce­dure.

Interference can result from a wide variety of sources
including TV station signals, other wireless equipment
in use nearby, or from intermodulation within a multi­channel wireless system itself.

The pre-coordinated frequencies in the tables on the
previous pages address in-system compatibility, but
obviously do not take into account RF signals from
external sources that may be present in the location
where the system will be operating.

The scanning process will identify external RF signals,
but it does not address the compatibility of the selected

frequencies. Always go through the following steps to
make sure the frequencies that are chosen are com­patible within themselves and also free from external
interference.

1. Set up the system for testing. Place antennas in
the position they will be used and connect to the
receivers. Place transmitters about 4 to 5 feet apart
and about 20 to 25 feet from the receiver antennas.
If possible, have all other equipment on the set,
stage or location turned on as well, especially any
mixing or recording equipment that will be used with
the wireless system.

2. Turn on all receivers. Leave transmitters off.
Look at the RF level display on each receiver. If
an indication is present, change the frequency to
a clear channel where no signal is indicated. If a
completely clear channel cannot be found, set it for
the one with the lowest RF level indication. Once all
receivers are on clear channels, go to the next step.

3. Start with all transmitters turned off. Then turn
on one transmitter at a time. Look at the matching
receiver to verify a strong RF signal is received.
Then, look at the other receivers and see if one of
them is also picking up the signal. Only the match­ing receiver should indicate a signal. Change fre­quencies on either system slightly until it will pass
this test, then check again to see that all receivers
are still on clear channels as in Step 2. Repeat this
procedure for each transmitter, one at a time.

4. With all transmitters and receivers turned on,
turn each transmitter OFF one at a time. Look at
the RF level indicator on the receiver that matches
the transmitter that is turned off. It should “fall silent”
and the RF level should disappear or drop to a very
low level. If it does not, change the frequency on
that receiver and transmitter and try it again.

IMPORTANT: Any time a frequency is changed on any
of the systems in use, you must start at the beginning
and go through this procedure again for all systems.
With a little practice, you will be able to do this quickly
and save yourself some grief.

22

LECTROSONICS, INC.

Specifications and Features

Operating Frequencies: 941.525 - 951.975 MHz

952.875 - 956.225 MHz

956.475 - 959.825 MHz

Frequency selection steps: Selectable; 100 kHz or 25 kHz

Receiver Type: Dual conversion, superheterodyne

IF Frequencies: Ch.1: 248.450 MHz and 350.000 kHz
Ch. 2: 243.950 MHz and 250.000 kHz

Frequency Stability: ±0.001 %

Front end bandwidth: 25 MHz @ -3 dB

Sensitivity
20 dB SINAD: 1.0 uV (-107 dBm), A weighted
60 dB Quieting: 2.2 uV (-100 dBm), A weighted

Squelch quieting: Greater than 100 dB typical

AM rejection: Greater than 60 dB, 4 uV to 1 Volt

Image and spurious rejection: 85 dB

Third order intercept: 0 dBm

Diversity methods: • SmartDiversity
combining with two separate audio channels

• Ratio Diversity using both receivers for a
single audio channel

FM Detector: Digital Pulse Counting Detector operating
at 250 and 350 kHz

RF spectrum analyzer: Coarse and fine scanning modes for
RF spectrum site survey

Antenna inputs: 50 Ohm; SMA female connectors

Audio output connectors: • Interchangeable D connector adapters
for camera slot and multicoupler
interfaces

• Dual TA3 male (mini XLR) balanced
output adapter

• Digital/Analog output and power adapter

Audio output level: Adjustable -50 to +5 dBu in 1 dB steps;
unbalanced output is 6 dB lower

Audio channel crosstalk: -80 dB or better

Audio test tone: 1 kHz, -50 dBu to +5 dBu output (bal);
1% THD

Phase invert: Audio output phase normal or inverted

Compatibility modes: • NU HYBR (new) ETSI compliant Digital Hybrid
Wireless®

• IFB IFB transmitters in IFB mode

SmartNR (noise reduction): OFF, NORMAL, FULL modes
(available in NU HYBR mode only)

Audio Performance (overall system):

Frequency Response: 32 Hz to 20 kHz (+/- 1dB)

THD: 0.2% (typ.) 100 Hz to 20 kHz

System Dynamic Range:

SmartNR No Limiting W/ Limiting

OFF 103.5 108.0

NORMAL 107.0 111 .5

FULL 108.5 113.0

TM

phased antenna

Note: The dual envelope “soft” limiter
provides exceptionally good handling of
transients using variable attack and
release time constants.

Once activated, the limiter compresses
30+ dB of transmitter input range into

4.5 dB of receiver output range, thus
reducing the measured S/N ratio figure
by 4.5 dB.

UHF Digital Hybrid Wireless

Front Panel Controls/Indicators: • Sealed panel with membrane
switches

• LCD monitors pilot tone; antenna
phase, receiver battery level;
transmitter battery
status; audio level, RF level

External DC input: Rear panel locking coaxial connector

Powering and current consumption: Min. 7 VDC; max. 18 VDC; 2.2 W

• 125 mA at 18 VDC

• 180 mA at 12 VDC

• 295 mA at 7 VDC

Transmitter battery type Selection: AA alkaline, AA lithium, timer

Transmitter battery level tracking: LCD display with battery icon or timer
readout

Operating temperature: -20°C to +50°C

Weight w/ SREXT adapter: • SRc: 195 grams (7 ozs.)

Dimensions w/ SREXT adapter: 2.92” wide x 1.22” high x 4.93” deep
(74 mm x 31 mm x 125 mm)

Specifications subject to change without notice

FCC Notice

NOTE: This equipment has been tested and found to
comply with the limits for a Class B digital device, pur­suant to part 15 of the FCC Rules. These limits are de­signed to provide reasonable protection against harmful
interference in a residential installation. This equipment
generates, uses and can radiate radio frequency energy
and, if not installed and used in accordance with the
instructions, may cause harmful interference to radio
communications. However, there is no guarantee that
interference will not occur in a particular installation.
If this equipment does cause harmful interference to
radio or television reception, which can be determined
by turning the equipment off and on, the user is encour­aged to try to correct the interference by one or more of
the following measures:

• Reorient or relocate the receiving antenna.

• Increase the separation between the equipment
and receiver.

• Connect the equipment into an outlet on a circuit
different from that to which the receiver is connect­ed.

• Consult the dealer or an experienced radio/TV tech­nician for help.

Changes or modifications to this equipment not ex­pressly approved by Lectrosonics, Inc. could void the
user’s authority to operate it.

®

Rio Rancho, NM

23

SRc-941 Dual Receiver

Troubleshooting

Symptom Possible Cause

INITIAL POWER ON

LCD display not active or lit External power supply disconnected or inadequate.

Wrong polarity power source. The external power input jack requires
POSITIVE (+) to be on the center pin.

Version message shows DSP or COM This indicates an internal error. Please contact the factory for
assistance.

Display indicates CHECK FREQ This is a warning that a strong RF signal is present that is not
centered on the channel, and the audio is likely to be distorted.

There are three principal causes:

1) The transmitter is set to the wrong channel, but close to the
the correct channel. Check frequency setting of transmitter.

2) A foreign signal is causing the condition, such as from a local
TV station or from intermodulation from another transmitter.
Retune the receiver and transmitter to a clear frequency.

3) The transmitter carrier frequency is not correct (rare occurrence).
Contact factory for repair.

If any of these solutions don’t remove the warning message, the
transmitter or receiver may need repair.

PILOT TONE SQUELCH

Pilot Tone indicator (P) present, but no sound (Check audio meter first)

Audio output cable bad or disconnected.

Audio Output level too low. Use the built-in test tone to verify levels.

Pilot Tone Indicator (P) keeps flashing when transmitter turned on

Pilot tone detection can take several seconds. Turn on the transmitter

power (and the audio switch on some models) and wait 3 to 5 seconds
for the “P” to indicate steadily.

Transmitter and receiver not on same frequency.

Receiver compatibility mode does not match the transmitter in use.
(See Selections from Main Window, COMPAT Window.)

Noise on audio and Pilot Tone Indicator is “b”

The pilot tone bypass has been activated. Navigate to the Main

Window. Hold SEL and press the UP arrow to reset channel 1. Hold
SEL and press the DOWN arrow to reset channel 2. (only from the
Main Window)

NOTE: In the NU HYBR mode the PILOT indicator on the LCD shows as a solid “P” to indicate that the audio has been turned on at
the transmitter, and that the audio output on the receiver is enabled. If the “P” is flashing the pilot tone is not detected and the audio
will be muted (squelched).

Regardless of the compatibility mode, activating the “pilot tone bypass” causes a lowercase “b” to appear on the LCD main
window and forcing the squelch to open and deliver audio. When no matching transmitter is turned on, loud noise will be
present at the receiver output.

24

LECTROSONICS, INC.

UHF Digital Hybrid Wireless

Symptom Possible Cause

ANTENNAS AND RF SIGNAL STRENGTH

RF Level is weak Receiver may need to be moved or reoriented.

Antenna on transmitter or receiver may be defective or poorly
connected - double check antennas.

Improper length of antenna, or wrong antenna on transmitter or
receiver. UHF whip antennas are generally about 3 to 5 inches long.
UHF helical antennas may be shorter, but are often less efficient.

No RF Signal Make certain the frequency set on the transmitter matches the receiver
frequency setting.

Check battery in transmitter.

AUDIO SIGNAL QUALITY

Poor signal-to-noise ratio Transmitter gain set too low.

The noise may not be in the wireless system. Turn the transmitter
audio gain all the way down and see if the noise remains. If the
noise remains, then turn the power off on the transmitter and see if it
remains. If the noise is still present, then the problem is not in the
transmitter.

If noise is still present when the transmitter is turned off, try lowering
the audio output level on the receiver and see if the noise lowers
correspondingly. If the noise remains, the problem is not in the
receiver.

Receiver output is too low for the input of the device it is feeding.
Try increasing the output level of the receiver and lowering the
input gain on the device the receiver is feeding.

Distortion Transmitter input gain too high. Check and/or readjust input gain on
transmitter according to the LEDs on the transmitter and then verify
the setting with the audio meter in the main window.

Audio output level too high for the device the receiver is feeding.
Lower the output level of the receiver.

Poor frequency response or generally poor audio quality

Ensure the receiver is set to the compatibility mode that matches
the transmitter in use.

®

Rio Rancho, NM

25

SRc-941 Dual Receiver

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 the interconnect­ing cables and then go through the Troubleshooting section in this 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

For timely service, please follow the steps below:

A. DO NOT return equipment to the factory for repair without first contacting us by e-mail 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 A.M. to 4 P.M. (U.S. 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 or FEDEX 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 dam-

age to equipment that you ship. Of course, we insure the equipment when we ship it back to you.

Lectrosonics USA:

Mailing address: Shipping address: Telephone:

Lectrosonics, Inc. Lectrosonics, Inc. [phone]
PO Box 15900 561 Laser Rd NE, Suite 102 [phone] Toll-free
Rio Rancho, NM 87174 Rio Rancho, NM 87124 [phone] Fax
USA USA

Web: E-mail:
www.lectrosonics.com [e-mail]

Lectrosonics Canada:

Mailing Address: Telephone: E-mail:

720 Spadina Avenue, [phone] Sales: [e-mail]
Suite 600 [phone] Toll-free Service: [e-mail]
Toronto, Ontario M5S 2T9 (877-7LECTRO)
[phone] Fax

26

LECTROSONICS, INC.

UHF Digital Hybrid Wireless

®

Rio Rancho, NM

27

LIMITED ONE YEAR WARRANTY

m

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.

581 Laser Road NE • Rio Rancho, NM 87124 USA • www.lectrosonics.com
[phone] • [phone] • fax [phone] • [e-mail]

23 May 2018