Nautel NDB Systems

for the
Offshore Market
 Offshore NDB System Components
ATU-LP
ATU500SR
Vector125
Transmitting Antennas

125 W Antenna Tuning Unit

125 W Beacon 125 W Antenna Tuning Unit 250 W Antenna Tuning Unit CL-HD
125 W Beacon 250 W Antenna Tuning Unit CL-HD

AXESS
VRLINK with ECMP2 NRB4
NLA/2

Receiving Loop Antenna

Beacon Monitor Receiver Receiving Loop Antenna
Remote Control/Monitor with Beacon Monitor Receiver
Remote Control/Monitor with Remote Control/Monitor Application
Extended Control/Monitor Panel Remote Control/Monitor Application
Extended Control/Monitor Panel
Vector System Approach

Vector Remote Control and Monitoring

Ant
Ant

Comms
Comms
Network
Network

Network Operation Typical

TypicalTransmission
TransmissionSite
Site
Centre
Product Application
VECTOR 125
• 125 watt transmitter used to guide helicopters to offshore
oil drilling platforms or vessels with a bearing via ADF
(compass)

ATU500SR & ATU-LP

• antenna tuning units used to match the 50 ohm output
impedance of the transmitter to the impedance of the
antenna system (typically a lower resistance and some
value of capacitance base on the geometry of the antenna)
Product Application
ECMP2 (Extended Control/Monitoring Panel)
• used to provide extended remote control and monitoring of
the NDB system with connection to the transmitter via
parallel wiring

VR-Link
• used to provide remote control and monitoring of the NDB
system, at greater distances than that provided by the
ECMP2, via a hosted web page and via ECMP2 over serial
connection

AXESS
• COTS software application ideally suited to control/monitor
multiple NDB sites and other systems
Product Application
NRB4 (Beacon Monitor Receiver)
• used to provide “off-air” monitoring of the NDB system by
receiving and monitoring key parameters of the transmitted
signal

NLA/2 (Receiving Loop Antenna)

• use in conjunction with the NRB4 to receive and monitor
the “off-air” signal from the NDB system

Antenna
• used to radiate the required signal and may be either a
whip antenna or Helideck antenna configuration
Enhanced Features - Vector System
• Patented solution to maintain system coverage regardless
of undesirable antenna effects such as salt build-up on
insulators (ATU-LP only)

• Automatic Resistive Matching (ATU-LP only)

• Remote control and monitor of the ATU limits worker

exposure to strong RF fields

• Password protected Vector remote control/monitor software

application

• Multiple NDBs can be easily controlled and monitored from

1 central site
Enhanced Features - Vector System
• Built in Diagnostics allows the user to easily identify fault to
Lowest Repairable Unit locally or remotely

• Non operational side can be tested locally or remotely

without need for dummy load while main side remains on
air

• Easily configured site control and monitoring available

locally or remotely
 Vector 125W/250W Transmitter
Exciter/Monitor 125 W/250 W
RF Power System
• Available with Single or Dual
Direct Digital Synthesizer, • Available with Dual or Single
LVPS, modulator driver, keyer, Highly efficient power
monitor modules containing PAs,
modulators, SMPS
• Analog and digital metering
• Frequency agile harmonic
• Remote Interface with several filter
standard and optional
configurations

• Simple LCD graphical user

interface Back-up DC Supply Option

• +24 V dc or + 48 V dc Input is optional with

reverse polarity protection and low voltage
disconnect
• External +24 V dc or + 48 V dc Battery
charger available
 Vector 125W/250W Front and Rear View
Diagnostic Display and
RF Output
Graphical User Interface

Analog Meter
User configurable
Harmonic Filter

AC Power Input DC Power Input

 Carrier Frequency and Emission Modes
• Standard NDB carrier frequency band (190 kHz – 535 kHz) or
Extended band (536 kHz – 1250 kHz and 1600 kHz - 1800 kHz)
for VR125

• NON (CW no modulation)

• A2A (MCW double sideband keyed tone)

• A2A & A3E (Simultaneous AM double sideband telephony and

MCW double sideband keyed tone)

• Optional A1A (keyed CW) (A2A, A2A and A3E not available
when A1A emission mode used)
 Monitor Failure Thresholds

Adjustable threshold normally set so that changeover can

occur if:

• Carrier power reduces more than 3 dB

• Carrier power increases more than 2 dB

• Modulation level reduces more than 4 dB

• Incorrect identification code

When the output power level changes in current feed

back mode, the fault thresholds adjust to reflect the new
output power level.
 Harmonics, Hum & Noise, Distortion

• Harmonic Levels not exceeding -70 dB relative to carrier

when used in conjunction with an ATU500SR or ATU-LP
into a standard antenna load

• Hum and Noise not exceeding -50 dB relative to 1,020 Hz

at a modulation level of 95%

• Audio Distortion Less than 3% at 95% modulation

 Reliability and Repair Time

MTBF Transmitter

• Greater than or equal to 12,590 hours for single and

17,640 hours for dual using MIL_HDBK 217E calculation
methods

• Field experience indicates MTBF in excess of 3,000,000

hours for Nautel NDB systems

MTTR Transmitter

• Less than or equal to ½ hour at PWB/module level

Environmental, Climate, and Altitude

Environmental Limits
Operating: -10ºC to +55 ºC
0% to 95% relative humidity
Storage: -30ºC to +70 ºC
0% to 95% relative humidity

Climate
Any including tropical

Altitude
Up to 3, 048 m (10, 000 ft)
 Input Power Requirements

Vector 125

Single phase 90 V ac to 270 V ac, 50/60 Hz, 500 VA maximum,

dc 24V dc @ 12.6A max or dc 48V dc @ 6.3A max
 Compliances

• Designed with intent to comply with Safety Code 6,

IEEE C95.1-1999

• Compliance with Industry Canada RSS117

• ICAO Annex 10, Volume 1, Part 1, Section 3.4

• Designed for R&TTE 1999/5/EEC compliance

• ISTA Procedure 1A/1B

• Compliance with EN60215:1996 safety

requirements for radio transmitting equipment

• Compliant with Green Passport requirements

Options
• Dual operation
• + 48 V dc back-up operation for Vector 125/250
• + 24 V dc back-up operation for Vector 125
• External Battery chargers
• Extended warranty
• Extended frequency band (536 kHz – 1200 kHz and 1600 kHz
– 1800 kHz) for Vector 125
• NDB site control/monitor
• Modem or USB
• NDB extended and remote control/monitor
• CSA Inspection
• A1A (keyed carrier)
• 19 inch deluxe [185.9 cm H (73.2 in) and 104 cm H (40.9 in)
available] and IP66 Cabinets
 ATU500SR 125W Antenna Tuning Unit
ATU500

Adjustable Spark Gap

with intrinsic static
drain IP66 Compliant Cabinet
manufactured from
Marine Grade Aluminum
with protective finish
suitable for global
Servo Controlled and environments
Automatic Fine Tuned
Astatic pair of Loading
coils which can be
connected series or Bandwidth Optimization to
parallel for maximum minimize VSWR, sideband
agility attenuation and distortion as
compromise between
125 W Antenna Tuning Unit bandwidth and range
125 W Antenna Tuning Unit
 ATU500SR 125W ATU Features

Remote Control/Monitor

• Limited capability to be controlled and monitored at the Vector transmitter

and remotely via the Vector remote control/monitor application

Bandwidth Limitation Solution

• Optional adjustable series resistor

• Optimize range and bandwidth

• Minimize VSWR, sideband attenuation and distortion

 ATU500SR 125W ATU Features

MTBF ATU500

• Greater than or equal to 99,844 hours using MIL_HDBK 217E

calculation methods

• Field experience indicates MTBF in excess of 3,000,000 hours

for Nautel NDB systems

MTTR ATU500

• Less than or equal to ½ hour at PWB/module level

 Vector ATU-LP Overview

Optional Sunshield
or Optional
External Series
Resistor

High Voltage Automatic Servo

Output Controlled, Astatic & Low
Insulator and Loss Inductors (Q of 600)
Adjustable for Reactive Tuning
Graphite Spark
Balls

ATU Control/Monitor
Fixed Pwb contains status
Resistive LEDs to ensure correct
Matching tuning and matching is
Transformer achieved
 ATU-LP Enhanced Features

• Automatic resistive matcher allows resistive changes in the antenna

system such as salt build up on the antenna to be automatically matched.

• The ATU-LP serial data link between the Vector series transmitters and
the ATU-LP allows increased capability to control and monitor the ATU-LP
from the Vector transmitter and remotely via the Vector RCMS.

• The Vector series transmitters when used with the ATU-LP (and not the
ATU500) provide a Constant field strength output for higher system
availability. The serial data link between the ATU-LP and the Vector
transmitter stabilizes the antenna current, and the radiated power, by
automatically adjusting the transmitter output power.
ECMP2 – Extended Control/Monitor

• Extended control and monitor functions within a maximum

distance of 152 m (500 ft) from the Vector NDB.

• 7 visual system indicators (LEDs) and 2 user configurable spare

status indicators.

• 4 switches for remote command and 1 user configurable spare

command switch.

• User configured and enabled timer and audible alarm.

• User configurable to remotely control/monitor any of the Vector

System’s remote control/monitor points.

• Site control/monitor pwb for Vector NDB required.

 Vector NDB RCMS via VR-Link

• Economical means of remote control/monitor of one Vector NDB system.

• Standard VR-LINK connections to the NDB include RS232, RS422. Optional

leased line/dial-up modems and Wired/Wireless Serial Server connections for
network applications are also available.

• Complete control/monitor of the NDB and ATU using a text based display via
hosted web page.

• ECMP2 (Extended Control/Monitor Panel) can be integrated into VR-LINK or a

total of 3 ECMP2s can be connected externally to the VR-LINK via RS-485 serial
communication.
 Typical Offshore RCMS Configuration
Heli-tower

ECMP2

Offshore Vessel
RS485

TCP/IP
VR-LINK
NDB

TCP/IP
RS232 RS485
or On Shore
RS422
or ECMP2
CCR Customer
Dial-up/
leased line Supplied
( requires modems) PC
Vector NDB RCMS Application

Axess software used to

control/monitor multiple
NDB sites
NRB4 & NLA/2 “OFF AIR” Monitor
NRB4

Beacon Monitor Receiver

Beacon Monitor Receiver

NLA/2

Receiving Loop Antenna

Receiving Loop Antenna
NRB4 & NLA/2 Features
Precise and Frequency Agile
• Direct Digital Synthesizer

• No additional parts required for change of frequency

• Excellent selectivity defined by stable IF crystal filter

Off-Air Monitoring of FAA and ICAO requirements

• Adjustable thresholds and Time delays for reduction in
carrier power , reduction in modulation depth and loss of
keying

• Local and Remote Audio Monitoring

• Calibrated Carrier Level Meter

Offshore NDB Antennas

Product Antenna Type

Whip Antennas 8 m (26 ft.) - 10.7 m (35 ft.)

Nautel CL-HD Helideck Longwire antenna

Whip Antennas

• 8 m (26 ft.) - 10.7 m (35 ft.) high

• Low Cost

• Frequency Agile

• Narrow Band can result in problems due to sideband

attenuation and VSWR related issues

• Inefficient Radiator
CL-HD Helideck Antenna

• Designed to suit a variety of Helideck

configurations

• Designed for Compliance to CAP437

• Frequency Agile

• Approx. 7.54 pF/m (2.3 pF/ft)

• Sold to suit Helideck configuration

(not 1 size fits all)
 Whip Antenna Performance

35 ft.(10.7m) whip antenna, 130 pF

Transmitter RF Power: 125 watts
ATU: ATU500SR
Required Signal Strength: 70 uV/m
Conductivity over Saltwater: 5 mS/m

Physical Height at base Range Estimate and Range Estimate and Range Estimate Range Estimate Range Estimate
of antenna above Sea Bandwidth @ 200 Bandwidth @ 250 and Bandwidth @ and Bandwidth @ and Bandwidth @
Water kHz kHz 300 kHz 400 kHz 500 kHz
220 km 260 km 320 km 380 km
65 ft. (19.8 m) N/A BW - 870 Hz BW - 1080 Hz BW - 1550 Hz BW - 2180 Hz
280 km 320 km 380 km 420 km
100 ft. (30.5 m) N/A BW - 900 Hz BW - 1140 Hz BW - 1750 Hz BW - 2650 Hz
320 km 380 km 420 km 460 km
130 ft. (39.6m) N/A BW - 940 Hz BW - 1210 Hz BW - 1970 Hz BW - 3190 Hz
340 km 400 km 440 km 480 km
160 ft. (48.8 m) N/A BW - 980 Hz BW - 1290 Hz BW - 2240 Hz BW - 3840 Hz
 CL-HD Helideck Antenna Performance

CL-HD: 100 - 300 ft (30.5 - 91.5 m), 2.3 pF/ft, 200 ft (61 m) used for estimate
Transmitter RF Power: 125 watts
ATU: ATU500SR
Required Signal Strength: 70 uv/m
Conductivity over Saltwater: 5 mS/m

Physical Height at base Range Estimate and Range Estimate and Range Estimate Range Estimate Range Estimate
of antenna above Sea Bandwidth @ 200 Bandwidth @ 250 and Bandwidth @ and Bandwidth @ and Bandwidth @
Water kHz kHz 300 kHz 400 kHz 500 kHz
240 km 300 km 340 km 380 km 440 km
65 ft. (19.8 m) BW - 720 Hz BW - 940 Hz BW - 1210 Hz BW - 1910 Hz BW - 2990 Hz
320 km 380 km 400 km 440 km 460 km
100 ft. (30.5 m) BW - 760 Hz BW - 1040 Hz BW - 1410 Hz BW - 2570 Hz BW - 4590 Hz
380 km 420 km 460 km 480 km 480 km
130 ft. (39.6m) BW - 810 Hz BW - 1160 Hz BW - 1660 Hz BW - 3350 Hz BW - 6500 Hz
400 km 460 km 480 km 500 km 500 km
160 ft. (48.8 m) BW - 870 Hz BW - 1310 Hz BW - 1970 Hz BW - 4330 Hz BW - 8910 Hz
 Antenna Performance Notes

• The minimum bandwidth required for 400 Hz modulation should be in excess of 800 Hz
and for 1020 Hz modulation should be in excess of 2040 Hz.

• Modulating tone which exceeds the bandwidth will result in significant sideband
attenuation, inability to achieve 95% modulation and VSWR at the transmitter.

• The addition of series resistance (available as standard in the ATU500 and optionally in
the ATU-LP) can be used as a trade off between bandwidth and range if necessary

• The ATU500/ATU-LP will not tune most whip antennas below 250 kHz due to the low
capacitance of the antenna.

• Increased length of radiating wire will increase the bandwidth and range. Decreased
length of radiating wire will reduce the bandwidth and range. It is always best to install as
close to the maximum supplied length of radiating wire (300 ft./91.5m) as possible. The
minimum recommended length for the radiating wire of the CL-HD is 100 ft.(30.5 m).
 Key NDB System Configuration Parameters

• Carrier frequency (kHz)

• Modulation frequency (400 Hz or 1020 Hz)

• Identification (Morse) Code

• Maximum carrier power (125 Watts typical for offshore applications)

• Transmitter configuration (single or dual)

• Transmitter enclosure requirement (customer cabinet, deluxe cabinet, or IP66 enclosure)

• DC operation requirement (DC or battery back-up)

• Remote control/monitoring requirement (number of locations and distances to the site)

• Off-air reception and monitoring requirement (NRB4 Receiver + NLA/2 Loop Antenna)

• Antenna style (whip or Helideck)

Other Considerations

• Training
• Nautel factory
• Nautel representative/distributor premises
• end user premises

• Installation Supervision
• end user technical staff
• Nautel representative/distributor technical staff
• Nautel technical staff

• Commissioning and Site Acceptance

• end user technical staff
• Nautel representative/distributor technical staff
• Nautel technical staff

• Extended warranty (available in yearly increments after initial 13 month warranty)