AXIL RT 202 User Manual

Manual

RT-202

Precision Direction Finder

Page 2 of 34

Edited by:

RHOTHETA Elektronik GmbH
Neuegling 7
82418 Murnau
Germany

Tel.: [phone] - 0
Fax: [phone] - 15

Internet: www.rhotheta.de
E-Mail: [e-mail]

Copyright © RHOTHETA Elektronik GmbH
All rights reserved
Issue: [2008/06/23] [Rev 3.03.a]

HINT

The manufacturer reserves on making modifications at any time and without previous
information of the here described product.

Manual RT-202

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PLEASE NOTE:

As a result of the advanced development of the direction finder bearing unit, it is not possible
to combine devices of the new generation (serial-number higher than 1000) with devices out
of older generations, e.g. antenna unit N° xx-xx-0999 does not work with display unit N°xx-xx­1001 and conversely due to the advanced technical standard!

Manual RT-202

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Index

1 GENERAL INFORMATION 7

1.1 Intended purpose of the Direction Finder 7

1.2 Delivery content of the Direction Finder 7

1.3 Front view of the Display Control Unit (DCU) 8

1.4 Rear view of the Display Control Unit (DCU) 10

2 TECHNICAL DATA 11

2.1 Electrical characteristics 11

2.2 Power supply and Remote – interface 12

2.3 Mechanical characteristics 13

3 PUTTING INTO OPERATION 14

3.1 Installation of the Display Control Unit 14

3.1.1 Mounting of the Display Control Unit 14

3.1.2 Connecting the power supply 15

3.1.3 Grounding of the Display Control Unit 15

3.1.4 Connecting the antenna cable 16

3.2 Installation of the DF antenna 18

3.2.1 Selecting the antenna position for mobile uses 18

3.2.2 Selecting the antenna position for stationary uses 18

3.2.3 Assembly of the antenna 18

3.2.4 Mounting of the antenna rods 19

3.2.5 Adjusting the antenna for mobile uses 20

3.2.6 Adjusting the antenna for stationary use 20

3.3 Serial RS-232 Data Interface / Data protocol 21

3.3.1 Interface data 21

3.3.2 Data output 21

3.3.3 Data input 23

3.3.4 Connector holding 23

3.3.5 Connecting cable Direction Finder Ù PC 24

3.4 Installation of supplement devices 24

3.4.1 External speaker 24

3.4.2 Alarm bell 24

3.4.3 External ON/OFF switch 24

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4 OPERATION 25

4.1 Display functions 25

4.1.1 Switch-on reaction 25

4.1.2 Bearing display - circle of LED’s 25

4.1.3 Display > Level < 25

4.1.4 Display > Signal < 26

4.1.5 Display > < 26

4.1.6 Display > Test-Freq. < 26

4.1.7 Display > Speaker Off < 26

4.1.8 Display > ELT only < 26

4.1.9 Signal device 26

4.2 Operating functions 27

4.2.1 Switching ON/OFF of the Direction Finder 27

4.2.2 Function > CLEAR < as clearing function for the average memory 27

4.2.3 Function > CLEAR < as analysis of bearing quality 27

4.2.4 Function > REPEAT < 27

4.2.5 Function > VOLTAGE < displays the actual battery voltage or power supply 28

4.2.6 Function > : < (Speaker) switch off / on speaker 28

4.2.7 Function > IDENT < (Distress-Signal identification) 28

4.2.8 Function > FREQ. < 29

4.2.9 Function > SQUELCH - < 29

4.2.10 Function > SQUELCH + < 29

4.3 Additional functions 30

4.3.1 Adjusting of a display-offset 30

4.4 Testing of nominal qualities 30

4.4.1 Testing of nominal qualities on watercrafts or land vehicles 31

4.4.2 Testing of nominal qualities, stationary use. 32

5 AVAILABLE ACCESSORIES 32
6 DECLARATION OF CONFORMITY 33
7 APPENDIX 34

7.1 Test protocol 34

7.2 Drawing for mounting of the Display Control Unit 34

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List of Figures

Front view of the Display Control Unit (DCU) in standard POM-version 8
Rear view of the operating / display unit 10
Power / Remote - interface 12
Direction finder antenna 13
Connection of antenna cable 16
Assembly of the antenna rods 19
Example: time diagram of data output with existing receiving signal 21
List of all possible serial messages 22
Pin holding serial connector on Direction Finder 23
Serial connection cable for Direction Finder 24
Display of actual battery voltage or power supply 28
Approach to the transmitter despite 30° bearing error 31
Stencil drawing for mounting of the display unit 34

Manual RT-202

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Thank you very much for buying a direction finder of the company RHOTHETA Elektronik
GmbH. We would like to ask you now to read this operating manual completely and carefully
in order to avoid possible damages caused by incorrect operation or assembly.

1 General information

1.1 Intended purpose of the Direction Finder

The direction finding system RT-202 is designed for detecting and locating emergency
signals, transmitted by a beacon on the international emergency frequency 121.500 MHz. So
the unit can be used as a homing DF-system to a beacon and support so rescue activities.

The direction finder satisfies all requirements put to a professional direction finding system
during hard operation on vessels, land vehicles or when used as a portable device.

The direction finder RT-202 is not designed for navigation requirements.

1.2 Delivery content of the Direction Finder

The delivery content of the Direction Finder consists of following parts:

• 1 Manual

• 1 Display unit (standard version: POM-housing)

• 1 Antenna (standard version: screw-flange)

• 1 Mast bolted joint (standard version)

• 1 Reducer 50 to 40 mm (standard version)

• 8 Antenna rods

• 1 Antenna cable 10 m with connectors

• 1 Spare fuse (0,8A inert)

• 4 Assembly bolts M4 stainless

• 4 Washers M4 stainless

• 4 Assembly nuts M4 stainless

• 1 Power / Remote cable with fuse holder

• 1 Test protocol

• 1 Stencil drawing for mounting display unit

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1.3 Front view of the Display Control Unit (DCU)

18

17

16

2

4

15

14

13

Front view of the Display Control Unit (DCU) in standard POM-version

Operating elements of the Direction Finder RT-202

(Look for more detailed description in the chapters)

(1) On/Off - switch of the direction finder.

11 12

10

9

6

8

(2) Green Power-On-LED flashes when ready for operation (every second).
(3) Selection between the two receiver-channels / frequencies.

frequency I = international distress-frequency: 121.500 MHz
frequency II = test-frequency: 121.650 MHz

(4) Red indication-LED for selected test-frequency (frequency II).
(5) On/Off - switch for internal SPEAKER

external speaker and alarm-output.

(6) Red warning-LED for switched off speaker and alarm exit.

Manual RT-202

: and - if connected to remote interface -

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(7) On/Off - switch for distress-signal-Identification.
(8) Red indication-LED for activated Distress-Signal-Identify.
(9) CLEAR-push-button for clearing the averaged direction value memory and display of

the not averaged direction value for signal quality analysis.

(10) REPEAT-push-button for last given direction value.
(11) SQUELCH +: Pressing this button will show the current squelch level on circular

display. Pressing the button for more than 2 seconds will increase and
simultaneously show the squelch level.

(12) SQUELCH -: Pressing this button will show squelch level on circular display.

Pressing the button for more than 2 seconds will decrease and simultaneously show
the squelch level.

(13) VOLTAGE-push-button for indication of the present supply voltage.
(14) internal speaker : (under the foil)

(15) Display of the LEVEL of the incoming signal by four green LED’s.
(16) SIGNAL squelch indicator, red LED lit when signal is received.
(17) Direction finding indication by 36 red LED’s.
(18) Red warning-LED for intolerable frequency deviation of the received signal

(> ± 5.5 kHz).

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1.4 Rear view of the Display Control Unit (DCU)

Rear view of the operating / display unit

(1) Type label (do NOT remove, warranty depends on it)
(2) Rubber sealing
(3) D-Sub socket “Antenna” for connecting the antenna cable
(4) D-Sub socket “Power / Remote” for

• power supply

• optional connection of a PC (serial RS-232)

• an external speaker

• activation of alarm

• an external ON/OFF- switch

(5) Screw socket for fixing the display unit (4x M4) and connection for ground

Manual RT-202

2 Technical Data

2.1 Electrical characteristics

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• Method of bearing

• Bearing reverence

• Accuracy 1:

• Internal resolution:

• Sensitivity:

• Receiving

Doppler-principle (3 kHz frequency of rotation, cw / ccw)

relative bearing (reverence is antenna orientation)

± 5°

2°

< 2 µV/m;

121.500 MHz & Test-frequency 121.650 MHz

frequencies:

• Bearable kinds of
modulation:

• Polarisation:

A3E, F3E, A2X (Distress-Signal-modulation); DF is largely
independent on kind of modulation

vertical

• Polarisation error: ≤ 5° at 60° vectorial field rotation

• Garbling cone:

ca. 30° measured to the vertical

• Attack time 2: ≤ 50 ms (at sufficient signal strength)

depends on the signal level and modulation.

• Distress-Signal­Identification
specification

Down/Up-ward audio sweep, frequency range = [300 Hz .. 1600 Hz],
repetition rate = [250 ms .. 500 ms], Δf/100 ms = [-140 Hz .. -520
Hz]

• Operating voltage:

• current capacity:

12 .. 24 V DC, (±10%)

max. 350 mA (without external speaker)

max. 600 mA (with external speaker)

• Monitoring:

with inbuilt miniature speaker; modulation: A3E

1

In undisturbed wave field and sufficient field strength. The bearing value results by changing the direction of

incidence, in course of which the antenna is turned on a rotating device to exclude environmental influences
on the DF value.

2

Receiving very low signal levels can increase attack time considerably!

Manual RT-202