Hardware Installation

Assembly

M3 screws are recommended for mounting. In saline environments such as coastal and oceanic, the screw material must be stainless steel.

Vibration Isolation

There might be situations where external isolation of vibrations might be needed.

SDL can be mounted in different ways in order to reject the airframe vibration. The simplest way could be achieved by just using double-sided tape on the bottom side. Other ways may use some external structure which could be rigidly attached to the airframe and softly attached to SDL (e.g. foam, silent blocks, aerogel, etc).

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The user should take into account that wiring should be loose enough so vibrations may not be transmitted to SDL.

In cases where mechanical isolation is not viable, it is possible to use soft engine mounts. It is also recommended when there are other sensible payloads like video cameras or for high vibration engines.

Antenna Integration

The system uses different kinds of antennas to operate that must be installed on the airframe. Here you can find some advice for obtaining the best performance and for avoiding antenna interferences.

  • Maximize separation between antennas as much as possible.

  • Keep them far away from alternators or other interference generators.

  • Always isolate antenna ground panel from the aircraft structure.

  • Make sure the antenna is securely mounted.

  • Always use high-quality RF wires minimising the wire length.

  • Always follow the antenna manufacturer manual.

  • SMA connections shall be tightened applying 1Nm of torque.

  • For all-weather aircrafts, insert SMA lightning protectors.

Take into account

The recommended protection against lightnings is to install a surge arrestor at the antenna and another one at the interface. Surge arrestors should be fully interconnected with all the electrical system to have a commond ground.

SDL may only operate using an antenna which type and power are approved by the transmitter. To prevent radio interferences to other users, the antenna type must be chosen and sized to not beam more than the necessary EIRP.

The number of antennas employed on a single network has an effect on the performance of the link rate, since it is shared by all nodes.

The physical distance between antennas (transmitter and receiver) dictates their performance and required lengths. To choose the antenna type, consider the directivity (omnidirectional or directional) of the antennas being used.

Terrain is also an important consideration for antenna height sizing, since antennas should have a LOS, (they need to “see” each other). Nonetheless, LOS is not enough to completely satisfy RF path requirements for a robust communications link. LOS requires a clear path denominated “Fresnel Zone”.

The fade margin is the difference between the supposed receive signal level and the minimum required. Usually, a desired fade margin is approximately 20 dB, but 10 dB may work properly.

Radio frequencies are not affected by rain. Frequency ranges penetrate through foliage and around small obstacles. Then, some may scrimp on physical equipments, specially antenna heights.

FHSS is a method to transmit radio signals by rapidly changing the frequency to different frequencies, occupying a large spectral band. It allows to work well in an environment with sources of interferences at certain bands.

Antenna types

An omni directional antenna spreads its energy in all directions (hence the name ‘omnidirectional’), with a donut as energy field shape and vertical polarization.

A yagi antenna has a focused energy shape with a greater gain, since it has the shape of a raindrop moving along the antenna direction. If the poles of the yagi are perpendicular to the ground, the signal will be vertically polarized; if they are parallel, the signal will be horizontally polarized.

Operating antennas

This device has been designed to operate with the antennas listed below with a gain lower than 13.2 dBi. Different antennas are strictly prohibited. The required antenna impedance should be 50 ohms to prevent potential interferences to other users, the antenna type and its gain should be chosen that the EIRP is not more than required for communication.

Operating antennas list for SDL04 and SDL09

Type

Commercial reference

Description

Rubber Ducky

MHS031000

2dBi, 900MHz Rubber Ducky Antenna RPTNC Swivel

MHS031070

2dBi, 900MHz Rubber Ducky Antenna Reverse SMA Swivel

MHS031080

2dBi, 900MHz Rubber Ducky Antenna Reverse SMA Straight

Transit antennas

MHS031210

3dBd, 900 MHz Transit Antenna with Ground Plane

MHS031220

3dBd, 900MHz Transit Antenna No Ground Plane

MHS031230

3dBd, 900MHz Transit Antenna Permanent Mount GP

MHS031240

3dBd, 900MHz Transit Antenna Permanent Mount NGP

Yagi Antennas

MHS031311

6dBd, 900MHz Yagi Directional Antenna Antenex, RPTNC Pigtail

MHS031431

6.5dBd, 900MHz Yagi Directional Antenna Bluewave, RPTNC Pigtail

MHS031501

9dBd, 900MHz Yagi Directional Antenna Antenex, RPTNC Pigtail

MHS031441

10dBd, 900 MHz Yagi Directional Antenna Bluewave, RPTNC Pigtail

MHS031451

11dBd, 900 MHz Yagi Directional Antenna Bluewave, RPTNC Pigtail

Patch Antennas

MHS031440

8dBi, 900 MHz, Patch Antenna, RPTNC Pigtail

Omni Directional

MHS031251

3dBd, 900MHz Omni Directional Antenna Antenex, RPTNC Pigtail

MHS031461

3dBd, 900 MHz Omni Directional Antenna Bluewave, RPTNC Pigtail

MHS031321

6dBd, 900MHz Omni Directional Antenna Antenex, RPTNC Pigtail

MHS031471

6dBd, 900 MHz Omni Directional Antenna Bluewave, RPTNC Pigtail

Note

Mounts for Transit Antennas have a RPTNC Pigtail.

Operating antennas list for SDL24

Type

Commercial reference

Description

Rubber Ducky

MHS031100

2 dBi,2.4 GHz Rubber Ducky Antenna RPTNC Swivel

MHS031110

2 dBi, 2.4 GHz Rubber Ducky Antenna Reverse SMA Swivel

2.5 dBi, Shenzhen Norminson Technology CO.LTD. - 2.4 GHz Rubber Ducky Antenna

NW001

Reverse SMA Straight

WCP2400-MMCX4

2.5 dBi, Laird Technologies - 2.4 GHz Rubber Ducky MMCX

Yagi antennas

MHS034100

9 dBi, 2.4 GHz Yagi Directional Antenna RPTNC Pigtail

MHS034000

12 dBi, 2.4 GHz Yagi Directional Antenna RPTNC Pigtail

MHS034120

14 dBi, 2.4 GHz Yagi Directional Antenna RPTNC Pigtail

MHS034150

14.5 dBi, 2.4 GHz Yagi Directional Antenna RPTNC Pigtail

Patch antennas

MHS034200

8 dBi, 2.4 GHz Mini Flat Patch Directional Antenna RPTNC Pigtail

MHS034210

14 dBi, 2.4 GHz Flat Patch Directional Antenna RPTNC Pigtail

Omni Directional

MHS031260

5 dBi, Omni Directional Antenna RPTNC Pigtail

MHS034000

6 dBi, 2.4 GHz Omni Directional Antenna RPTNC Pigtail

MHS031340

8 dBi, Omni Directional Antenna RPTNC Pigtail

MHS034020

10.5 dBi, 2.4 GHz Omni Directional Antenna RPTNC Pigtail

MHS034030

12 dBi, 2.4 GHz Omni Directional Antenna RPTNC Pigtail

MHS034040

15 dBi, 2.4 GHz Omni Directional Antenna RPTNC Pigtail

Pinout

Connector pinout

Connector pinout

Clarification

Corresponds to the connector on the radio module side (commercial reference T4144015081-000):

../_images/pinout_radio.png

Number

Name

Function

Description

1

Vin

Power

Voltage supply 6.5-36V

2

GND

Power

Ground for logic, radio, and I/O pins

3

RS232-RX

Input

Receive Data

4

RS232-TX

Output

Transmit Data

5

GND

Power

Ground for logic, radio, and I/O pins

6

RSSI1

Output

Received Signal Strength Indicator 1. 0 V for low / 3.3 V for high

7

RSSI2

Output

Received Signal Strength Indicator 2. 0 V for low / 3.3 V for high

8

RSSI3

Output

Received Signal Strength Indicator 3. 0 V for low / 3.3 V for high

RSSI pins are digital output signals that indicate RF connection quality.

Signal strength according to RSSI pins

Pin 6 - RSSI1

Pin 7 - RSSI2

Pin 6 - RSSI3

Signal strength

HIGH

HIGH

HIGH

Strong

HIGH

HIGH

LOW

Medium

HIGH

LOW

LOW

Weak

LOW

LOW

LOW

Lost

Connections

After configuring SDL it has to be connected to the rest of the devices according to the following diagram, where each pin is refered in the Pinout section of this manual.

../_images/assembly.png

Electrical assembly diagram

An Autopilot 1x can be used as serial device employed. To know how to do it, read Veronte SDL - Integration examples section of 1x Hardware Manual.