вход по аккаунту



код для вставкиСкачать
Impact of systems
engmeemg on strategic
A case study of the installation of a VSAT network
This article describes how a new satellite-delivered racing channel was
introduced to the UK betting industry. The background is given to the
various technical and commercial declsions that had to be taken. The
planning, management and installation of the organisation’sIO 000
systems is recounted and the overall impact of the system assessed.
by Dr. Barry Stapley
ff-track betting was legalised in the
UK in 1961, and the number of betting
shops quickly expanded to nearly
16 000 in the late 1960s. After the initial growth
the number consolidated to about 11 000 by
1986. At that time the betting shops were fed an
audio service giving commentaries, results and
various betting information. This ‘blower’
service as it was known was supplemented in
some shops by a ‘text service’, basically a set of
six or eight screens displaying the various
betting information needed in the shops. Both
the audio and text systems were delivered via a
terrestrial leased line network. Most shops were
supported by the service of Extel, although a
few of the large multiples had their own
In 1986 legalisation was passed that allowed
television into betting shops for the first time.
Although there was a limited coverage of racing
by the public broadcasters, there was clearly an
opportunity for a ‘racing channel’ specifically
targeted at the betting shop clientele and
available the whole of the time shops were
open-six days a week.
The betting industry, through its trade
association BOLA, retained CIT Research to
investigate the feasibility both technically and
commercially of a specialised racing channel.
The positive outcome of this study led to the
setting up of Satellite Racing Developments,
which was charged with the task of establishing
the service.
General requirements
At its most basic level the requirement is for
a system that will take television pictures from
the racecourse and transmit them to the betting
shops. The main links in this transmission chain
picture gathering
collection network
central processing facility
distribution to betting shops.
Picture gutbenng: At each racecourse and
greyhound track choices had to be made to
which/whose cameras would be used to gather
Fig. 1 Collection
t ransportable
the basic television pictures. For the greyhound
tracks the most cost-effective solution was to
use SIS’s own teams operating from simple
‘three-camera’ trucks, while at the racecourse
the solution was to upgrade the facilities of
Racecourse Technical Services, which already
performed basic television surveillance for the
race stewards.
At the racecourse it was also necessary to find
a way of linking up to five cameras back to the
ccntral scanner. Some cameras could be hard
wired, but some have to be mobile and for these
39 GHz microwave links were used.
Collection network: One possibility might have
been to transmit pictures direct from the
racecourse. Unfortunately on most days there
are three horserace meetings and two
greyhound meetings, rising to 17 meetings on
some bank holidays. To co-ordinate these
different events it was necessary to bring all the
pictures back to a central site via a ‘collection
Initially use was made of the outside
broadcast occasional use network by British
Telecom. Later SE’s own teams operating
under the SSSO licence provided this function
using transportable satellite uplinks (see Fig. 1).
There were some locations that were visited
sufficiently often that it proved cost effective in
installing permanent fibre links.
Centvul rite: The two main functions of the
central site are to edit together the various
incoming picture sources and, secondly, to
process the various betting information
reported back from the racecourses. The
picture-editing component is much the same as
any small TV station-ontaining
edit suit,
sound mixing booths, control galleries-but
the emphasis is of course live coverage,
typically six hours a day for six days a week.
The processing of the betting information is
at the core of the operations. It is this
information that drives the workings of the
studio etc. and is absolutely essential to the
running of a betting shop. Reliability and
integrity are the key, and this was achieved by
using multiple local-area networks (LANs) to
link 37 personal computers (PCs).
The whole central site was up and running
after only five months from obtaining the
Delivery options
There were three broad options for
distributing a T V channel throughout the UK,
over the air/radio systems
(ii) terrestrial cable systems
(iii) satellite.
Fig. 2 Different
types of dish
The option of radio broadcasting could be
quickly dismissed as in 1986 there simply was
not the frequency spectrum available for
practical receiving equipment. (This situation
may change in the future as frequency bands in
the 40-60GHz range and the relevant
technology become available.)
The terrestrial cable option was not
commercially feasible, as cable TV networks
were simply not sufficiently developed (nor are
they still), and a dedicated cable system would
be prohibitively expensive. This left satellite as
the only practicable contender, and it
was fortunate that the technology had just
become sufficiently inexpensive and available
to make using satellite financially viable.
Within the satellite option there were three
sub-options, namely: using either BT or
Mercury for the complete delivery system or,
using one of them to uplink the signal to the
satellite and arranging the dishes to be installed
by SIS. BT was chosen for two reasons; the first
is that it was recognised that there would be
some shops which for some reason or another
could not have a dish fitted on the premises.
Such shops would need to be fed via a cable
from a nearby dish-typically another betting
shop. While both BT and Mercury are allowed
order taking
landlord’s perrnission
to survey
6T survey
SI 5
landlord’s permission
t o install
11 590 MHz). The outage can be reduced by
increasing the size of dish.
While all customers would like a system with
no outages there are practical and commercial
considerations that limit the size of the dish that
can be readily installed. Larger dishes cost
more, are more difficult to install, more difficult
to obtain local authority planning permission
and impose much greater structural strain on
The final compromise was for a 1.3m
diameter dish, as this was the largest size for
which BT did not under many circumstances
need to obtain local authority planning
permission (see Fig. 2). This size together with
the then available LNBs of 2.5 dB noise figure
led to an average outage of 40 minutes per year.
Today with the improvements in the
cost/performance of LNB a similar
performance could be obtained with a much
more convenient 90 cm dish.
local authority
planning permission
~ , p q p k
d i s h install
i n s t a l l a t ion
Fig. 3 Information
by the Telecom Act to suply these cable links,
in practice only BT has a nationwide network
of ducts that would allow cables to be laid
sufficiently cheaply. The second reason for
choosing BT, and in colloquial terms the
‘clincher’, was that BT had control over the
only suitable satellite transponder available and
used this to ensure it gained control over the
distribution of the signal.
The space segment chosen was the full
transponder 69/69 on the West Spot beam of
Intelsat VA F12 at 27.5” West. This allowed a
signal strength ERIP of 48 dBW to be
guaranteed (in practice nearly 49 dBW). At the
time this was the strongest signal available in the
UK, only later being surpassed by the Astra and
BSB satellites.
The fundamental importance of the satellite
signal strength is of course that a stronger signal
allows reliable reception on smaller dishes. The
factors affecting the size of dish are:
satellite signal strength
the sensitivity of the front-end low-noise
amplifier (LNB noise figure)
the modulation process
the acceptable average outage.
The latter is caused by atmospheric absorption
of the Ku band signal (carrier frequency
Modulation/encr yption
A modulation and encryption system had to
be chosen that would allow audio, video and
data signals to be securely and reliably
transmitted. Clearly some form of encryption is
necessary on the broadcast service as we wanted
customers to pay for the service. There was also
a requirement that the encryption system
chosen should be centrally addressable. The
main reason for this was to allow switch-on by
areas, i.e. even though the process of installing
systems in a town could be spread over several
months using the over-the-air addressing, all
the systems in a particular town could be
switched on at the same time. The importance
of this was due to the fact that any shop without
the service would immediately lose all its
customers to those that had the service.
The system chosen was the Scientific
Atlanta’s B-MAC system. This provided for
the secure transmission of one video signal plus
six high-quality audio and a 9600 baud data
signal. B-MAC is often seen as a North
American derivative of the European MAC
system, but as engineers we may regard it as
British, as it was developed by ex IBA engineers
who joined the ‘brain drain’ to North America.
Display system
In each betting shop the MAC signal is
converted back to a simple baseband PAL
signal for display on normal domestic-quality
TV monitors. The 9600 baud signal interfaces
to a special-purpose computer based on a SlOO
bus and manufactured by HTEC. This drives
up to 12 separate display monitors (baseband
RGB signals) together with a manager’s
monitor that allows the manager some control
over what is being displayed, together with the
ability to access any of the information that has
been transmitted, but is not currently on
The computer also by way of the infra-red
control on the TV monitors allows the TVs to
be centrally switched to any channel. The
whole of the display system was supplied and
installed by Granada.
The main focus of this article is the
installation of the delivery component of the
whole network. But, before proceeding with a
detailed discussion of this, it is imporcant to
realise that there were two other major
components, namely the collection network
and the central studio itself, which required
tremendous effort by all those involved to get
set up in time.
Customer installations
Before the major installation programme
commenced it was necessary to pilot the
installation process. This was done by a very
detailed survey of a random sample of 157
betting shops. The survey provided valuable
information as to the range and likely numbers
of different brackets that would be needed, as
well as practical details such as safe access.
In total there were 9765 bookmakers in
mainland UK that finally took the system. (In
practice all bookmakers had to take the service
when Extel withdrew from the market in 1989.)
Because of the very high fixed cost, i.e.
programme production, satellite rental etc., it
was imperative to roll out the installation
programme as quickly as possible, but at the
same time there was the industry-wide
agreement not to switch on a town until
everyone who subscribed to the service was
able to get it.
The whole process was complicated by there
not being any central register of betting shops
(lists of shops in a local area are available from
the local magistrates office). As well as that the
existing supplier Extel was out to convince its
customers not to take the full range of SIS
services. Each installation was a project in its
own right, requiring the co-ordination of teams
from SIS, Granada and BT, as well as
shopfitters. And of course the bookmaker
expected this to be done without any
interference to his normal day-to-day trading.
Fig. 3 shows the simplified flow diagram of
the various activities during an installation. In
practice things are often much more complex.
Planning permission, or landlord’s permission,
may be refused requiring a re-survey and resubmission for planning or landlord’s
permission. The diagram also does not show
the details at, for example, Granada or BT coordinating the various suppliers and
The lapsed time for a simple installation from
the initial consent to completion could be as
little as 10 weeks. But this could stretch to 22
weeks if planning permission were required. In
the worst case, where permission was refused
and a cable had to be installed, the process could
take 53 weeks.
In the latter stages of the roll-out programme
several sites were encountered where for one
reason o r another the projected time for
installing the cable alternative was getting
unacceptably long. For these very difficult sires
BT developed a 2 9 G H z microwave system
that allowed rapid installation of both point-topoint and broadcast transmission facilities (see
Fig. 4). In total 20 sites were served by
The technical aspects of the project, such as
installation, were
straightforward to organise. By far the greatest
problem was managing the flow of information
and documents. This ranged from the various
correspondence with landlords or their agents
to obtain permission to install, to the handling
of the detailed drawings required for obtaining
planning permission, the latter being complicatrd by there being 465 different local
authorities that dispense planning permission
and each has its own set of forms.
In total 10 000 systems were installed over a
period of 31 months with a peak rate of 710 per
month and altogether 6900 planning permissions were obtained. Subsequent expansion
into Ireland and Northern Europe has
increased the installed base to 11 600.
Planning methods
At the start of the
was given to using
~ 2 %
classical planning techniaues such as critical
path analysis. However, a
rejected as the level of
complexity and variability
timescales was too great.
Furthermore as no one
had carried out a similar project before, there
was no practical experience of many of the
problems that were encountered.
Extensive use was made of computers to
keep track of the 10000 different installation
projects. In particular intensive use was made of
simple readily available database software
(Dbase 111) running of PCs linked by local-area
networks and telecommunication links. This
allowed information to be passed between the
various contractors.
The most important aspect of the project was
the flexibility that had to be adopted to
overcome problems as they arose, for example
designing new brackets, finding alternative sites
for installations and hiring alternative
subcontractors. Again an important tool in this
area was the spreadsheet on the PC. This
enabled the financial and timing consequences
of any decision taken to be quickly accessed and
communicated to those who needed to know.
For example the initial aim was to switch on the
as early as possible, but the
experience of the first installations showed that
greater expertise needed to be gained in several
areas. To this end there was a strategic switch to
small towns. It was essential that the full
ramification of such a switch could be quickly
analysed before it was implemented.
N o w that the project is finished and the
various teams dispersed it is instructive to look
back at the impact of the project.
The first is on the UK betting industry. Here
it has been an unqualified success as the annual
turnover in the shops went up from f 4 billion
to $5 billion. Secondly, there is the E8 million
contribution that SIS makes to horseracing and
the E5 million it earns from exporting the signal.
There was also a secondary impact that arose
from SIS experience in dealing with a
monopoly telecommunications supplier. This
experience helped shape
the deregulation of
satellite downlinks in
1989 and the i n m duction of the Suecial!,{
ised Satellite Service
Licences in 1989 (SIS
through its subsidiary
SISLink has used its
licence to build up a
significant satellite news
gathering business).
It should be stressed that the BT staff made a
very significant input to the whole project with
their engineering and management skills. But
the experience of trying to work with a
monopoly supplier on a major project has
convinced the author that the present move to
end the duopoly of telecommunications in the
UK is essential to the development of
telecommunication services and products in the
Finally, the SIS service has acted as the
demonstration model that satellite has a role to
play in Europe in providing private
broadcasting (narrowcasting) and telecommunications networks.
This article is based on a lecture given by the author
to the IEE on the 26th March 1991.
Dr. Barry Stayley is Technical Director of Satellite
lniormation Services Lrd., Satcllire Housc, 17 Corcham
Srrcer, London N I ~ D R UK.
H~ j, an JEE ~~~~~i~~~
Без категории
Размер файла
444 Кб
Пожаловаться на содержимое документа