DCF49 (also known as 39?)

[Andre' Kesteloot]

Geri wrote
I have found some interesting information compiled
by Tom, DL8AAM a while ago, that he posted on the packet radio
network. It
should even be possible to decode the signal.

The callsign that Tom states (DCF49)  probably is only valid for the
129.1
kHz transmitter, same is true for the power.  There is
even some uncertainty about the callsign within the company running
it, I
have heard people saying that they received "DBF39" as well as "DCF39"
in
ASCII.

Best 73

Geri, DK8KW (W1KW)
http://www.qru.de
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EFR - Europaeische Funk-Rundsteuerung GmbH
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Many European dxers have logged DCF49 on 129.1 kHz. The station is
still listed by some publishers as 'BMPT, Bonn', but that is not
correct.
So, if it isn't BMPT Bonn, then who is responsible for the
transmissions?
this month I have the true story for you.
Remember where you read it first.......  YES, in the WUN newsletter!!!

My sincere thanks to Klaus Betke for his research and to EFR Berlin
for their help and information.
 Station          : EFR Berlin
 Callsign         : DCF49
 Transmission site: LW-facility Mainflingen
 Radiated Power   : 60 kW
 Frequencies      : 129.1 and 139.0 kHz
 Transmission mode: 200 bps ASCII
 Modulation       : FSK
 Control protocol : DIN 19244
 Message format   : FT 1.2
 Service          : Long wave Teleswitching

Long wave teleswitching is a new way in load management technology. It

replaces the well adapted ripple-control technology, which is widely
used in the utility industry worldwide.
First a few words about ripple control. It is used for
tariff-switching
applications and load management as well as for the control of street
lighting for example. Basically, ripple control systems are used to
spread information to lots of receivers installed in the supply region

of a utility. Today, ripple control is not considered to be a very
economical method but, for that, a relatively safe method.
Ripple control systems use the existing mains as signal carrier (i.e.
energy suppliers transmit 'tones' over the power lines for this
purpose).
since the mains network is designed for 50 Hz, a ripple control freq
of
a 100 Hz is being affected under certain circumstances. Consequently
the conventional ripple control will face changes due to new transmis-

sion methods and additional intelligence in modern receivers. The
newly
offered long wave teleswitching system is using a radio channel to
transmit the information via air, apart from that it follows the same
basic principles known from conventional ripple control.
The economical management of modern power supply systems requires
possi-
bilities to transmit commands to control the consumption of
electricity
at any time. Audio frequency ripple control systems have been used for

many years. They help to transmit control commands from the control
centre of an utility via the mains which can be received at any point
of
the network. Many utilities are already using these systems (some 410
companies in Germany alone).

The main LW Teleswitching system components are:
     - control centre
     - central computer
     - LW teleswitch transmitter
     - LW teleswitch receiver
The CONTROL CENTRE of the utility consists of a standard computer
system (PC). The program used, enables every participant to initiate
his own messages. A reference-receiver signalises back the messages
sent by radio for monitoring purposes.
The CENTRAL COMPUTER is located in Mainflingen. This computer serves
to assign priorities, buffer, manage and pass on messages to the
trans-
mitter.
The LW TELESWITCH RECEIVER is based on existing conventional ripple
control technology. The network filter has been replaced by a RF
(radio
freq) filter. The areal is fixed on the receiver but can also be in-
stalled separately, if the location poses problems. The receiver has a

program memory to store repetitive control functions. This means that
only program changes have to be transmitted.
The LW TRANSMITTER operates at carrier freqs of 129.1 and 139.0 kHz.
modulation is by FSK; keying is done by shifting between a freq above
and below the carrier freq.
CONTROL TASKS. Modern LW teleswitch can fulfill the same tasks as
conventional ripple control. For example,
- switching tasks, such as:
 o rate switching of multi tariff meters (night and day rates)
 o switching of streetlights
 o switching of water heaters (to cause heaters to use the night
charge)

 load control tasks, such as:
 o group heating control depending on the weather
 o load decrease
 o influence of load variation in industrial companies etc.
 o blocking of heat pump systems
- special tasks, such as:
 o transmission of tariff information remote parameter assignment of
   receiver groups or individual receivers.
o TELEGRAM FORMAT
most telegrams are a few bytes long i.e. about 1 second), but a length

of up to 30 bytes will be possible soon. Reaction time is a few
seconds.
Each telegram is transmitted asynchronous at 200 Baud and 340 Hz
shift,
using 8 data bits plus even parity bit. The format is derived from the

international standard IEC 60870-5, or 870-5 in the old numbering
system.
It consists of 7 header bytes, a user data field of up to 16 bytes,
and
 trailing bytes:
       - Start        68h (h = hexadecimal)
      - L field
      - L field
      - Start        68h
      - C field
      - A field
      - CI field
      - User data    0-16 bytes
      - Check sum
      - Stop         16h
After the start character 68h, the length field (L field) is
transmitted
twice, followed by the start character once again. This is followed by

the C field, the A field and the CI field. The L field gives the
number
of user data bytes plus 3 (for C, A, CI).
The C field (control field, function field) specifies the direction of

data flow and is responsible for various additional tasks. The A field

address field) serves to address the receiver; adresses 1 through 250
can be allocated to individual parties. Address 255 (FFh) is used to
transmit information to all participants (broadcast). The meaning of
the
CI field (control information field) is not clear. Maybe it is used as

an address extension. Most often, however, it is identical to the A
field.
The user data field is followed by the check sum, which is the least
significant byte of the arithmetical sum of C, A, CI and the user
bytes.
Finally the stop character 16h is transmitted.
Most telegrams are sent twice. Currently the lengths range from L = 5
to L = 13. Occasionally the string "DCF49 TEST" is transmitted in the
user data field, with L = 13, C = FFh, A = FFh (broadcast), CI = FFh.
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