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).

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

Clarification

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

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.

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.