FCC ID: QNEM760REM AVIATION TRANSCEIVER

Microair Avionics M760REM Declaration of Design Performance M760REM-01-0 Airband VHF Transceiver Declaration of Design Performance M760REM-DDP 01R3.doc Page 1 of 21 18th April 2011 Microair Avionics M760REM Declaration of Design Performance Table of Contents INTRODUCTION............................................................................................3 1.0 DEVELOPMENT HISTORY.........................................................................3 2.0 PRODUCT DESCRIPTION...........................................................................4 3.0 AF Board........................................................................................................4 3.1 RF Board........................................................................................................5 3.2 Micro Board...................................................................................................6 3.3 Chassis ...........................................................................................................7 3.4 FREQUENCY TUNING .................................................................................8 4.0 PC EMULATION ............................................................................................8 5.0 TRANSMITTER FUNCTION .......................................................................9 6.0 RECEIVER FUNCTION ..............................................................................12 7.0 SPECIFICATION..........................................................................................13 8.0 NON-INTERFERENCE TESTING.............................................................14 9.0 Table of Testing ...........................................................................................14 9.1 9.2 Test Equipment ............................................................................................14 10.0 SUPPORTING DATA...................................................................................15 11.0 TECHNICAL DRAWING ............................................................................21 M760REM-DDP 01R3.doc Page 2 of 21 18th April 2011 Microair Avionics M760REM Declaration of Design Performance of for the and under standards, which define items 1.0 Introduction The M760REM-DDP lists and describes the performance transceiver. Where necessary, the performance items are referenced to RTCA the the method of performance measurement. this All performance measurements document are made at Microairs factory at Bundaberg Australia, standard environmental conditions. 2.0 Development History The M760REM is a development of the Microair M760 Airband Transceiver. This development replaces the human interface display assembly, with a serial data interface. The M760REM retains the serial data SL30 interface from the M760, for control over the active frequency, standby frequency, and dual monitor mode. The serial data interface replaces all controls normally accessible from the display assembly, with serial command codes. A third party control unit can use these commands to maintain full control and operation of the M760REM. Existing controls and interfaces such as the microphone audio in, headphone audio out, and PTT line remain unchanged from the original M760. M760REM-DDP 01R3.doc Page 3 of 21 18th April 2011 Microair Avionics M760REM Declaration of Design Performance 3.0 Product Description The M760REM consist of three major sub assemblies:

AF Board RF Board Micro Board

(p/n M760_AF_01R18-6A)

(p/n M760_RF_01R19-2)

(p/n M760UAV_MICRO_01R1-0) 3.1 AF Board The AF (Audio Frequency) board holds the following systems:

IF filter, three stage strip, & Detector AGC Mute Microphone input and audio compression PTT switching Audio PA DB15 electrical connector RS232 line driver 9.5V regulator 5V regulator M760REM-DDP 01R3.doc Page 4 of 21 18th April 2011 Microair Avionics M760REM Declaration of Design Performance 3.2 RF Board The RF (Radio Frequency) board holds the following systems:

TCXO PLL/VCO Receiver front end & LP filter Transmitter & PA Modulator M760REM-DDP 01R3.doc Page 5 of 21 18th April 2011 Microair Avionics M760REM Declaration of Design Performance 3.3 Micro Board The Micro Board holds the following systems:

Microcontroller Squelch adjust Headphone audio adjust 5V regulator M760REM-DDP 01R3.doc Page 6 of 21 18th April 2011 Microair Avionics M760REM Declaration of Design Performance 3.4 Chassis The M760REM has a sheet aluminium chassis with a divider plate in the centre, to which the AF and RF boards are fixed. The MICRO board is fixed to the front of the divider plate. Harnessing from the MICRO board connects the AF and RF boards. The chassis is completed by a base plate, front plate, back plate, and top cover. The top cover features mounting flanges, to facilitate installation. M760REM-DDP 01R3.doc Page 7 of 21 18th April 2011 Microair Avionics M760REM Declaration of Design Performance 4.0 Frequency Tuning The M760REM frequency control is via the SL30 command interface. Upon receipt of a valid set active or set standby command, the microcontroller will decode the frequency value and pass it to the PLL via an SPI interface. The PLL will set the control volts for the VCO, which in turn provides the signal source to the transceiver. 5.0 PC Emulation Microair provides a PC application emulate a standard M760 display. The emulator interfaces to the M760REM via the PCs serial port, and used the SL30 command set. All functions can be the application provides a communications window to confirm the command traffic. tested, and to M760REM-DDP 01R3.doc Page 8 of 21 18th April 2011 Microair Avionics M760REM Declaration of Design Performance 6.0 Transmitter Function M760 Transmitter Figure 1 The above figure shows the basic layout of the transmitter in block diagram. The VHF fundamental frequency is generated by the PLL / VCO pair, both of which are separately supplied by their own individual low noise voltage regulators. The VCO is an integrated module that also encapsulates its own 50 ohm buffer. The VCO output level is +10 dBm (10mW). This energy is fed through a -6dB resistive splitter that provides a constant 50 ohm load across the air band. Approximately -3 to -4dBm of RF is then presented to the buffer amplifier. Virtually no gain is obtained from this stage. Its job is to isolate the rest of the transmitter chain from the VCO and to impedance match to the pre-amplifier. The rest of the transmitter chain consists of two RD01 MOSFETs and the PA RD30. All three transistors are very conservatively rated for power dissipation. The RD01 transistors are rated at 1 watt each with no heat sinking and with thermal bonding to PCB ground plane can easily dissipate in excess of two watts each. The PA (RD30) is a 30W MOSFET and with direct source bonding to the aluminium chassis can easily dissipate double this figure. The first RD01 generates +14dBm

(25mW) of RF to drive the second RD01. The driver RD01 is tasked with providing

+24dBm (250mW) average power to the PA and up to 500mW of instantaneous peak power on modulation peaks. Because of the very low input impedance of the final PA (~ 3 ohms) and an output impedance of ~ 65 ohms at the drain of the driver, a matching network was required. The best solution proved to be a high pass /low pass / strip line combination. This circuit is a band pass with 3dB points at 90MHz and 165MHz. For best broad band performance (118 to 138 MHz) and repeatability no inter-stage LC matching was used in the low power preceding stages. M760REM-DDP 01R3.doc Page 9 of 21 18th April 2011 Microair Avionics M760REM Declaration of Design Performance The output (PA) stage has approximately 15dB of gain and produces 5W carrier with a Vdd of 6 volts. The output impedance in this configuration is approximately 8 ohms. The main reason to choose such an over rated transistor is the need to provide 4 times average power (PEP) on the modulation peaks when the modulator voltage will drive Vdd to about 11 volts and still remain linear. This device will tolerate a 20:1 VSWR indefinitely, 30V on the drain and 75W of dissipation. In this role it is virtually indestructible. The native biasing of the RD30 is class AB1 which was deemed good enough as this allowed for the source grounding tabs to be bonded directly to the chassis. With correct output matching the PA proved to be exceptionally free on harmonic content. The output to the antenna is a classic 11 pole Chebychev low pass designed to ramp the impedance gently up to 50 ohms. Chebychev was chosen over Butterworth because 60dB of attenuation was achievable at 236MHz (twice the lowest transmit frequency) at the cost of a small amount of band-pass ripple. That is, the carrier power fluctuates from 4.8 to 5.1 watts across the 20MHz tuning range but the harmonic suppression remains better than 60dBc. The Chebychev cutoff frequency is 160MHz. All stages from VCO to the driver are biased linear class A. The PA is biased linear class AB1. This makes for a very inefficient transmitter in terms of DC power draw

(20 watts drawn from the battery to produces 5 watts of RF at the antenna) but makes for a very clean low harmonic output. The modulator makes use of a linear low drop out 3A voltage regulator. It is configured to provide just under 6 volts on PTT to the drain of the PA. A 500 mV pk-

pk audio signal applied to the programming pin of this IC will drive the output voltage from 1V to 11V in a faithful linear reproduction of the applied audio. M760REM-DDP 01R3.doc Page 10 of 21 18th April 2011 Microair Avionics M760REM Declaration of Design Performance The M760 strategy to avoid adjacent channel splatter is to limit the amplitude of the modulation signal. To this end the audio amplitude is constrained by a 10:1 compressor on the audio board and does not vary within the range of 200mV pk-pk to 2000mV pk-pk of applied external microphone audio. With a typical 13.8 volts supply the modulation is adjusted to 70%. This allows for battery operation at 12V when the modulation will rise to approximately 90%. Modulation will not intercept 100% until the battery voltage falls to 11V by which time the battery is expended in any case. The audio modulation bandwidth is controlled by the audio processing on the audio board. It has sharp band pass characteristics with 3dB points at 300Hz and 3 KHz and corner frequencies of 400 Hz 2.7 KHz. The modulator is also class A with all the attendant inefficiencies. A large finned heatsink is installed to distribute the waste heat. M760REM-DDP 01R3.doc Page 11 of 21 18th April 2011 Microair Avionics M760REM Declaration of Design Performance 7.0 Receiver Function The M760REM has a superhetrodyne receiver with an IF frequency of 10.7MHz. The receivers mixer is high side tuned (eg for 127.000MHz the VCO is tuned to 137.700MHz. The M760REM is also fitted with a dual monitor function, where the PLL is rapidly switched between the active and standby frequencies. If carrier is detected, the switching process is locked to receive that signal. When carrier is no longer present the M760REM will return to rapid switching between the active and standby. If the M760 is receiving on the standby frequency, it will regularly resample the active for the presence of carrier. If carrier is detected on the active, the M760REM will switch back to the active frequency. The M760 can be pout into or out of dual monitor by setting the applicable bit in either the set active or set standby commands. M760REM-DDP 01R3.doc Page 12 of 21 18th April 2011 Microair Avionics 8.0 Specification Radio Type Channels Receiver Transmitter M760REM Declaration of Design Performance Amplitude Modulation (AM) Aircraft Transceiver 760 channels - 25KHz spacing TX: 118.000 136.975MHz RX: 108.000 139.975MHz RTCA/DO-186B Class D RTCA/DO-186B Class 4 TX Frequency Stability 0.4 ppm (0.00004%) Frequency Control Microprocessor controlled: phase lock loop / voltage controlled oscillator Memories Priority Key Power consumption Input Voltage Power output Modulation 99 programmable memories Active & Standby channels with Dual RX monitoring function Fast access to memory 25 (typically 121.500MHz) Receive (no signal) 100 mA Transmit 1.8 A 10.7 16.0 Volts dc Minimum operation 10.7V (receive only) 5.0 5.5 Watts carrier no modulation 70% (nominal) VSWR Tolerance

< 5:1 Receiver sensitivity

>20dB SINAD @ 1.0uV Receiver Selectivity 3.75KHz @ 3dB 8.75KHz @ 90dB Microphone Types Electret or Amplified Dynamic Headset volume output Adjustable: up to 100mW output into 600 ohms Temperature range

-20 - +55 degrees Celsius Dimensions Weight W-87mm H-64mm D-119mm (plus 35mm for harness) W-3.4 H-2.5 D-4.7 (plus 1.5 for harness) 338 grams 13 ounces M760REM-DDP 01R3.doc Page 13 of 21 18th April 2011 Microair Avionics M760REM Declaration of Design Performance 9.0 Non-Interference Testing In accordance with the requirements of RTCA/DO-186B:

Section 2.3.7(c) Emission of Radio Frequency Energy Harmonic emission products shall be at least 60dB below the rated output power, ie minus 60dBc. Harmonic emission products in ICAO Global Navigation Satellite Systems (GNSS) band extending from 1559 to 1610MHz shall be no greater than minus 60dBm. Testing for compliance with RTCA/DO-1686B Section 2.3.7(c) has been carried out in accordance with RTCA/DO-186B Section 3.2.2 Note 2 for spurious emissions greater than -40dBc and emission products greater than -60dBm. 9.1 Table of Testing Fc MHz 130.625 131.275 134.150 120.925 121.175 123.825 Where Harmonic 12 12 12 13 13 13 Fh MHz 1567.500 1575.300 1609.800 1572.025 1575.275 1609.725 Level dBm

<-70dBm

<-70dBm

<-70dBm

<-70dBm

<-70dBm

<-70dBm Fc = Carrier frequency Fh = Harmonic frequency 9.2 Test Equipment Motorola R2600B Communications Analyser Anritsu MS710E Spectrum Analyser M760REM-DDP 01R3.doc Page 14 of 21 18th April 2011 M760REM Declaration of Design Performance Microair Avionics 10.0 Supporting Data Fc = 127.000MHz Fc = 127.000MHz M760REM-DDP 01R3.doc Page 15 of 21 18th April 2011 Microair Avionics M760REM Declaration of Design Performance Fc = 127.000MHz ( No modulation) Fc = 127.000MHz (70% modulation) M760REM-DDP 01R3.doc Page 16 of 21 18th April 2011 Microair Avionics M760REM Declaration of Design Performance Fc = 130.625MHz Fc = 120.925MHz M760REM-DDP 01R3.doc Page 17 of 21 18th April 2011 Microair Avionics M760REM Declaration of Design Performance Fc = 121.175MHz Fc = 131.275MHz M760REM-DDP 01R3.doc Page 18 of 21 18th April 2011 Microair Avionics M760REM Declaration of Design Performance Fc = 123.825MHz Fc = 134.150MHz M760REM-DDP 01R3.doc Page 19 of 21 18th April 2011 Microair Avionics M760REM Declaration of Design Performance Fc = 127.000MHz FC = 127.000MHz M760REM-DDP 01R3.doc Page 20 of 21 18th April 2011 M760REM Declaration of Design Performance Microair Avionics 11.0 Technical Drawing M760REM-DDP 01R3.doc Page 21 of 21 18th April 2011

Microair Avionics M760REM User Manual M760REM-01-0 Airband VHF Transceiver User Manual M760REM-USER 01R1.doc Page 1 of 12 10th March 2011 Microair Avionics M760REM User Manual Table of Contents INTRODUCTION............................................................................................3 DEVELOPMENT HISTORY.........................................................................3 INSTALLATION.............................................................................................4 Mounting.................................................................................................................. 4 Connection ............................................................................................................... 4 Location ................................................................................................................... 4 Antenna .................................................................................................................... 4 Wiring ...................................................................................................................... 5 Wiring Diagram ....................................................................................................... 5 Technical Drawing................................................................................................... 6 TRANSCEIVER CONTROL .........................................................................7 RS232 Serial Data Interface..................................................................................... 7 Transceiver Function ...................................................................................................7 Transceiver Status........................................................................................................8 Set Squelch Level ........................................................................................................8 Report Squelch Level...................................................................................................9 PTT Line ................................................................................................................ 10 Microphone Audio Input........................................................................................ 10 Headphone Audio Output ...................................................................................... 10 SPECIFICATION..........................................................................................11 1.0 2.0 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 4.0 4.1 4.1.1 4.1.2 4.1.3 4.1.4 4.2 4.3 4.4 5.0 M760REM-USER 01R1.doc Page 2 of 12 10th March 2011 Microair Avionics M760REM User Manual 1.0 Introduction The M760REM-USER describes installation, data interface, and operation of the transceiver. The M760REM-USER is a controlled document and may not be chnaged without the prior consent of Miroair Avionics. 2.0 Development History The M760REM is a development of the Microair M760 Airband Transceiver. This development replaces the human interface display assembly, with a serial data interface. The M760REM retains the serial data SL30 interface from the M760, for control over the active frequency, standby frequency, and dual monitor mode. The serial data interface replaces all controls normally accessible from the display assembly, with serial command codes. A third party control unit can use these commands to maintain full control and operation of the M760REM. Existing controls and interfaces such as the microphone audio in, headphone audio out, and PTT line remain unchanged from the original M760. M760REM-USER 01R1.doc Page 3 of 12 10th March 2011 Microair Avionics M760REM User Manual 3.0 Installation The M760REM has no display or human interface control. The unit can fixed to any appropriate aircraft structure which is inside the aircraft cabin. The M760REM should be located clear of air vents or cabin heating, and should not be subject to outside weather. For pressurised aircraft, the M760REM shall be located inside the pressure hull, in a temperature controlled space. 3.1 Mounting The M760REM has mounting flanges with four M4 x 10 (5/32 x 3/8) slotted holes. 3.2 Connection Electrical connection is made using a Sub-

D15 connector, which is held in place using thumbscres or lock bolts (4-40). The RF connection is made using a 50 ohm BNC connector. 3.3 Location The location of the M760REM should consider access to the adjustment trimpots for microphone and headphone aduio level. Consideration should also be given to the connector and cable bending radius for the wiring harness and coax cable. 3.4 Antenna The M760REM is compatible with any TSO C37d/C38d compliant Airband antenna. The coaxial cable shall be 50 ohm (eg RG58/RG400). sidetone level, gain, M760REM-USER 01R1.doc Page 4 of 12 10th March 2011 Microair Avionics M760REM User Manual 3.5 Wiring Microair recommends the use of the Mil-Spec wiring for all lines, and installaed in accordance with the techniques described in FAA AC43-13-2A Pin 1 2 5 7 9 10 11 12 14 BNC Line Pilot Microphone RS232 RX RS232 TX PTT Power Power Ground Ground Headphone Aerial Wire Electret or amplified dynamic RS232 TX (data in) RS232 RX (data out)

<3Vdc to activate

+14V (do not exceed 16Vdc)

+14V (do not exceed 16Vdc) Aircraft Ground Aircraft Ground Line level Audio (typical 100mW into 600Ohms) 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. 3.6 Wiring Diagram M760REM-USER 01R1.doc Page 5 of 12 10th March 2011 M760REM User Manual Microair Avionics 3.7 Technical Drawing M760REM-USER 01R1.doc Page 6 of 12 10th March 2011 Microair Avionics M760REM User Manual 4.0 Transceiver Control The M760REM is fully controlled via the following connections:

RS232 Serial Data Interface PTT line Microphone Audio Input Headphone Audio Output 4.1 RS232 Serial Data Interface Data Rate:

The M760 supports the basic SL30 command set for transceiver control. 9600 Baud 8 bit Parity = none Stop = 1 bit Flow = none Command Description Input Input Input Input Output Output Output

$PMRRV24iidda<chksm><CR<LF>

$PMRRV29mka<chksm><CR<LF>

$PMRRV42mka<chksm><CR<LF>

$PMRRV51<ss><chksm><CR><LF>

$PMRRV32S<ss><chlsm><CR><LF>

$PMRRV20<chksm><CR<LF>

$PMRRV35mkmkas<chksm><CR<LF>

Request for Data Output Set Standby Comm Frequency & Function Set Active Comm Frequency & Function Set Squlech Level Reports Squelch Level Reset function (M760 ready for data) Comm Transceiver Status SL30 4.1.1 Transceiver Function In both the set standby and set active commands the a field represents the transceiver function:

N = Normal M = Monitor 0 = Unchanged Transceiver function setting not changed Transceiver receives and transmits on the active. Transceiver receives on both active and standby, and transmits on active. 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. M760REM-USER 01R1.doc Page 7 of 12 10th March 2011 Microair Avionics M760REM User Manual 4.1.2 Transceiver Status The Comm Transceiver Status command contains the a field for the transceivers status:

R = Normal receive M = Monitor service T = Transmit enabled S = Stuck mic F = Comm failure Normal receiver mode monitor function inactive Monitor function active PTT button is down - transmitting Transceiver transmitting for longer than 45 seconds 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). 4.1.3 Set Squelch Level

$PMRRV51<ss><chksum><CR><LF>

Where Each four bit nibble is added to 0x30 (30 hex). The most significant nibble is transmitted first:

Example

<ss> is the ASCII representation of the seven bit squelch value. If the squelch value is to be set to mid-scale (64 decimal, 40 hex) <ss> would be 40

(0x34 0x30)<chksum> the message checksum, including message identifier through data characters. The two digit checksum is generated by adding all values of valid characters together ignoring carry (if any). This value is converted into two encoded hex characters (0x30-0x3F). A command to set the squelch value to mid-scale (0x40) would result in the command string of

$PMRRV51??>4<CR><LF>

M760REM-USER 01R1.doc Page 8 of 12 10th March 2011 Microair Avionics M760REM User Manual 4.1.4 Report Squelch Level

$PMRRV32S<ss><chksum><CR><LF>

Where S indicates it is the Squelch value is being reported.

<ss> is the ASCII representation of the seven bit squelch value. Example Each four bit nibble is added to 0x30 (30 hex). The most significant nibble is transmitted first. If the squelch value is to be set to mid-scale (64 decimal, 40 hex) <ss> would be 40

(0x34 0x30)<chksum> the message checksum, including message identifier through data characters. The two digit checksum is generated by adding all values of valid characters together ignoring carry (if any). This value is converted into two encoded hex characters (0x30-0x3F). A report to a command to set the squelch to mid-scale will report the following string

$PMRRV32S407=<CR><LF>

The M760UAV will automatically report the new value of the squelch setting immediately following a Set Squelch Command. There is approximately a 100mS delay between processing the command and reporting the new value. M760REM-USER 01R1.doc Page 9 of 12 10th March 2011 Microair Avionics M760REM User Manual to an Audio Panel 4.2 PTT Line The M760REM PTT line is designed to activate the transmitter when the PTT falls below 3Vdc. The line may be completely grounded if required. 4.3 Microphone Audio Input The M760REM provides a 9Vdc bias voltage for Electret or Amplified Dynamic microphone types. Where the M760REM is to be connected type equipment, the optimum input is line level

(1V P-P). The microphone gain and sidetone are adjustable via the trimpot(s) which can be accessed via the small hole(s) in the side of the chassis. 4.4 Headphone Audio Output The M760REM will deliver line level audio out. The level is adjustable via the trimpot which can be accessed via the small hole in the front plate. M760REM-USER 01R1.doc Page 10 of 12 10th March 2011 Microair Avionics 5.0 Specification Radio Type Channels Receiver Transmitter M760REM User Manual Amplitude Modulation (AM) Aircraft Transceiver 760 channels - 25KHz spacing TX: 118.000 136.975MHz RX: 108.000 139.975MHz RTCA/DO-186B Class D RTCA/DO-186B Class 4 TX Frequency Stability 0.4 ppm (0.00004%) Frequency Control Microprocessor controlled: phase lock loop / voltage controlled oscillator Memories Priority Key Power consumption Input Voltage Power output Modulation 99 programmable memories Active & Standby channels with Dual RX monitoring function Fast access to memory 25 (typically 121.500MHz) Receive (no signal) 100 mA Transmit 1.8 A 10.7 16.0 Volts dc Minimum operation 10.7V (receive only) 5.0 5.5 Watts carrier no modulation 70% (nominal) VSWR Tolerance

< 5:1 Receiver sensitivity

>20dB SINAD @ 1.0uV Receiver Selectivity 3.75KHz @ 3dB 8.75KHz @ 90dB Microphone Types Electret or Amplified Dynamic Headset volume output Adjustable: up to 100mW output into 600 ohms Temperature range

-20 - +55 degrees Celsius Dimensions Weight W-87mm H-64mm D-119mm (plus 35mm for harness) W-3.4 H-2.5 D-4.7 (plus 1.5 for harness) 338 grams 13 ounces M760REM-USER 01R1.doc Page 11 of 12 10th March 2011