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Satélites, Espias |
Enough of the theory. After nine episodes in the series questions to the
author regarding reception details are piling up. Other sections of the
media have picked up this theme in the meantime. Der Spiegel had a special,
PLAYBOY report on DXing and a report on ORF about Dr. Dish and the espionage
series.
It is only natural that many readers will want to experience the described
results for themselves. Not everything is possible as the home computer
cannot always cope with it all. For example, an extremely high resolution
satellite picture of northern Germany requires around 100 Mb and software is
not yet available for amateurs that decodes the LANDSAT photos. But there
are still a fair few satellites whose output can be interpreted and manned
space travel that can be followed by both word and picture.
The easiest route into this field is by radio amateur satellite. Programs
and data are accessible from many BBSs and specialist publications, so there
is no need to discuss this any further here.
Obviously their major purpose is to monitor and predict the weather. A
network of geostationary satellites spans the globe. The three most
important systems are GOES (USA), METEOSAT (Europe), and ELEKTRO (CIS). All
3 types operate in the L-band and the picture resolution is not overly
impressive. The pictures that are generally accessible are really
second-hand as the raw data is first sent to the ground station of the
operators. There the picture is computer processed (coastlines and such are
emphasized) and sent back to the satellite. Even so, the picture resolution
is good enough to show, for example, the burning oil wells in Kuwait and the
smoke that ensued during the Gulf war. The cost of reception for these
satellites is quite high if you buy all the equipment off the shelf. A
figure in the region of DM 2000 to 3000 would be about right. The addition
of a YAGI antenna or a dish (of 70 cm and upwards) fitted with a 1.7 GHz
feed and a downconverter (from 1.7 GHz to 137 MHz) sends the cost sky high.
Only once the signal has been converted to 137 MHz is the work taken over by
assemblies for the reception of the orbiting satellites. These obital craft
have a decisive advantage over their geostationary brothers. There are many
of these satellites and thanks to their low orbits (between 300 and 900
kilometres) they supply significantly clearer images (often with bandwidths
of between 400 and 600 kilometres), some of which are of high resolution.
The reception set-up is also cheaper to buy and easier to build at home
oneself. One disadvantage is the system’s dependence on a tracking program
which has to be supplied with a constant stream of real-time data, whilst
METEOSAT works 24 hours a day to a fixed broadcasting schedule. The
reception equipment for an orbital satellite consists of a simple
cross-dipole or a commercially prepared special antenna. These cost between
two and three hundred Marks (approximately £90-130). In practice, however,
it has been shown that reception is possible using a simple DIY
cross-dipole. Instructions for the construction of such can be found in
antenna manuals and specialist amateur radio publications.
The signal is fed to a receiver via a 137 MHz amplifier. A 137 MHz scanner
could be used as a receiver but the standard filters would be unsuitable for
this purpose. The scanners generally use filters of 12 kHz (FM-N) and
150-180 kHz (FM-W), whereas a bandwidth of 40 kHz is required to receive the
weather satellites. Of course it is possible to have a scanner of this kind
converted but this would lead to one of the two bandwidths being lost and
the so-called Doppler Effect will necessitate the constant re-tuning of the
signal owing to the lack of a decent AFC (automatic fine tuning of the
active reception frequency) in most scanners. In such cases it would be wise
to buy or build a small dedicated receiver. Ready-made units can be bought
for DM 350 (approx. £ 150) or are relatively easy to build. However, when
buying a ready-made unit remember that features such as a digital frequency
display, a scan function and AFC are essential. Some manufacturers offer the
receivers with integrated decoders and the necessary computer interface.
This converter is available as both a finished device or as a DIY project.
The resolution of 256 gray scales is an important factor here.
Having been processed by the decoder the signal is transferred via a
serial interface to the PC where it is processed by suitable software. The
shareware program JV-FAX has proven ideal for a large range of applications.
The program works with all WX photo formats allowing zooming in and out of
the image, processing with false colours (so as to better distinguish
features) and playing them as films. As well as this the program can be
utilised for various other picture processing tasks in the amateur
television realm (SSTV). Known orbital weather satellites are the American
NOAA’s, the Russian METEOR, OKEAN and the SICH-1. OKEAN and SICH in
particular deliver very highly detailed pictures from their steep
South-North track. They have the disadvantage of storing their pictures
using on-board memory until they overfly their own earth station. This is
not a problem for Europe watchers but can be most frustrating for those in
other parts of the globe. As well as this both of these satellites are not
amateur-friendly as they don’t work on a weekend. The picture quality is
good enough to allow not only weather watching but also para-military
activities. For example during the Chechen conflict SICH-1 provided
conspicuously large numbers of pictures of this region. These satellites are
already being used by poorer third world countries to monitor events
covering a wide area.
The military obviously protects its data from a curious public and other countries but even here people can get sloppy. During the Gulf war anyone that was sufficiently interested could occasionally get quite a good idea of the situation as uncoded radio chatter was often to be heard on the US-FLTSATCOM satellites. As with the weather satellites there are two distinct groups of satellites; geostationary and orbital. The American system is based upon the FLTSATCOM series and the DSCS satellites. they additionally use the UHF band of the MAREC and INMARSATs (200-400 MHz). The UK puts its trust in its SKYNET satellites and Russians have probably already lost track of their military and spy satellites. The most well known series is the COSMOS series. These satellites can carry out just about every function you can think of. They can be configured as amateur radio, weather, scientific or military satellites. A complete overview of the area of application and technical data can be found in the SATELLITE’S ENCYCLOPEDIA by Jean-Philippe Donnio. This, probably the most reliable reference work, is available on disk.
The complexity of receiving and decoding transmissions from these satellites is enourmous. From time to time decoding is not possible. In spite of all this, these satellites can be a valuable source of information in times of crisis as a considerable proportion of traffic is voice. Video signals can’t be received but faxes pose no problem and thus programs such as CODE-3 with appropriate decoder are adequate for some data. The requisite receivers are expensive. The frequency range from 100 to over 2000 MHz is recommended and that doesn’t come cheap. Suitable units cost between 2000 and 9000 Marks (or £ 850-4000). When it comes to the antennas compromises can be made. A good Discone antenna with integrated amplifier is adequate for the reception of FLTSATCOM (200-400 MHz). Better however is the cruciform YAGI antenna for this frequency range. FLTSATCOM can be easily picked up in Europe. A Discone with a band amplifier gave good results in Holland. A good LOG periodic antenna is fine for the L- and S-bands.
In addition to their numerous COSMOS satellites the Russians also operate
a large number of geostationary RADUGA satellites. A glance at a good
satellite list will assist in locating these. The purpose of these most
versatile satellites is to supply TV images, enable normal
telecommunications and to serve the military, who use the lower C-band
(below 3.65 GHz). Worth searching out is RADUGA 29 (drifting) at
approximately 12.3° East. Simply switch from the Hot Bird position to the
C-band and use the black carriers to target the satellite. FDM and SCPC can
be found here. Outside of the UHF, L, S and C-band the military is obviously
increasingy moving into the X-band. Rejected military equipment for this
band is available from surplus dealers but the prices are usually out of the
reach of amateurs. It’s a great source for poor, small countries to stock
up their military electronics.
A large proportion of all video information comes from these satellites. They are sometimes employed for purely scientific tasks and at others they are used as an information source by the military. The French SPOT provide excellent pictures to order (time and geographic location) and the French secret services will doubtlessly make use of them, partly so that they can earn good money by selling the pictures to other, friendly services. For satellites like COBE, EUVE, GRO, IUE and ROSAT we know the downlink and telemetry frequencies but a home PC can’t make anything out of the pictures as there is no decoding software available to handle the telemetry and the floods of data. Only the Surrey University constructed Micro satellites have telemetry that can be read as these satellites are based on the UOSATs used in the amateur television region. Suitable software is available from AMSAT. Space Shuttle Video feeds from TDRS in the frequency range 13.750-13.775 GHz were always a generally well-known secret. Unfortunately since STS-72 nothing has been seen and it is highly likely that the feed is now carried digitally. But the Shuttle missions still supply a huge volume of data and voice communications. Curious readers and listeners tune in to the short wave or the UHF- and S-bands. From time to time the Shuttle signals can be picked up directly during an overflight or via one of the TDRS satellites (Europe - 41° West).
Similarly bountiful are the frequencies offered by the Russian space station MIR. The voice communication between space station and ground control can be picked up at 143.625 MHz with a cheap hand scanner. Video is very occasionally carried via SDRN at 116° West and from March/April it is foreseen that an S-band videolink will be installed. Identical hardware is required for both the Space Shuttle and MIR - a wide band receiver capable of reaching 2.6 GHz or 2 GHz with a suitable converter. The receiver should be able to receive AM, FM-N, FM-W and SSB.
Rockets have their own telemetry too. PROGRESS is the Russian transporter that provides the Cosmonauts in MIR with water, food, papers and all the other little things required for day-to-day living. PROGRESS is unmanned and transmits between 160 and 950 MHz. SOYUZ, however, is manned and is employed to swap over the personnel in MIR. This transporter is considered as a normal aeroplane and so its communications frequencies are to be found in the AIR-band. Not just AM like normal ‘planes but also 121.750 MHz in FM-W. The navigation satellites of the COSMOS series send their situation reports at around 150 MHz and can be heard with a very simple receiver in FM. American DELTA rockets downlink their data in the S- and high C-band. For those without antenna and without receiver many of these above-mentioned satellites can also be seen. Often in the early morning and late evening the naked eye, or a simple telescope, is enough.
STS PLUS is especially suitable for tracking satellites and other flying
bodies in space extremely accurately in real time. The program is available
from many bulletin board systems (BBSs) and the current version can always
be found at AMSAT on the Internet. Such a program is fed with up to date
orbital data of all flying bodies. These TLE's are also to be found in BBSs
but are often not sufficiently current. Using the Internet the most up to
date offering can always be found. The files are stored with the name
TLExxx.ZIP (i.e. TLE748.ZIP). Always pick up the latest version (with the
highest number). Nearly 900 satellites are contained in such a file. STSPLUS
is also offered here.
Firms like Grundig, SSB-Elektronik, WRAASE amongst others offer complete systems. NOAA transmits not only at 137 MHz but also transmits high resolution images at 1.7 GHz. The hardware and software required to receive and process these pictures can be purchased from the company U. Hansen in Stolberg near Aachen.
Suitable well known units are the R-7000 and 7100 from ICOM, R-9000 also
from ICOM but overpriced, AOR 5000 (works from 10 kHz to 2.6 GHz) and
various surplus military receivers.
The LOG-PERIODIC antenna from the company Koeditz in Giessen is a good all-rounder. It works in the region 900 Mhz to 4 Ghz and has a 40 dB amplifier incorporated. Additionally the long YAGI is available in amateur radio shops which is suitable for use by ameteurs and operates in the 13cm -(S)band.
To convert S-Band signals to a region that a wideband receiver can cope with (2.3-2.7 Ghz to 950-1350 Mhz) one needs a normal S-band convertor (e.g. Chaparral, Echostar or CalAmp). Koeditz offers a convertor for their antenna that switches signals in the region 2 to 4 Ghz down to 0 to 2 GHz.
On Saturdays one can rummage through the gear on offer at the surplus
shop Singer-Elektronik in Aachen. Here everything from the military, HF to
Ku-band, is to be found.
TELE-satellit provides reports on this special area at regular intervals. drdish@TV also gets to grips with this topic every month during the live TV programme. Those that wish to delve deeper into this subject should read the US specialist publication SATELLITE TIMES. Enthusiasts from around the world have got together on the Internet and setup their own special interest group, HEARSAT. Here you can get all the information you could possibly want. The author works with a small but active group of enthusiasts himself. Information is swapped easily and quickly by ‘phone, fax or Internet.
This article appeared in TELE-satellite
International Magazine, issue 4/96.
TELE-satellite International Magazine is available at major newsstands
around the world, as well as by international subscription.
Mònica Pujadó Coll y Rodolfo Lomascolo Szittyay, 1997-2002
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