Zeitalter der Digitaltechnik: Einschleus-Matrix von Ankaro
The digital age: distribution matrix from Ankaro
Digital satellite reception multicast
Viewing habits will definitely change, at least according to Astra: the digital age will not only improve the quantity of television but also the quality, as new levels of customer service, new applications and comprehensive addedservices will become possible. The Internet is one element that will actually boost the spread of digital technology. Even today the Internet is a widespread tool for millions of people to send and receive electronic mail, and to exchange all kinds of data, audio and video. There are a number of ways to get connected to the Internet, either via conventional telephone lines, via fibre glass cable or via satellite, depending on the customers needs. Astra has already introduced Astra-Net which allows the transmission of Internet-based data via Astra satellites. With the launch of Astra 1H in the first quarter of 1999 the technology will be upgraded to bi-directional mode. Two transponders of 1H will be used to transmit data in the Ka-band range between 18.80 and 19.30
GHz for downlink and between 29.50 and 30.00 GHz for uplink. New applications based on point-to-point and point-to-multipoint systems will be possible and return channels via satellite will become available for the first time. The transceiver (transmission/reception) unit is small and dish sizes between 60 and 120 cm will be enough to guarantee extremely high transmission speeds. So what are the benefits for the specialised dealer? Astra provides a complete listing of Astra-Net service partners who have to rely on the dealers to install the systems for Astra-Net customers. To put it in Gernot Buschs words, only those willing to embrace the future will be successful. Many dealers seem to think alike, since over half of them raise their hands when asked whether they are connected to the Internet. Put into perspective the Internet is of course only one aspect. The major point concerns the future of analogue and digital TV and radio channels. Astra is definitely on the digital track, arguing that more and more service
providers go digital in order to be more cost efficient. Some experts suggest that next year all channels that are still analogue will get a digital twin, and that by 2004 the number of digital homes will outnumber analogue homes. By 2010 analogue television will be a thing of the past. Towards the end of the meeting dealers exchanged information and revealed some secrets of their success. Currently, the upgrading of conventional cable distribution systems for (analogue) satellite reception seems to be booming business. A huge Bavarian buffet finishes off the meeting and leaves the specialised dealers with many figures, projections and suggestions. The general feeling seems to be lets wait and see what the months ahead will bring.

A typical application of ARCS will be access to the Internet. Even today it is technically possibly and financially feasible to get bidirectional Internet and multimedia services via satellite. However, in order to address the remote servers and to initialise downloads a conventional telephone line is needed as a return channel. Even if the phone line is upgraded to ISDN access to the Internet is still very slow and expensive when compared to communication via satellite. In such a conventional combined terrestrial/satellite scenario the ordered data is not sent to a local ISP but to a satellite hub station which uplinks the requested data. Three elements contribute to the substantial costs of such an Internet connection: firstly, the telephone line has to be paid; secondly, providers might charge either for connection time or download volumes; and thirdly, using the satellite providers services incurs charges as well. Professional users can very well end up paying 1000 Euros per month or even more, especially if a permanent line to the ISP is set up and leased. In a professional environment ARCS might be the less expensive option and will in any case provide the faster connection. An alternative scenario that would also justify the application of ARCS is a newspaper or magazine newsroom. Editors, photographers and writers would be able to send large amounts of data (like reports, photos or video sequences) to the layout department which would then send the assembled files to the printer which for financial reasonsmight be located in a different country. The newsroom as a central location is used a kind of control centre that juggles enormous quantities of data across the continent. In a conventional environment permanent lines in combination with ISDN are used for these data transfers, enabling transfer speeds of up to 128 kbits/s. If the same setting is considered with ARCS every work station would have to be equipped with a satellite terminal interface (SIT) consisting of a 60cm-plus satellite dish, an indoor unit and a multimedia PC. Even with a tiny 60cm antenna transfer speeds can easily reach 150 kbits/s, and a 120cm dish allows up-link speeds of around 2.048 kbits/s. Access to the satellites data network is based on MFTDMA (multi-frequency time division multiple access). That way a number of individual SITs can access the system at the same time. The hub station allocates the available frequency and time slots to the individual SITs and thus assures synchronisation of the system. A central hub co-ordinates all incoming data and addresses the outgoing material to the correct terminals or stores the data for a time-delayed download. The download is based on the DVB MPEG 2 standard which allows speeds of up to 38 Mbits/s. The very high transfer ratewith a 120cm dish for uploadsdoes not only support data exchange but is ideally suited for interactive television in the educational sector, live coverage in the professional sector (SNG), or company-related video material in the business sector. The high speed of ARCS allows a simultaneous transmission of video, audio and data, and thus should be the ideal tool to handle the transfer of huge chunks of data in the professional sector. Correspondingly, a high level of security is intentional reception of material by unauthorised users of the system can be prevented. With the new Astra 1H satellite continental Europe will be covered including Scandinavia, Poland, Hungary, Romania, some regions of the Mediterranean countries, Spain and parts of England. This satellite is scheduled to become fully operational in early 1999. Astra 1K will extend the potential service area of ARCS to the Canary Islands, all of Scandinavia and much of the CIS states. Finally, there is the question of ARCS for

private users. Most Internet users would all too happily leave their slow telephone providers to turn to satellites. However, the substantial costs of ARCS will deter most private users from this innovative system, at least for the time being. However, the cost factor will become less important as more and more countries will license satellite providers which will bring the cost down to affordable levels even for private users. Some countries that are open to new media technologies will grant general licenses so that the installation of such systems does not involve bureaucratic steps. Other countries, however, will shy away from such a huge leap forward since they might still have an economic interest in nationalised telecom operators and their Internet-generated revenue. The technology is there and the installation is as easy as setting up an Astra dish for satellite television. ARCS will be distributed through local service providers. In the Netherlands HERTZinger dataNET BV and Bombeck Eindhoven have already signed agreements with Astra that will allow them to offer ARCS to their local customers.
achieved by the reliable address system. Any sent or requested package of data can only be received by the authorised addressee. Even
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Zwei neue Satelliten: Hot Bird 5 und W2
Eutelsat erweitert seine Flotte um zwei neue Satelliten und wird damit knftig ber eine Kapazitt von 171 Transpondern auf nunmehr 13 Satelliten verfgen. Eutelsat W2, der erste Satellit der neuen W-Serie fr Telekommunikatio nsdienste und Rundfunk, wurde am 5.Oktober von einer Ariane-Rakete ins All befrdert. Der neue Satellit wird Eutelsat II-F3 ablsen und die Position 16 Grad Ost ausbauen. Hot Bird 5 hob am 9. Oktober mit einer amerikanischen Atlas-Rakete ab. Der Satellit ersetzt den schon etwas ltlichen Eutelsat II-F1 auf 13 Grad Ost. Mit seinen 22 Transpondern, die sowohl digitale und analoge Signal wie auch Multimedia-Dienste bertragen werden, wird Hot Bird 5 ber 68 Millionen Haushalte in Europa, Afrika und im Nahen Osten erreichen. Die Eutelsat-Flotte bertrgt derzeit rund 400 TV-Kanle und dient in zunehmendem Mae als Plattform fr Multimedia, geschftliche Kommunikation, Telephonie und Euteltracs, das satelliten-basierte Ortungssystem fr Fahrzeuge und Schiffe. Sechs weitere Satelliten sind bereits bestellt und befinden sich im Bau. Sie werden sowohl die technische Reichweite als auch die Auswahl der verfgbaren Dienste erweitern.

MORE INFORMATION -www.TELE-satellite.com/TSI/9812/praxis.shtml
with the LOF (e.g. 5.150, 9.750 and 10.750, or any other) and position. Once in operation, the Info button will not only show the channel name, but the satellite, time, channel ID and analogue or digital as well. Whenever a channel (TV or radio) provides additional programme information this is processed by the Electronic Programming Guide which springs into action after pushing the Guide button. For every TV and radio channel you can choose between stereo, mono, or left/right separately.

ANALOGUE

We have seen it with many other universal (analogue/digital) receivers so far: any old thing will do for the analogue part. But not here as Praxis have developed a high-quality low-threshold analogue receiver for use within this universal receiver. It has a threshold extension which is adjustable in 32 steps. Even when using a 140cm dish, this gives good results on the C-band. The threshold extension not just narrow the bandwidth, since this would only distort the video signal. The analogue menus are more or less equal to the digital part. When there is no reception or if it is very bad, the on-screen display will still be readable as the original video signal is replaced by a black background. It supports two bandwidths, 18 and 27MHz. The video level can be adjusted in four steps which will do in most situations. Up to four different decoder types are supported. We tried a DC2-MAC decoder from Philips and a Syster decoder. Now that the number of analogue channels is decreasing, we believe 700 channels memory is really enough. On the audio reception side, six bandwidths are supported between 130 and 500 kHz. In practice this will be more than enough the get rid of hissing sounds. No Panda Wegener was found on this boxinstead, theres an adaptive system based on a chip from ITT. The built-in DiSEqC control system not only works in the digital part but in the analogue part as well. In combination with the 22kHz and 0/12 Volt control it will enable you to do many different ways of configuration for both digital and analogue. The pre-programming was up to date, and adding channels or deleting channels is very easy.

It was in the late summer of 1996, when we tested the XCOM 200 digital receiver, made in France. It was the first digital receiver capable of processing SCPC signals--with a little trick that is, but still. A lot of things have happened in the meantime and a lot of other manufacturers have come with SCPC capable digital set-top boxes, operating at faster processing speeds. But as always, the one who brings new technologies and new features first doesn't fall asleep. And while other brands were focusing on SCPC and other goodies, XSAT was developing its combined analogue/digital receiver, which was introduced in March 1998. This XSAT CDTV350 was not right away tested by TSI, since we just wanted to wait for the first problems to be resolved.
Late summer 1998, we received a production sample from German Doebis GmbH. Rumours say that this CDTX 350 is not SCPC compatible. To clarify this, we checked it and found out the following: the CDTX 350 is in its basic version not SCPC compatible. That is only available as an option. However, most distributors decided to only sell the SCPC version of this box. So symbol rates start from 3Msym/s instead of the 20Msym/s for the non-SCPC version.
This CDTV 350 is not only an FTA-receiver but also able to handle Viaccess signals as well. So you can watch Russian, Arabic, French and many channels from other origins, as long as you have the appropriate smartcard. A smartcard slot is positioned at the left. For FTA operation no smartcard is required. Built into a metal housing, this receiver
doesnt offer a display for channel indication, just four LEDs to indicate the status. So you can see if it is in standby mode, if another satellite receiver or video recorder is activated, if a channel is encrypted, etc. Of course, the emergency buttons with standby and channel up and down are present on the front. Lets take a closer look at the back of the receiver. There is an LNB input and output so you can connect another (analogue or ADR) receiver to it. Two Scart (Peritel) connectors are in place. These are mounted to the housing, which makes it much less sensitive for damaging while connecting and disconnecting. They supply a proper signal to your television set and to the video recorder. To supply your stereo with the audio signal of the receiver it features two phono jacks. Two small DIN jacks are in place to supply an Y/C video signal to your television or video and the other one is used for serial interface (RS232). Unfortunately, XSAT has chosen to install this small DIN socket instead of the more common nine-pin connector. Although there is no RF modulator according to the manual, our sample receiver did have one, although setting the channel had to be done with an adjusting screw. The remote control may seem a little larger compared to what we are used to. Still, its layout is very clear and although the texts are in French we could very well understand what was meant. After all, things like Quitter is very easy to understand. Whenever you feel insecure about how to do something, just refer to the manual. It clearly and understandably explains how the receiver should be operated and supports its explanation with use of extensive graphical images to make it as clear as a blue sky. Other manufacturers should take a good look at such a manual, they really can learn something of this. Perhaps adding just a few more technical specifications would make this the absolutely perfect manual.

-www.TELE-satellite.com/TSI/9812/weiss.shtml
consistently good video quality the video level can be adjusted in two levels for different satellites. Not every user will want to keep the manufacturers channel line-up, so the three-page setup menu in either German or English has to be used. Since some frequency charts publish only the IF frequencies of transponders this figure can be keyed in directly. If the LOF of the LNB has to be adjusted fine-tuning of the frequency is possible. The LNB power control can be switched off in case the KSR-3010 is used as slave receiver in a more complex configuration. You might think that a low-cost receiver like this one can only be used for receiving one satellite, but this is not the case. Apart from supplying a 22 kHz control the KSR-3010 also features tone/pulse switches for both 60 and 400 Hz and even DiSEqC 1.0. The conventional power unit is spread out within the chassis and thus avoids developing too much heat. In fact, the KSR-3010 can easily be squeezed between a VCR and a digital receiver without any danger of choking in its own heat. The only point of criticism we have is the fact that the scart sockets are placed directly on the main board rather than being fixed at the back panel. This method of assembling receivers has become frequent due to cost reductions, but if scart connectctions are changed frequently this might eventually lead to loose contacts.

MORE INFORMATION

Everyone looking for a good-value satellite receiver to be added to an existing system or to get to know satellite television in the beginning will be happy with the Koscom KSR-3010. The quality of workmanship is good and the variety of features is good basic standard. Everyday operation of the receiver is easy and convenient and a programme memory of 500 is large enough to accommodate the channels of two or even three satellites. The KSR-3010 can receive both Ku-band and C-band signals and thus can be used in a variety of different set-up environments. Among the positive aspects of this unit are Panda stereo, the well structured users manual and a consumer-friendly on-screen menu which makes the initial set-up a hassle-free procedure. However, more languages should be added to the on-screen menu to boost the product in other markets as well. But then again, there is also big brother KSR-3020 with four languages to choose for the OSD (German, English, French, Turkish), three scarts, two IF-in sockets (with two bandwidths), a low-threshold level of <3.5 dB, and an integrated timer for VCR recordings.
Manufacturer/distributor I.E.V. Weiss, D-93437 Furth im Wald Fax +841717 IF-input 900-2150 MHz Second IF bandwidth 27 MHz (optional 18 MHz) Threshold level <6 dB (optional LT <3.5 dB) Scart connectors 2 Audio line-out 2 x phono Channel memory 500 OSD yes DiSEqC 1.kHz yes Tone/pulse 60/400 Hz Panda stereo yes Audio bandwidths 150/280 kHz Deemphases 50/75s, J17, Panda

Go green

No matter how we presently put a spacecraft into orbit, it involves a tremendous amount of waste. Spent boosters, discarded rocket stages, hundreds of tonnes of fuel, fairings, etc. Some bits, such as the solid rocket boosters used by shuttle craft, fall back to earth and can be re-used. Other bits and pieces burn up, the remainder add to the ever increasing and trouble-some space junk orbiting in the danger zone 110 to 480 km above our heads. If the Rotary Rocket Company (RRC) have their way, this waste will be reduced drastically. Sounds too good to be true, but with the advent of the revolutionary single stage to orbit Piloted Space Vehicle (PSV,) putting satellites into space can become a cleaner, safer, cheaper affair.

A Grand Day Out

A fleet of Rotons will provide fast, reliable and economical service in a similar way to any of todays airfreight companies, fundamentally changing the economics of carrying cargo to space. This contrasts strongly with the current industry practice of simply throwing away an expensive launch vehicle each flight. On average each mission will last between two and eight orbits, rarely will the crew spend more than a day in space. With the fast turnarounds therell be no need. The Roton is being developed for unparalleled operability, reliability, and safety while providing singlestage-to-orbit capability. To achieve the goal of an SSTO space vehicle requires both high performance rocket engines and a lightweight vehicle structure to contain propellants and cargo.

Lift off.

RRC estimate that over 2,000 low earth orbit satellites will be launched during the coming decade, representing a business opportunity of more than US$10 billion. The Roton will be the worlds first fully re-usable piloted commercial space vehicle, operated by a twoperson crew. It will revolutionise space transportation
by simultaneously offering human intervention on orbit on demand and low cost on orbit payload delivery. In true H. G. Welles fashion, RRCs Roton C-9 will launch, orbit and recover for a fraction of the cost of similar missions using Shuttle, Ariane or Proton vehicles. The idea is simple: a manned craft launches vertically, enters orbit, deploys its payload, then re-enters and lands back at the launch site. And yet forty years on from the lunar landings, all attempts to master the technique of a controlled landing in this fashion have failed. Only recently the Delta Clipper programme proved that this was no easy task, when the bullet-shaped Clipper Graham crashed in flames during trials. The Roton is unique in that it was designed from the outset to be capable of returning to earth with a fully loaded cargo bay. It will take off vertically like a traditional expendable rocket, and is able to return to earth by deploying rotors during re-entry, landing vertically as an auto-rotating helicopter. Powered by the revolutionary rotary RocketJet aerospike engine burning liquid oxygen and jet fuel, the Roton will deliver cargo to low earth orbit and return for reuse without discarding or expending any component. As with a conventional jet aircraft, only liquid propellant will be consumed during a flight, and no refurbishment will be needed to prepare the vehicle for another mission. The RocketJet engine automatically compensates for the decrease in atmospher-

Making light work of it

Another feature of the Roton is its lightweight vehicle structure achieved through the extensive use of sophisticated composite materials. These materials have been used successfully in the DC-X programme and in dozens of advanced aircraft. Many of these advanced aircraft have been built by Scaled Composites, the integrating contractor for the Roton. Scaled Composites, of Mojave, California, headed by aerospace legend Burt Rutan has built many composite aircraft and space vehicle structures, including the McDonnell-Douglas DC-X aeroshell. Rutan also designed Voyager, the only aircraft to have flown around the world without refuelling,which was piloted incidentally by his brother, Dick. Scaled Composites is responsible for building the Rotons composite airframe, propellant tanks, cargo bay fairing, rotor, and thrust structure/heat shield. In Rutans words the Roton is The most important project ever to come in the doors at Scaled Composites.

What goes up.

Of course getting to orbit is only part of the challenge. The other key aspect of a reusable vehicle is return from space. The Roton accomplishes this using conventional thermal protection to moderate the heat of re-entry into the earths atmosphere, in a similar way to NASAs Apollo craft, but a unique enhancement will be introduced, until now only used in classified military projects. To keep the temperature of the heat shield down to below 700C during re-entry, RRC plan to cool the shield and recessed combustors with a constant
The Roton-C space vehicle is a vertical take-off and landing SSTO design, approximately 16 meters high. At take-off, the Roton is powered by a proprietary Rocketjet aerospike engine at the base of the vehicle that rotates about the vehicles vertical axis. The rotation pumps the liquid oxygen and aviation kerosene propellants into the combustors at high chamber pressure. The engine combustors being placed at the periphery of the engine. This eliminates the need for turbopumps to feed the engine. The Roton-C will deliver its cargo directly to low earth orbit (LEO) and then return to its initial take-off site. The Roton-C has the capability to remain on-orbit should weather conditions preclude landing on schedule. After atmospheric reentry, the Roton-C will deploy rotors that will allow it to land like an autorotating helicopter. The autorotating blades provide directional control and braking for a precision, soft, landing. The Roton-C lands vertically, essentially empty of propellants. The vehicle has been designed from the outset to be serviced by a small team of ground personnel and to be turned around in 24 hours or less.

Today, Hughes can deliver satellites in 12 to 18 months from contract start, depending upon the size and complexity of the design. The realization of a satellite network is a complex task and is the result of effective cooperation between the operator of the satellite, the manufacturer, and the boosting rocket supplier. What measures does Hughes take to extend its services (e.g. the main control stations operation, training of personnel, etc)? Outward-focused customer support begins early at Hughes typically a year or more before contract award. Purchasers of Hughes satellite systems usually send their engineers to the firms Integrated Satellite Factory for training. The engineers then participate in testing, launch, mission, and orbital operations as productive members of the spacecraft build team. This type of experience builds pride of ownership and expertise in its operation of their satellite system. Hughes Space and Communications Company, while being the worlds largest satellite manufacturer, is also a satellite systems house. for example, the company is currently building two geomobile satellite systems which expand Hughes offering beyond satellite manufacturing to integrating a high-power geosynchronous satellite with a complete ground segment and user handsets, which will provide a range of cellular-like services over large geographic regions. The realization of a satellite network is an investment of about $150 - $200 million. The realization of such an investment in the developed countries or its regions could in many ways solve the requirements of telecommunications. In what manner does Hughes help in the seeking out of financial resources and covering the cost? Hughes works with the customer to establish a business plan, a set of payment arrangements, and contract terms that will facilitate financing. Hughes also helps the customer obtain financing through institution and public offerings. In the developing countries, not only financial sources, but also the lack of expertise hinders satellite network realization. What kind of programs are organized by Hughes to train proper experts? Operations and ground training take place at Hughes and at the customers site. Hughes offers trainees the opportunity to become familiar with the actual equipment they will use and how to operate it. Experienced Hughes engineers, in addition to engineers provided by other suppliers, conduct classroom, hands-on, and on-the-job training. A suite of simulators that mimic their spacecraft and its telemetry and commands are also part of Hughes training program. In 1945, Arthur C. Clarke dreamed up his three GSO satellite system, by the help of which everyone can attain radio and TV programs. What type of global GSO satellite realization is Hughes concerned in? What services will Hughes assure and when will such a system be realized? Hughes Space and Communications Company is a satellite systems supplier. Several of our affiliates are involved in providing service, such as Hughes Global Services, a subsidiary of Hughes Space and Communications Company, that was formed in 1997 to package commercial satellite services on a value-added basis for government and military customers. To accomplish this, Hughes Global Services has agreements with providers of bandwidth, terminal equipment, and satellite mobile telephone services. Hughes Global Services also works with other Hughes Electronics companies to provide end-to-end solutions for underserved commercial markets. Hughes Network Systems and Hughes Space and Communications Company are jointly developing SPACEWAY, a satellite-based service that will use the Ka-band portion of the broadcast spectrum. The SPACEWAY system is expected to bring the power of broadband satellite technology directly to businesses and

homes. SPACEWAY will make high-speed, two-way communications possible through ultra-small, low-cost antennas. In doing so, it will provide users with inexpensive bandwidth on demand, including fast access to the Internet, corporate Intranets, local area and wide area networks, and the public-switched telephone network. DIRECTV is Hughes direct-to-home television service. It uses satellites, compact dishes and digital receivers to provide hundreds of channels of video and audio programs featuring sharp pictures and crystal clear sound to millions of TV viewers on three continents. DIRECTV pioneered the small-dish industry and is the leading service provider in the U.S. and Latin America and the Caribbean. In the U.S., DIRECTVs 185 video channels were received by more than 4 million subscribers In Latin America and the Caribbean, Galaxy Latin America (GLA), a partnership created by Hughes and major communications and media firms in Venezuela, Brazil and Mexico, sends 140-plus video channels in Portuguese and Spanish to more than 300,000 subscribers. In Japan, a partnership Hughes and eight Japanese firms launched DIRECTV Japan, with 88 video channels as of April 1998. Hughes Network Systems offers services with DirecPC, which provides unprecedented speed to Internet users nationwide. At 14 times faster than standard modems, it is the fastest Internet access service available throughout the U.S. PanAmSat Corporation, an affiliate of Hughes Electronics, owns and operates 17 satellites, with plans to launch eight more by the end of 1999. PanAmSat is the worlds leading commercial provider of satellite-based communications services. In the coming time span, several NGSO satellite systems are expected to make a debut, with complex services. What role has Hughes in the realization of these networks? Hughes Space and Communications Company (HSC) is building 12 communications satellites for London-based ICO Global Communications. The satellites will be used in a global satellitebased mobile communications system designed primarily to provide services to dual-mode (space/terrestrial) cellular phones. The system will offer digital voice, data, and facsimile services, as well as a range of messaging services anywhere in the world. ICO ordered the 12 satellites from Hughes in July 1995. They are versions of the popular HS 601 model, with selected subsystems modified for the special requirements of medium earth orbit. The first ICO satellite is scheduled to launch in early 1999.

Der Feedhornumbau

Es geht auch anders! Ohne auch nur einen Euro oder einen Schilling ausgeben zu mssen, lt sich das Problem in einer halben Stunde lsen. Wir haben ja alle unser Feedhorn genau nach Gebrauchsanweisung im Spiegel montiert. Natrlich nahmen wir alle an, da es so gehrt und nicht anders. Das Wort der Stunde heit Umbau! Bild 1 zeigt den Urzustand meines Seavy Feeds. Das C-Band LNC ist links oben, das Ku-Band LNC gegenberliegend, rechts unten montiert. Um sich der militrischen Ausdrucksweise zu bedienen: Das 4 GHz LNC steht auf 11 Uhr, das Ku-Band LNC auf 5 Uhr. Das rechts im Bild zu sehende S-Band LNC spielt bei unserer Betrachtung keine Rolle. Bild 2 zeigt eine Nahaufnahme des Seavy Feed Hohlleiters. Man sieht, da das Feed
Das berwltigende Ergebnis
Eine weitere Verbesserung haben all

The C-Band Miracle

Thomas Riegler Now that Panamsat 4 has become fully operational at 68,5 East we satellite enthusiasts have had to realise that not all signal on the C-band are circular. Panamsat 4 and Thaicom use linear (i.e. horizontally and vertically polarised) signals.
small but still annoying interference, BBC World was almost strangled by ESPN Asia (being transmitted in B-MAC) and Music Asia (opposite MTV India) was a complete dud. And all this with a solid 4.5m dish. In the digital universe only those packages being transmitted on a single level (either horizontal or vertical) could be received. Nothing else. The question of the day was what to do to improve the situation. Theres been word of a Seavy feed with two polariser motors, one for left hand and right hand circular, the other one for vertical and horizontal. That way a reliable distinction between all possible transmission level can be guaranteed. However, such an upgrade would set you back some 1500 Euros (Austrian price), so most people wonder if a few channels are worth such an amount of money. the C-band flange on the upper part of the feed which is also mounted with four hexagonal screws. So we took a screwdriver and started out with loosening the four screws that hold the middle part of the concave conductor on the groove feed so that we could move the part until the Ku-band LNC points towards 12 oclock (picture 3). Then we fixed the screws again. Next we loosened the upper screws a little and rotated the part with the flange for the 4 GHz LNC until the LNC pointed towards 7 oclock (picture 4). All thats left to do is to make sure all screws are fixednow the Seavy feed is ready for reception of both linear and circular signals. The receiver, however, is not. Due to the adjustment of position of the LNCs the polarisation parameters of all stored channels have to be changed. This easy adjustment works not only for the Seavy feed butas I learned from reliable sourceseven for the Corotor.

chen DXer: das inzwischen eingemottete S-Band LNB wieder ausgraben; und fr den spezialisierten Fachhandel: der Ladenhter ist keiner mehr. Der S-Band-Konverter liefert seine ZF an einen ganz normalen Sat-Receiver, und da die Abstrahlung auch noch in FM ist, wird dieser die TUBSAT-Signale auch brav akzeptieren und verarbeiten. Ein Problem wird fr viele die Antennengre sein. An Bord befindet sich eine Helix-Antenne mit einem ffnungswinkel von ca. 70. Somit ist zwar die Streuung des Signals recht gro, doch dafr die Nachsteueranforderungen uerst gering. Nachteil: wegen dieses Giekannenprinzips geht ein betrchtlicher Teil der abgestrahlten Sendeleistung verloren. Im Moment geht man in Berlin von einer Spiegelgre von ca. 3m aus. Bei der niedrigen Frequenz reicht da auch der alte schlappe MeshSpiegel, doch die Gre ist nun mal nicht berall unterzubringen. Erste Tests direkt nach dem Start werden Auskunft geben, ob der Empfang mglicherweise auch mit gestockten Yagi-Antennen mglich ist. Daneben kann der DLR-TUBSAT auch digital
As always my desk was filled with potential stories for this edition of TSI, but they were all so boring, and if they were somewhat interesting they didnt exactly focus on TSI topicseven though, or just because, my mailbox is crammed with everything that even only remotely touches on espionage. Theres still this lady who feels stalked by a satellite, but thats a problem for which talk radio was invented. Then theres trade with allegedly genuine meteorites directly from Nigeria. Not exactly satellite-oriented. Then we happened to overhear a conversation via IOR Inmarsat about arranging a new identity for somebody. A passport and a drivers license from Belise together with a patent should do the trick, as we learned. The person requesting the new identity was told a URL on the Internet and a Philippine bank account to which he should transfer 57.000 US$. We checked the URL and discovered that official documents and papers are traded there like in the sales. But even this would not make a good story since most details cannot be revealed in an international publication, and anyway, who would want to try out the system? And yes, there is also a death threat against the author of this article. Some old U.S. military fanatic must have somewhat disliked our January 1998 story about FleetSatCom and has ever since promised to hunt me. Californias sun really can have adverse effects on some people. So what about a non-violent report from which many readers can profit without annoying anybody else? Here it is.

Preisbrecher

Dieses Gemeinschaftswerk von DLR und TU-Berlin ist ein inzwischen vollbezahltes Preiswunder. Der Satellit kostete etwa 400.000 Euro. Dazu mu man allerdings sagen, da Prof. Renner und sein siebenkpfiges TU-Team ihre Arbeitsleistung kostenfrei einbrachten. Die weitere Finanzierung wurde durch die DLR bernommen. Die Launch-Kosten erforderten nochmals denselben Betrag. Billiger gehts nun wirklich nicht. Und wie gesagt, bezahlt ist das ganze Vorhaben auch schon. Es mssen somit keine Kunden unter Druck gesucht werden.

Monitore gesucht

drdish@tv wird als ersten Medium gleich nach dem Start in einer Sondersendung dabei sein, erste Steuerbefehle an die Kontrollstation geben und dabei natrlich auch auf Zuschauerwnsche live eingehen. Wichtiger jedoch ist die Suche nach geeigneten Amateuren, die in der Lage sind, Signale vom DLRTUBSAT zu empfangen und die Bilder aufzuzeichnen. Hierzu wird auf jeden Fall eine Monitorstation in Berlin dringend gesucht, die unmittelbar nach dem
there is a Helix antenna with an aperture angle of 70. That way the signal has a very large footprint but also requires a good deal of signal improvement on earth to get perfect results. Naturally such a huge service area causes quite some signal loss. Currently the experts in Berlin assume that a 3m antenna should be large enough. For low frequency transmission even the good old Mesh antenna should work, but many people just dont have enough space at their disposal to use these large-size dishes. Apart from broadcasting in analogue the satellite is also able to transmit digital signals with a transfer rate of 125 kb/s (biphase level encoded). In this transmission mode a 1.2 m antenna is all thats needed for good results. The feed can be constructed quite easily and assembled the do-it-yourself way. Also, many manufacturers and dealers will soon offer appropriate equipment for smaller antennas that can be used by virtually everybody. Following the satellites path is not too much of a problem since it will be put in a sun-synchronous orbit. That means that it will always appear to be located on the imaginary axis between the Earth and the sun. Such an orbit allows a relatively long access time from a monitor station on earth. This makes TUBSAT a quick tool for getting live video material. The satellite will be able to deliver images from any desired point within 24 hours. Every time the satellite passes its control centre it will receive new orders with the exact location of the target areas, and as soon as the satellite reaches the selected spots it will turn its cameras to the exact location. The attitude control of the satellite is based on a star sensor on the back side of the unit which uses the stars configuration to determine its exact position. Small flywheels, driven by miniature motors, are used to align the satellite according to customers needs. With this technology TUBSAT can focus on any object even though it moves at a speed of 7.5 km per second, which is 24 times the speed of sound. Of course TUBSAT is also able to deliver still images which are stored on board the satellite and