MicroAir Avionics M760 User manual

Microair Avionics Pty Ltd
Airport Drive
Bundaberg
Queensland 4670
Australia
Tel: [phone]
Fax: [phone]
e-mail: [e-mail]

Microair Avionics M760 Transceiver Installation & User Manual
M760Q Install & User Manual 01R12.doc Page 2 of 36 30th March 2010
About This Document
This manual describes the various installation configurations
available for the Microair M760 Transceiver. The
Transceiver’s controls and design features are described and
illustrated.
This is a controlled document and may not be amended,
copied or distributed, without the prior consent of Microair
Avionics Pty Ltd.
© Microair Avionics Pty Ltd
Ensure that the M760 transceiver is switched off during
engine starting and stopping to avoid damage occurring.
CURRENT REVISION STATUS
Revision Date Change
K 31/01/00 Initial release
L 18/11/01 Additional install data and wiring diagram added
M 04/10/02 Additional wiring diagram added
N 08/12/03 Updated for revision N
P 01/10/06 Updated for revision P
01R3 13/10/06 Updated for proposed functionality of revision P
01R4 30/05/07 Proposed functionality for revision P amended
01R5 28/06/07 Updated for functionality as of M760_MICRO_1-3-3
01R6 3/06/08 Warranty Statement Upgrade
01R7 08/12/08 Updated for revision P2
01R8 25/2/09 Updated Limited Warranty Statement & deleted Warranty cards
01R9 24/4/09 [email protected] added to Warranty Statement
01R10 24/4/09 Updated for revision Q
01R11 13/07/09 Additional Installation data added
01R12 30/03/10 Drilling template updated

Microair Avionics M760 Transceiver Installation & User Manual
M760Q Install & User Manual 01R12.doc Page 3 of 36 30th March 2010
TABLE OF CONTENTS
1.0 INTRODUCTION......................................................................................................................................4
2.0 UNPACKING..............................................................................................................................................4
2.1 USER / INSTALL MANUAL.................................................................................................................................................4
2.2 NAMEPLATE DETAILS........................................................................................................................................................4
2.3 AUTHORISED RELEASE CERTIFICATE...........................................................................................................................4
3.0 INSTALLATION .......................................................................................................................................5
3.1 WIRING...................................................................................................................................................................................6
3.2 COAX TERMINATION .........................................................................................................................................................8
3.3 ANTENNA ..............................................................................................................................................................................8
3.3.1 METAL SKIN AIRFRAMES................................................................................................................................................................9
3.3.2 NON-METAL SKIN AIRFRAMES......................................................................................................................................................9
3.4 POWER..................................................................................................................................................................................10
3.4.1 BACKLIGHTING...............................................................................................................................................................................10
3.4.2 POWER SAVINGS.............................................................................................................................................................................10
3.5 MICROPHONE .....................................................................................................................................................................11
3.5.1 ELECTRET.........................................................................................................................................................................................11
3.5.2 DYNAMIC..........................................................................................................................................................................................11
3.6 SPEAKER..............................................................................................................................................................................11
3.7 INTERNAL VOX INTERCOM............................................................................................................................................12
3.8 HEADSET ADJUSTMENT..................................................................................................................................................12
3.8.1 SIDETONE.........................................................................................................................................................................................12
3.8.2 MIC GAIN..........................................................................................................................................................................................12
3.9 EXTERNAL INTERCOM.....................................................................................................................................................13
3.10 DUAL COMM INSTALLATION.........................................................................................................................................13
3.11 AUXILIARY AUDIO ...........................................................................................................................................................14
3.12 DATA INTERFACE (SL30).................................................................................................................................................15
3.12.1 TRANSCEIVER FUNCTION.............................................................................................................................................................16
3.12.2 TRANSCEIVER STATUS..................................................................................................................................................................16
3.13 PC INTERFACE....................................................................................................................................................................16
3.14 NOISE SUPPRESSION.........................................................................................................................................................17
3.14.1 POWER FILTER ................................................................................................................................................................................17
3.14.2 FERRITE CHOKES............................................................................................................................................................................17
4.0 OPERATIONAL CONTROLS...............................................................................................................18
4.1 PRIORITY SWITCH.............................................................................................................................................................19
4.2 VOLUME / SQUELCH KNOB ............................................................................................................................................19
4.3 ANNUNCIATOR LED .........................................................................................................................................................19
4.4 MODE SWITCH....................................................................................................................................................................20
4.5 TOGGLE SWITCH ...............................................................................................................................................................20
4.6 FREQUENCY ADJUST KNOB ...........................................................................................................................................21
4.7 REMOTE MEMORY BUTTON...........................................................................................................................................22
4.8 PUSH TO TALK BUTTON..................................................................................................................................................22
5.0 OPERATIONAL MODES ......................................................................................................................23
5.1 ACTIVE/STANDBY MODE................................................................................................................................................23
5.1.1 108 TO 118 MHZ TUNING................................................................................................................................................................23
5.2 MONITOR FUNCTION........................................................................................................................................................24
5.3 CHANNEL MODE................................................................................................................................................................26
5.4 VOX MODE ..........................................................................................................................................................................27
6.0 PROGRAM MENU..................................................................................................................................28
6.1 CD LOCKOUT......................................................................................................................................................................28
6.2 VOX.......................................................................................................................................................................................29
6.3 MONITOR SETUP................................................................................................................................................................29
6.4 NEW MEMORY CHANNEL ...............................................................................................................................................30
6.4.1 SET FREQUENCY.............................................................................................................................................................................30
6.4.2 SET LOCATION ................................................................................................................................................................................30
6.4.3 SET SERVICE....................................................................................................................................................................................30
6.5 EDIT MEMORY CHANNEL ...............................................................................................................................................31
6.6 EXIT MENU..........................................................................................................................................................................31
7.0 WIRING DIAGRAM...............................................................................................................................32
8.0 SPECIFICATIONS M760Q....................................................................................................................33
9.0 DRILLING TEMPLATE........................................................................................................................34
10.0 LIMITED WARRANTY.........................................................................................................................35

Microair Avionics M760 Transceiver Installation & User Manual
M760Q Install & User Manual 01R12.doc Page 4 of 36 30th March 2010
1.0 INTRODUCTION
Thank you for purchasing this Microair product. The M760 is a 760 channel VHF aircraft transceiver, packaged
to fit a standard 57mm (2 ¼”) instrument hole. The M760 has been produced in accordance with CASA APMA
approval E2000-004.
2.0 UNPACKING
The M760 is boxed in polystyrene for physical protection, and wrapped in an anti-static bag for electrical
protection. Once the box is opened and the radio unwrapped, the owner is responsible for physical and
electrical protection.
Enclosed with the radio are: User / Install Manual
CASA form 1 – release certificate
DB15 solder plug and backshell
2.1 USER / INSTALL MANUAL
Please read this manual completely before attempting to install or operate this radio. There are several
installation options you may wish to consider, which are clearly laid out in the installation section.
IMPORTANT NOTE
This manual may be used as technical data to support an installation
under the FAA form 337 process.
The M760 has all of the basic radio operations, and many other management and programming options,
which are described in the operation and memory sections of this manual.
Please refer to the Microair Avionics Website www.microair.com.au for more installation information.
2.2 NAMEPLATE DETAILS
The M760 has a nameplate fixed to the
bottom plate of the chassis.
The Nameplate records the M760’s part
number, revision, and serial number.
Microair recommends the M760 serial
number be noted in the aircraft’s
maintenance records for future reference.
2.3 AUTHORISED RELEASE CERTIFICATE
The CASA form 1 – release note is an internationally recognised document which clearly identifies the
part/component the form 1 is associated with. Please keep this certificate with the aircraft’s file or log
book.

Microair Avionics M760 Transceiver Installation & User Manual
M760Q Install & User Manual 01R12.doc Page 5 of 36 30th March 2010
3.0 INSTALLATION
The M760 has a simple physical installation for aircraft instrument panels. Select or cut a 57mm (2 ¼”)
instrument hole for mounting (refer panel drilling template in section 9.0).
For panel locations which do not afford sufficient space behind the radio to reach the connectors, Microair
recommends connecting the wiring harness and coax cable before fitting the radio to the hole in the panel.
Present the M760 to the rear face of this hole. The stepped round face
will insert through the hole, and should appear flush with the front of
the instrument panel when correctly positioned. Rotate the M760 to
align the four M4 machine screws.
Loose fit all four M4 screws. For installations where the existing
instrument panel screw holes are 1/8”, the holes will need to be
enlarged to 5/32” to fit the M4 machine screws.
Insert and tighten all four M4 machine screws. The M760 requires no
rear support, the M4 screws provide all of the physical mounting
required.
The M760 should be located in the aircraft within view of the pilot
seated in the pilot-in-command position, and afford this pilot good
access to the front face controls.
Do NOT oversize the mounting holes in the front face of the radio,
to an imperial size. Drilling will damage internal components.
Do NOT replace the M4 machine screws supplied with the radio
with longer screws. Over-length screws will touch or even crush
internal components and cause damage.
Either of these actions will void the warranty

Microair Avionics M760 Transceiver Installation & User Manual
M760Q Install & User Manual 01R12.doc Page 6 of 36 30th March 2010
Bare Wire Soldered WireStripped Wire
Tinned Solder Cup Solder Wire to Cup Heatshrink
3.1 WIRING
Microair recommends the use of the wiring in the table below for the various parts of the radio harness:
Pin Line Wire
1 Pilot Microphone Tefzel 22 awg single core shielded
2 RS232 RX Tefzel 22 awg two core shielded (with RS232 TX)
3 Co-pilot Microphone Tefzel 22 awg single core shielded
4 Dual Comm Suppression Tefzel 22 awg
5 RS232 TX Tefzel 22 awg two core shielded (with RS232 RX)
6 Auxiliary Audio Input Tefzel 22 awg single core shielded
7 PTT Tefzel 22 awg two core shielded (with Memory)
8 Backlighting Tefzel 22 awg
9 Power Tefzel 22 awg
10 Power Tefzel 22 awg
11 Ground Tefzel 22 awg
12 Ground Tefzel 22 awg
13 Memory Tefzel 22 awg two core shielded (with PTT)
14 Headphone Tefzel 22 awg single core shielded (Pilot & Co-pilot)
15 Speaker Tefzel 22 awg single core shielded
BNC Aerial RG58C/U 50 ohm Coaxial Cable
All wiring is connected by soldering to the DB15 connector. Inspect the solder cup side of the DB15
carefully to determine the pin numbering.
Strip the insulation back 2mm (1/16”), and “tin” the exposed conductor with solder. Slide a 5mm length
of 1.6mm (1/16”) heatshrink tubing over the end of the wire. After checking the wiring diagram for the
correct pin number, push the “tinned” end into the “tinned” solder cup, and solder into place. Check the
soldered joint has been made, by gently pulling on the wire. Slide the heatshrink tubing down over the
soldered pin, to completely cover the conductor.

Microair Avionics M760 Transceiver Installation & User Manual
M760Q Install & User Manual 01R12.doc Page 7 of 36 30th March 2010
Cover the soldered joints with the grey plastic
backshells. Ensure that the thumbscrews are in
place before closing the backshells. Connect to
the rear of the radio with a push fit, and secure
the thumbscrews (top and bottom).
Microair recommends the use of its pre-wired
M760 harness. The harness is available from
Microair, and comes complete with all
switches, sockets, buttons, and mounting
hardware.
Separate lines have been wired for Pilot and
Co-pilot:
Headphone
Microphone
PTT
Remote Memory

Microair Avionics M760 Transceiver Installation & User Manual
M760Q Install & User Manual 01R12.doc Page 8 of 36 30th March 2010
3.2 COAX TERMINATION
The coax is cut to length and terminated in a BNC
connector. Soldered or crimp type connectors are
preferred to the solderless variety, as they have
lower signal loss and better shielding.
Microair recommends using only soldered or
crimped BNC connectors.
Solderless BNC connectors are NOT recommended,
as their performance is not good enough for VHF
transmissions.
3.3 ANTENNA
For certified aircraft the M760 should only be
operated with a TSO compliant antenna. The
antenna may be ¼ wave whip or ½ wave dipole,
using 50ohm coaxial cable and a BNC connector for
connection. The VSWR should ideally be less than
2:1 across the 118.000MHz to 136.975MHz airband.
For non-certified aircraft using a non-TSO
compliant antenna, the VSWR must be checked to
ensure the ratio does NOT exceed 3:1 on
118.000MHz, 127.000MHz, and 136.975Mhz. The
M760 will tolerate a VSWR of 5:1 without injury to
the transceiver, but the performance is severely
deteriorated.
Do not use the stubbie “rubber duckie” antennas meant for use with handheld radios.

Microair Avionics M760 Transceiver Installation & User Manual
M760Q Install & User Manual 01R12.doc Page 9 of 36 30th March 2010
3.3.1 METAL SKIN AIRFRAMES
For metal skin aircraft a ¼ wave whip is the easiest antenna to fit. Ensure that the antenna base and the
coax shield are firmly grounded to the skin of the airframe, on the inside of the aircraft. Ensure that any
anti-corrosion product, which may be used to seal the exterior surface, does not isolate the antenna base
from the airframe. For best performance the whip should be straight and vertical, when mounted on the
airframe.
Refer to the Microair Avionics website www.microair.com.au for more detail on antennas suitable for
metal skin airframes.
3.3.2 NON-METAL SKIN AIRFRAMES
For non-metal airframes, a ¼ wave whip may still be used, but a ground plane must be installed, on the
inside face of the aircraft skin. The ground plane should ideally be circular, and as a minimum, have a
diameter of half the height of the whip. The ground plane should be fabricated from a lightweight metal,
eg thin aluminium sheet. For best performance the whip element should be as vertical as possible.
An alternative antenna for non-metal airframes is the Ground Plane independent dipole. This antenna is
physically similar to the ¼ wave whip, but has a small flexible stub antenna pointing downwards from
the antenna base. The stub section of the antenna takes the place of the ground plane, and simplifies
installation.
Avoid mounting locations which position the antenna parallel to nearby metallic airframe structures such
as tube framing, brackets, ribs, or frames. Metal objects which are close and parallel to the antenna will
adversely affect performance.
If the installation has two radios, the two antennas should be separated horizontally by at least the length
of the antenna. In the case of airband antennas this should be approx 1m (3ft). The further apart the
better.
Beware of fabric surfaces with silver dope finishes. The silver dope is a conductive surface, and will
screen antennas which are mounted internally.
Refer to the Microair Avionics website www.microair.com.au for more detail on antennas suitable for
non-metal skin airframes.

Microair Avionics M760 Transceiver Installation & User Manual
M760Q Install & User Manual 01R12.doc Page 10 of 36 30th March 2010
3.4 POWER
The M760 is designed to operate on a 14V aircraft electrical supply. The radio will operate down to
10.7V on receive.
It is unlikely that a power supply operating below 11V would
have sufficient power to allow clear transmissions.
The M760 will draw up to 1.8A when transmitting.
Low power will produce a BURRRRRRRRRR signal.
NEVER operate the M760 on voltage exceeding 16V.
Damage will occur if the M760 is operated from power supplies
which exceed 16V, even for very short (transient) periods.
Operation on a supply which exceeds 16V will void the warranty.
The M760 has a FET switch and internal fuse to protect against reverse polarity. If reverse polarity is
applied the internal fuse (4A) will blow. Damage however may not be limited to the fuse.
Please ensure that the correct polarity is observed. The most
common reason for reverse polarity, is misreading the pin
assignments on the DB-15 connector.
Applying reverse polarity to the M760 will void the warranty
Check your wiring! Always check the voltage at the DB15 BEFORE it is
plugged into the radio.
Use a multi-meter to check the voltage at the following pins:
Positive Pin 9 Negative Pin 11
Positive Pin 10 Negative Pin 12
3.4.1 BACKLIGHTING
The backlighting is activated, by taking input supply voltage to pin 8. This line can be individually
switched outside the DB15 connector to enable the backlighting to be turned off.
3.4.2 POWER SAVINGS
For installations, operating from a battery only, Microair recommends saving battery power by NOT
wiring the backlighting – do NOT wire pin 8. The backlighting will draw an additional 80mA of power.
This nearly doubles the standby power demand.
Not connecting the backlighting can effectively double the running time on your battery.

Microair Avionics M760 Transceiver Installation & User Manual
M760Q Install & User Manual 01R12.doc Page 11 of 36 30th March 2010
3.5 MICROPHONE
The M760 can be operated with an Electret Insert or Amplified Dynamic microphone. These alternatives
cover most aviation headsets and hand microphones.
When the PTT is pressed both microphones are live. To reduce background noise, the M760 can be
installed with relays across the mic lines and the PTT line, to allow only one microphone at a time to
operate.
3.5.1 ELECTRET
Electret microphones are the most common microphone in use on aviation headsets. They are small in
size, and can have noise cancelling capability. It is important to wire the Electret microphone with the
correct polarity. The Electret will only work if the positive and negative are wired correctly.
Electrets are a high signal device, and do not normally require amplification. Some headset
manufacturers elect to use an amplifier to improve the Electret’s response, and to provide some noise
filtering.
3.5.2 DYNAMIC
Dynamic microphones are a low signal device. A dynamic microphone will not operate directly with an
M760 radio, because of the low signal produced.
For operators wanting to use a
dynamic microphone, a mic
amplifier must be used.
Microair recommends the
installation of the Microair
MD-01a amplifier. This amp is
compatible with 150-600 ohm
dynamic microphones.
Refer to the Microair Avionics
website www.microair.com.au
for further details on
microphone types, and wiring
configurations.
3.6 SPEAKER
Microair recommends using a speaker of 8 ohms
impedance, rated at a minimum of 5 watts. The
speaker is wired to the speaker line (pin 15). Do NOT
attempt to connect a speaker to the headphone line
(pin 14). Likewise do NOT attempt to connect the
headphones to the speaker line.
Microair recommends the SP01 Box Speaker. The
SP01 has a durable thick film plastic cone of 8 ohms,
and is rated at 5 watts. The SP01 is fitted with a
mounting bracket, and 1.5m of screened cable.
Check your speaker installation by ensuring the audio
is clear all the way up to full volume.
MD-01a
CONNECTOR (RADIO END)
CONNECTOR (MIC END)
CRIMP TERMINALS
MIC SIGNAL LINE
(7-9 VOLTS)
GROUND
LINES TO DYNAMIC MIC
OR MIC JACK

Microair Avionics M760 Transceiver Installation & User Manual
M760Q Install & User Manual 01R12.doc Page 12 of 36 30th March 2010
3.7 INTERNAL VOX INTERCOM
The M760 is fitted with a VOX intercom feature which utilises the sidetone facility of the radio. The
VOX threshold level is controlled in software by use of the VOX Adjust Mode. See section 5.4 to adjust
the internal VOX intercom.
3.8 HEADSET ADJUSTMENT
It is important to ensure that the sidetone and mic gain are set to the correct levels, for best headset
performance. The sidetone level will set the intercom’s headset volume. The mic gain will set the level of
microphone sensitivity for each headset.
3.8.1 SIDETONE
Adjust the sidetone if necessary for good volume level in the headset using the intercom. Ensure that the
headset volume adjust (typically a knob located on the headset earcup) is set to mid range, so the volume
came be adjusted up/down by the user.
3.8.2 MIC GAIN
Adjust the microphone gain if necessary for best audio “quality” not volume level, when transmitting.
The M760Q is fitted with separate mic gain trimpots to allow for adjustment of individual headsets.
Punch the black dot carefully with a screwdriver blade, to expose the slotted plastic head of the trimpot,
located appox 3mm (1/8”) below the surface of the casing. The second mic gain position is not marked,
refer to the drawing below for location.
Note the position of the slot before making adjustments. Use a small flat bladed screwdriver to make
adjustments before testing with a headset again. The total movement of all trimpots is only 300 degrees
(4/5th turn). The factory setting positions the slot of the trimpots at 10 O’clock.
Do not attempt to adjust the modulation or power output. These
adjustments can only be set correctly by a qualified technician.
Adjustment of the power output or modulation by anyone other than
Microair or their approved agent will void the warranty.

Microair Avionics M760 Transceiver Installation & User Manual
M760Q Install & User Manual 01R12.doc Page 13 of 36 30th March 2010
3.9 EXTERNAL INTERCOM
Where the M760 is to be installed with an external intercom, the internal VOX intercom should be
disabled in the Program Mode Menu. See section 6.2.
Wire only a single mic line (pin 1), along with the PTT (pin 7), the headphone (pin 14), and a ground line
(pin 11 or 12) to the intercom. Follow the intercom manufacturer’s instructions for further installation.
Wire the remote memory line (pin 13), directly to the remote memory button location. This line is
NEVER connected to the external intercom. Refer to the Microair Avionics website
www.microair.com.au for more details and wiring diagrams with commonly used intercoms.
3.10 DUAL COMM INSTALLATION
Where two M760’s are to be installed in the aircraft, the interlock or
suppression lines must be installed. Each interlock line shall be wired from
(pin 4) on the first radio to the PTT line (pin 7) on the second radio, and
vice versa.
The interlock lines allow a radio to sense when the other radio is
transmitting, and deactivate to prevent any chance of damage, or allow
distortion noise to occur.
Microair recommends the use of a clearly labelled rotary selector or multi-
pole switch to switch the microphone and PTT lines Refer to the Microair
Avionics website for additional wiring diagrams ( www.microair.com.au ).
Switching from comm1 to comm2 will move all radio functions
including intercom from one radio to the other. Ensure that both
radios have the internal VOX intercom set up correctly

Microair Avionics M760 Transceiver Installation & User Manual
M760Q Install & User Manual 01R12.doc Page 14 of 36 30th March 2010
3.11 AUXILIARY AUDIO
The M760 Q can accept a line level audio input via pin 6 of the DB15 connector. The volume of this
audio can be set by the auxiliary equipment, but will be muted down to a low level when the VOX
intercom is triggered, or a signal is received. The auxiliary audio will remain muted for approx 1 second
after intercom or receiver activity has finished, before rising again to the set volume.
Do not attempt to feed the speaker output of a car stereo directly into
pin 6. The audio level is too high and will damage the audio system
of the M760, and void the warranty. Input only line (headphone)
level audio.
The auxiliary audio input is mono. Most music sources will have a stereo output consistent of left (L) and
right (R) audio channels. L and R audios must be combined before connection to pin 6 of the M760Q.
The auxiliary audio can be used to input the altitude alert warnings from the Microair T2000SFL
transponder.
Audio signal
Audio ground
Pin 6
Pin 11,12
Pin 6 Pin 1

Microair Avionics M760 Transceiver Installation & User Manual
M760Q Install & User Manual 01R12.doc Page 15 of 36 30th March 2010
3.12 DATA INTERFACE (SL30)
The M760Q is SL30 compatible, and allows the user to change the active and standby channels from
EFIS equipment. The M760Q can also be put in and out of dual monitor mode if the EFIS equipment
supports this type of function.
Some types of EFIS equipment do not support SL30 in both directions, ie the user can change channels at
the EFIS and the M760 will update, but the user cannot change channels at the radio and have the EFIS
update.
The M760Q supports all modes of SL30 except the frequency list
upload function. All other SL30 comm commands are supported in
both directions.
The SL30 data connection is made via an RS232 data interface:
Pin 2 RS232 RX
Pin 5 RS232 TX
Pin 11,12 Ground
Data Rate: 9600 Baud
8 bit
Parity = none
Stop = 1 bit
Flow = none
The M760 supports the basic SL30 command set for transceiver control.
SL30 Command Description
Input $PMRRV24iidda<chksm><CR<LF> Request for Data Output
Input $PMRRV29mka<chksm><CR<LF> Set Standby Comm Frequency & Function
Input $PMRRV42mka<chksm><CR<LF> Set Active Comm Frequency & Function
Output $PMRRV20<chksm><CR<LF> Reset function (M760 ready for data)
Output $PMRRV35mkmkas<chksm><CR<LF> Comm Transceiver Status
TX
RX RX
GND GND
TX

Microair Avionics M760 Transceiver Installation & User Manual
M760Q Install & User Manual 01R12.doc Page 16 of 36 30th March 2010
3.12.1 TRANSCEIVER FUNCTION
In both the set standby and set active commands the “a” field represents the transceiver function:
N = Normal Transceiver receives and transmits on the active.
M = Monitor Transceiver receives on both active and standby, and transmits on active.
0 = Unchanged Transceiver function setting not changed
Hence it is possible for the external equipment (if it supports these commands fully) to change the active
and standby frequencies, and switch the M760Q in and out of monitor mode.
3.12.2 TRANSCEIVER STATUS
The Comm Transceiver Status command contains the “a” field for the transceiver’s status:
R = Normal receive Normal receiver mode – monitor function inactive
M = Monitor service Monitor function active
T = Transmit enabled PTT button is down - transmitting
S = Stuck mic Transceiver transmitting for longer than 45 seconds
F = Comm failure Transceiver inoperative
IMPORTANT NOTE
After 45 seconds of transmission, the M760Q will flash the red LED
TX annunciator. During this period the transceiver status will default
to S (stuck mic).
3.13 PC INTERFACE
The M760Q Frequency Compiler software can be used to connect to a PC or laptop with a
windows operating system (XP or later version).
The user can quickly compile channel lists and write them to the M760Q. Refer to the Microair Avionics
website for full details of the M760 PC application ( www.microair.com.au ).

Microair Avionics M760 Transceiver Installation & User Manual
M760Q Install & User Manual 01R12.doc Page 17 of 36 30th March 2010
3.14 NOISE SUPPRESSION
After installation there may be unwanted noise present in the radio’s audio system. There a variety of
sources for this noise, but they usually fall into one of two categories:
Electro-Magnetic Induction (EMI)
Radio Frequency Induction (RFI)
3.14.1 POWER FILTER
EMI typically affects radio equipment by inducing noise on to the
power supply. Microair recommends the installation of a power
filter on the power wire to the M760. A simple line filter is
sufficient to ensure that the voltage is smooth, and causes no
interference to the radio. If engine noise can be heard, and it rises
and falls with the RPM, install a power filter.
Refer to the Microair Avionics website www.microair.com.au for
more information on aircraft electrical systems.
3.14.2 FERRITE CHOKES
RFI typically affect radio equipment by radiating RF noise into
the wiring. The most vulnerable are the microphone, headphone,
speaker, and power lines. The instance of RFI can be reduced by
installing ferrite chokes on the wiring harness.
Locations for best effect are on the wiring
harness immediately behind the DB15
connector at the radio, and on the
microphone/headphone lines just behind the
headset jacks.
Another form of RFI is the impulse noise from equipment like strobe lighting. This
equipment can create large impulses on the power supply which have RF
components.
These signals can radiate to adjacent wiring to create noise. The best defence here
is a filter capacitor on the power input to this type of equipment. A 0.01uF ceramic
capacitor with a 3KV voltage rating is most suitable for this task.
Refer to the Microair Avionics website www.microair.com.au for more information on aircraft electrical
systems.

Microair Avionics M760 Transceiver Installation & User Manual
M760Q Install & User Manual 01R12.doc Page 18 of 36 30th March 2010
4.0 OPERATIONAL CONTROLS
Front Face Control Column
ITEM CONTROL DESCRIPTION
1 Priority Switch Momentary push down switch
2 Volume / On / Squelch Click On - Rotate knob for volume
Rotate ring for squelch
3 Receiver / Transmit Annunciator Red / Green LED
4 Mode Switch Momentary push down switch
5 Frequency Adjust Knob Rotate to adjust value
Press to move cursor
6 Toggle Switch Momentary push down switch
7 Remote Memory Button Momentary push button
8 Push to talk (PTT) Button Momentary push button

Microair Avionics M760 Transceiver Installation & User Manual
M760Q Install & User Manual 01R12.doc Page 19 of 36 30th March 2010
4.1 PRIORITY SWITCH
The priority switch is a push down switch. When pushed down briefly, the radio will go into channel
mode, and select the frequency stored in memory 99. Memory 99 should be considered the priority
channel, which the user can quickly select when required. Memory 99 must be programmed for the
priority switch to operate. Memory 99 is set at the factory as the international distress frequency
121.500MHz. Memory 99 can be programmed the same way as any of the other channels; hence the
factory default can be edited. Refer to section 6.5 to edit this memory.
The priority channel (memory 99) can be edited but not be deleted.
4.2 VOLUME / SQUELCH KNOB
The M760 is turned on, by rotating the volume knob. A
positive “click” is heard and felt at the start of the rotation to
indicate the on/off position. The volume is increased by
rotating the knob clockwise, and decreased by rotating counter
clockwise.
The squelch is adjusted by rotating the ring behind the volume
knob. There is no automatic level set for the squelch, however
the ring affords a large manual adjustment to suit all situations.
Rotate the ring clockwise to increase the squelch threshold, and
counter clockwise to lower the threshold. When the squelch is
“broken” (ie the static hiss can be heard), the annunciator LED
lights green.
Note: This does NOT mean you are receiving a signal!
4.3 ANNUNCIATOR LED
The LED operates red or green, and indicates the following states:
Clear (off) Radio is squelched, and is not receiving a signal
Green Squelch is broken or a signal is received
Red Radio is transmitting
Flashing Red Radio has transmitted for over 45 seconds (warning)
The flashing red signal is designed to draw the pilot’s attention to the fact that the aircraft may have a
stuck PTT button!
Transmissions in excess of 30 seconds should be avoided.
While the M760 is in the program mode menu or memory programming mode the M760 is in its setup
state. The radio can not transmit or receive while it is in the setup state.

Microair Avionics M760 Transceiver Installation & User Manual
M760Q Install & User Manual 01R12.doc Page 20 of 36 30th March 2010
Press Mode Switch
Press Mode Switch
Press
Mode
Switch
4.4 MODE SWITCH
The mode switch is a push down switch, which will cycle through the operational modes of the M760.
When pushed down briefly the radio will step to the next operating mode.
ACTIVE / STANDBY MODE (Refer section 5.1)
CHANNEL MODE (Refer section 5.3)
VOX ADJUST (Refer section 5.4)
If the internal VOX intercom has been disabled in the program mode menu the intercom adjust mode
will be skipped. See section 6.2 to enable / disable the internal VOX intercom.
By holding the mode switch down and turning on, the M760 will start in PROGRAM MENU (refer
section 6.0)
4.5 TOGGLE SWITCH
When the toggle switch is pressed briefly in Active/Standby mode, the active and standby frequencies
exchange places. Hold the toggle switch down for 3 seconds to activate the monitor function.
When the M760 is in monitor mode, press the toggle switch briefly to disengage the monitor
function.
When the M760 is in channel mode the toggle switch is used to quick save the frequency.
The toggle switch is also used in the PROGRAM MODE for programming functions.