Hello Lowfers,
I have send the audio file with the 1-minute recording of DCF39 on 138.830
kHz to some people in the U.S.
John KD4IDY has volunteered to put it on the LWCA homepage (I myself share
the space on my LF homepage http://www.qru.de partly with my othe rpage
htp://www.piperswine.de, also including a lot of audio files, so my own web
space is somewhat limited).
Now André, asks:
I like that file! Now I wonder why the Germans would transmit such a
signal?
What do they do with it ?
Maybe it just doesn't do anything, except annoy the lowfers..
I have digged in my files and 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 tru for the power (Gamal had posted some technical
information on the transmitter in Burg, DCF39, here a while ago). 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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VLF @EU de:DL8AAM 12.01.98 16:00 360 6803 Bytes
DCF49 on 139 kHz
*** Bulletin-ID: 121803DB0NDR ***
980112/1603z DB0ABZ, 980112/1600z DB0ERF, 980112/1557z DB0MAK
980112/1457z OK0PKL, 980112/1611z DB0DLN, 980112/1538Z DB0TUD
980112/1530z DB0NDR
de DL8AAM @ DB0NDR.#NDS.DEU.EU (Tom)
to VLF @ EU
*!* HOT NEWS *!*
EFR - Europaeische Funk-Rundsteuerung GmbH
-----------------------------------------
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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