[escepticos] Estaciones num éricas

[barrueco]

SECRET SIGNALS - THE EURONUMBERS MYSTERY
By Simon Mason
The author extends his thanks to
V. Nevdachin for the Lincolnshire Poacher lyrics
and to Dr. D. Lightowler for help with the word processor.
©1991 by Tiare Publications
All rights reserved.
No part of this book may be reproduced or transmitted in any
form or by any means electronic
or mechanical, including photocopying, recording or by
information storage and
retrieval systems, without permission in writing from the
publisher,
except for a reviewer who may quote brief passages in a
review.
Layout and Design: Next Wave Graphics, Caledonia, NY
Published by Tiare Publications, P.O. Box 493, Lake Geneva,
WI 53147, USA
ISBN: 0-936653-28-0
Introduction
If you've ever ventured outside the shortwave broadcast and
ham radio bands and tuned around the areas allotted to
so-called "fixed" stations you may have heard voices reading
out long lists of numbers in either four or five digit
groups. These transmissions are generally called "numbers
stations" and appear in a variety of languages.
Transmissions in Spanish are heard most often in the United
States but, in Europe, German, English and French, as well
as a variety of Slavic languages are the most commonly
heard.

What are they? Finding the answer to this question is not an
easy task. For a start, none of these stations operates
"legally". And, with two exceptions, no callsigns are used.
Consulting frequency listings does no good either since the
publications that do list such stations give their origins
as "unknown". Relatively few people in the radio industry
know about these stations, as this item from a recent issue
of the British publication Shortwave Magazine shows: A
letter from a Mr. B. Greater recalls the days in the early
1960's when Greater, then a teen, used to enjoy receiving
and decoding weather reports. These transmissions are sent
over shortwave in a format not unlike that used by the
number stations. But he couldn't decode the data being sent
in what he assumed were weather transmissions so he wrote to
the meteorological office to ask where he was going wrong.
The reply, from the senior signals officer, said the
transmissions were German river soundings being transmitted
in voice format from automated equipment! Other explanations
suggested over the years include coded information for drug
smugglers, lottery numbers, weather data, commodity prices
and so on.

The most likely explanation is that these transmissions are
coded messages sent to espionage agents. In various spy
cases over the years agents have been caught in possession
of certain items of "tradecraft". These have included
shortwave radios, microdots , invisible ink and the
so-called "one-time" pad. This pad consists of a number of
pages of randomly generated four or five figure groups. The
pages are made of a special material that can be easily
destroyed by burning or perhaps even eating. As the name
suggests, each piece of paper is used only once. When the
station broadcasts it usually sends a numerical identifier
to single out the page of the pad to be used for that
particular message. When the message has been sent the
recipient subtracts the number sent over the air from the
corresponding number on the sheet (or vice-versa). This is
the key to the pad's security. Without the particular sheet
in question the message is unbreakable. Other methods of
encryption could include the use of a book available to both
sender and recipient, with a code to indicate individual
words on a page. For example, "312 02" would denote the
second word on page 312. It has been suggested that one
particular station that has a 3/2 figure format may be using
this system.

It has been noted that some stations send the same numbers
up to a year apart -in one case even two years. This might
suggest that practice traffic is being sent to agents for
training purposes. Also, stations could be transmitting
"disinformation" and time-wasting traffic to try and bog
down the electronic eavesdropping efforts of an opposing
intelligence service. Whatever the real explanation, a
shroud of mystery surrounds these stations and only rarely
is one allowed a glimpse into this shady world. One such
occasion was during the trial of British spy Geoffrey Prime.
It was revealed that Prime received his instructions via
shortwave radio. His traffic was encoded in five figure
groups and sent over the air in Morse code. This type of
revelation is rare however and one can only guess at the
full story behind these mysterious and fascinating
broadcasts.

My own interest in number stations goes back some years. But
it was only with the advent of shortwave receivers with
digital frequency readout that I have been able to take an
active interest in them. I decided to analyse these stations
and perhaps figure out their purpose. This was no simple
task since there were no frequency guides to refer to. It
was a case of starting from square one. The first job was to
separate the different types of stations and it soon became
clear which stations were on a given frequency. Operating
schedules were drawn up and it was exciting to hear a
station pop up at the predicted time. Of course their
locations, purpose and the meaning of the messages were
practically impossible to deduce from merely listing times
and frequencies. But this, at least, was a start and better
than nothing.
Part One
SILENT STATIONS
THE FOUR NOTE RISING SCALE STATION
I began with a station I had first heard in 1971. It was a
German station using a female voice machine. It is easy to
tell if a machine is being used as all the numbers are
spoken with an identical delivery. This female German
numbers station had a rigid schedule and format. It also
used a musical marker or interval signal - a four note tune
rising up the scale: "so-la-te-do" played on some sort of
electronic organ. This tune was aired for a five minute
period before the hour. On the hour the woman would send the
headings of each message to follow, for example:

34324/05 67545/07 55433/11 34534/15
11244/18 53466/21 32124/26 12334/29
15566/33 12456/38 98676/41 75555/47

The stroke symbol (/) was spoken as the word trennung. These
headings were sent for exactly five minutes. As you can see,
the two figure number after the first trennung symbol is
"05", which indicates when message number 34323 is due to
start.

At five minutes past the hour there was a pause and the
woman said "achtung" and then the first heading was sent
again but this time the "05,, was replaced by the number of
five figure groups in the message. For example, 34324/22
meant that 22 five figure groups were in message 34324.
Example:
"Achtung34324/22. Achtung34324/22 11223 24566 55454 46578
25555 33367 57567 45585 34665 66477 58577 54888 01123 63645
58999 10122 46547
09991."

After this, "achtung" was sent again, followed by the
heading for the second message -67545/39, for example. As
can be seen, the final message has a suffix "/47, which
means that this message starts at 47 minutes past the hour.
Presumably the recipient would listen to all of the headings
in the first five minutes and then not need to listen again
until the time his message was due to begin if, indeed, a
message was intended for that recipient on that night. After
the last message the word "ende" was sent and the station
fell silent until five minutes before the next hour when the
sinister-sounding electronic tones were sent again,
heralding a new set of headings and messages.

3217 kHz at 1800, 1900, 2000, 2100
3820 kHz at 2000, 2100, 2100, 2200

During the summer months in Britain the station kept to
British Summer Time, i.e. UTC plus one hour.
The same messages sent on 3217 were re-broadcast two hours
later on 3280 so if the first airing was missed there was
still an opportunity to hear it. This was one of the very
few numbers stations that changed its schedule when daylight
savings was in effect. Most kept to the same UTC time so
here was a tiny clue that the messages and the station were
genuine. One could imagine that the agents involved would
have a set monitoring routine somewhere in West German
society and the schedule would be ordered so as to produce
the least inconvenience to their routine. The same station
also appeared during the day using the same format but with
perhaps only half as much traffic as in the evening.

This was the normal daytime schedule:

5820 - 1000, 1100, 1200
6450-0800, 0900, 1000
(UTC times in winter, British Summer time in summer) 
There was apparently no connection between the traffic on
the two frequencies. Only on three occasions did I note any
additional broadcasts: once on 3820 the woman was heard with
some kind of test transmission at 0500 but the signal kept
switching on and off in the middle of the transmission,
making it impossible to copy the full text. On another
occasion the station was on 7625 at 2000 and 2100. The last
unusual transmission was heard on 7430 at 2100. These were
apparently "one-off' broadcasts and were not repeated.

The great changes taking place in East Germany as the 1980's
neared an end also changed the output from this station.
Gradually the traffic lessened to a point where perhaps only
two transmissions per night were heard - sometimes none at
all. In the last days of this station the schedule became
even more erratic and eventually fell to only once per week.
Then, towards the end of April, 1990, the station vanished.
It made me wonder if perhaps the whole shadowy world of
numbers broadcasts was about to end, along with the careers
of all those thousands of former East German agents. It
certainly seemed so when another numbers station
disappeared.

This station had a very distinctive interval signal (musical
marker) and it is difficult to describe the eerie feeling
one got when hearing it. People who live near the sea know
the sound of bells used to warn ships of foggy conditions.
This interval signal sounded like a lightship bell recorded
on tape, except that the tape sped up or slowed down which
made the bell sound very distorted. The tune was of eight
notes, the first four descending down the scale, the last
four rising, as: Fa - Me - Ray - Do - Ray - Me Fa - So."
With all of the dynamic "wow" on the tape the whole thing
sounded very strange. The female voice machine used was also
unique.
Continued on Page 33