Sercel LRU Appendix B Emission Designator Spec Change Update

LRU

User Manual

March 2002

To contact SERCEL

Nantes, France

Commercial; Customer Support;
Manufacturing & Repair.

B.P. 439, 16 rue de Bel Air
44474 Carquefou Cedex

Tel: [phone], Fax: [phone]
Hot-Line: Land: [phone]

Marine: [phone]

E-mail: [e-mail]

[e-mail]

www.sercel.com

St Gaudens, France

Vibrator Customer Support;
Vibrator Manufacturing & Repair;
Streamer Manufacturing & Repair.

Tel: [phone], Fax: [phone]
Hot Line: [phone]

Alfreton, U. K.

Streamer Manufacturing & Repair;
Customer Support.

Tel: [phone], Fax: [phone]

Houston, USA

Commercial; Customer Support;
Manufacturing & Repair;
Streamer Manufacturing & Repair.

Tel: [phone], Fax: [phone]

Hot-Line: [phone]
E-mail: [e-mail]

[e-mail]
[e-mail]

Ponca City, USA

Vibrator Customer Support;
Vibrator Manufacturing & Repair.

Tel: [phone], Fax: [phone]

Moscow, Russia

Commercial; Customer Support.

Tel: [phone], Fax: [phone]

Beijing, P. R. of China

Commercial; Customer Support.

Tel: [phone], Fax: [phone]

Tanggu, P. R. of China

Manufacturing & Repair.

Tel:[phone] , Fax:[phone]

Xian, P. R. of China

Manufacturing & Repair.

Tel: [phone], Fax: [phone]

Singapore

Streamer Manufacturing & Repair;
Customer Support.

Tel:[phone], Fax:[phone]

Dehradun, India

Customer Support.

Tel: [phone], Fax: [phone]
E-mail: [e-mail]

In no event shall SERCEL be liable for incidental or consequential damages or related expenses
resulting from the use of this product, or arising out of or related to this manual or the informa­tion contained in it, even if SERCEL has been advised, or knew or should have known of the
possibility of such damages.

The information included in this documentation is believed to be accurate and reliable.
However, SERCEL reserves the right to make changes to its products or specifications at any
time, without notice, in order to improve design or performance and to supply the best possible
product. This documentation does not form in any way a contractual agreement of sales
promise on the part of SERCEL.

Software mentioned in this documentation is sold under a precise licence agreement and as
such the documentation may cover technical areas for which the user may not have a final
licence.

No part of this documentation, or any of the information included herein may be modified or
copied in any form or by any means without the prior written consent of SERCEL.

Acknowledgments: All brand or product names are trademarks or registered trademarks of
their respective companies or organizations.

LRU User Manual

General

The LRU (Line Remote Unit) relay is a long range po int-t o-p oint ra di o
relay cell that can be inserted anywhere in a spread as an element of the
408UL network to re lay the data transmission o n a Line or a Transverse.
It connects to any type of 408UL field electronics (LAUX, LAUL, FDU
Link, etc.). Built in the LRU is a full per formance LAUX.

In the LRU transmission pro tocol (Half-du plex), time i s shared betwee n
transmission of Master-to-Slave messages and transmission of Slave­to-Master messages.

Master-to-Slave messages are called Network Control Sequences
(NCS), used for synchronization, zero-time transm ission and contro l.

Slave-to-Master messages are called Data Transfer Sequences (DTS),
used for data retrieval, seismonitor and collec ting test results.

1-1

Typical setups

CAUTION

If you wish to test a radio relay cell through a wireline link between the
coaxial connectors of two LRUs, use a 60 dB (minimum), 20 W
attenuator.

Attenuator

20 W
60 dB min.

Typical setups

12 V

For optimal performance of

the radio link, do not

place any electric
device (including LRU,

FDPA408, etc.) on the
same side as the radia ting
elements!

Do not raise any antenna
near electric power
distribution lines!

The antenna should be at
the top the mast.

LRU

(test setup)

8 m

LRU

12 V

NO

YES

12 V

LRU

12 V

LRU

1-2

12 V

12 V

Use the whole cable length
to keep clear fro m the anten na .

March 2002

LRU User Manual Typical setups

CAUTION

Antenna height is limite d to 6.1 metre near airports .

Below are typical examples of setups along with the associated
specifications in terms of covered range and transmission capacity.

Basic radio relay cell

.

LAUX and
radio functions

See

below

Line or
Transverse

to Central

Unit

1

Typical performance (Ground-Wave propagation above flat

LRU

12 V

Battery

Coax downlead

1

7-element
Yagi antenna

LRU

12 V

terrain):

- Range: 24 km, 60 Ch @ 2 ms, Real time.

- Range: 10 km, 240 Ch @ 2 ms, Real time.

See

CAUTION

on

page 1-2

.

For the Left/Right and Low/High ports of the LRU, connect as usual
(Left to Right; Low to High).

1-3

Radio relay in series connection

To extend the relay range, you can use two relay cells in series
connection a s shown below. You can choose between two types of
series setups, one with fewer antenna masts to raise, the other
optimizing th e da ta rate.

• Two-mast series setup (high data rate)

Requirements:

- At least 300 m between antenna s,

- At least 13 MHz frequency separation.

Typical setups

Line or
Transverse

to Central

Unit

Battery

1

Typical performance of each relay cell (Ground-Wave propagation

LRU

12 V

For optimal

performance,
use vertical polar­ization in one cell
and horizontal in
the other.

See

below

1

LRU

12 V

LRU

12 V

Line or
Transverse ports

See

below

1

LRU

12 V

above flat terrain):

- Range: 24 km, 60 Ch @ 2 ms, Real time.

- Range: 10 km, 240 Ch @ 2 ms, Real time.

Setups with more than two relay cells in serie s connection have not bee n
tested yet.

See CAUTION on

1-4

page 1-2

.

March 2002

LRU User Manual Typical setups

• Single-mast series setup

Line or
Transverse

to Central

Unit

Battery

LRU

12 V

See

below

LRU

12 V

1

(Line or
Transverse
cable)

LRU

12 V

See

below

1

LRU

12 V

1

Typical performance of each relay cell (in Ground-Wave

propagation conditions above flat terrain):

- Range: 24 km, 30 Ch @ 2 ms, Real time.

- Range: 10 km, 120 Ch @ 2 ms, Real time.

For the single-m ast serie s s etu p, a spe ci al sof twar e con fig urati on ne eds
to be programm ed in the LR Us, us in g an FD PA408 po cket term in al or
the 408UL HCI workstati on: in each intermediate pair, not to have one
of the LRUs transmitting while the other is receiving, you must have
them working on two distinct “

Subframes

”. That’s why the date rate is

divided by two in the above exampl e.
See LRU Operational Description.

1-5

Typical setups

Where more than two relay cells are used in “single-mast series
connection”, you can avoid reducing the data rate any further if you still
work with only tw o Subframes, provide d adjacent relay loc ations do not
use the same Subframe.

In the example below, relay cell (A) can use the sa me Subframe as relay
cell (C) if they are distan t enough and if the y use two separate frequency
channels.

LRU 1

Relay

Cell

(A)

(B)

(C)

(A)

LRU

No.

LRU 2

LRU 3

Transmit on

Subframe 1

(B)

LRU 4

LRU 5

1 ✔
2 ✔
3 ✔
4 ✔
5 ✔
6 ✔

(C)

Transmit on

Subframe 2

LRU 6

1-6

March 2002

LRU User Manual Typical setups

Radio relay with REM

Line or
Transverse

to Central

Unit

LRU

12 V

Battery

See

below

Requirements:

- At least 300 m between antennas,

- At least 13 MHz frequency
separation.

1

SU6R

LRU

12 V

REM

SU6R

Insert a
bandpass
cavity filter for
each REM
(case of multi-REM
setup) and one
more if Audio is
used with SU6-R

SU6R

(Transverse cable)

1

Typical performance of each relay cell (in Ground-Wave above flat

12 V

terrain):

- Range: 24 km, 60 Ch @ 2 ms, Real time.

- Range: 10 km, 240 Ch @ 2 ms, Real time.

The antenna of the REM and the antenna of the LRU attached to that
REM can be mounted on the same mast, but in that case a minimum
vertical separation of 30 metres (100 feet) should be provided. The rule
is to have at least 80 dB attenuation between the two antennas to allow
each system to work at i ts full sensitivity. The cavity f ilters for the
REMs are still require d.

A REM upgrade may be required.
See CAUTION on

page 1-2

.

1-7

SU6R

Requirements:

- At least 300 m between antennas,

- At least 13 MHz frequency
separation.

Typical setups

SU6R

SU6R

SU6R

REM

12 V

LRU

12 V

up to 24 km

LRU

12 V

REM

12 V

1-8

March 2002

LRU User Manual Antennas

Antennas

The LRU is used as a point-to-point radio relay. For a stationary relay,
directional antennas are used, allowing maximum performance and
protection from int erferen ce. Whe re one of th e two LR Us involv ed in a
radio relay is subjec t to rovin g (Marine, S halow-wa ter operati on, etc.)
omni-directional antennas are more suitable.

Directional antenna

Below are the specifications of a wide-band, 7-element Yagi antenna
available from SERCEL.

This directional antenna can be used either horizontally or vertically.
A 50-ohm impedance coax cable should be used to connect the antenna

to the LRU. To increase the system performance, a low-attenuation,
double-shie l d coa x cable is recommen de d.

Prior to using the antenna, especially after assembly, a VSWR check
should be done, including the coax cable. The maximum VSWR within
the bandwidth of interest should be less than 1.5:1 to work in good
conditions.

• Specifications

• Type: Wideband 7-Element Yagi
(Sercel P/N: 07-820070-001).

• Frequency: 215 to 240 MHz.

• Power Gain: 10.5 dBi, Center frequency.

• VSWR: 1.6:1 Max.

1.3:1 Center f r equency.

• Front-to-back Ratio: 20.45 dB, Center frequency

• 3-dB beamwidth: E = 48 degrees.
H = 57 degrees

1-9

• Feed Impedance: 50 ohm.

• Connector type Type UHF.

• Antenna Boom length: 1.9 m (75").

• Longest Element: 68 cm (26.772").

• Shortest Element: 48 cm (18. 898'').

• Weight: 900 g (2 lb).

• Maximum mast OD: 5 cm (2").

Antennas

1-10

March 2002

LRU Specifications

GENERAL

Radio Functions Communication with another LRU

Cable Functions full LAUX capabilities
Tests capabilities Power supply

Antenna spectrum monitoring capability
Radio setup Pocket terminal connection

Memory 4Mb local buffer for non-real time

Interval between
LRU's or LRU and LAUX
on transverse Up to 300 m with ST cable

for data transmission with error
recovery and temporary storage

Radio data transmission
Cable data transmission
Field tests
Instrument tests

capability

transmission mode

Up to 250 m with WPSR
Up to 400 m with WPSRLR

RADIO PERFORMANCES

Radio link between LRU’s
(Typical propagation condition, bit error rate better than 10
8 m (26 feet) antenna mast, Yagi type antenna)

- 16 km (10 miles) up to 240 Channels (*) @2ms sample
rate real time retrieval.

- 24 km (15 miles) up to 60 Channels (*) @2ms sample
rate real time retrieval.

-6

PHYSICAL

Material Aluminium
Dimension and Weights

Size
Weigths 12.6 kg (27.8 lbs)

Power

Operating Power Voltage

Power consumption

Operating Temperatures
Storage Temperatures
Water Depth 1.5 m

,

380x380x225 mm (14.9x14.9x8.8 in)

10.5 to 15 VDC, 2 battery
connectors, to allow
uninterrupted operation during
battery replacement

Master : 23 W
Slave : 80 W when retrieving
Sleep : 1,2 W

-40°C to 70°C

-40°C to 70°C

RF Characteristics :

RF Frequencies USA use : limited to 216 MHz to

RF Output Power RF power management ; 6W nominal
RF Output
Impedance 50 Ω
FCC Emission
Designators 250KD1D and 800KD1D

218 MHz and 219 MHz to 220 MHz

Canadian use : limited to 217 MHz to
218 MHz and 219 MHz to 220 MHz
Other countries : in respect with local
regulation
Overall capability : 215 MHz to 250 MHz

CABLE PERFORMANCES

(Typical @ 2 ms sample rate and 25°C)
Maximum number of FDU's per LRU :

- 120 with up to 30 m interval

- 96 with up to 55 m interval

- 80 with up to 75 m interval
Maximum number of FDU's between LRU's or between LRU
and LAU :

- 60 with up to 30 m interval

- 48 with up to 55 m interval

- 40 with up to 75 m interval

(*) the number of channels increases proportionally with the ratio :

(shot cycle time) / (acquisition time).