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Technical Information
Operating Instructions
DOAL
DCF77 Optical Antenna Link
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Impressum
Meinberg Funkuhren GmbH & Co. KG
Lange Wand 9
D-31812 Bad Pyrmont
Phone: +49 (0) 52 81 / 9309-0
Fax: +49 (0) 52 81 / 9309-30
Internet: http://www.meinberg.de
Email: info@meinberg.de
February 14, 2011
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Table of Contents
Impressum ............................................................................................ 2
Features of DOAL ................................................................................ 4
Installation ................................................................................... 5
Technical Specifications ....................................................................... 6
DOAL/A ..................................................................................... 6
DOAL/R ..................................................................................... 8
CE Label .............................................................................................. 9
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Features of DOAL
DOAL is a DCF77 Optical Antenna Link set for connecting a Meinberg DCF77
antenna to a Meinberg DCF receiver via an optical fiber. The module DOAL/R is to
connect to the receivers antenna input via a patch cable and can be assembled
somewhere around. The module DOAL/A is to mount indoor, connected to the
Meinberg DCF antenna (AI01, AW02 or AK03) via a coaxial cable. Both modules are
linked to each other via a GI50/125µm or GI62,5/125µm multimode gradient fiber. This
kind of connection provides several advantages:
- large antenna cable distances (up to 2000 mtrs.)
- no destructive overvoltage via the antenna cable
- no unintentional monitoring via optical fiber
The receiver-side module DOAL/R is supplied with power via the antenna input
connector of the DCF radio clock, therefore no external power supply is necessary. The
module DOAL/A needs an external supply for operating and feeding the connected
DCF77 antenna. The DOAL system is suitable for all Meinberg DCF77 radio clocks,
even upgrading existing installations is possible, also for the correlation receivers
PZF5xx.
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Installation
Antenna
DOAL/A
Receiver
B
A
Fig. 1: Installation Scheme
C
DOAL/R
The maximum cable length of the fiber optical connection (C) is up to 2000 mtrs.
However, the maximum distance depends on the field strength of the received DCF
signal. If the signal is weak, the maximum possible cable length might be shorter. If a
maximum cable length is required, the optical link should be continuously, with no
additional and attenuating FO connectors, and with the most short coax cable connection
to the antenna (A) and to the receiver (B).
On the other hand, if the antenna input level is very high, e.g. due to a preconnected
amplifier (AV4) or because of quite nearness to the DCF77 transmitter (Frankfurt a. M.,
Germany), the Optical Antenna Link could be falling into a saturation that prevents the
receiver from synchronisation. To avoid such problems, the DOAL/A has a jumper on
board that lowers the incoming signal level by approx. 20dB before converting it into an
optical signal. To set this jumper the housing has to be opened by removing the
aluminium front panel.
In order to compensate the group delay caused by the DOAL system together with
PZF correlation receiver, 80km should be added in the "Distance to Transmitter" menu
(refer to the receivers manual).
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Technical Specifications
DOAL/A
ANTENNAINPUT: for active DCF77 antenna (77,5 kHz) via coaxial cable
FO LINK: ST connector for GI 50/125µm or GI 62,5/125µm gradient fibre
Wave length: 850nm (transmit)
Launchable optical output power: typ. 15µW (into GI 62,5/125µm)
STATUS LED: Power OK
CONNECTORS: ST connector (FO Link)
female BNC connector (Antenna)
power supply via 5pin. DFK connector
POWER
REQUIREMENTS: 100 - 240VAC / 50/60Hz
optional: 18 - 72VDC
power consumption: 5W max.
FUSE: 500mA SB / 250V
AMBIENT
TEMPERATURE: -25 ... 65° C
HUMIDITY: 85% max.
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HOUSING: black eloxadized aluminium housing, with aluminium front and
rear panel, IP30 protected
PHYSICAL
DIMENSIONS: 44mm x 105mm x 165mm (height x width x depth)
DCF77 Optical Antenna Link
DCF77 Antenna Power FO Link
Front View DOAL/A
100-240V AC 50/60Hz
100-240V DC
+
Rear View DOAL/A
T0.5A/250V
CLASS 1 LED PRODUCT
CO NO NC
Error
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DOAL/R
FO LINK: ST connector for GI 50/125µm or GI 62,5/125µm gradient fibre
Wave length: 850nm (receive)
Optical input level: min. 3µW
CONNECTORS: ST connector (FO Link)
female BNC connector (Receiver)
AMBIENT
TEMPERATURE: -25 ... 65° C
HUMIDITY: 85% max.
HOUSING: Aluminium HF housing, IP30 protected
PHYSICAL
DIMENSIONS: 25mm x 25mm x 95mm (height x width x depth)
Side View DOAL/R
Front/Rear View DOAL/R
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CE Label
This device conforms to the directive 2004/108/EG on the
approximation of the laws of the Member States of the European
Community relating to electromagnetc compatibility.
Attention:
The optical transmitter and receiver of the DOAL are very sensitive components!
Do not use other than the specified cables/connectors. Do not clean the components
with unsuitable methods or instruments but use the enclosed dust covers
while no FO cable is connected, e.g. during transport.
Disregarding this notes may cause permanent damage of the device!
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