GRT Avionics ADS-B User manual
GRT Avionics, Inc. April 2021
1 FOREWORD
Thank you for choosing the ADS-B Discovery Dual Band Receiver!
This manual describes the installation and operation of this receiver, usin the software
version shown in the Record of Revisions. Some differences may be observed when
comparin the information in this manual to other software versions. GRT Avionics is
not responsible for unintentional errors or omissions in the manual or their
consequences. The builder of the aircraft and the pilot have the final authority on the
airworthiness of the aircraft.
Information in this document is subject to chan e without notice. GRT Avionics, Inc.
reserves the ri ht to chan e or improve their products and to make chan es in the
content of this material without obli ation to notify any person or or anization of such
chan es or improvements.
Co yright © 2021 GRT Avionics, Inc. or its subsidiaries. All rights reserved.
1.1 Important Safety Information
*CAUTION*: When used with a tablet or phone application, the attitude, air data, and
GPS position data transmitted via wi-fi is provided to the receiver by the EFIS. Thus, it is
not an independent source of data. It should not be used to cross-check the data from
the EFIS that supplies this data to the receiver, since it is the same data.
1.2 Warranty and Return Policy
All GRT products include a 2-year warranty, startin on the day the instrument is put
into service (or three years after purchase, whichever comes first), a ainst manufacturer
defect.
Contact Tech Support before returnin a component to GRT for repair or warranty work.
Many issues are installation-related and can be resolved over the phone, savin time
and expense. All returns for repair or up rade must be accompanied by a Service
Request Form, downloadable from the GRT website.
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1.3 Technical Support
Our tech support staff has real-world experience installin , flyin , and troubleshootin
GRT equipment in many different types of aircraft. We are here to help you.
Please visit our website for up-to-date contact information for tech support via email.
Check the home pa e of the GRT website often for new manual updates, video tutorials,
and other instructional materials as we release them.
1.4 Record of Revisions
Revision Date SW Revision Descri tion
A April 2021 1.00 Initial Release
Contents
1 FOREWORD................................................................................................................................................I
1.1 Important Safety Information......................................................................................................I
1.2 Warranty and Return Policy..........................................................................................................I
1.3 Technical Support...........................................................................................................................II
1.4 Record of Revisions........................................................................................................................II
2 INTRODUCTION......................................................................................................................................1
2.1 Warnin s, Cautions, and Notes.................................................................................................1
2.2 Electronic Manuals and Internet Links....................................................................................1
2.3 Feedback and Corrections...........................................................................................................1
2.4 The Discovery ADS-B Receiver...................................................................................................1
2.5 General Specifications...................................................................................................................2
2.6 Compatible Antennae....................................................................................................................2
3 INSTALLATION.........................................................................................................................................3
3.1 Choosin an Antenna Location.................................................................................................3
3.2 Mountin the Antenna..................................................................................................................4
3.3 Choosin a Receiver Location....................................................................................................4
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3.4 Mountin the Receiver..................................................................................................................4
3.5 Antenna Wirin ................................................................................................................................5
3.6 Receiver Wirin to a GRT Avionics EFIS..................................................................................5
3.6.1 RS-232 Wirin ..........................................................................................................................6
3.6.2 USB Wirin ................................................................................................................................7
3.7 Required GRT EFIS Settin s for connectin via RS-232...................................................8
3.8 Required GRT EFIS Settin s for connectin via USB.........................................................8
3.9 Other Applicable EFIS Settin s..................................................................................................8
3.10 Dimensional Drawin ................................................................................................................9
2 INTRODUCTION
This manual was written to help both builders and pilots learn how to install, use, and
maintain this receiver. The receiver may be used in certified aircraft when operated as a
portable electronic device per FAA uidance. This uidance allows the receiver to be
wired to the aircraft wirin for electrical power.
2.1 Warnin s, Cautions, and Notes
Throu hout this manual, you will see notes punctuated with the followin bold type:
!WARNING!: A special notice that could lead to injury or death if not followed.
*CAUTION*: A notice that could lead to dama e of equipment if not followed.
NOTE: An item of special interest that is not immediately apparent throu h normal
usa e.
2.2 Electronic Manuals and Internet Links
Many customers now choose to store electronic copies of the manuals on a tablet
computer or phone for easy access to the newest material. It is easy to carry a lot of
written materials aboard the aircraft without the added wei ht and bulk of paper.
Because of this, we have added links to videos and other aids to the manual text. Simply
touch or click on the link to access interactive materials and tutorials.
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2.3 Feedback and Corrections
If you notice any errors or would like a better explanation of somethin that relates to
this product, please contact GRT tech support. We are always strivin to make our
customers’ lives easier.
2.4 The Discovery ADS-B Receiver
This receiver accepts the followin :
ADS-B weather and traffic data from 978 MHz ADS-B round stations
Airplane-to-airplane traffic data from other ADS-B OUT equipped airplanes
Traffic data from airplanes with 1090 MHz mode S transponders with extended
squitter
This data is provided to the EFIS via an RS-232 or USB serial data connection and via Wi-
Fi to phone/tablet apps.
2.5 General Specifications
Dual-frequency ADS-B UAT (978 MHz), Extended Squitter (1090 MHz) Receiver
Physical Dimensions: 8.0” x 2.5” x 1.3” (203 x 63 x 33 mm)
Weight (W/O Wiring): 0.7 lbs (0.32 k )
Power In ut: 7-35V DC, 8W
Tem erature Range: -10° F to 158° F (-25° C to 70° C)
O erating Altitude: No limit
Cooling In ut: Not required
Interfaces: -RS-232
-USB
-Wi-Fi
2.6 Compatible Antennas
For maximum sensitivity, an external antenna is recommended. Althou h an antenna is
included with the receiver, any external antenna desi ned for ADS-B may be used.
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3 INSTALLATION
Installation consists of the followin steps:
Mount the Receiver
Connect Power and Data Wirin
Install and Wire the Antenna
Confi ure the EFIS and Apps to Use the Data
The location of the antenna often dictates the location of the receiver.
3.1 Choosin an Antenna Location
The main considerations for the location of the antenna are:
3’ away from the transponder, ADS-B OUT (if equipped), and VHF communication
antennae.
6’ away from other transmittin antennae, such as DME.
Preferably within 6’ of the receiver location (this can be extended to 12’ or more
by supplyin your own RG-58 coax cable).
Mountin the antenna on the bottom side of the airplane reduces the probability
of water intrusion.
A round plane is required. For an aluminum airplane, the skin of the airplane
functions as a round plane. For a composite (or tube and fabric) airplane, a
round plane should be incorporated. The round plane can be a sheet of
aluminum, at least 5” in width and len th. The thickness of the aluminum is not
important. Increasin the size of the round plane, up to 25” on each side,
improves the sensitivity of the receiver. Minimal improvement can be expected
beyond this size. The antenna should mount throu h the round plane, so that
its mountin hardware makes electrical connection with the round plane.
The antenna must be mounted vertically.
The antenna must be mounted away from major protrusions, such as en ine
nacelles, landin ear le s, etc.
Typically, the transponder and its antenna are located near the front of the airplane (to
minimize the cable len th between the two). In order to achieve the 3’ spacin required,
it is common to locate the ADS-B receiver antenna aft of the transponder antenna, on
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the opposite side of the airplane’s center line. However, if this placement isn’t feasible,
any location more than 3’ from another transmittin antenna is acceptable.
3.2 Mountin the Antenna
Usin the included hardware, the antenna can be mounted as follows:
Drill a ½” mountin hole usin a stepped drill.
Install the rubber asket on the antenna.
Place the antenna in the mountin hole.
Secure the antenna with the lock washer and nut.
Further uidance is provided by AC43.12-2A, Chapter 3.
3.3 Choosin a Receiver Location
The main considerations for the location of the ADS-B receiver are as follows:
The aluminum base plate of the receiver is used to passively cool the receiver.
This base plate should not be mounted in a way that thermally insulates it. When
mountin to thermally insulatin materials, such as on a composite airplane, use
½” standoffs to allow for airflow around the base plate.
The receiver must be accessible for installation and maintenance purposes.
Physical access to the receiver is not required for software updates when it’s
wired to a GRT EFIS.
The receiver must be within 12’ of the antenna. Receiver sensitivity diminishes
due to si nal losses in lon er coaxial cables.
The location should not expose the receiver to heat or water.
Position the receiver so that the D-Sub remains accessible for wirin purposes.
Similarly, if a backup GPS is oin to be connected to the receiver, maintain
space for this connection.
3.4 Mountin the Receiver
The receiver is mounted with four #6 screws put throu h the holes in its aluminum base
plate. For ease of installation and removal, select a location (or fabricate a tray) that
allows for the use of #6 nut plates.
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3.5 Antenna Wirin
RG-58 or RG-400 coaxial cable (50 Ω characteristic impedance) are acceptable wirin
choices. RG-400 is recommended for cable len ths reater than 6’ (2m).
3.6 Receiver Wirin to a GRT Avionics EFIS
The receiver may be connected to a GRT EFIS via RS-232 or USB connections. An RS-232
connection is preferred, as the d-sub connector is a proven technolo y in airplane
applications and includes hardware to keep the connector in place. In installations that
lack a spare serial input, the USB output can be used.
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3.6.1 RS-232 Wirin
The followin dia ram illustrates the wirin to a GRT EFIS usin RS-232. While the
“Serial Out” connection from the EFIS display unit to the receiver is optional, it provides
the receiver with AHRS and GPS data that it can then output to tablet/phone apps via
Wi-Fi. This connection also allows for updates to the receiver’s software.
The receiver provides
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3.6.2 USB Wirin
The followin dia ram illustrates the wirin to a GRT EFIS usin the USB port. The USB
port provides the receiver with AHRS and GPS data that it can then output to
tablet/phone apps via Wi-Fi. This connection also allows for updates to the receiver’s
software.
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3.7 Required GRT EFIS Settin s for connectin via RS-232
On the Set Menu > General Setu pa e, confi ure the serial input and output ports (if
wired) to “GRT Discovery ADS-B In,” at 115,200 baud.
3.8 Required GRT EFIS Settin s for connectin via USB
On the Set Menu > General Setu pa e, confi ure the USB ADS-B to ON.
3.9 Other Applicable EFIS Settin s
If a USB GPS is connected to the USB Type A port (on the side next to the mountin
holes) and is oin to be used as a GPS source for the EFIS, confi ure it as GPS1 or
GPS2 on the Set Menu > General Setu > GPS from ADS-B Receiver pa e.
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3.10 Dimensional Drawin
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