Group for Earth Observation

The Independent Amateur Quarterly Publication for

Number 10

Earth Observation and Weather Satellite Enthusiasts

June 2006

DVB-S Special Issue
David Lee describes the
new EUMETCast AVHRR
service which recently
started to disseminate
NOAA high resolution
images to end users
We also explain how toregister for this new service
and describe the newsoftware from David
Taylor that you require toprocess the raw data
NOAAPORT is a similar
DVB system available in
the United States. We
summarise a seminal
article from José Nieves on
setting up a NOAAPORT
station. The full article canbe downloaded from the
GEO website.
Constructing the PADAT
137 QFH antenna: Ruud
Jansen leads readers
through the final
construction phase.
Rob Alblas explains how
you can improve theresolution of colour MSG
images using his software.
Reflections: Peter J
Bradley explains how
reflections in satellite
images can be related tothe terrain below

Keep up with the latest
WXsat News every Month
Radio and Communications Monitoring Monthly
provides a regular 4-page Weather Satellite
column, “Satellites' View”, by Lawrence Harris. In
addition, there is an annual ‘special’ issue
covering WXsats (illustrated) containing
additional features and reviews, also written by
Lawrence.
Radio and Communications Monitoring Monthly(ISSN 1749-7809) aims to become the magazineof choice for all serious radio enthusiasts and isavailable from most good newsagents as well as
direct from the publishers
The May 2006 WXSAT Special edition

Construct the PADAT 137 QFH Antenna
See Ruud Jansen’s article on page 12

Subscriptions are available world-wide.
For more information contact Nice One Publishing Ltd,
Tel: +44 (0)1202 862690, Website: www.monitoringmonthly.co.uk

World View - a feature of GeoSatSignal that combines thermal data from geostationary satellites around the EarthCONTACT INFORMATIONW

ho could have foreseen the developments that have taken placein the field of weather satellite imaging since GEO Quarterly
first appeared on the scene just two and a half years ago. Our firstissue heralded EUMETCast, a hastily contrived stop-gap alternative
to direct reception of HRIT and LRIT from the crippled MSG-1
satellite. Using DVB-S (Digital Video Broadcast by Satellite) relayed
from the Hot Bird-6 satellite, EUMETCast has become so successfulthat it is now accepted as the acknowledged standard for direct
reception of MSG satellite images. The EARS-AVHRR service, albeit
still on a trial basis, has already been added to the EUMETCast
stream to provide NOAA HRPT imagery, and should gain operational
status later in the year. This will be followed by a test period with
AVHRR imagery from EUMETSAT's MetOp-A polar satellite whichshould become operational early in 2007. All this new material comesunder the umbrella of ‘essential data’, and as such is free andunrestricted to users.
VB-S is evolving across the Atlantic too. With the demise of
WEFAX, NOAAPORT has become the only means by whichamateurs can now achieve direct access to images from the GOES
geostationary satellites. Last November NOAAPORT switched to a
DVB-S transmission format too; and like EUMETCast, NOAAPORT
will soon be making NOAA HRPT available as well. Inside this issue,
you will find a number of articles relating to both systems.
inally, a stark reminder to all WEFAX and PDUS afficionados
among the GEO readership: the direct dissemination service willdefinitely cease at 09:00 UT on June 14, 2006. There have been anumber of extensions during the past year or so, but if you have nottaken steps to set up a EUMETCast station for Meteosat-8 by thatdate, your screen is going to go blank. After quarter of a century of
dedicated service, the lights go out on Meteosat First Generation as
far as Europe is concerned.

D
F

Contents

GEO Report
Symposium 2006 - Preliminary Report
AVHRR Imagery on EUMETCast
Emergency Power for Radio Communications
Quarterly Question
Broaden your Horizons with EARS-AVHRR
Bid for a Lassen SKII GPS Receiver
Pushing the Limits of MSG Reception
PADAT137 RQH Antenna - part 2 (construction)
GeoSatSignal 5 - Advanced Options
Solar Degradation of Hot Bird-6 Transmissions
The Wraase WRX-137 APT ReceiverFrancis BellPeter GreenDavid Lee
Robert Denton
Francis BellLes Hamilton
Pete GreenFrancis Bell
Ruud Jansen
Douglas DeansDavid Taylor
Les Hamilton

2
2
3
4
6
7
10
11
12
16
19
21

Looking to the Future
Copy Deadline for Next Issue
GEO Shop Page
NOAA Satellite Predictions for the UK and western Europe
GEO Membership Renewal Form

i
i
ii
iii
iv

News in Brief
High Resolution MSG Images in Colour
Rob Alblas
The Oregon Scientific WRR-968 Weather Station Alan Sewards
NOAAPORT - transmitting environmental data by C-band
One Year with NOAAPORT
José F Nieves
C16 Iceberg Smashes into Ice Shelf
Earth Imaging News
Peter Wakelin
Goa
Ruud Jansen
ReflectionsPeter J Bradley
Software Showcase
Douglas Deans
Visit to Lowell Observatory, Arizona
Robert Moore
New Horizons
John Wills

23
24
27
30
31
32
33
36
38
42
43
44

Public Relations
Francis Bell,
Coturnix House,
Rake Lane,
Milford,Godalming,
Surrey GU8 5AB
England.
Tel:(01483) 416 897
e-mail: francis@geo-web.org.uk
General Information
John Tellick
e-mail: info@geo-web.org.uk
EditorLes Hamilton,
8 Deeside Place
Aberdeen AB15 7PW
Scotland, UK.
e-mail: editor@geo-web.org.uk
Membership and Subscriptions
Nigel Evans,
L’Eventail, 7 Gloster Ropewalk, Aycliffe,
Dover CT17 9ES
England, UK.
e-mail: members@geo-web.org.uk
Meteorological Consultant
Peter Wakelin
e-mail: meteo@geo-web.org.uk
Webmaster and Website Matters
Ray Godden
e-mail: webmaster@geo-web.org.uk
Education Coordinator
David Paintere-mail: education@geo-web.org.uk
GEO Shop Manager
Clive Finnis
e-mail: shop@geo-web.org.uk
International LiaisonPeter Green‘Hollowtree’
Eggesford
Devon EX18 7QX
Tel:(01769) 580 700
e-mail: international@geo-web.org.uk
PublisherGroup for Earth Observation Ltd.
The Group for Earth Observation Limited is acompany in England and Wales limited byguarantee and not having share capital.
Company number 4975597.
The registered office is Coturnix House, Rake
Lane, Milford, Godalming, Surrey GU8 5AB
Printing
Advent Colour Ltd., Unit 1, Crown Way,
Walworth Industrial Estate
Andover, Hampshire SP10 5LU.
Responsibility for Constructional
Projects and Software
Every effort is made to ensure that the technicaland constructional articles published in thisQuarterly are correct. However, the ultimate
responsibility is with the reader to ensure thesafety of constructions and for any interfacingwith other equipment. GEO cannot accept
liability for shortcomings in any publisheddesign or any constructions carried out bymembers or other third parties.
Copyright GEO © 2006
The contents of this Quarterly remain theintellectual property of the Group for Earth
Observation Ltd. and its contributors. Copyingof text or images, either from the printed
Quarterly or from any electronically stored
source, is forbidden without permission from theeditor.

GEO Quarterly No 10Group for Earth Observation

June 2006

Peter GreenFrancis BellI have just returned home from
Leicester and I am trying to recoverfrom a busy but rewarding weekend.
The feedback I have already received
about our Symposium has been
positive and the day judged a great
success. I must offer my thanks to allconcerned: the delegates, about 60+,the speakers, GEO’s management
team and to our hosts at the NSC
who are always helpful andsupportive. I hope a full report withphotographs will appear in our next
GEO Quarterly.
All the speakers during the day were
outstanding. We enjoyed speakers
representing EUMETSAT, the UK Met
Office, our software consultant, ourastronomer member who alsodelivered a message from NOAA andour good friends from The
Netherlands. They all madeinteresting and informative
presentations.

Douglas Mansfield at Leicester
Photo: David Taylor

management team who are voluntary
and unpaid.
It is important that you read thenotices on pages 6 and 10 which
relate to the Editor of GEO’s Quarterly
publication and our Membership
Secretary. You must read thesenotices and respond to them if you
are willing. In short, GEO is looking
for new blood to take on these roles.
These positions have been filled foralmost three years by two dedicatedManagement Team members who,
quite understandably, wish to carry a
reduced burden in the future. I think
this is expected and understandable.
The bonus is that it offers to others an
opportunity to contribute to our
distinguished amateur educationaland non-commercial group. Please
read the notices and consider whether
you wish to offer your skills and time
to GEO’s future.
Just a reminder here may beappropriate. GEO has a corporate
structure with a defined memorandum
and articles of association. This
document is available from me onrequest as a PDF file. Each year
returns are made to Companies
House, containing details of our
accounts and directorships. This
information is in place and is in the
public domain. Remember there are
no shareholders: the company
belongs to its members!

Sally Wannop’s presentation relating
to EUMETSAT contained up-to-datedetails of their satellite programmes,
data dissemination policy and theirinteraction with other agencies,
particularly NOAA.

Dates for your Diary
GEO will be attending the German
Hamtronic rally at Friedrichshafen on
June 23-25, 2006. You can find detailsat

A similar meeting for GEO’s
membership next year is underdiscussion: either the same venue
with an adjustment of date to avoid
the Bank Holiday weekend, or ameeting in Darmstadt if we cansecure the invitation from EUMETSAT.
Darmstadt may be attractive for our
European members. Please let us
know what you think!

Also, GEO have been invited toattend AMSAT-UK’s colloquium in
Guildford this year on July 29-31,
details at

Management TeamI would like to turn to GEO’s
Management Team, who have looked
after the affairs of our organisation foralmost three years. They have done
an outstanding job, producing a
successful Group with a respected
and talented membership numbering
about 600, located in 30 countries.
This has been achieved with a2

www.messe-friedrichshafen.de

www.uk.amsat.org

The location at Guildford my be an
opportunity for some of our members
who could not attend our meeting at
Leicester to come and exchange
weather satellite experiences.
ThanksMy final comment as usual is asincere thanks to our supportive
membership and the contributors to
GEO Quarterly. If you have notcontributed anything so far, do not be
shy in coming forward. Experiences,equipment, location, images: we all
wish to share these with each other.

www.geo-web.org.uk

What a great day!
The sun shone on the 3rd annual GEO Symposium
held at the National Space Centre in Leicester on
April 28 when upwards of 70 delegates enjoyed apacked day.
Douglas Mansfield, a senior forecaster at the UK Met
Office, explained how they use satellite images in
conjunction with numerical models. Sally Wannop, theUser Support Manager for EUMETSAT, described what
we could expect from EUMETSAT in the way of
upcoming launches and how these are going to provide
more products that we and the wider user community
can take advantage of. There are now 850 registeredamateur users of their services.

The packed lecture theatre at the Symposium
Photo: Arne van BelleAn extended lunch break gave some time to visit the
GEO Shop and demonstrations of hardware andsoftware by our Dutch and Finnish friends, and to visit
the newly installed MSG station in the Space Centre.
In the afternoon, David Taylor told us about the newdata types coming from EUMETSAT and announced
the launch of MSG Data Manager 2.5, software which
would deal not only with MSG1 data but MSG2 data at
the same time. David also announced GeoSatSignal-6
which has many enhancements and improvements anddemonstrated AVHRR Manager. The quality anddefinition from this data type, displayed with HRPT
Reader, is amazing.
We were then treated to an excellent presentation from
Ferdinand Valk on hurricanes, followed by Arne van
Belle who, with his usual enthusiasm and good
humour, described how to set up a twin PC system tocapture both MSG and MetOp data to maximum effect.
He completed his presentation with some advice on
keeping your computer clean and some novel
approaches to keeping it running cool.
The final presentation came from Lawrence Harris whocame to be interested in weather and weather satellites
through his love of astronomy. Frustrated when goingto his observatory at night only to find it too cloudy toobserve, Lawrence discovered weather satellites,
which showed him when he could expect clear views of
the stars.
A more detailed, illustrated report on Symposium 2006
will appear in GEO Quarterly No 11, issued in
September. Any reader who took interesting
photographs on the day is welcome to send them tothe editor for possible inclusion.

June 2006

Group for Earth Observation

GEO Quarterly No 10David LeeMany GEO members are already experienced in receiving thewonderful images produced by the AVHRR instrument of the NOAA
series of satellites. The equipment for receiving the APT real-timetransmission of the NOAA satellites is readily available and isrelatively inexpensive. The informative and beautiful results that canbe obtained illustrate many of the pages of GEO and attest to thegreat possibilities of studying the Earth and her weather fromspace.
Local Real-Time Data on your Computer
Receiving APT transmissions allows you to instantly see exactly
what a satellite is viewing when it is above the horizon at yourparticular receiving location. This means not only being able to see
weather in your immediate surroundings, but also many hundredsof kilometres around, and gives the opportunity to view theapproaching weather systems.
The same ability is used by professional weather agencies andnational meteorological services in their provision of weather
forecasts. However, these organisations are typically receiving
another real-time transmission from the spacecraft, namely HRPT.
As this is a digital transmission, it can be readily be utilised bycomputers. Reception of HRPT is more expensive in terms ofhardware as it requires a tracking antenna system.

Figure 1 - Geographical coverage of EARS-AVHRR service from five
HRPT stations. Coverage is indicated as a percentage ofthe total ‘global’ coverage of the AVHRR instrument.

Reception of real-time APT and HRPT gives a wonderful ability toobtain images from around the receiving antenna site as thespacecraft is actually making its observations. However, theseimages are only available if the satellite is in direct line-of-sight withthe antenna. Observations from further afield, made while thesatellite is below the horizon, cannot be obtained. For this reason
the data is stored onboard the spacecraft then dumped to a NOAA
acquisition station once per orbit. From here the data is processed
and archived so that it can be made available to users. While thisgives access to all of the observations taken by the satellite over
the whole globe, there is a penalty to be paid in that the data canbe quite old by the time a user is able to retrieve it. This is asignificant problem for agencies trying to produce large scale,timely and accurate weather forecasts.
Regional Weather Forecasting
In the last few years this situation has, in part, been overcome formany European weather services due to the development of asystem from EUMETSAT called EARS. EARS originally stood for
EUMETSAT ATOVS Retransmission Service. ATOVS (which is itself

HRPT station ow ner

HRPT station location

Danish Meteorological Institute (DMI)
Hellenic National Meteorological
Service (HNMS)
Kongsberg Satellite Services (KSAT)

Kangerlussuaq, Greenland
Athens, Greece

National Institute for Aerospace
Technologies (INTA)
National Oceanic and Atmospheric
Administration (NOAA)
Meteo France, Centre de
Météorologie Spatiale (CMS)
Meteorological Service of Canada(MSC), Canadian MeteorologicalCentre (CMC)

Tromsø, Norway
Svalbard to be added in the future
Maspalomas, Canary Islands, Spain
Gilmore Creek, Alaska, USA
Wallops, East Coast, USA
Monterey, California, USA
Lannion, France (to be added in the future)
Bedford, East Canada
Edmonton, West Canada

Table 1: HRPT stations contributing to EARS.

Figure 2 - Segments of data from stations with overlapping coverage
are selected for dissemination to users as a regional pass.

another acronym for Advanced TIROS Operational Vertical
Sounders) is the name for another set of instruments carried by the
NOAA satellites.
Measurements from these instruments can be used to obtain
information about the vertical profiles of temperature and humidity
in the atmosphere. The radiation measurements from the ATOVS
instruments can be assimilated directly into numerical atmosphericmodels using advanced computing techniques developed over thelast decade. As the temperature and humidity measurements are
obtained at many altitudes throughout the atmosphere, and at
many points over the globe, they are incredibly useful for weather
forecasting.
EARS offers a larger geographical coverage than can be obtainedby a single HRPT receiving station. This is done by establishing a
network of nine HRPT stations around the Atlantic and Arctic
Oceans. These stations are listed in Table 1. This enables
EUMETSAT to take advantage of the inherent real-time nature of
HRPT reception and rapidly distribute the collected instrument data

www.geo-web.org.uk

3

GEO Quarterly No 10

to end-users, typically within 30 minutesof the observation being taken by the
spacecraft itself.
The data obtained during a satellite
pass over each of the EARS reception
stations is processed and distributed tousers via the EUMETCast systemfamiliar to GEO readers. In fact it wasfor the rapid dissemination of ATOVS
data that EUMETCast was originallydeveloped! It has subsequently been
greatly expanded to carry a wide rangeof satellite imagery and othermeteorological data and products.
The objective of the system is toprovide data quickly. For this reason the
products from each pass over a station(which has a maximum duration of
about 15 minutes) are distributed rapidly
through the system without combining
them into longer stretches of data or
into merged mosaics of a region. Thesetypes of products require data fromlonger time periods to be available andwould therefore delay the delivery ofdata to users. The activity of collecting
together the required set ofmeasurement is left to the numerical
forecasting model systems.
The ATOVS service has been operating
since 2002 and has provided benefits tothe meteorological community. Now
EUMETSAT is working on extending theservices provided by this system toinclude the more familiar AVHRR data,
which is in fact the major component of
the data making up the HRPT
transmission from the spacecraft. The
extended set of services is called the
EUMETSAT Advanced Retransmission
Service (EARS).
Regional AVHRR Imagery
Five stations that are providing data to
EARS will contribute to the AVHRR
service and provide a combined
European and north Atlantic coverage(figure 1). To ensure the efficient andtimely delivery, the received HRPT datais handled in small chunks, orsegments, of one minute duration. Thismeans that a more continuous flow of
information can be passed through thecommunications network and
EUMETCast dissemination system
without significantly delaying it. The useof segments also allows the system tomonitor the data provided from thevarious stations and select which is tobe disseminated on the basis of quality.
This avoids unnecessary duplication ofdata that may have been acquired for
those regions where more than one
station was able to see the spacecraft(figure 2). This use of segments issimilar to the approach utilised in thedissemination of image data from
Meteosat-8.
Users receiving the AVHRR segments
will easily be able to combine them into

4Group for Earth Observation

June 2006

longer sequences of data by
concatenating them together. The
format of the data is such that it can bereadily displayed and manipulated using
existing and readily available software.
Receiving AVHRR data through
EUMETCast will allow users to get
access to this incredibly rich data with
the inexpensive equipment required for
EUMETCast. There is no need topurchase the significantly more
expensive HRPT system hardware.
Further, as the AVHRR service expands,
the geographical area from which data
can be received will be significantly
greater than can be received from asingle station. Satellite data enthusiasts
will be able to see lands and weather
systems much further from home than
before.
AVHRR on Metop too!
AVHRR has been flying on the USNOAA satellites for many years and is
still a great work-horse formeteorological and Earth-resources
studies.
Europe and the US are working
together to ensure the continuation of
the polar satellite system. Starting with
MetOp-A, to be launched in July 2006,
EUMETSAT will have the operational
responsibility for the morning (localtime) orbit with the MetOp satellites,
while NOAA will cover the afternoon
orbits. The European and American
satellites will carry a set of identical
AVHRR and ATOVS instruments.
The MetOp satellite will make HRPT
transmissions using a new generation ofdigital technology, very different fromthe long-running NOAA satellites. This
will mean that users wanting to receive
HRPT data directly would need topurchase new hardware and softwaresystems. The stations within the EARS
network are currently being upgraded toreceive these new MetOp transmissions
and process the AVHRR and ATOVS
data. These will be disseminated over
EUMETCast. While the format of the
AVHRR data sent out to users will bedifferent for MetOp, this is only a matterof product format; this can be handled
by software without the need for acomplete new hardware installation.

Robert Denton G4YRZ

Emergency Power for Radio
Communications
Don’t be fooled by the title. This book does notjust deal with radio communications; it can beapplied to many subjects, weather satellites andhome use included. Would you like to run yourweather station for free? This book will show you
how to make enough power to do so. You will not
only be learning about the weather but about
how to harness it to further your hobby as wellas helping the environment.
I knew this book was going to be a riveting readright from the start because I burned my dinnerreading the first few pages, it was so interesting.
This is an easy to follow, no nonsense book which
deals with all aspects of emergency powersources: solar, wind, water and gas. There ismuch information available on the subject ofsolar power in particular. What would you do inan emergency if you lost all power to your house?
Have you thought about the consequences? No
light, no heat, no water! Are you prepared forsuch an event? This book will prepare you for
major power outages and explain how to deal not
only with the power side of things but also
surviving such an event. There are also several
projects at the back of the book, one of which I
have already started myself.
This book is very educational and explains how
you can experiment and understand how things
work, as well as allowing the satisfaction of freeenergy and the knowledge you built something
yourself. A whole chapter has been allocated tocovering safety issues. Subjects covered include
charge controllers, inverters, batteries, power
supplies, generators, torches etc.
I bought my copy of this book from the RSGB
bookshop; it was the best value and mostabsorbing book I have ever bought and will pay
for itself over and over again with the savings I
will make on the solar power projects.

All of this means that wonderful satellite
imagery will soon be available toenthusiasts via a simple ‘home’ systemthat can produce many wonderfulimages of Earth from space.

In my opinion this book is a life-saver. The only
downside to it is that some issues relate to the120-volt American supply—but it is easy toconvert and apply to UK voltages. 12-volt
supplies are also covered. As energy supplies tothe world dwindle, what will you do to beprepared and survive?

The author, David Lee (Moltek
Consultants Limited), works at
EUMETSAT for the EARS project.

Emergency Power for Radio Communications(ARRL), by Michael Bryce, is available in soft
cover from

Acknowledgements to EUMETSAT,
Anders Meier Sørensen and ChristellPonsard.

www.geo-web.org.uk

www.rsgb.org.uk/shop

Members price £12.74 + p&p (non-members
price £14.99 + p&p)

John Spacey spotted this spectacular sandstorm blowing out over the Gulf of Sidra on the north African coast towards Malta (above). The
Meteosat-8 image was processed using David Taylor’s GeoSatSignal software from an image captured on February 23. John also sent us
an image acquired 24 hours later (below) which shows that the sandstorm had moved out of Libya and into Egypt while the winds had swunground, blowing the sand towards Turkey and Cyprus.
Image © EUMETSAT 2006

GEO Quarterly No 10Group for Earth Observation

June 2006

Francis BellThe last Quarterly Question
related to the location of thehottest air mass in the world
between May and July eachyear and its consequent effecton the monsoon seasons in
Asia. There was a photographof the area in question together
with attached notes which I
read on page 75 of the book
‘Global Earth Observation
System of Systems GEOSS a
10-Year Implementation Plan
Reference Document’. The
question posed was: ‘Where is
this area?’ The answer is the
Tibetan Plateau.
Thanks to all readers who
submitted answers. I selected
Hann Redwin from London as
the winner. From our e-mailexchanges I learned that Hann
went to some trouble to secure
the correct copy of the bookreferred to in the question. His
first request to the publisher
generated the abbreviatedbooklet rather that the full
publication.
If this has happened to others,
the full book is, I believe, stillavailable from ESA Publication
Division, ESTEC, PO Box 299,
2200 AG Noordwijk, The
Netherlands. I suggest you
write to the publishers and ask
for a free copy but quote ISBNNo 9290929863 to ensure you
receive the full edition.
I chose the question because
the answer surprised me. I
thought the Indian monsoons
were controlled by the heatingof the central land mass of India
but the book, which I’m sure iscorrect, said it was controlled by
the Tibetan Plateau.
The Question
The Quarterly Question thistime may have a less definitive
answer; it is: ‘How many
complete country outlines canyou see from weather
satellites?’
The area I am considering inthis context includes Europe,
north Africa and the Middle
East. This represents the areasthat can be imaged by satellite
reception from Europe (frompolar orbiting satellites and the‘European’ images from
Meteosat-8.
I have long been curious aboutcountries and how they are
established within theirrecognised boundaries. Thereseem to be the ephemeral
elements of military strengthand perhaps a local consensus,
plus the more permanent
natural geographical boundaries
between different nations. I’m
not even sure what constitutes
a country: a permanent seat in
the UN General Assembly? I’mjust not sure.
With these thoughts in the backof my mind I often look at mysatellite images of Europe andask myself how many countries
I can see, from the image,which have a definitive outline?
I came up with an answer ofjust two. Yes, I know Europe
has about 20 to 30 countries.
But can you see their outlines
from space? For me the answer

in most cases was ‘no’. You
may say: ‘What about Spainand Italy—they show up clearlyenough’? I concluded this was
not the case. I cannot see theboundary between Spain andPortugal nor those separating
Italy from France, Switzerland
and Austria. So how many
countries with a definitiveboundary can be seen from aweather satellite?
Recently I was looking back atsome images from Earthobservation satellites such as
SPOT and Landsat. I did notice
two images showing distinct
political land boundaries. These
did not cover the wholecountries in question but itinterested me that in somecases you can see landboundaries. One was between
Israel and Egypt, bordering the
Sinai peninsula. The other wasalong the 49th parallel between
the USA and Canada. In bothcases it was the differing
agricultural practices whichshowed up. The traditional
arable field sizes in the USA are
different to those in Canada andthis shows up clearly on asatellite image. On the Israeliside of the Sinai border there is
agriculture whereas the
Egyptian side is just left as
desert—again these show up
on satellite images.
I have said that my answer tothe question is just two
countries but I’m willing to be
persuaded otherwise if anybody
thinks differently. E-mail me, or
contact me by post, with youranswer, giving the names of thecountries you can identify.
Interestingly, the software I am
using for EUMETCast images
provides an overlay of mostcountry boundaries but only oneof my two qualifying countries is
included in the overlay. On an
arbitrary basis I am excluding
UK Crown Dependencies in ananswer because I’m not surewhether they qualify as
countries—in spite of some ofthem being recently
represented in the Melbourne
Commonwealth Games.
We will debate the winner indue course: but the usual prizeof a complementary entry to
GEO’s next symposium isoffered to the winner or theirnominee.
Here’s another challenge—notpart of the Quarterly Question,
but you may wish to try. Can
you see, on any satellite image,the land boundary between
Norway and Russia?
Yes! A land border does exist
but you may have to look it up
on a map. Any satellite image
will qualify here. However, bewarned that this border is sodifficult to identify that, during
the Cold War years when NATOand the Warsaw Pact wereclosely monitoring it, patrols
would often stray on to eachother’s territory. I don’t think
there was ever a serious
incident. An unintentional
incursion was met by the otherside politely escorting theoffending patrol back to its own
side of the border, thus avoiding
World War Three.

GEO is on the lookout for members prepared to research
topics with the aim of creating new articles for GEO Quarterly.

After 3 years in post, Nigel Evans plans to retire as GEO
Membership Secretary at the end of this year.

See page i of the centrefold for more details.

Turn to page i of the centrefold for further imformation.

6

www.geo-web.org.uk

June 2006

Group for Earth Observation

Les Hamilton
Many GEO readers have been thoroughly
enjoying the MSG imagery disseminatedover the EUMETCast service during thepast three years or so. It seems certainthat last December’s launch of MSG-2,
coupled with the termination of theWEFAX and PDUS services on June 14,
will encourage many more enthusiasts toregister for EUMETCast. But did you
realise that the EARS-AVHRR HRPT [1],which launched as a trial service last
March, now allows you to access NOAA
HRPT images via EUMETCast too?
EARS [2] has been designed to provide
high resolution images from the
AVHRR/3 [3] scanning radiometers aboard
both the current American NOAA and theforthcoming European MetOp polar orbiting
satellites via its EUMETCast service. The
AVHRR is a six-channel device which
detects energy in the visible and infrared
regions of the electromagnetic spectrum
and provides a maximum ground resolutionof 1.1 km/pixel. These data have been
available to readers possessing an HRPT
reception system (and a reduced resolutionsubset is available as the familiar NOAAAPT in the 137 MHz band).

Figure 1 - EARS dissemination

NOAA themselves have the capability torecord data from distant parts of the globe
on board their satellites, dumping this once
per orbit to their central ground stations,thus giving them global coverage. EARS
will at last provide the amateur enthusiast
with the opportunity to share in this global
coverage via the EUMETSAT [4] network of
HRPT stations ranged around the Atlantic
and Arctic Oceans (figure 1).
The geographical coverage of EARS is
primarily over data-sparse seas and oceans
around Europe (figure 2). Hitherto,
amateurs could only receive HRPT datatransmitted from the NOAA satellites while
they were actually flying above their groundstations and the images were necessarily
restricted to a limited geographical area.

EARS provides NOAA HRPT data in twomodes:• By direct transmission from thesatellite to one of EUMETSAT’s HRPT
ground stations. This provides thedata at close to real-time but is limited
to the region around the station.
However, this mode does make use ofmultiple stations, i.e. those shown infigure 2. It is referred to as ‘NRT’(near real-time), currently
disseminates ATOVS data, and isbeing extended to include AVHRR
data. In the short term, the Tromsø
station will provide coverage while theone at Svalbard is finalised.
• by once-per-orbit data dumps sent tothe central NOAA ground station. This
provides global data coverage but withdelays of up to 2 hours before it
reaches the user. This mode will be
used with MetOp—not NOAA-17 and
NOAA-18. Current understanding isthat NOAA-17 and NOAA-18 will only
be utilised to provide the limited
resolution GAC data for the full orbit.
EARS will be provided until at least the endof 2008. An extension of the service
beyond this date requires approval from the
EUMETSAT Council.
Access and Registration
The great news for everyone is that thiswealth of HRPT data comes absolutely
free, although you must register withEUMETSAT to receive it. The EARSAVHRR service is considered ‘essential
data’ so does not require a licence. This
also means that there are no restrictions on
sharing data with other enthusiasts.
Anyone already registered for MSG HRIT
etc., and therefore already a licensed user
in possession of a EUMETCast Key Unit
(EKU) and client software, need only sendan email to ops@eumetsat.int to requestthat their existing EKU be activated for the
EARS-AVHRR service.
If you are not registered for any
EUMETCast service, you must complete
the new EUMETCast registration form
(December 2005), indicating on it theservice(s) you wish to receive. A copy ofthis form can be downloaded from the GEO
website where you will also find a handy
guide to filling it in. The address is:
http://www.geo-web.org.uk/eumreg.html

www.geo-web.org.uk

GEO Quarterly No 10

You will have to take the following steps:
1 Return your completed EUMETCastregistration form to EUMETSAT.
2 EUMETSAT will contact you regarding
the purchase of the EUMETCast client
software and EKU, which is required,for all services, including theunlicensed EARS-AVHRR stream.
3 If you have requested access to oneof the ‘licensed’ services such as
MSG data, EUMETSAT will forward
your registration form to the relevant
Licensing Agent so that the licensing
procedure can begin. This agent is the
Met Office for UK users. If you request
only the NOAA AVHRR data, a Met
Office licence is not required.
4 Once any required licensing
procedure is complete and you have
paid for the EUMETCast client
software and EKU, access to theservices on EUMETCast will be
granted. You will be sent a copy of the
EUMETCast client software, an EKU
and the username and password
required for the installation process.
5 Above all, read the explanatory
notes at the end of the EUMETCastregistration form.
The current understanding is that only
registrations for NOAA HRPT are possible.
Once the MetOp AHRPT data service
becomes available, probably in early 2007,
you will have to register again, specificallyfor this data.
Pass Scheduling
The actual HRPT data available will bebased on a prioritisation scheme related tothe status and performance of theoperational polar orbiting satellites. This will
be revised in response to events and also
when a new satellite enters service. In
particular, over the European region, theaim is to give first priority to reception fromthe primary morning satellite (currently
NOAA-17) during the local morning andevening periods and to the primary
afternoon satellite (currently NOAA-18)
during the local afternoon and overnight.
Following the start of Metop operations,
MetOp-A will replace NOAA-17 as theprimary morning satellite.

The regional geographical coverageafforded by the service (figure 2) is basedon EUMETSAT’s Atlantic network of HRPT
stations. The colour coding indicates thefraction of the actual AVHRR observations
that the EARS network is capable ofreceiving under ideal conditions. Normally,
only satellite passes lasting 7 minutes andmore are included.
The EARS-AVHRR Transmission Format
In much the same way as with EUMETCast
MSG imagery, the EARS-AVHRR data willbe transmitted in segments. These will becompressed files, each one representing
one minute’s worth of HRPT data. There
will be occasions when the same 1-minutesegment will be available from more than
one station: for example, from the end of7

GEO Quarterly No 10Group for Earth Observation

Figure 1 - EARS AVHRR coverage
Image: EUMETSAT

Figure 3 - AVHRR Reader

Figure 4 - NOAA-17 pass on March 14, 2006
Image: EUMETCast EARS-AVHRR service

8

Figure 5

www.geo-web.org.uk

June 2006

June 2006

the Tromsø pass and from the beginning of
the Maspalomas pass. In such cases the 1minute segment with the best quality will bedisseminated via EUMETCast.
When the first MetOp starts transmitting
data later this year, the EARS network willagain provide data in segments. As
provided by the satellite, these will initiallybe of 3-minutes duration, starting from thecommencement of each pass; but they will
be converted into 1-minute segmentsaligned to minute boundaries before being
sent to end-users via the EUMETCast
uplink.

Once you are a registered user and EARSAVHRR data is streaming into your
EUMETCast station you will require
software to combine the segmented data
into HRPT files and further, convert the raw
data into images. A new program from
SatSignal Software, AVHRR Manager
does just this, then interfaces seamlessly
with HRPT Reader to create the final
images.
Both items may be downloaded from their
dedicated pages on the SatSignal websiteat:http://www.satsignal.net

by clicking its link in the ‘Satellite Tools’
section.
Installing AVHRR Manager
To install AVHRR Manager on to yourcomputer, create a new folder called
AVHRR and extract the ‘zip’ archive into
this. It is useful to create a short-cut to thefile AVHRmanager.exe by right-clicking on
the file and dragging it to your Desktop orStart menu.
If, when you first run AVHRR Manager, you
obtain a message about missing DLLs, youneed to install the Runtime Library Bundle.
This can be downloaded from a link on the
SatSignal page of the website.
There is a choice of two backgrounddisplays for the main screen: an outline
map as reproduced on the inside front
cover of GEO Quarterly No 8 or a NASABlue Marble image (figure 3). You canselect between these backgrounds on the
program’s ‘Setup’ tab.
You require the file countries.dat to produce
the outline map background display. If thisalready exists in your WXtrack folder,
AVHRR Manager will find it and make useof it. If need be, countries.dat can be
downloaded from a link on the
HRPT Reader page of the website andextracted into the AVHRR Manager folder.
Installing HRPT Reader
HRPT Reader comes as a ‘zip’ archive.
Create a new folder on your hard driveGroup for Earth Observation

called ‘HRPT Reader’ and unzip all thecontents into this. It is also important tocreate a sub-folder called ‘Keps’ to holdfiles of current and historical NASA 2-line
element data. Typically, a current 2-line
data file will be called noaa-12.txt,
noaa-15.txt and so on, and contains justthe two lines of data elements. Consult the
HRPT Reader documentation for fuller
details.
Getting Started
When you run AVHRR Manager for the firsttime you are presented with a window
reminding you that you only have a 30-day
evaluation period before registration isrequired. After a 4-second delay the ‘OK’
button is enabled allowing access to theprogram. To register the software you mustclick the ‘Enter key’ button and note thereported ‘Hardware fingerprint’ for yourcomputer. You must include your hardware
fingerprint in the ‘Comments’ section ofyour registration form.
Program Setup
Before you can use AVHRR Manager you
must first define various paths so that the
program ‘knows’ how to access all the data
it requires. Run AVHRR Manager and clickthe ‘Setup’ tab to reveal the ‘File controls’
input panel.
Kepler Path
Current Keplerian 2-line elements areneeded to operate AVHRR Manager. If you
already have a multisatellite 3-line element
file such as noaa.txt or weather.txt inside
your WXtrack folder, or a standard ‘Keps’
folder inside your HRPT Reader folder,
AVHRR will find and make use of thesewhen you click the ‘Auto’ button.
Tellicast Received Files Location
Use the ‘Browse’ button to navigate to thefolder where EUMETCast raw data is
downloaded on your computer, e.g.
C:\Tellique\Received\

Processed Combined Data Location
Use the ‘Browse’ button to navigate to thefolder where the reassembled 1-minutesegments are saved, e.g.
C:\MSG-1\images\AVHRR\

The program can delete data older than acertain number of days. If you wish to use
this facility, set the ‘Combined dataretention period’ to a non-zero value.
As a single combined HRPT file canoccupy in excess of 100 MB, you will soon
have problems if you allow the data toaccumulate for too long.
Saved Segment Files Location
Should you wish to retain the original HRPT
1-minute segments, use the ‘Browse’ button
to navigate to a suitable folder you havecreated for this purpose.
File Options
Files are normally stored in dated folders to

www.geo-web.org.uk

GEO Quarterly No 10

make the data more manageable (just like
MSG data). This feature can be disabled if
desired.
The source data will normally be deleted
after processing by the program.
Unchecking ‘Delete files from RX’ will
prevent this from happening.
Running AVHRR Manager
Once you have set up AVHRR Manager toyour specification and ensured that yourKepler element files are up-to-date, you areready to start. Click the ‘Map view’ tab toreveal the main screen (figure 3) and click
the green LED-type button at lower left tostart. The message ‘Waiting for segments’should appear and the program willautomatically read in and recombine HRPT
segments as they are downloaded on to
your machine by EUMETCast. Figure 3
shows a set of HRPT segments
superimposed over the Blue Marble
background map.
To view the image open the ‘AVHRR
Browser’ tab (figure 6) where you cannavigate through a menu of the day’s
downloads and select an image of yourchoice. If you checked the ‘Save
thumbnails’ box during setup, a single click
on a file will display this in the right-handpane. A double-click on any thumbnail or its
associated ‘raw16’ HRPT file opens HRPT
Reader (which you must have installed to
produce the HRPT images). A single clickon the ‘Open AVHRR’ button has the same
effect. The filename is automaticallytransferred to HRPT Reader; all you needto do now is select the ‘Northbound’ or‘Southbound’ button to generate the image.
The creation of images using HRPT Reader
was detailed in an article in GEO Quarterly
No 5, page 18.
Available AVHRR Images
The ‘Ground Stations’ tab compiles a list ofpasses from relevant satellites (currently
NOAA-17 and NOAA-18) for thesubsequent 24-hour period for each of thesix EUMETSAT HRPT ground stations. This
will help you to decide on your datarequirements. Even during the current trial
period with just the Maspalomas station(Canary Islands) active, saved data willamount to about 1GB per day.
On March 14, AVHRR imager telemetry
from the 11:09 UT NOAA-17 pass wasreceived at the Maspalomas station andsent on to EUMETSAT in Darmstadt tobecome the very first official HRPT data to
be added to the EUMETCast stream (which
can be received via the Hot Bird-6 satellite).
Figure 4 shows the entire span of the passat reduced resolution while figure 5 is ahigher resolution section showing detail of
Van Kármán vortices over the CanaryIslands and river estuaries and the offshorearchepelago of Dos Buagos in GuineaBisseau. The HRPT pass was received byDavid Taylor in Edinburgh and processedusing AVHRR Manager and HRPT Reader.

9

GEO Quarterly No 10Group for Earth Observation

June 2006

PC Requirements
This software is intended for use on a
500 MHz or better PC with at least 512 MBof memory. Windows 95, 98, 98 SE and ME
are not supported; whilst the program maywork on these platforms, correct operation
is not guaranteed.
Appendix -Keplerian Elements
An alternative way of handling Keplerianelement sets is to create a subfolder called‘Keps’ anywhere you like—even directly on
your ‘C:’ drive. Just save 2-line files foreach individual satellite (noaa-nn.txt) into it.
But you will have to type the path leading tothis folder into the ‘Kepler path’ field of
AVHRR Manager by hand, and with an
added trailing backslash thus: ‘C:\’.
Notes• A noaa.txt 3-line multi-element filestored in the AVHRR Manager folder
is not recognised: noaa.txt andweather.txt multi-element files are only
recognised when they reside in the
WXtrack folder.
• A ‘Keps’ folder within WXtrack is notrecognised under any circumstances.
Acknowledgements
Our thanks to are due to EUMETSAT and
NOAA for making so much information
available on their respective websites, andfor allowing amateurs free access to
AVHRR data from both NOAA and MetOp
satellites.

Figure 6 - The AVHRR Manager image browser tab

Abbreviations
1. High Resolution Picture Transmission
2. EUMETSAT Advanced Retransmission
Service
3. Advanced Very High Resolution
Radiometer
4. European Organisation for the Exploitationof Meteorological Satellites

User Service Helpdesk
For further information, please contact the
EUMETSAT User Service Helpdesk:
EUMETSAT User Service
Am Kavalleriesand 31
D - 64295 Darmstadt, Germany
Telephone: +49 (0) 6151 807 366 / 377
E-mail: ops@eumetsat.int
Web Site: http://www.eumetsat.int

Should you wish to bid for this exciting product, please send yourmaximum bid to Peter Green by 18:00 GMT on Saturday, July 8,
2006.
Bids can be sent by e-mail to: international@geo-web.org.uk or bysnail mail (details on page 1)
GEO has been donated two Trimble Lassen SKII GPS receivermodules, complete with compact active micropatch Magmountantenna, five metres of cable and CDs containing the technicalmanual, to help raise funds. The first of these was raffled at our2006 Symposium.

To allow the full membership of GEO to benefit from this opportunity
we have decided to hold an auction for the second of these units.
This is a great opportunity for an enthusiastic and knowledgeable
home constructor to build their own time-standard or navigation
system!
These modules are used a lot in car SatNav systems, and you canfind more information on the Web at:

The highest bidder will then win the auction. Please do not bid unless
you are serious as this will waste time and may prevent a member witha genuine interest from owning this unit.
The winning bid will include the cost of postage and all funds raised will
go to GEO. This auction is open to all members of GEO regardless ofcountry of residence.

Les Hamilton has combined the roles of Principal Feature
Writer with both Editor and Make-up Editor since GEO first
appeared. He now looks to take a well-earned break.

http://www.trimble.com/lassensk2.shtml

10

www.geo-web.org.uk

Full details on page i of the centrefold.

June 2006

Group for Earth Observation

GEO Quarterly No 10

Francis Ball
Introduction
During frequent conversations I have with GEO members,
questions are quite often raised which I cannot answer. However,
one of the strengths of our membership is that it is highly likelythat someone within the Group will have the answer, or at leastsufficient experience to offer guidance or help.
Recently, a member telephoned me and said he was thinking of
installing a satellite dish for Hot Bird-6 and EUMETCast
reception in his loft. I was unsure about the viability of this planbut encouraged him to try if he had no other option. During thesame conversation we also spoke about locating a dish inside aroom but looking through a suitable sized window facing thecorrect direction. We left that conversation there.
I was a little uneasy about what I had said. I usually take anempirical approach in these matters because I do not have thenecessary technical and theoretical skills to calculate RF signal
path losses and gains with different sizes of dish: however, I know
others have these skills. I was left with the empirical approach.
EUMETCast Reception through Glass
I tried the window experiment first but immediately faced aproblem because my house does not have a suitable window to
conduct such an experiment. My main patio windows, which
otherwise would have been ideal, face the wrong way and mysouth facing windows are too small and have leaded glazing. As
an alternative, I set up a 45 x 35 cm receiving dish—one I often
use for experiments—in the front garden. As usual, I connected it
to my main receiving computer. The S-meter in the circuit read
98 units while the TechniSat software on the computer showed agood satellite signal strength of 50% and indicated that it was
locked on to the satellite.

dishes bolted to their ancient external stone walls—this is more
the province of a research facility or a radio telescope outstation.
But my friend did have a room with a suitable window, so hearranged for his 1-metre dish to be located in his office ‘looking’out of his window. His setup successfully received Meteosat
WEFAX transmissions and the last time I visited him all seemed
to be working well.
What happens if you move up from 1.7 GHz to 11 GHz ? I don’t
know.
Loft Experiments
A did try the loft experiment as well. The upper limits on the sizeof dish I could use were defined by the hatch opening into the loft.
Trying to increase the size of the hatch might have led to adomestic dispute, so this was avoided. I settled for using the samedish as for the window experiment and checked readings with thedish in the clear: the S-meter and computer readings were thesame as before. I then moved the dish into my loft and adjusted
its azimuth and elevation for Hot Bird-6. This time my S-meterreading was zero and the computer reading was consistently outof lock. No adjustments to the dish orientation could improvethese poor readings. Again there must be variables to consider
here.
• the type of roof tiles (Mine were 270 x 170 x 12 mm. As they
were laid, I expect there were two tile thicknesses covering
the roof making them effectively 24mm thick.)• the distance of roof surface to the dish• the wooden joists within the roof space• roof tiles wet or dry• other possible variables ...

Now for the the experiment. I introduced a large pane of clear
2 mm glass (a spare pane for my greenhouse) in front of the dishto simulate reception through a window. The S-meter dropped to
46 units while the computer now gave a reading of just 10%: inthe red and no lock!

If anybody asked me for an opinion I would say: ‘experiment withreception behind glass but a loft-located dish may prove to be achallenge’. I know many people do receive 137 MHz APT using anaerial located in their loft. I have done this myself but with
Hot Bird-6 we are dealing with 11 GHz.

I did not experiment further but it seems to me there are anumber of variables that could contribute to this effect:• the distance of the glass from the dish• the thickness of the glass (what about double glazing?)• the chemical composition of the glass. (Is plastic moretransparent to RF than glass? Try glazing one of yourwindows with polycarbonate and evaluate the difference!)• the angle of incidence of the incoming signal to the glass• the size of the receiving dish• perhaps other variables ...

These issues are significant because, for manyreasons, not all our members can locate external
dishes on their homes. Positioning a dish behinda window or in a loft may be a viable alternative.
It would be great to share your experiences,whether successful or otherwise.

I was not discouraged by my results because the introduction of
the glass did not reduce the signal strength to zero, thus leaving
scope for a different sized dish with a different orientation
resulting in possible success.
I know reception through a window can be achieved at 1.7 GHz.
A meteorologist friend of mine at Cambridge University had aroom in one of the central college buildings. Now the beautiful
and architectural nature of the colleges, not to mention their
tourist attraction, do not lend themselves to having satellite

The Invitation
Please, will any reader who has experience of Ku band reception
behind glass or in a loft please write a few paragraphs for GEO
Quarterly and if possible attach a photograph. Some members
may wish to understand the theory behind the signal loss andsubmissions on this aspect of the problem are also welcome. Are
the losses due to reflection, refraction or signal absorption?
Please somebody explain. Experiences of 137 MHz APT reception
inside a loft would also be interesting.
Submissions to the editor please.

www.geo-web.org.uk

11

GEO Quarterly No 10Group for Earth Observation

June 2006

Ruud Jansen
Last issue I explained the design processthat led to the development of the
PADAT137 RQHA. Now it’s time todescribe how you can actually build suchan antenna yourself.

The lid itself is just a simple disc of POM
or Lexane, anything from 3 to 8 mm thick:and of course this lid must also be drilledwith eight 3 mm holes to secure it to theheadpiece.

this assembly sturdier, two PVC sockets
can be mounted over the pipe at thesepoints (the ridge which occurs halfway
down the inside of each socket can beremoved with a file or rasp).

The Headpiece
The most difficult part of this antenna is
the headpiece, which should beconstructed from polyoxymethylene(POM), a plastic with excellent HF
properties. POM is water resistant, wearresistant, very strong and easy tomachine. It is supplied under the brandname Delrin.

The Rod Components
For the upper cross-members, cut two
127 mm and two 132 mm lengths from
12 mm aluminium rod using a hacksaw.
Drill a 4 mm hole with a depth of 25 mm
or a little longer into one end of each. You
will also need to drill a second 4 mm holethrough each rod,
15 mm from the
opposite end. Finally,
a 2.4 mm hole must
be drilled, at rightangles to this 4 mm
hole, just 4 mm fromthe end of the rod
Figure 3(figure 3). The eight
4 mm holes must be tapped for M5
thread and the four 2.4 mm holes for M3
thread as shown in figure 4.

The vertical distance between the centresof these two holes amounts to 40 mm andthey must be drilled at
90 degrees to each other.
The respective distances
between the centres of
the upper and lower ofthese two rods and thecentres of thecorresponding rods
immediately above on
the headpiece are
845 mm and 885 mm
Figure 6(figure 7, opposite page).

For the lower cross-members, cut one
278 mm and one 288 mm length of thesame aluminium rod and drill a 4 mmdiameter hole, 25 mm deep, into bothends of each. A 3.2 mm hole then has tobe drilled at right angles through the
mid-point of each piece of rod. Tap M5
thread into the 5 mm holes and M4
thread into the 3.2 mm holes (figure 5).

The Vertical Aluminium Strips
Now it’s time to deal with the aluminium
strips. Cut four strips, two 900 mm longand two 940 mm in length then drill a
5 mm hole 10 mm from both ends of each.
Now you have to create a 90° twist ineach strip in order that it can be fitted
correctly to the cross-pieces. Here’s how I
do it.

The Mast
The mast consists of a length of 32 mm
outside diameter PVC pipe. You have tobore two 12 mm holes where the twolower aluminium rods must be pushed
through the mast and secured. To makeStart by clamping 30 mm at one end of a
strip in a vice or fixed clamp. Next, clamp
30 mm at the opposite end of the strip
between two pieces of hardwood, andsecure them with a clamp (figure 8). Now
turn this end about 120° in a clockwise

Starting with a 55 mm length of 70 mm
diameter solid POM rod, use a lathe to
cut a 32 mm diameter hole the full lengthof its axis. This will accommodate thevertical length of PVC piping whichfunctions as both mast and loop support.
At the top, expand the hole to 42 mm
diameter for a depth of 23 mm (figure 1).

Figure 1 - The headpiece mounting block

Next, drill the four 12 mm horizontal
holes needed to accommodate thealuminium rods of the antenna elements.
This is very precise work because theserods must be mounted perfectly
horizontally. A deviation of only a few
millimetres at the end of a length of rod
results in a change of a few centimetresin the diameter of the antenna—andhence the impedance, as well as thephase shift between the two loops andthe radiation pattern.
Another four holes (5 mm) must be
drilled from the top to allow fixing of thelengths of rod with M5 bolts, along witheight 2.4 mm holes which should betapped with M3 thread and used tosecure the lid (figure 2 - opposite page).

12

Finally, bore two 4 mm holes throughboth the PVC sockets and the mast inorder to secure the two lower rods using
4 mm bolts (figure 6)

Figure 4 - The RQHA upper element rods

Figure 5 - The RQHA lower element rods

www.geo-web.org.uk

June 2006

Group for Earth Observation

GEO Quarterly No 10

Figure 2 - Plan and elevation views of the upper block

Figure 7 - Mast dimensions
Figure 8 - Twisting the aluminium strips

direction, in a single movement.
When you release it, the strip will
return to about 90°.
If necessary, repeat this turning
process a few times: do so as
smoothly as possible to avoid
tearing the aluminium. Repeat forthe other three strips.

Figure 9 - The masthead PCB

The Printed Circuit Board
When the the time comes to connect
up the aluminium rods in theheadpiece, this will be done using asmall piece of printed-circuit board.
To prepare this, take a piece of
single-sided printed-circuit board
and saw or file it to a circular disk;
then etch or scrape away part of thecopper in such a way that two

www.geo-web.org.uk

insulated copper segments remain(figure 9). Later, the upper rod
components will be mounted on tothese segments with solder lugs.
Constructing the Balun
Start with approximately 520 mm
of 50 Ω RG58 co-axial cable and
150 mm of RG59 75 Ω co-ax. At one
end of each, make a short slit ineach side of the co-ax so that theouter insulation layer and braid canbe folded back—but do not cut themoff!
Solder the two inner conductors
together in such a way that there isa minimum of space between the
inner insulation layers of the two
cables. Cut a short length of inner

13

GEO Quarterly No 10

insulation from a spare piece of co-ax,
split it in half lengthwise, and mount itover the soldered inner conductor.
Finally, fold both outer braids back so

Figure 10 - Balun construction (not to scale)Figure 11 - Making the joinGroup for Earth Observation

June 2006

that they cover the join and solder them
together. Finish these connections neatly
with some shrink tubing. Trim both
lengths of co-ax to their correct lengths
then join the other end of the 75 Ω RG59
cable to the RG58 receiver downlead in asimilar fashion. The correct dimensions
for the lengths of co-ax are shown infigure 10 (though not to scale) and you
can see photographs of the joining
process in figure 11.
Another possibility for joining the lengths
of co-ax cable is by making a special toolfrom a small piece of 0.3 mm thick brassor tin sheeting measuring about
25 x 20 mm (figure 12). Cut this piecehalf-way through in two places, 7 mmfrom each end then bend it around a
5 mm drill and fold the middle lip back.
Now cut the co-ax as shown in thephotos, push through both ends of thetube, and solder the braid of the cables tothe tube. Use a hot soldering iron with alarge tip to ensure that the shield issoldered to the tube quickly and makesure that the inner insulation does not
melt away. Both inner conductors can
now be soldered together and the
protruding lip can be folded over to makea neat cylinder which may be finishedwith some shrink-tubing (figure 12).
If you find this approach too muchtrouble, it is of course also possible to use
50 Ω and 75 Ω Teflon co-axial cable. Takecare however, because the velocity factor
for Teflon co-ax is 0.695 rather than the
0.66 for RG58 and RG59. The length of
the two upper co-ax pieces may be
calculated with the PASAN software byentering this value in the ‘Transmission
line’ field; both pieces will be slightly
longer (512 mm and 105 mm). The use of
Teflon cable prevents the inner insulationfrom melting away as a result of theextensive soldering activities.
Now slide the ferrite rings or tubularcores over the 487 mm length of RG58
(use Type 43 cores with a narrow innerdiameter to fit as tightly as possible overthe co-ax cable). Should the inner

Figure 13 - Adding the ferrite rings

Figure 15 - The solder tags

Figure 16 - Connections in the headpiece

diameter of these cores be just a little tootight, there is no problem in removing theouter insulation over the required length
since ferrite cores are not themselves
conductive (figure 13).
Finally, slide a piece of shrink tubing
over the ferrite cores and crimp with a
hot air source (hair dryer) to ensue that arigid assembly is obtained. Complete thejob by soldering the PCB to the balun(figure 14).
Assembly
Slide the assembled co-ax cable and PCB
through the POM headpiece until the
PCB stops on the ridge. Slide the four
upper aluminium rod cross-pieces
sideways into position as shown infigure 15. Take care: the two long pieces
should be positioned opposite each other,as should the short ones. Screw solder
lugs to the M3 holes at the end of eachrod using a spring washer then bend thelugs in such a way that, when they are
twisted by a quarter turn, their ends rest
flat on the PCB. Secure the four rods
from above by tightly screwing the four
M5 bolts (labelled ‘A’) through theheadpiece and into the threaded holes ineach rod: then solder the four lugs to the
PCB (figure 16).
Note: the short length of co-ax drawn inthis figure serves only to illustrate how
the balun co-ax, which runs down themast, is attached to the PCB.

Figure 12 - The join: step by step

14

Figure 14 - Soldering to the PCB

www.geo-web.org.uk

For the time being, slide the end of theJune 2006

co-ax cable through the PVC mast and fit
the headpiece on to it till it just touches
the PCB.
Slide the longer rod through the lower
40 mm hole in the mast and the shorter
length through upper one, taking care not
to damage the co-ax cable running
through the PVC tube. Now twist theheadpiece so that the longer rods(132 mm) are perpendicularly above theshort (278 mm) lower rod. The distance
between the centres of these rods is now
845 mm. The perpendicular distance
between the two short upper rods (127mm) and the long lower rod (288 mm) is
now 885 mm.
Securing the Headpiece
You will need to drill two final holes near
the top of the PVC mast in order tosecure it to the headpiece. Screw the two
M5 bolts near the base of the headpieceagainst the mast and then unscrew themagain. This should leave a slightindentation in the mast. Now remove theheadpiece and drill a hole through themast, a little smaller than 5 mm, exactly
where each M5 bolt left its impression.
Take care not to drill into the co-ax cableor balun. Replace the head on the mastand screw in the M5 bolts so thatapproximately 5 mm protrudes throughthe hole in the mast. Bolts with a thread
length of around 15 mm are quite
suitable for this purpose. The head is now
secure on the tube and cannot move.
Mounting the Aluminium Strips
Mount the four aluminium strips using
M5 bolts and washers. Bolt each short(900 mm) strip between one of the short(127 mm) upper rods and one end of thelower short (278 mm) rod, making aquarter turn anti-clockwise around themast (see top-down view in figure 17).
Each long (940 mm) strip should beconnected similarly between one of thelong (132 mm) upper rods and the long(288 mm) lower rod. All four strips will
bow a little when tightened, andassuming that all measurements arecorrect, they will form an imaginary
cylinder (figure 17). The cylindrical shapeof both large and small loops may bechecked by means of a ruler or a home-

Group for Earth Observation

Materials List
• 2 aluminium strips, 15 mm wide,
900 mm long and 3 mm thick.
Hard or semi-hard• 2 aluminium strips, 15 mm wide,
940 mm long and 3 mm thick.
Hard of semi-hard• 2 x 127 mm lengths of 12 mmaluminium rod• 2 x 132 mm lengths of 12 mmaluminium rod• 1 x 278 mm length of 12 mmaluminium rod• 1 x 288 mm length of 12 mmaluminium rod• 1 piece P.O.M. (Polyoxymethylene)
70 mm diameter and 55 mm long
• 1 piece P.O.M. or Lexane(Polycarbonate) 70 mm round and 3
to 8 mm thick (lid)Match construction• 1 length of RG58 co-axial cable(520 mm)• 1 length of RG59 co-axial cable(150 mm)• 1 length of RG58 co-axial cable length dependent on distance
between antenna and receiver.
Balun construction• 25 pieces, Amidon FB-43-2401(FP-43-2401, www.amidon.de ) or
• 12 pieces, Amidon FB-43-6301(FP-43-6301, www.amidon.de ) or
• 15 pieces, Richcom RT11-050-090(www.conrad.nl ) or
• 17 pieces, Richcom RT09-050-080(www.conrad.nl )Display Electronics also stocks
suitable Ferrite rings and tube cores;
however I have not tested these.
• Shrink tubing to put over the solderedconnection and the solderedassembly of the shield and ferrite ringcores.

made template, by measuring the
distance between the mast and strips
along the full length of the mast. If
everything works well, use eight bolts tofasten the lid to the head. To make theassembly waterproof, a suitable rubber
seal, obtainable from your local hardware
store, may be added. You could also use aring fashioned from a bicycle inner tube.
Also, the use of a (thin) coating of asuitable sealing compound (not silicone)
will keep moisture out. To protect theanchor points of the strips against
corrosion, they may be treated with asuitable preserving compound such as
Tectyl.
Author’s Footnote

Figure 17 - Mounting the aluminium strips

Standard POM tubes with 30 mm inner diameterand 70 mm outer diameter are available atmany hobby shops and shops specialising inplastics; you can also find suppliers on theInternet. Mostly they will sell this material in any
desired length. I buy this material in 1000 mm
lengths. If you have trouble finding a source, I
can send you a 70 x 55 mm piece of POM. It is
not expensive. Indeed, I can provide all theneeded raw materials and send them anywhere
www.geo-web.org.uk

GEO Quarterly No 10

Connecting the rods to the co-ax• 1 piece single-sided printed circuitboard, 40 mm diameter• 4 solder lugs, 3 mm hole.
• 4 bolts, M3 cylinder head, 12 mm• 4 washers with 3 mm hole
• 4 spring washers with 3 mm hole
Securing the four upper rod pieces• 4 bolts, M5 cylinder head, 20 mm• 4 washers, 5 mm hole
• 8 spring washers, 5 mm hole
Mounting strips on the rod pieces• 8 bolts, M5 25 mm long
• 8 washers, M5• 8 spring washers, M5(above and below)
Fixing loops and lower rods to mast
• 1 piece plastic pipe, 32 mm outer
diameter (PVC), about 2 meter length(for mast)• 2 sockets for 32 mm (PVC) pipe
(refer foto).
• 2 bolts, M5 (thread length 15 mm)with washers, to secure upper piece
to mast (refer photos).
• 2 bolts, M4 with washers (thread
length around 25 mm) to secure thetwo lower rod pieces.
• 8 bolts, M3 (stainless steel or Nylon)
with washers to secure lid.
Please noteAll bolts, washers etc. are stainlesssteel material. Galvanised bolts andwashers would result in less galvanic
corrosion, as compared to aluminium;
however the ss - aluminium
combination, covered with e.g. Tectyl
is a usable alternative.
If required, a corrosion protecting
agent, e.g. Tectyl.
http://tectyl.valvolineeurope.com/nl/

Address details for suitable suppliersof the above mentioned materials
may be obtained from the author.
in the world for just the basic cost of thematerials, postage and administration.
Postscript
I have happily spent a lot of my time on thisproject and have tried to present a total picture,
starting from conception to the point ofpublishing complete construction details. I
would like to thank everyone who has assisted
me in making this project a reality, in particular
my wife Adri. During the multitude of ‘garden’
measurements, the required testing equipment
was often parked in the living room waiting for adry spell of weather. I would also like to thankher for the use of her sewing room, which I used
to make dozens of drawings and photos of thevarious components—as well as bringing me
snacks and drinks in the attic when there wasno time to go downstairs.
Also thanks to Chris van Lint for the translationof this article. Without his knowledge of RQHAs,
translation of my article would have been very
difficult.
When planning construction of this antenna, domake sure that you read this article thoroughly
first, and use the correct tools! If any errors havefound their way into this article, please e-mailme at
ruud@farbridges.net
so that I can quickly amend the article.

15

GEO Quarterly No 10Group for Earth Observation

June 2006

Douglas Deans - dsdeans@tiscali.co.uk
Readers who digested Part 1 of this article will now appreciatethat GeoSatSignal 5 (GSS5) is a very comprehensive piece ofsoftware with just about every conceivable post image-processing
option you could think up—and probably a few you had not. I am
now going to look at a number of the more advanced features
which the program has to offer. Perhaps the use of the word‘advanced’ is misleading, as one or two of these functions are very
likely to be used regularly, some of them perhaps on a daily basis.
However, I consider those functions to be best tackled after you
have become familiar with the more basic ones described in detailin GEO Quarterly No 9. In particular, I will specifically look at
the use of remapping, manual and automatic animations (yes,automatic animations are possible with GSS5), the use of RGB
mode and the rather impressive World View.
RemappingThink of remapping as a way of selecting an area to view fromwithin a larger image such as a Meteosat or GOES full disc. The
choice of settings (described later) will dictate the size of the area
to view and, to some extent, how detailed the remapped image
will be. Moreover, there are a number of very useful additionalfeatures which allow the selected area to be viewed with various
forms of correction and overlays.
When a remapped image is formed it will appear under the‘Remapped’ tab in the main GSS5 window. Setting up aremapped image is done on a per-Job basis; select your chosen
Job number then select the ‘Remapping’ tab in <Options Æ Job
setup> (figure 1). As well as allowing you to select specific areasfrom within an image, such as a full-disc HRIT, remapping
provides a range of options for image correction to compensate forsuch things as Earth’s curvature. This is a very powerful anduseful tool and an example is seen in figure 2 where, despitefeaturing a region lying between 50° and 60° north of the equator,
the UK appears undistorted in shape thanks to the orthographic
setting—quite impressive when you consider how far away the
UK is from the sub satellite point.
The settings for remapping are all available under the‘Remapping’ tab (figure 1). The first and most obvious
requirement is to tick ‘Enable remapping’, and indeed, all theother setting options are greyed out until this is done.
‘Remapped image size’ dictates the overall size of the completed
image in pixels. This choice is partly dependant on your monitor
resolution settings and how much you are prepared to tolerate
scrolling. My own 19-inch flat screen monitor has a resolution of1280 x 1024 but of course some of that is given up to the program
taskbars and buttons. I find the setting of 1280 x 960 just about
perfect with only minimal scrolling: the 1024 x 768 setting issmaller than the available space. Of course, if you prefer asmaller image, just pick an appropriate option. A little
experimentation with this will very quickly give you the feel for it
and help you find what best suits your own setup for theparticular images you are making up. The key to where the image
is centred, and how much you see within the overall size selected,
comes in the settings for ‘Meridian’, ‘Parallel’ and ‘Span’. The‘Meridian’ and ‘Parallel’ settings will define the coordinates of thecentre point of the remapped image and are basically longitude
and latitude; ‘Span’ (in degrees) dictates how far from the centre
point your image will extend north, east, south and west.

16

Figure 1 - the ‘Remapping’ tab

Let’s look at an example which positions a centred close-up of the
UK in the image window. The settings described below extracted
the image seen in figure 2 from a Meteosat-8 HRV channel-12
frame, using channel-9 to contribute the colour.
If you include the Channel Islands, the UK lies between
approximately 49°N and 59°N. The centre of this is 54°N and thatis the figure to use as the ‘Parallel’ setting. To include Ireland andsome of the Atlantic (rather than Europe)—as that is often the
more likely source of our weather—I have centred the longitude
on 4°W. By convention west from 0° is negative, so ‘–4’ is enteredas the ‘Meridian’ setting. In order to ensure that the remapped
image does indeed stretch from 49°N to 59°N, centred on 54°N,
we require a total span of 10° (i.e. 5° each side of the centre point).
‘10’ is therefore the setting that goes into the ‘Span’ box, a valuethat also dictates the E-W span.
Finally, decide if you want to add overlays or grids to yourremapped image and whether it requires any form of correction.
Figure 2 uses orthographic projection, which in my opinion isparticularly suitable for a close-up of a country rather far fromthe sub-satellite point. I think you will agree that the result isvery pleasing. Clearly, if you choose a larger span, it will cover amuch larger area within your chosen window size and the detailwill be reduced. However, the way remapping is designed allows
the user infinite control over both the positioning and outcome of
the final image. Do not be afraid to experiment with this; it will
greatly help the learning curve.
There is also an option in the set-up to use overlays, and a large
number are supported by GSS5. Of course it is for the user todownload and save the relevant overlay data. For overlays towork they have to reside in the same folder as the image they areoverlaying. This option allows you to overlay charts, synoptic

www.geo-web.org.uk

June 2006

Group for Earth Observation

GEO Quarterly No 10

Figure 2 - Orthographic Meteosat-8 image of the UK

Figure 3 - RGB mode

Figure 4 - Colours used to highlight snow over Turkey

Figure 5 - A geostationary image composite in WXtrackGL

data, radar and many other useful features, and ensures thatboth the data and the remapped image are correctly aligned andoverlain fully automatically. When an overlay is selected it overrides your usual ‘Meridian’, Parallel’ and ‘Span’ settings andautomatically crops and positions the Meteosat image to matchits own area. This is in fact very handy, as it is then a simple
matter to add an overlay to any remapped image you havepreviously set up: your original parameters are restored as soon
as you decide to stop using the overlay. An example of this isshown in figure 7, where a Bracknell surface pressure chart has
been overlain on a remapped channel-9 image from Meteosat-8. I
think you will agree that this can be used as an excellent learning
tool.
Animations.
One of the great joys of receiving images from geostationary
weather satellites is making and running animation sequences.
This is not just a fascinating exercise and visual experience but agreat educational tool: all the more so when the satellite provides
high resolution digital data with a repeat scan period of fifteen
minutes. GeoSatSignal is able to produce animations, not just ofbasic received images, but of complex images made up using
colour, RGB mode, remapping and many other options. In otherwords, anything you can produce from GSS5 can be animated.
But be warned; complex images may take some time to create,
depending on your particular computer specification.

www.geo-web.org.uk

Figure 6 - the ‘Animation’ tab

17

GEO Quarterly No 10Group for Earth Observation

June 2006

To set up an animation for a specific Job, select it from the <Job>menu then open <Options Æ Job setup> and select the ‘Animation’tab (figure 6). The procedure is very straightforward but one
basic concept needs to be clearly understood first. You start withyour currently loaded image (not necessarily the latest) and thenwork back for the number of hours required for the animation.
GSS5 will look for similar files with the appropriate timestamps
and can work with a variety of folder and file structures.
Let’s examine the setup options shown above. The ‘Take picture
every’ panel refers to the time gap between available images, orat least the gap you may want. For HRIT imagery from
Meteosat-8 that would of course be 15 minutes whereas for the
FSD relays from GOES through EUMETCast, 3 hours would beselected. Of course, if you wish, you could choose a 30 minute gap
or more for the HRIT data, although I cannot think of any goodreason why you would want to do this; but the point is that thesetting should not be less than the frequency of your saved data.
If you want to animate the previous 12 hours from a Meteosat-8
channel (15 minute scan/4 images per hour) then you would set‘Number of pictures’ to 48. ‘Animation speed’ can be set between
1 and 30 frames per second; this is really down to personal taste
and, to some extent, experimentation based on the length of theanimation and other settings. I find a setting of about 8 fps a nicecompromise. ‘Smooth Animation’ uses a system called ‘tweening’(apparently short for in-betweening), where intermediate frames
are generated between images to help smoothing. You could beforgiven for thinking that with 15 minute scans from Meteosat-8
smoothing would be unnecessary but it does work well.
‘Cache animation’ is an option which can speed up the creation ofanimations. When unticked, all frames will be processed andincluded in the animation. With ‘Cache Animation’ ticked theframes will be saved and, if you come back a little later to update(extend) the animation, only the new frames need to be createdand processing time is greatly reduced. However, you have toappreciate that caching will only commence after the number offrames selected has been reached. In other words if you arerunning an animation to show the latest 12 hours for a particular
image then your frame number will be 48 (for Meteosat-8).
Once this animation has reached 48 frames it will start caching.
As each new image is received, it will be added to the animation,
while the oldest frame will be deleted. This means that you will
always be able to view the most recent 12 hours of images. If you
do not run your station overnight, and just run animations on adaily basis, caching will not work. It will just be reaching therequired number of frames when you shutdown for the night! For
the 24/7 enthusiasts this is a great processing and time saving
setting.
To create your animation, once the image you wish to animate ison the screen, simply press the ‘Animate’ button. You will beoffered a filename based on the Job title. You can alter this if you
wish and you will also be warned if there is an existing file namein use and prompted whether you want to overwrite it. Animation
controls are provided at the bottom of the image once theanimation is formed and ready to run.
As I mentioned at the beginning of this article, there is a way toautomate GSS5 animations. This is possible because David
Taylor has provided batch-mode operation with the program,allowing it to be driven by command-line instructions. If you run
such a batch file from a scheduling program such as ‘Scheduled
tasks’ provided with Microsoft Windows, you can have a fully
automated system. Of course, batch-mode can be used just to saveimages at any level in the processing chain, but it is particularly
useful for automating animations. I do not intend to discuss batch
commands as they are very well detailed in the help files. Suffice
to say that the commands control where processing should stop
for a given Job. You may only want to see the thermal image, or
perhaps colour; or you may want to proceed as far as a remapped
image. Again, you can animate at any stage but, if you specify the18

Figure 7 - A Bracknell mean sea level chart overlay

animation as ‘Last’, then the processing will be completed as per
the settings in the Job setup.
A typical batch command example is shown below. To avoid
difficulties and aid explanation, it is split over three lines but it
must be entered as a continuous instruction.
Note: [ ] at the end of Line-1 represents a single ‘space’ character.
“C:\Program Files\David J Taylor\GeoSatSignal\GeoSatSignal.exe”[ ]C:\MSG-1\Images\HRIT\*ch09.png -j4”-anim:
C:\Program Files\David J Taylor\GeoSatSignal\UK_IR_Close.avi” –close

Line-1 simply gives the location of the GSS5 program. Line-2
confirms the use of an HRIT channel-9 image to be processed inaccordance with Job No 4. The final line confirms the location
required for the output file. Notice the ‘close’ instruction at theend which removes the image from the screen.
This complete instruction can be used as the run command in a
Windows scheduled task. If you are running MSG Data Manager
and MSG Animator, then the computer processor is particularly
busy on the hour, quarter past, half hour and quarter to, saving
images and processing animations. One of the real benefits ofrunning scheduled tasks is that you have control over when toschedule. If you are animating images every 15 minutes, thendelay this so that it is processed at times other than the busy ones
mentioned above. The system works well and allows you to
automate some very complicated animations as well as a host ofother things.
RGB ModeThis mode is principally provided to allow the combination ofarbitrary channels from Meteosat-8 and subsequent Meteosat
Second Generation satellites by mapping the channels to either
the red, green or blue component of the output image. Of course
red, green and blue are the three colours of light which can bemixed to produce any other colour, and correspond to the colour
receptors in the human eye. Perhaps in the future other countries
will design and launch geostationary weather satellites withmultiple wavelength channels but for the moment it seems that
Europe is way ahead in this field.
RGB mode is not difficult to set up and can be used very easily.
However the meteorological reasons for using it and the purposes
and benefits of mapping and combining specific channels aremuch more complex. I do not intend to explore this in depth as
there are many sources of excellent information alreadyavailable. However a brief explanation is required along with thesource of other useful reading.
The use of the RGB principle permits specific meteorologicalconditions to be highlighted. Knowing which channels andcombinations aid clarification of particular meteorologicalwww.geo-web.org.uk

June 2006

Group for Earth Observation

conditions is, of course, the skillful part. There are a number of
useful guides available but by far the most comprehensive, and in
my opinion the easiest to follow and understand, is the MSG
Interpretation Guide produced by EUMETSAT. This is a hugeguide on a whole range of interesting topics relating to MSG data,
including the use of RGB, and is broken down into a series ofPowerPoint presentations. There are nearly 50 presentations inthe set and you can download just the ones you want. For more
information and to download please go to :http://oiswww.eumetsat.org/WEBOPS/
msg_interpretation/index.html

RGB mode can be accessed from <Options Æ Job setup> using the‘Processing’ tab; the options become available when ‘RGB’ isselected under ‘False Colour’. Simply select which channel you
wish to be associated with each colour. There is also an option
under ‘RGB Xfer’ which allows you to influence the output image
by choosing a colour transfer table. Indeed, you can make up you
own such table and choose different settings for each of thecolours to influence the final image output. Believe you me: there
are many hours of fun and experimentation to be had here!
RGB mode can also be used in an effort to develop pleasing
colours for both land areas and cloud tops. Figure 3 is an exampleof this, where the land has been coloured but where clouds haveretained their white appearance. The real benefit of the technique
is to accentuate meteorological conditions and an example of thisis shown in figure 4 where the 0.8 µm VIS channel is mapped tored, the 1.6 µm NIR channel to green and the 3.9 µm IR channel(set negative) is mapped to blue. The lilac/pale purple colour, seen
over parts of Turkey, for example, highlights snow cover whereas
clouds are shown in white through to orange for the highest andcoldest. This mode can be fun to experiment with but is also avery useful mode for serious meteorological work.
Another feature which can be used in conjunction with RGB modeis the subtraction of MSG channels, also explored and explainedin the EUMETSAT guide. I understand that David Taylor hopes
to add this option to a future release of GSS.
World View
Because of the global sharing and availability of geostationary
images, by direct dissemination from satellites, through theEuropean EUMETCast service and from the Internet, weather
imagery is readily available for all parts of the globe. The <File ÆOpen world view> option in GSS5 takes advantage of this tocombine thermal data from satellites all round the planet andproduce a composite image. This can also be overlain on acoloured map of the Earth.

Twice a year, during the spring and autumn, the sun will appear to moveimmediately behind the satellite used for DVB transmission. As the suncomes within the beamwidth of the receiving dish, the noise energy fromthe sun at 11 GHz will affect the satellite signal, causing a reduction in thesignal-to-noise ratio and hence a higher bit error rate.
Figure 1 shows the bit-error-rate (BER) due to solar interference when
receiving Hot Bird-6 in Edinburgh. You can see the effect during one day,Thursday, March 2. As the data was sampled at 5 minute intervals the fullstructure of the sudden increase in BER is not really visible. The whole
event takes about 15 minutes when the sun is closest to the satellite as
viewed from the receiver.

GEO Quarterly No 10

A range of data can be used, including that from EUMETCast,
PDUS and even WEFAX files. Setting up World View is verystraightforward and the set-up window is shown on the inside
front cover of this issue.
Without doubt the most important aspect of setting up is toensure that you correctly specify the data location for the fivegeostationary satellites which contribute to the world view.
There are options included to have the combined image overlain
on a coloured map of the world. A setting of 0 has no map and theremaining settings of 1 to 10 dictate the transparency/opacity of
the underlying map. There is an option to save the combined
image for viewing and perhaps further processing in anotherprogram but by far the most impressive option is to load theimage into David’s WXtrackGL program. This is a completely freeprogram which provides a 3D display. The globe can be turned bymeans of a mouse so it is possible to view the entire world cloud
cover just as it would be seen from space. An example of this canbe seen in figure 5 but you have to try this out yourself to fully
appreciate just how good it is.
And finally ...
I hope the two-part article has been of help to those new to theprogram and perhaps a refresher to others. It has certainly
brushed up my knowledge of the software! Of course it is notpossible in an article of this size to cover all aspects of the
program, but I have tried to include those that I consider to be themost popular and useful as well as some others where additional
explanation from a user may be helpful. The help files provided
with the software are very comprehensive and some of the moredifficult concepts such as CLUTS (colour lookup tables) andautomation by batch files are given a very thorough airing. The
help files should be your first port of call when an explanation isneeded or a problem arises.
David Taylor has assured me that we can look forward to future
developments for GeoSatSignal and perhaps some of these will
already be available by the time this article goes to press. Just
another reminder that the program can be downloaded from the‘Satellite Tools’ section on David Taylor’s web site at :http://www.satsignal.net

GSS5 is also available on the GEO Software CD, GS1 along withmany of David’s other programs. Please remember that some ofthe options discussed in both articles are only available with theregistered version……another good reason to register.
All original Meteosat-8 images © EUMETSAT 2006

David Taylor
Figure 2 shows the BER averaged over a 30 minute period, and peaks
due to solar interference can be seen from Sunday February 26 until
Thursday March 2. As you would expect, as the sun moved nearer to thecentre of the antenna beam, the interference worsened and the BER
increased. Note that the 30 minute average is lower than the 5 minute
average so, whilst the absolute numbers are meaningless, the pattern ofthe outage is clear.
For more information about collecting this data on your own PC, pleaserefer to ‘Monitoring EUMETCast’ in GEO Quarterly number 8, page 5.

Figure 1
www.geo-web.org.uk

Figure 2

19

20

NOAA-18 at 12:11 UT on March 19, 2006, captured using the Wraase WRX-137
in conjunction with a Chris van Lint QFH antenna and processed with WXtoImg

June 2006

Group for Earth Observation

GEO Quarterly No 10

Les Hamilton

A few months ago, Hartmut Schaksmeier,one of GEO’s German members, suggested
that readers might be interested to learn
about the Wraase WRX-137 APT weather
satellite receiver that he uses for his APT
imaging. Hartmut introduced me toVolker Wraase, of Wraase ElectronicGmbH, Altenholz, Germany who kindly
loaned a unit for evaluation. Hartmut has
used this receiver for some time, and you
can view some of his images in previous
copies of GEO Quarterly [1].
Background
The Wraase WRX-137 is a professional
APT receiver which is used widely on thecontinent by airports, ships and military
installations. Consequently, immunity
against the strong VHF signals that canbe experienced in such locations has beena major design criterion, though it was notdesigned for UK-specific pager problems.
Receiver Overview
The WRX-137 is a rugged, weatherproof
top-of-the range receiver housed in arobust yet attractive metal case (figure 1).
The front panel is uncluttered andsupports all necessary controls apart fromthe power on/off switch which is located on
the rear of the instrument. The rear panel
carries BNC connectors for both an APTantenna and a (now obsolete) Meteosat
downconverter, plus a phono output foraudio output and an RS-232 serial port
which doubles for computer control andoutput to Prosat for Windows andJVcomm imaging software. The receiver ispowered from a 12-volt plug-top adaptor
which connects into a a standard 3.5 mm
jack socket on the back of the receiver. You
can use either the supplied continental
PSU, via a suitable adaptor, or one of yourown designed for the UK.
This receiver has been designed for use
with Wrasse turnstile antennas which are
fitted with an intrinsic masthead preamplifier as standard, for which 12 V dc ispermanently output from the receiver’s
VHF-ANT connector through the antenna
co-ax and cannot be switched off.
Setting Up
Connect the PSU to the WRX-137, theantenna to the VHF-ANT connector andfit an audio lead between the AF-OUT
jack and your PC soundcard—then switch
on. The WRX-137 announces itself on the
LCD screen then displays the message ‘PC
Control Yes/No’ for 3 seconds. If you allow

Figure 1 - The Wraase WRX-137 APT weather satellite receiver

this message to time-out, PC control isselected automatically. The logic behind
this is to enable you to power-up into PCcontrol mode by default when the receiver
is located in an inaccessible remotelocation. Pressing the Yes button during
this period also selects computer control.
If you wish to disable PC control you mustpress the No button before the message
times out. Users who prefer to continue
using their existing soundcard software
should press the No button to selectmanual control.
Manual Control of the WRX-137
There are three different control modes
that can be called upon
• Auto Scan Mode
• Progressive Scan Mode
• Manual Modeby simply pressing the Mode button
repeatedly.

Auto Scan Mode
The WRX-137 enters this mode by default
once manual operation has been selected.
Just press the Up button to start the unit
scanning through the five APT frequencies. As soon as a satellite signal is detected the receiver locks on to it for the duration of the pass.

soon as you have repeated this for theremaining four frequencies autoscan
commences, but only for the selected
frequencies.

Manual Mode
Once you have opted to run the receiver
manuallly, press the Up button repeatedly
to cycle through the various channels,
which are:
• Meteosat channel-1• Meteosat channel-2• 137.10 MHz• 137.40 MHz• 137.50 MHz• 137.62 MHz• 137.91 MHz
The first two options are now redundantand it remains to be seen whether they
will be retained in new models. The
remainder cover all the current and future
NOAA frequencies as well as retaining
137.40 MHz that might conceivably yet
come into use if another Okean or Sichsatellite materialises.
Although you are unlikely to require thefacility, you can, once you have selectedyour frequency, fine-tune it by firstly
pressing the Down button; subsequently
pressing either the Up (or Down) button

Progressive Scan Mode
Similar to the above, this allows you toselect specific frequencies which will bescanned then confines scanning to thesealone. Press the Mode button to selectProgressive Scan Mode then press the Up
button once to display ‘? 137,10 MHz ?’on the LCD screen. If you wish to scan thisfrequency press Yes, otherwise No. As

www.geo-web.org.uk

Figure 2 - The MX-137 antenna21

GEO Quarterly No 10Group for Earth Observation

June 2006

will add (or subtract) 10 kHz from thebase frequency; keeping a button
depressed will scan continuously in
10 kHz steps. This function is disabled onpressing the Mode button once more.
The Wraase Antennas
Wraase kindly supplied me with one of
their MX-137 ‘Mobile’ turnstile antennas(figure 2). This miniature antenna has
been designed for use aboard ships where
reducing bulk and minimising wind loadin rough seas are important. It consists ofa built-in preamplifier with ~17 dB gain,
to which four stubby flexible elements clipby means of BNC connectors. These are‘internally electrically extended’; Wraaseclaim that low-loss direct coupling to thehighly selective preamplifier ensures that
the MX-137 is scarcely inferior to theirfull-sized KX-137 turnstile. All electricalcomponents are protected from corrosion
in a sturdy casing made from tough UVresistant plastic. The downlead connection
is made using a high-quality, waterproof
N-type socket. There are no reflector
elements.

Antennas without a Preamplifier
If you wish to make use of an existing rooftop turnstile or QFH antenna (but whichlacks a masthead preamp), you may havea problem. It will almost certainly short at
the receiver input and make it ‘howl’alarmingly.
In this event, disconnect immediately
to avoid possible damage to the unit.
If you wish to use such an antenna ofyour own you must insert a blocking
capacitor into the antenna feed. I
used a 22 nF one, which proved very
effective.
Capture Software
The WRX-137 receiver is an exceptionallysophisticated unit and contains a built-in
microprocessor which provides thenecessary interfacing hardware to enable
the receiver to control both Prosat for
Windows and JVcomm through its RS232
serial port (without the need of a
dedicated external interface unit). The
receiver can also interface with WXtoImg
by the same method.
The WRX-137 can be used manually withany of the current soundcard recording
programs. All that is required is an audio
connection between its AF-OUT socket
and a PC soundcard. I have successfully
imaged using WXtoImg, WXsat and
APTDecoder in this manner. With these
programs now being so widely used, thebuilt-in APT decoder is almost obsolete
these days and could well be left out in a
future redesign—which could lead to amore attractive price.
Results using the MX-137 Turnstile
For my initial tests the MX-137 ‘Mobile’
antenna was lashed to a washing pole atthe foot of the garden in a situation

22

Figure 3 - A NOAA-18 channel-2 APT image acquired at 13:06 UT on February 22, 2006

providing good horizons in mostdirections. As would be anticipated for an
expensive, top-of-the-range receiver likethe WRX-137, results were excellent. Eventransmissions from NOAA-18 when using
its original frequency of 137.91 MHz
showed no sign of pager interference.
Thus encouraged, I next mounted the
MX-137 turnstile indoors under the eavesof my house. Results were truly dreadful,with pager banding over the entire lengthof each pass—far worse then I experience
with my own loft-mounted QFH. I assume
that this simply reflects the fact that theroof of the house attenuates the satellite
APT signals much more than the powerful
pager signals, and that the result is simply
compounded by the mast-head preamplifier.
However, there is no doubt that, when
mounted outdoors in a good situation, theMX-137 ‘Mobile’ mini-turnstile is verymuch equal to its task and is the ideal
companion to the WRX-137 receiver.
Though I have not had the opportunity totest it, I am confident that the full-sized
KX-137 turnstile (with reflectors and preamp) would be the prefect antenna toaccompany the WRX-137 for the homeuser.
Using Antennas without a Preamp
I already had both a turnstile and a QFH
antenna permanently mounted for my
APT activities and my next move was totest these with the WRX-137. As I had nowish to climb on to my roof in the middle

www.geo-web.org.uk

of winter to mount the MX-137 there, I
decided to press my own antennas into
service instead.
Neither of my antennas makes use of apreamplifier so the first hurdle was toinsert a blocking capacitor into thedownlead. I fitted the ends of a shortlength of co-ax with male and female BNC
connectors then cut it in half. After
stripping back the braid, the centre
conductor at each end was shortened byabout a centimetre. A 22 nF capacitor wasthen soldered across the break andwrapped in a few turns of PVC tape.
Finally, the braid was reconnected andwrapped in a sleeve of aluminium foil thenbound with more PVC tape. The entire
unit was now used as a link between the
WRX-137 and the antenna downlead.
Images continued to impress, and ifanything were even better than thoseusing the MX-137, where the extremitiesof passes tended to exhibit light speckling.
Figure 3 is typical and, for my station in
Aberdeen at 57°N, 2°W, exhibits finedetail well into northern Africa
Summary
The Wraase WRX-137 APT receiver is a
top-of-the range unit that can be
guaranteed to produce the very best
possible APT images. For the enthusiast
for whom cost is not a consideration it ishighly recommended for use, whether with
one of the company’s dedicated antennas
or one of your own. Pricing for Wraaseconcluded on page 26 ...

June 2006

Group for Earth Observation

GEO Quarterly No 10

Copy Deadline
for GEO Quarterly No 11

Saturday, July 29, 2006

If the many comments GEO has received
since its inauguration are to be believed, theorganisation has been an unqualified success.
This of course stems in no small part to thededication and enthusiasm of the current
Management Team; but success brings
increased demands on those working on
GEO’s behalf and can be time-consuming andrestrictive for the individuals concerned. As in
all organisations, there is inevitably a periodic
turnover within the management structure, and
GEO is no different.
GEO has now reached the stage where two of
its stalwarts, Nigel Evans (Membership
Secretary) and Les Hamilton (Editor) arelooking, in the medium term, to retire fromtheir posts. Both have chosen to relinquish
office at the end of 2006, having helped to
guide GEO through the first three years of its
existence. Consequently, GEO is seeking new
blood to fill these vacancies on its
Management Team, that will arise at the endof this year.

MEMBERSHIP SECRETARY
Nigel Evans has occupied this post since GEO
was founded in late 2003 and, ably assisted by
his wife Michele, has seen our membership risefrom zero up to its current level of over 500.
Unlike many of GEO’s management team, Nigel
has a full-time job and family commitments, andnow wishes to be able to devote more time tothese.
By identifying a successor in good time wehope to be able to ensure a smooth transition of
responsibilities, so that the new incumbent will
be able to take over completely transparently.

What does the Position Entail?
GEO membership is renewable on a rollingbasis so renewals are spread over 12 months.
The post would require about 3 to 4 hours aweek at peak times (which is usually just after
an issue of GEO Quarterly is published), but
generally less.
The new Membership Secretary should have:• a good working knowledge of a data base
(MS Access is currently used)• Production of mailing labels for each issue
of GEO Quarterly• access to a PC with a Broadband Internet
connection (principally for banking)• ready access to a Post Office• an understanding spouseMembership Secretary involves looking after
GEO’s most valuable asset—its membership.
This is a highly rewarding experience which
involves making regular contact with members
and contributing to an organisation which has
achieved international recognition and respectin just three short years.
As with all GEO posts, Membership Secretary is
an honorary position; you are not paid for yourtime. Anyone interested and willing to undertakethe role of GEO's Membership Secretary canobtain further information from
Nigel Evans at: members@geo-web.org.uk orFrancis Bell at: francis@geo-web.org.uk

GEO EDITORLes Hamilton , though nominally the GEO
editor, has in fact been wearing three distinct
hats. Not only has he edited all the content for
ten GEO Quarterlies to date, he has also been
responsible for researching and preparing, on
average, three articles per issue (over 25% of
the entire Quarterly content), as well creating
the actual page make-up to send to the Printing
House. Not surprisingly, Les finds this aconsiderable drain on his time, and is looking tostand down on the completion of three years’service. Ideally, the package of tasks he iscurrently handling could be better spreadamongst a team which could include an Editor,a Make-up Editor and several Feature Writers.

How is the Quarterly Produced
Make-up is the crucial stage, where GEO
Quarterly pages are actually created frommembers’ contributions. This process is handledusing Quark Express, a frame-based software
package that is standard with most printing
houses. If you have used Microsoft ‘Word’ or‘Publisher’ with text and images, it should nottake long to master Quark Express. Lesassures us that he mastered this software(hitherto unseen) and produced his firstmagazine within the space of eight weeks.
Additionally, a good image processing package
such as Photoshop or Paintshop Pro is requiredfor cropping and resizing images.
Editing skills are based on common-sense andthe use of a spell-checker. Basically thisinvolves ‘streamlining’ submissions, checking
grammar, cutting out waffle and irrelevantmaterial, and liaising with the author as to thefinally agreed copy.
Les assures us that he is prepared to work withhis successor over an extended period to ease
the transition and to ensure that the quality of
the Quarterly will be maintained.

FEATURE WRITERS
Much of the burden of writing regularly for GEO
Quarterly has so far fallen on Les Hamilton,
Francis Bell, Peter Wakelin, John Tellick andseveral members of Werkgroep Kunstmanen.
Over the years we have enjoyed a number of
one-off submissions from readers; but sadly,less than 25% of the features you have read in
GEO Quarterly were penned by its vast majorityof UK members
GEO requires a panel of members who areprepared to research material and write it up in
the form of feature articles for the Quarterly
from time to time. If you feel you could do so forevery issue this would be superb—but even if
you feel able to research a topic and produce
an article just once or twice a year, we would
love to hear from you.
Any member who feels they can help GEO inthis arena, or would like further information, iswelcome to contact Les Hamilton at:editor@geo-web.org.uk

or Francis Bell at:
francis@geo-web.org.uk

www.geo-web.org.uk

The Editor is always on the lookout for articles
and images for inclusion in GEO Quarterly.
These can relate to any aspect of Earth
Imaging, especially:• Technical articles concerning relevant
hardware / software• Construction projects• Weather satellite images• Reports on weather phenomena• Descriptions of readers’ satellite imaging
stations• Activities from overseas readers• Letters to the Editor• Problems and Queries for our experts toanswerContributions should of course be original and,
where possible, should be submitted to theeditor in electronic format (floppy disc, e-mailattachment, CD). But of course we will also
accept handwritten or typed copy should theneed arise.
Please note, however, that major articles
which contain large numbers of satellite
images, photographs or other illustrations
should be submitted as early as possible sothat they can be prepared and made up into
pages in time for publication.

Images and Diagrams
Images can be accepted in any of the major
bitmap formats, e.g. JPG, BMP, GIF, TIFF etc.
Images in both monochrome and colour are
welcomed for inclusion. Line drawings anddiagrams are preferred in Windows metafile
and postscript formats. We can also scanoriginal photographs, negatives and slides.
Gridding, Overlays and Captions
Please note that readers’ satellite images
should be provided without added gridlines,
country outlines or captions unless these areconsidered essential to illustrate an article.
If your article submission contains embedded
images and diagrams, please note that it isessential that you also submit the individual
images in one of the formats describedabove: these are essential for page make-up
purposes.
Submission of Copy
All materials for publication should be sent to
the Editor, Les Hamilton, 8 Deeside Place,
Aberdeen, AB15 7PW, Scotland.
Materials may also be sent as attachments tothe following e-mail address:
editor@geo-web.org.uk

Larger attachments (1 Mb to 10 Mb) are best
sent to:editor.geo@googlemail.com

And finally . . . if you do have material readyfor the next GEO Quarterly, please submit it
as soon as it is ready—do not wait till thedeadline before sending it in. This simply
creates an editorial log-jam.

i

GEO Quarterly No 10Group for Earth Observation

June 2006

GEO PIC 1.0 for the RX2
Programmed with the
new channel frequencies
required for NOAA-18.
UK
Continental Europe
Rest of World

-

£7.00
£7.80
£8.40

GEO/Dartcom EPROM v 1.3
R2FX APT Weather Satellite
ReceiverThis diminutive German-built APT receiveris packed with features and is the ideal
receiver for the newcomer to the hobby.
May be affected by pagers on the upper
NOAA frequency of 137.91 MHz.
UK member’s price
UK non-member’s price-£135.00£149.00

TechniSat SkyStar 2 USB BoxThis external 'free-to-air' DVB satellite TV
and data receiver plugs into a USB port onyour computer and comes complete withpower supply, USB cable and a CD-ROMof driver software.
UK£94.50Continental Europe- £119.50

Telestar 80 cm dish and Universal
0.6 dB LNB(or similar model)
A quality German made aluminium dishand LNB with an AZ/EL mount to fit onto avertical pole. (Wall or patio mounts areavailable from local satellite TV dealers)
UK members price£49.00
UK non-members price£56.00R2FX Accessory Pack
This contains everything required to
implement a complete APT receiving
system when used with the R2FX receiver.
It comprises:• 137 MHz Turnstile Antenna• UK plug-in power supply• PC audio lead + PC Serial ‘computer
control’ lead
• Aerial lead (20 m with fitted connector)• CD of PC shareware starter software• Instructions
We do not normally ship outside the UK as
this receiver should be available elsewheremore cheaply from the manufacturer. But
contact the GEO Shop if you wish a quote.
UK member’s price£59.00
UK non-member’s price£69.00This new EPROM forthe Dartcom APT
receiver is available
exclusively from GEO.

Ordering and Shipping

UK
Continental Europe
Rest of World-£10.00£10.75£11.25

Martelec MSR40 EPROM
UK
Continental Europe
Rest of World-£10.00£10.75£11.25

If you are not a GEO Member?

We will ship by post, so please allow a
few days for items to arrive in Europe
and perhaps a few weeks for the Rest of
the World.

TechniSat SkyStar 2 PCI Card
This 'free-to-air' DVB satellite TV and data
receivercard
recommended
by
EUMETSAT must be installed inside yourcomputer. It comes with comprehensive
installation instructions and a CD-ROM ofdriver software (if you do not feel confident
about installing cards inside yourcomputer, we recommend the USB version
above)UK members price- £53.50
UK non-members price- £59.50

Orders should be sent to:
GEO Shop,

GEO can provide most of the items
advertised (with the exception of GEO
Quarterly back-issues and CDs) to both
members and non members. However,the latter cannot benefit from thediscounted
pricesavailable
tomembers.

44 Disraeli Road
Christchurch BH23 3NB
Dorset, England
If you are paying by credit card, you can
FAX us your order to:+44 (0) 1202 893 323

Why not join GEO and takeadvantage of the discounted
prices we can offer members.
Subscription Rates (12 months/4 issuesof GEO Quarterly) are just £18 (UK),£21 (EU) and £24 (rest of world).

GEO Members’ PRICE LIST
Members Prices
UK
EU RoW

Non Members
UK
EU RoW

135.00- 147.00
59.00
239.00179.00349.00259.00 279.00
37.50
7.00 7.80 8.40
10.00 10.75 11.25
10.00 10.75 11.25

149.00- 161.00
69.00
259.00189.00369.00279.99 299.99
42.50
7.00 7.80 8.40
10.00 10.75 11.25
10.00 10.75 11.25

53.50 55.00
94.50 113.50
49.00
11.00 12.50
21.50 24.50

59.50 61.00
119.50 123.50
56.00
17.50 19.00
24.50 27.50

APT Equipment

TechniSat SatFinder
Antenna Alignment Meter
Vierling ‘Weatherman’ APT Weather
Satellite ReceiverThis professional receiver is German-built
and designed by Vierling, to satisfy themost dedicated enthusiast. It features an
LCD display and has proved to haveexcellent resistance to pager interference
at all frequencies, including 137.91 MHz.
UK member’s price
UK non-member’s price-This sensitive meter is a great help insetting up and aligning the dish for
maximum signal. The meter comes with full
instructions.
UK members price- £21.50
UK non-member’s price- £24.50

EUMETCast Equipment
TechniSat SkyStar 2 PCI Card
Technisat Skystar USB box
Telestar 80 cm dish with LNB
Telestar Ku band universal LNB
Technisat Satfinder alignment meter£239.00£259.00

Vierling ‘Weatherman’ QFH AntennaThis kit can be assembled into a rugged
all-metal QFH antenna within 30 minutes.
UK member’s price- £179.00
UK non-member’s price- £189.00

Complete ‘Weatherman’ System
This comprises the APT Receiver, QFH
Antenna plus Windows-based computer
control software.
UK members price- £349.00
UK non-members price- £369.00

ii

R2FX APT Receiver (no PSU)
R2FX Accessory Pack
Vierling Weatherman APT Receiver
Vierling QFH Antenna
Vierling Weatherman Complete Kit
Dartcom high quality QFH antenna
Turnstile APT antenna
GEO- PIC 1.0
GEO/Dartcom EPROM v 1.3
Martelec MSR40 EPROM--

Miscellaneous
Telestar Universal Ku-band 0.6 dB
Universal LNB(or similar model)
Digital satellite TV Universal LNB for use
with the SkyStar receivers above or any
DVB satellite TV receiver.
UK members price£11.00Continental Europe£17.50GEO Quarterly Back Issues
3.50 4.20 5.10
(subject to availability)
GEO 2004 CD (PDF back issues)
8.00 8.80 9.30
GEO 2005 CD (PDF back issues)
8.00 8.80 9.30
GEO Membership (4 x GEO Quarterly) 18.00 21.00 24.00

n/a

n/a

n/a

n/a
n/a
n/a
n/a
n/a
n/a
18.00 21.00 24.00

All prices are in £ sterling and include postage and packaging

www.geo-web.org.uk

June 2006

Group for Earth Observation

GEO Quarterly No 10

NOAA Satellite Predictions(Based on latitude 52°N, longitude 2°W, times in UT/GMT)NOAA 12137.50 MHz

NOAA 15137.50 MHz

NOAA 17137.62 MHz

NOAA 18
137.10 MHz

Jun 01 04:38 06:17 16:04 17:45
Jun 02 05:53 07:33 15:39 17:19
Jun 03 05:28 07:08 15:15 16:54
Jun 04 05:04 06:44 14:51 16:29
Jun 05 04:39 06:19 16:05 17:46
Jun 06 05:54 07:34 15:41 17:21
Jun 07 05:29 07:10 15:16 16:56
Jun 08 05:05 06:45 14:52 16:31
Jun 09 04:40 06:20 16:06 17:47
Jun 10 05:55 07:36 15:42 17:22
Jun 11 05:31 07:11 15:18 16:57
Jun 12 05:06 06:46 14:54 16:32
Jun 13 04:42 06:21 16:07 17:49
Jun 14 05:57 07:37 15:43 17:23
Jun 15 05:32 07:12 15:19 16:58
Jun 16 05:07 06:47 14:55 16:33
Jun 17 04:43 06:23 16:09 17:50
Jun 18 04:18 05:58 15:44 17:25
Jun 19 05:33 07:13 15:20 16:59
Jun 20 05:09 06:49 14:56 16:35
Jun 21 04:44 06:24 16:10 17:51
Jun 22 04:20 05:59 15:46 17:26
Jun 23 05:34 07:15 15:21 17:01
Jun 24 05:10 06:50 14:57 16:36
Jun 25 04:45 06:25 16:11 17:53
Jun 26 04:21 06:00 15:47 17:27
Jun 27 05:36 07:16 15:23 17:02
Jun 28 05:11 06:51 14:59 16:37
Jun 29 04:47 06:26 16:13 17:54
Jun 30 04:22 06:02 15:48 17:28

05:47 07:27 15:35 17:14
05:23 07:03 16:50 18:31
05:00 06:40 16:26 18:07
06:16 07:56 16:03 17:43
05:52 07:32 15:40 17:19
05:28 07:08 15:17 16:55
05:05 06:44 16:31 18:12
06:21 08:01 16:08 17:48
05:57 07:37 15:44 17:23
05:33 07:13 15:21 17:00
05:10 06:49 16:36 18:17
06:26 08:06 16:13 17:53
06:02 07:42 15:49 17:28
05:38 07:18 15:26 17:05
05:14 06:54 16:41 18:22
06:30 08:11 16:17 17:58
06:07 07:47 15:54 17:33
05:43 07:23 15:31 17:09
05:19 06:59 16:46 18:27
04:56 06:35 16:22 18:03
06:12 07:52 15:59 17:38
05:48 07:28 15:36 17:14
05:24 07:04 16:51 18:32
05:01 06:40 16:27 18:08
06:17 07:57 16:04 17:43
05:53 07:33 15:40 17:19
05:29 07:09 15:17 16:55
05:05 06:45 16:32 18:13
06:21 08:02 16:08 17:48
05:58 07:38 15:45 17:24

10:48 12:28 20:35 22:15 01:26 03:07 11:20 12:59
10:25 12:05 20:13 21:51 01:16 02:57 12:49 14:31
10:02 11:42 21:28 23:10 01:06 02:46 12:38 14:20
09:39 11:19 21:06 22:46 02:36 04:17 12:28 14:10
10:56 12:36 20:43 22:23 02:26 04:07 12:18 13:59
10:33 12:13 20:21 22:00 02:15 03:57 12:08 13:49
10:10 11:50 19:58 21:37 02:05 03:46 11:58 13:38
09:47 11:27 21:14 22:55 01:55 03:36 11:48 13:28
11:04 12:44 20:51 22:31 01:45 03:26 11:38 13:18
10:41 12:21 20:28 22:08 01:35 03:15 11:28 13:07
10:18 11:58 20:06 21:45 01:24 03:05 11:18 12:57
09:55 11:35 21:22 23:03 01:14 02:55 12:47 14:29
09:32 11:12 20:59 22:39 01:04 02:45 12:37 14:18
10:49 12:29 20:36 22:16 02:34 04:16 12:27 14:08
10:26 12:06 20:14 21:53 02:24 04:05 12:16 13:57
10:03 11:43 21:30 23:11 02:14 03:55 12:06 13:47
09:40 11:20 21:07 22:48 02:03 03:45 11:56 13:37
10:57 12:37 20:44 22:24 01:53 03:34 11:46 13:26
10:34 12:14 20:22 22:01 01:43 03:24 11:36 13:16
10:11 11:51 20:00 21:38 01:33 03:14 11:26 13:06
09:48 11:28 21:15 22:56 01:23 03:03 12:55 14:38
11:05 12:45 20:52 22:32 01:12 02:53 12:45 14:27
10:42 12:22 20:30 22:09 01:02 02:43 12:35 14:17
10:19 11:59 20:07 21:46 02:32 04:14 12:25 14:06
09:56 11:36 21:23 23:04 02:22 04:03 12:15 13:56
09:33 11:13 21:00 22:41 02:12 03:53 12:05 13:45
10:50 12:30 20:38 22:17 02:02 03:43 11:55 13:35
10:27 12:07 20:15 21:54 01:51 03:32 11:44 13:24
10:04 11:44 21:31 23:13 01:41 03:22 11:35 13:14
09:41 11:21 21:08 22:49 01:31 03:12 11:25 13:04

Jul 01 05:37 07:17 15:24 17:03
Jul 02 05:12 06:52 15:00 16:38
Jul 03 04:48 06:28 16:14 17:55
Jul 04 04:23 06:03 15:49 17:30
Jul 05 05:38 07:18 15:25 17:05
Jul 06 05:14 06:54 15:01 16:40
Jul 07 04:49 06:29 16:15 17:57
Jul 08 04:25 06:04 15:51 17:31
Jul 09 05:40 07:20 15:26 17:06
Jul 10 05:15 06:55 15:02 16:41
Jul 11 04:50 06:30 16:16 17:58
Jul 12 04:26 06:05 15:52 17:32
Jul 13 05:41 07:21 15:28 17:07
Jul 14 05:16 06:56 15:04 16:42
Jul 15 04:52 06:31 14:40 16:18
Jul 16 04:27 06:07 15:53 17:34
Jul 17 05:42 07:22 15:29 17:08
Jul 18 05:17 06:58 15:05 16:44
Jul 19 04:53 06:33 14:41 16:19
Jul 20 04:28 06:08 15:54 17:35
Jul 21 05:43 07:24 15:30 17:10
Jul 22 05:19 06:59 15:06 16:45
Jul 23 04:54 06:34 14:42 16:20
Jul 24 04:30 06:09 15:56 17:36
Jul 25 05:45 07:25 15:31 17:11
Jul 26 05:20 07:00 15:07 16:46
Jul 27 04:55 06:35 14:43 16:21
Jul 28 04:31 06:11 15:57 17:38
Jul 29 05:46 07:26 15:33 17:12
Jul 30 05:21 07:01 15:08 16:47
Jul 31 04:57 06:37 14:45 16:23

05:34 07:14 15:22 17:00
05:10 06:50 16:37 18:18
06:26 08:07 16:13 17:53
06:03 07:43 15:50 17:29
05:39 07:19 15:27 17:05
05:15 06:55 16:42 18:23
04:52 06:31 16:18 17:58
06:07 07:48 15:55 17:34
05:44 07:24 15:32 17:10
05:20 07:00 16:46 18:28
04:57 06:36 16:23 18:03
06:12 07:53 15:59 17:39
05:49 07:29 15:36 17:15
05:25 07:05 16:51 18:33
05:01 06:41 16:28 18:08
06:17 07:58 16:04 17:44
05:54 07:34 15:41 17:20
05:30 07:10 15:18 16:56
05:06 06:46 16:33 18:13
06:22 08:03 16:09 17:49
05:58 07:39 15:46 17:25
05:35 07:15 15:23 17:01
05:11 06:51 16:37 18:18
06:27 08:07 16:14 17:54
06:03 07:44 15:51 17:30
05:40 07:20 15:27 17:06
05:16 06:56 16:42 18:24
04:52 06:32 16:19 17:59
06:08 07:48 15:55 17:35
05:44 07:25 15:32 17:11
05:21 07:01 16:47 18:29

10:58 12:38 20:45 22:25 01:21 03:02 12:54 14:36
10:35 12:15 20:23 22:02 01:11 02:51 12:43 14:25
10:12 11:52 20:01 21:39 01:00 02:41 12:33 14:15
09:49 11:29 21:16 22:57 02:31 04:12 12:23 14:04
11:06 12:46 20:53 22:33 02:20 04:02 12:13 13:54
10:43 12:23 20:31 22:10 02:10 03:51 12:03 13:43
10:20 12:00 20:08 21:47 02:00 03:41 11:53 13:33
09:57 11:37 21:24 23:05 01:50 03:31 11:43 13:23
09:34 11:14 21:01 22:42 01:39 03:20 11:33 13:12
10:51 12:31 20:39 22:18 01:29 03:10 11:23 13:02
10:28 12:08 20:16 21:55 01:19 03:00 12:52 14:34
10:05 11:45 19:54 21:32 01:09 02:49 12:41 14:24
09:42 11:22 21:09 22:50 00:59 02:39 12:31 14:13
10:59 12:40 20:47 22:26 02:29 04:10 12:21 14:02
10:36 12:16 20:24 22:03 02:19 04:00 12:11 13:52
10:13 11:53 20:02 21:40 02:08 03:49 12:01 13:41
09:50 11:30 21:17 22:58 01:58 03:39 11:51 13:31
11:07 12:48 20:54 22:35 01:48 03:29 11:41 13:21
10:44 12:24 20:32 22:11 01:38 03:18 11:31 13:10
10:21 12:01 20:09 21:48 01:27 03:08 11:21 13:00
09:58 11:38 21:25 23:06 01:17 02:58 12:50 14:32
09:36 11:15 21:02 22:43 01:07 02:48 12:40 14:22
10:52 12:33 20:40 22:19 00:57 02:37 12:29 14:11
10:29 12:09 20:17 21:56 02:27 04:08 12:19 14:01
10:06 11:46 19:55 21:33 02:17 03:58 12:09 13:50
09:44 11:23 21:10 22:51 02:06 03:48 11:59 13:40
11:00 12:41 20:48 22:27 01:56 03:37 11:49 13:29
10:37 12:17 20:25 22:04 01:46 03:27 11:39 13:19
10:14 11:54 20:03 21:41 01:36 03:17 11:29 13:09
09:51 11:31 21:18 22:59 01:25 03:06 11:19 12:58
11:08 12:49 20:55 22:36 01:15 02:56 12:48 14:30

NOAA 12137.50 MHz

NOAA 15137.50 MHz

NOAA 17137.62 MHz

NOAA 18
137.10 MHz

Aug 01 04:32 06:12 15:58 17:39
Aug 02 05:47 07:27 15:34 17:14
Aug 03 05:23 07:03 15:10 16:49
Aug 04 04:58 06:38 14:46 16:24
Aug 05 04:34 06:13 15:59 17:40
Aug 06 05:48 07:29 15:35 17:15
Aug 07 05:24 07:04 15:11 16:50
Aug 08 04:59 06:39 14:47 16:25
Aug 09 04:35 06:14 16:01 17:41
Aug 10 05:50 07:30 15:36 17:16
Aug 11 05:25 07:05 15:12 16:51
Aug 12 05:01 06:40 14:48 16:26
Aug 13 04:36 06:16 16:02 17:43
Aug 14 05:51 07:31 15:38 17:17
Aug 15 05:26 07:06 15:13 16:52
Aug 16 05:02 06:42 14:49 16:28
Aug 17 04:37 06:17 16:03 17:44
Aug 18 05:52 07:33 15:39 17:19
Aug 19 05:28 07:08 15:15 16:54
Aug 20 05:03 06:43 14:51 16:29
Aug 21 04:39 06:18 16:04 17:45
Aug 22 05:54 07:34 15:40 17:20
Aug 23 05:29 07:09 15:16 16:55
Aug 24 05:04 06:44 14:52 16:30
Aug 25 04:40 06:20 16:06 17:47
Aug 26 05:55 07:35 15:41 17:21
Aug 27 05:30 07:10 15:17 16:56
Aug 28 05:06 06:46 14:53 16:32
Aug 29 04:41 06:21 16:07 17:48
Aug 30 05:56 07:36 15:43 17:23
Aug 31 05:32 07:12 15:18 16:58

04:57 06:37 16:24 18:04 10:45 12:26 20:33 22:12
06:13 07:53 16:00 17:40 10:22 12:02 20:10 21:49
05:49 07:29 15:37 17:16 09:59 11:39 21:26 23:08
05:26 07:06 15:14 16:52 09:37 11:16 21:03 22:44
05:02 06:42 16:28 18:09 10:53 12:34 20:41 22:20
06:18 07:58 16:05 17:45 10:30 12:10 20:18 21:57
05:54 07:34 15:42 17:21 10:07 11:47 19:56 21:34
05:31 07:11 15:19 16:57 09:45 11:24 21:11 22:52
05:07 06:47 16:33 18:14 11:01 12:42 20:49 22:28
06:23 08:03 16:10 17:50 10:38 12:18 20:26 22:05
05:59 07:39 15:46 17:26 10:15 11:55 20:04 21:42
05:35 07:15 15:23 17:02 09:52 11:32 21:19 23:00
05:12 06:52 16:38 18:19 11:09 12:50 20:56 22:37
06:28 08:08 16:15 17:55 10:46 12:27 20:34 22:13
06:04 07:44 15:51 17:31 10:23 12:03 20:11 21:50
05:40 07:20 15:28 17:07 10:00 11:40 21:27 23:09
05:17 06:57 16:43 18:24 09:38 11:17 21:04 22:45
04:53 06:33 16:19 18:00 10:54 12:35 20:42 22:21
06:09 07:49 15:56 17:36 10:31 12:11 20:19 21:58
05:45 07:25 15:33 17:12 10:08 11:48 19:57 21:35
05:21 07:01 16:48 18:29 09:46 11:25 21:12 22:53
04:58 06:38 16:24 18:05 11:02 12:43 20:49 22:29
06:14 07:54 16:01 17:41 10:39 12:19 20:27 22:06
05:50 07:30 15:38 17:16 10:16 11:56 20:05 21:43
05:26 07:06 15:15 16:53 09:53 11:33 21:20 23:01
05:03 06:42 16:29 18:10 11:10 12:51 20:57 22:38
06:19 07:59 16:06 17:45 10:47 12:28 20:35 22:14
05:55 07:35 15:42 17:21 10:24 12:04 20:12 21:51
05:31 07:11 15:19 16:58 10:01 11:41 21:28 23:10
05:08 06:47 16:34 18:15 09:39 11:18 21:05 22:46
06:24 08:04 16:10 17:50 10:55 12:36 20:43 22:22

01:05 02:46 12:38 14:20
02:35 04:17 12:28 14:09
02:25 04:06 12:17 13:59
02:15 03:56 12:07 13:48
02:04 03:46 11:57 13:38
01:54 03:35 11:47 13:27
01:44 03:25 11:37 13:17
01:34 03:15 11:27 13:07
01:23 03:04 11:17 12:56
01:13 02:54 12:46 14:28
01:03 02:44 12:36 14:18
02:33 04:15 12:26 14:07
02:23 04:04 12:16 13:57
02:13 03:54 12:05 13:46
02:03 03:44 11:55 13:36
01:52 03:33 11:45 13:25
01:42 03:23 11:35 13:15
01:32 03:13 11:25 13:05
01:22 03:02 12:54 14:37
01:11 02:52 12:44 14:26
01:01 02:42 12:34 14:16
02:31 04:13 12:24 14:05
02:21 04:02 12:14 13:55
02:11 03:52 12:04 13:44
02:01 03:42 11:53 13:34
01:50 03:31 11:43 13:23
01:40 03:21 11:33 13:13
01:30 03:11 11:23 13:03
01:20 03:00 12:52 14:35
01:09 02:50 12:42 14:24
00:59 02:40 12:32 14:14

Sep 01 05:07 06:47 14:54 16:33
Sep 02 04:42 06:22 16:08 17:49
Sep 03 05:57 07:38 15:44 17:24
Sep 04 05:33 07:13 15:20 16:59
Sep 05 05:08 06:48 14:56 16:34
Sep 06 04:44 06:23 16:10 17:51
Sep 07 05:59 07:39 15:45 17:25
Sep 08 05:34 07:14 15:21 17:00
Sep 09 05:10 06:49 14:57 16:35
Sep 10 04:45 06:25 16:11 17:52
Sep 11 06:00 07:40 15:46 17:27
Sep 12 05:35 07:16 15:22 17:02
Sep 13 05:11 06:51 14:58 16:37
Sep 14 04:46 06:26 16:12 17:53
Sep 15 04:22 06:01 15:48 17:28
Sep 16 05:37 07:17 15:23 17:03
Sep 17 05:12 06:52 14:59 16:38
Sep 18 04:48 06:27 16:13 17:55
Sep 19 04:23 06:03 15:49 17:29
Sep 20 05:38 07:18 15:25 17:04
Sep 21 05:13 06:53 15:01 16:39
Sep 22 04:49 06:29 16:15 17:56
Sep 23 04:24 06:04 15:50 17:31
Sep 24 05:39 07:19 15:26 17:05
Sep 25 05:15 06:55 15:02 16:41
Sep 26 04:50 06:30 16:16 17:57
Sep 27 04:26 06:05 15:51 17:32
Sep 28 05:41 07:21 15:27 17:07
Sep 29 05:16 06:56 15:03 16:42
Sep 30 04:51 06:31 16:17 17:59

06:00 07:40 15:47 17:26 10:32 12:12 20:20 21:59
05:36 07:16 15:24 17:02 10:09 11:49 19:58 21:36
05:12 06:52 16:39 18:20 09:46 11:26 21:13 22:54
04:49 06:28 16:15 17:55 11:03 12:44 20:50 22:30
06:05 07:45 15:52 17:31 10:40 12:20 20:28 22:07
05:41 07:21 15:29 17:07 10:17 11:57 20:05 21:44
05:17 06:57 16:44 18:25 09:54 11:34 21:21 23:02
04:54 06:33 16:20 18:00 09:32 11:11 20:58 22:39
06:10 07:50 15:57 17:36 10:48 12:28 20:36 22:15
05:46 07:26 15:33 17:12 10:25 12:05 20:13 21:52
05:22 07:02 15:10 16:48 10:02 11:42 21:29 23:10
04:58 06:38 16:25 18:05 09:39 11:19 21:06 22:47
06:14 07:55 16:01 17:41 10:56 12:36 20:43 22:23
05:51 07:31 15:38 17:17 10:33 12:13 20:21 22:00
05:27 07:07 15:15 16:53 10:10 11:50 19:59 21:37
05:03 06:43 16:30 18:10 09:47 11:27 21:14 22:55
06:19 08:00 16:06 17:46 11:04 12:44 20:51 22:31
05:55 07:36 15:43 17:22 10:41 12:21 20:29 22:08
05:32 07:12 15:20 16:58 10:18 11:58 20:06 21:45
05:08 06:48 16:34 18:16 09:55 11:35 21:22 23:03
06:24 08:04 16:11 17:51 09:32 11:12 20:59 22:39
06:00 07:41 15:48 17:27 10:49 12:29 20:36 22:16
05:37 07:17 15:24 17:03 10:26 12:06 20:14 21:53
05:13 06:53 16:39 18:21 10:03 11:43 21:30 23:11
04:49 06:29 16:16 17:56 09:40 11:20 21:07 22:48
06:05 07:45 15:52 17:32 10:57 12:37 20:44 22:24
05:41 07:22 15:29 17:08 10:34 12:14 20:22 22:01
05:18 06:58 16:44 18:26 10:11 11:51 19:59 21:38
04:54 06:34 16:21 18:01 09:48 11:28 21:15 22:56
06:10 07:50 15:57 17:37 11:05 12:45 20:52 22:32

02:29 04:11 12:22 14:03
02:19 04:00 12:12 13:53
02:09 03:50 12:02 13:42
01:59 03:40 11:52 13:32
01:48 03:29 11:41 13:21
01:38 03:19 11:31 13:11
01:28 03:09 11:22 13:01
01:18 02:58 12:50 14:33
01:07 02:48 12:40 14:22
00:57 02:38 12:30 14:12
02:27 04:09 12:20 14:01
02:17 03:58 12:10 13:51
02:07 03:48 12:00 13:40
01:57 03:38 11:50 13:30
01:46 03:27 11:39 13:19
01:36 03:17 11:29 13:09
01:26 03:07 11:20 12:59
01:16 02:56 12:48 14:31
01:05 02:46 12:38 14:20
00:55 02:36 12:28 14:09
02:25 04:07 12:18 13:59
02:15 03:56 12:08 13:48
02:05 03:46 11:58 13:38
01:54 03:36 11:47 13:28
01:44 03:25 11:37 13:17
01:34 03:15 11:27 13:07
01:24 03:05 11:18 12:57
01:14 02:54 12:46 14:29
01:03 02:44 12:36 14:18
02:34 04:15 12:26 14:07

You can download a PDF version of these predictions from: http://www.geo-web.org.uk/predictions.pdf

iii

Subscription is valid for a period of one
year from your date of application, andwill entitle you to all the privileges ofmembership of the Group for Earth
Observation, including four issues of
GEO Quarterly.

Please note that your subscriptioncommences with the issue of GEO
Quarterly current at the time of yourapplication. Back issues, whereavailable, are advertised in your copy of
GEO Quarterly.

I wish to join the Group for Earth Observation (GEO) for aperiod of one year

Current Subscription Rates
United Kingdom-£18

Europe-£21

Rest of World-£24

Declaration

Name (please print clearly)

I have no objection to GEO holding my membership details on
its computer database. I understand that such information will
be used exclusively for internal GEO administration purposes.
Please sign and date below to confirm

Address

Signature

Town/City

Date

Postcode/ZIP

Callsign

Please send your completed form to
Nigel Evans (GEO subs),‘L’Eventail’, 7 Gloster Ropewalk, Aycliffe,
Dover CT17 9ES, England, UK.

Country

Telephone Number

FAX

E-mail Address (please print very clearly)

If paying by credit card, you may FAX a copyof this form to (01304) 207 731
UK residents who wish send theirremittance by cheque or postal ordershould make these payable to:‘Group for Earth Observation’Website address (... if related to Earth Imaging etc.)

If you prefer not to remove this page from your Quarterly, a photocopy or scan of this form is acceptable
The Group for Earth Observation Limited is a company in England and Wales, limited by guarantee and having no shares.
The company number is 4975597. The registered office is Coturnix House, Rake Lane, Milford, Godalming GU8 5AB.

iv

www.geo-web.org.uk

June 2006

Group for Earth Observation

GEO Quarterly No 10

Metop Launch Confirmed
The launch date of Europe’s first polarorbiting meteorological satellite has been
confirmed for July 17, 2006. The first in theseries of Metop satellites (to be called
Metop-A once in orbit) will be launched ona Soyuz launcher from the Baikonur
Cosmodrome in Kazakhstan into a polar
orbit with an altitude of 837 km and a 09:30
equator local crossing time (descendingnode).

Final Curtain for WEFAX
The days of Meteosat-7 WEFAX and PDUS
are drawing to a close. After a number ofextensions as delays beset the launch of
MSG-2, all services will end effective from
June 14, 2006. GEO readers who have notmade arrangements to set up a
EUMETCast system by this date will findthemselves without any access to live
geostationary imagery.
Raul Texeira, who monitors Meteosat
imagery from the Funceme meteorologicalstation in Brazil (GEOQ No 6, page 24),sent us a Meteosat-7 image he acquired
showing the umbra of the recent total solar
eclipse over Egypt at at 10:30 UT on
March 29.

RARS or RATIOSOVSRS?
Technical reports are full of acronyms andabbreviations these days. Recently, Peter
Wakelin came across ‘RARS’ in the latest
CGMS (Coordination Group for
Meteorological Satellites) report. The
glossary in appendix 7 to the report says:

Total solar eclipse of March 29, 2006. The umbral shadow is clearly evident centred over Egypt inthis Meteosat-7 image acquired from Brazil at 10:30 UT on March 29.
Image © EUMETSAT 2006

RARS is Regional ATOVS Retransmission
Service and ATOVS is Advanced TOVS
and TOVS is TIROS Operational Vertical
Sounder and TIROS is Television Infrared
Observation Satellite.
So RARS is Regional Advanced Television
Infrared Observation Satellite Operational
Vertical Sounder Retransmission Service.

‘Far East’ Competition
Despite Rob Denton’s challenge, and offer
of a prize, not a single entry has been
received from GEO members resident in
the UK to better his NOAA-17 image whichdisplayed most of the Caspian Sea.
Norbert Puetz obtained an image
containing both the Caspian and Aral seasfrom Muinich, Germany. The image wasreceived on an RX2 using a dipole (sic)antenna, recorded on minidisc andprocessed later using SatSignal.

The 12:20 UT NOAA-18 pass on October 13, 2005, received by Norbert Puetz from Munich.

www.geo-web.org.uk

23

GEO Quarterly No 10Group for Earth Observation

June 2006

Rob Alblas
I described XRIT2PIC, a program forhandling MSG data, in an earlier issue of
GEO Quarterly [1]. In this article I will
discuss some new features which havebeen added since then, perhaps the mostinteresting being a method of showing the
HRV channel images in full (false) colour. I
will also discuss briefly options to create
anaglyphs (3D weather images) andoffering simplified movie generation.
MSG Image Resolutions
It is important to understand that the spaceresolution of HRIT images is the same as
for LRIT. The differences between
comparable channels of HRIT and LRIT arein the number of bits per pixel (10 versus 8)
and the compression method employed(lossless Wavelet for HRIT and lossy JPEG
for LRIT). Note that the R in LRIT and HRIT
stands for Rate, not for resolution! There isjust one exception: the HRV channel of
HRIT.
Channels 1 to 11 all have a nominal subsatellite resolution of 3 km (at the 0°
meridian on the equator); channel 12 (HRV)
has a sub-satellite resolution of 1 km.
However, at the latitude of England, theresolution is lower by a factor of 1.7(cos 54°) as a consequence of geometricperspective, so that channels 1 to 11
actually have a resolution of about 5 km
and channel 12 (HRV) of 1.7 km.

There is one snag with this, however. The
HRV channel has a spectrum ranging
between 0.5 and 0.8 µm. The two visible
channels have spectral ranges of 0.56-0.71
and 0.74-0.88 µm, which lie well within the
HRV spectrum but the other channels havespectra outside the HRV range.
If a combination of channels is used tohighlight a certain phenomenon, but thisphenomenon is not visible in the HRVchannel, then this aspect will not be visible
in high resolution in the composite image.
Moreover, if the contribution of HRV in thisarea is zero then the whole phenomenon
will become invisible. Keeping thisrestriction in mind, it is still worthwhile
composing images in this way; in particular,
locations far from the equator look muchbetter.
FormulasEvery pixel in a low
resolution channel
overlaps nine pixels(3x3) of the HRV
image. To calculate
the high resolution
red, green and blue
contributions in a
false-colour HRV
image, the formulas
shown opposite are
used.

Rhi =

LUMhi x Rlo
LUMlo

Ghi =

LUMhi x Glo
LUMlo

Bhi =

LUMhi x Blo
LUMlo

HRV in Full Colour.
Coloured images are possible by mapping
different HRIT channels to red, green andblue. These images will have the lower
resolution because there is just a single
HRV channel. A combination of HRV withlower resolution channels is possible, but ofcourse, only that colour specificallyassigned to the HRV channel will be in highresolution.

Rlo, Glo and Blo represent the red, green
and blue levels of a pixel from three of the
low resolution channels while LUMhi
represents the value of one of the 3x3 HRV
pixels that they overlap.

To get the impression of a high resolution
image, chrominance (colour) differences
may be shown with a lower resolution thanfor luminance (brightness) differences. This
property of the human eye is used withcolour TV to transmit red, green and blue
via a channel with about the same
bandwidth as for black-and-white TV,
without drastic resolution reduction.

This value is used to normalise the colour
values; as a result, the luminancecontribution of the low resolution channels
is removed.

The same can be done when composing
MSG colour images: use HRV solely forthe luminance and a combination of
three of the remaining lower resolution
channels for chrominance. The resulting
image will show a lot more detail.

24

shown using HRV for luminance and
VIS006, VIS008 and IR-016 forchrominance, as described above. Clearly,
a lot more detail is visible now.
In figures 2a and 2b, IR-016 is replaced by
IR-039 to highlight the forest fires in
Portugal last summer. This example also
shows a big improvement in detail—with
the exception for the fire spots themselves!
This is because the HRV channel is notsensitive at 0.39 µm (so there is no highresolution information for thisphenomenon). Moreover, the luminancenear the fires is not very high in the HRV
spectrum, so the fire spots don’t pop-up
that much. The lower resolution of the firespots becomes clearer after zooming in(figures 2c and 2d).
The smoke plumes show a lot more detailbecause they show up well in the HRV
visible channel. (All the images are from12:00 UT on August 21, 2005). More
examples are given in figure 3a/b and 4a/b
(using the same colour mapping as infigure 1).
Creating High Resolution Colour Images
Figure 5 shows how these images can beproduced using XRIT2PIC. It is enough tocheck the ‘Enable’ and ‘Hires’ buttons in the‘Colours’ box. By default VIS006, VIS008
and IR-016 are used but this may bechanged in the ‘Colour map’ window whichpops up after clicking on the ‘Mapping’
button (figure 6, page 26). Here any
combinations of channels may be defined.

The luminance contribution for the low
resolution channels is:
LUMlo = Rlo + Glo + Blo

Rhi + Ghi + Bhi = LUMhi ×

R

G

B

=

( LUMlo lo + LUMlo lo + LUMlo lo ) LUMhi

So the HRV channel now provides theluminance and the low resolution channels
only contribute to the chrominance of eachpixel. This mapping method is implemented
in XRIT2PIC.
Results.
Figure 1a shows a normal colour composite
image using Blo=VIS006, Glo=VIS008 and
Rlo=IR-016. In figure 1b the same image iswww.geo-web.org.uk

Figure 5

At the bottom of the ‘Colour map’ screen
you can enter the percentage contribution
for each channel; by specifying negative
numbers, channels may be subtracted.
(Note that in this window HRV is notchecked, because this channel should only
contribute to luminance, not to the actual
colours!)
HRV Earth Coverage
The HRV channel covers a smaller part of
the Earth’s disc than channels 1 to 11. Also,
the upper part of the HRV channel covers a
different spread between west and east
compared with the lower part. As a result

June 2006

Group for Earth Observation

GEO Quarterly No 10

Figure 1a - The English Channel

Figure 2a - Portugese forest fires

Figure 2c - Fire hotspots (zoom)

Figure 1b - The English Channel

Figure 2b - Portugese forest fires

Figure 2d- Fire hotspots (zoom)

Figure 3a - Netherlands

Figure 4a - The Nile Delta

Figure 3b - Netherlands

Figure 4b - The Nile Delta
www.geo-web.org.uk

Figure 7 - An HRV colour composite

25

GEO Quarterly No 10Group for Earth Observation

several manual steps have to be done foreach image. XRIT2PIC can now generate
anaglyphs directly from HRIT/LRIT images;
it is enough to check the new ‘Anaglyph’
button (figure 8) on the toolbar at the top of
the window then click ‘Preview’—and put
on your coloured glasses.

June 2006

Cover Colour Images
Front Cover
There was a total eclipse of the sun overnorth Africa on March 29 and Meteosat-8
captured this image showing the umbra
poised between Niger and Chad at
09:45 UT. This false-colour HRIT image
was processed by David Taylor.
Image © EUMETSAT 2006

Figure 8

The methodology employed is very simple.
Two shifted images are generated, one in
red and the other in cyan, the amount ofshift for each pixel depending on its
brightness. The idea is that features nearer
the observer (i.e. clouds) are brighter than
far-away parts (land).

Figure 6

the HRV image is not square or rectangularshaped like the other channels.
Instead of extracting parts of the highresolution image, XRIT2PIC makes thecomposite image rectangular by displaying
the parts which lack an HRV contribution in
the normal low-resolution way. At theboundary there is a difference in brightness(because of the different mappings), andafter zooming in differences in resolutions
become visible. See figure 7, where thelower left and upper right parts are in low
resolution.
Processing Considerations
I use a PC with 512 MB of RAM and thatworks fine. Maybe 256 MB would just work,
but I wouldn’t recommend that; I think that
may cause lots of disc swapping.
Note that four images have to be decoded,
including the HRV, so processing is a bit
slow; but once you have created the colour
image in a preview window you can enable‘Fast’ in the ‘View’ menu. After one redraw
the whole processed pic is in memory, andthen zooming/panning is much faster(depending on how much memory you
have in your PC: as said, 512 MB worksfine).
The latest version of XRIT2PIC has a newfeature that allows you to save zoomed
pictures from the ‘Preview’ menu.

More New Features
Anaglyphs
Fred van den Bosch described how tomake 3D images from weather satellite
images in the last issue. Unfortunately,

26

Currently the quality is not quite so goodwhen compared with Fred’s method, but
the results can still be very attractive. Bothblack-and-white and coloured anaglyphs
are possible, although black-and-white
gives better 3D effects.
MoviesUp till now, XRIT2PIC needed an external
program (e.g. Mencoder) to generate
movies. The current version (2005.12 andlater) has a built-in movie generator—noexternal program is needed any more.

Back CoverNorbert Puetz captured this NOAA-18
APT image at 11:11 UT on March 6. The
satellite had a maximum elevation of only
12 degrees from Norbert’s location in
Erding in Germany. If you look carefully
you can detect the frozen rivers Volga and
Ural in the snow-covered terrain to thenorth of the Caspian Sea.

Erratum
Due to an unforeseen problem, thefraction ‘one quarter’ was omitted fromthe final print of Quarterly No 9. The lastparagraph on page 9 as well as the firston page 10 should have made reference toa ‘quarter wavelength’. We hope this did
not
spoil
your
enjoyment
andunderstanding of the article.

It is also possible to generate ‘live’ movies;
each time all required channels for a newimage are received, a new frame is added.
If desired XRIT2PIC can delete all raw data
after each generated frame.
In Conclusion
All mentioned features may be combined:
XRIT2PIC can generate high resolution
colour anaglyph movies. It is questionable if
this is useful. As I have already stated, thebest 3D-effects are produced with blackand-white images. Also, the human eye
needs some time to see the 3D effect, andthis becomes a bit more difficult withmoving images.

The Wraase WRX-137
Receiver(continued from page 22)

equipment, with approximate equivalents
in sterling are shown in the table below.
Unit

Price
(euro)

References

WRX-137 Receiver

695.00 486.50

1 XRIT2PIC, a Tool to generate MSG Images
Rob Alblas - GEO Q5, page 28
2 Create your own 3D Weather Images
Fred van den Bosch - GEO Q8, page 24

WRX-137 + Prosat for
Windows software

785.00 549.50

The program XRIT2PIC can be
downloaded, free, from Rob’s website at:

KX-137 Turnstile

295.00 206.50

MX-137 'Mobile' Turnstile

355.00 248.50

You can learn more by visiting

http://www.alblas.demon.nl/wsat

Follow the link to ‘Software’ and download
the following three files:• xrit2pic.zip• decompr.zip• gtk_dll.zip
You can also download an optional utility
called xrit2pic_install.exe which can
automatically unzip all the files and installthem in your C:/Program files folder.

www.geo-web.org.uk

Price
(£)

http://www.wraase.de

References
1. Images produced on the Wraase WRX-137
weather satellite receiver by Hartmut
Schaksmeier

•
•
•
•

GEO Q1, page 45
GEO Q2, page 17
GEO Q4, page 41
GEO Q7, back cover

2. APTDecoder, GEO Q8, page 15.

June 2006

Group for Earth Observation

GEO Quarterly No 10

Alan Sewards
Manufacturer’s Specifications

Oregon Scientific’s WMR-968 cable-freeweather station consists of fivecomponents:• An indoor unit withtemperature/humidity/barometer
sensors (figure 1)• an outdoor unit withtemperature/humidity sensors(figure 2)• a unit with wind speed and direction
sensors (figure 3)• a rain sensor (figure 5)• a display console (figure 6)
These units are all linked by a 433 MHz
radio link which has an effective range ofabout 30 metres in a masonry building.
The antennas are visible in figures 3,5
and 6. The kit comes with a simple
starter manual but a morecomprehensive one is available fordownloading from Ambient Weather.
Specifications for the system arepresented in the panel at right.
I later added another component—aremote temperature sensor for myoutdoor pool (figure 4); this has similar
specifications to the outdoor thermohygrometer unit, except that it has nosolar panel.
Why I bought this System
I bought the WMR-968 a little over five
years ago, direct from Ambient Weather. I
chose it because, living in a masonryhouse, the running of cables was
impracticable and the cable-free feature
gives one a lot of latitude in selecting theright emplacement for the various
sensors. At that time this was the only
cable-free weather station on the market
and there were no European suppliers. I
suspect that the frequencies used for thecable-free wireless communications were
not at the time allotted for this use inEurope, but no difficulties arose in
shipment, and of course, I did not ask forpermission to use them!
Setting up the Station
Before setting up the station using theconsole, it is advisable to locate thevarious sensor units where you had
planned to put them, to determine if
communications are possible. The outdoor
thermo/hygro unit should not, of course,
be placed where it will be in sunlight andit is better to shelter it from rain, but, inthe absence of a professional Stevenson
screen (or, to make one, Google

for the Oregon Scientific’s
WMR-968 cable-free weather station
The Console
This features touchscreen desktop control
with bright green HiGlo™ backlighting.
The console is about 20 cm wide —perfect for desktop or wall-mount use
anywhere. Console dimensions: 20 x 13.8
x 3.8 cm.
The Thermo-Hygrometer

Figure 1 - The indoor unit

‘Stevenson screen’), I put mine under theeaves on the north side of the house. The
anemometer should be located on thehighest point available and away fromtrees if possible. The rain sensor shouldbe placed well away from the house.
All the units require batteries, usually
AAA but some AA. The sensor units(except for the indoor temperature/humidity/baro sensor and the outdoor
temperature sensor with probe) havesolar panels and capacitors to provide
power during the day, so the batteries dolast a long time. Once each unit isinstalled you must push the reset button
using a ballpoint pen; then power up thedisplay unit, set up the measurement
units you wish to use, and press and holdthe channel button (on the touchsensitive screen) until it flashes. This
causes the display to scan the various
radio channels for the remote sensors andto acquire them. Once acquired, thevalues measured by the various sensors
will be displayed. You can choose which
units you want the station to use(degrees Fahrenheit or Celsius, mph orkph, inches or mm, and so on). The
display unit normally resides indoors
where it can conveniently be consulted. If
one wants to use the backlit screen, its
power transformer must be connected
and plugged into the mains. It is alsoessential to use an external power supply
if you want to connect the display unit to
a computer via the RS232 serial port.

www.geo-web.org.uk

The operating range of the outdoor
thermo-hygrometer is –50°C to +70°C
with resolution of 0.1°; humidity range is
2% to 96% relative humidity (RH) with anaccuracy resolution of 1%. Updating
occurs every 37 seconds. The thermohygrometer is powered by a solar cellwith battery backup.
The Anemometer
The anemometer measures wind speed
and direction. The anemometer operating
range is up to 125 miles per hour withaccuracy resolution of ± 0.4 mph. Datatransmission occurs every 14 seconds.
The anemometer is powered by a solar
cell with battery backup.
The Baro-Hygrometer
The baro-thermo-hygrometer measuresindoor temperature and humidity, andbarometric pressure. Its operating range
is -5°C to +50°C with an accuracy
resolution of 0.1°; 2% to 96% RH with anaccuracy resolution of 1%; 800 to1050 mB with an accuracy resolution of
1 mB. The baro-thermo-hygrometer
operates off four ‘AAA’ batteries.
The Rain Gauge
The rain gauge measures rainfall,reflecting current rainfall or accumulationof up to nine days’ history using a selfemptying collection unit. The rainfall
measurement range is 0 to 100 cm perhour with a cumulative operating range of
0 to 1000 cm with an accuracy resolutionof 0.1 cm. Transmission occurs every
47 seconds. The rain gauge is poweredby a solar cell with battery backup.
The entire kit has a 30-day return policy
and a one-year factory warranty. Further
information can be obtained from:www.ambientweather.com

27

GEO Quarterly No 10Group for Earth Observation

June 2006

Figure 2 - Outdoor temperature/humidity sensor sheltered from the rain

Figure 5 - The rain sensor

Figure 3 - Windspeed and direction sensors

Figure 6 - Display console

Figure 4 - Outdoor pool sensor

28

Figure 7 - The PC display of Virtual Weather Station
www.geo-web.org.uk

June 2006

Setting-up Problems
If a sensor is not acquired, try moving theantennas on both the sensor and display.
If this does not work, it it may benecessary to try another location for thesensor unit. This is a trial and error
process but with a little application
suitable emplacements which allow
communications can be found. I had themost difficulty with the rain sensor,
which I wanted to keep as far away fromthe house as possible to avoid it being
sheltered and thus giving incorrect
readings. The add-on temperature sensor
which I used for my pool also gave me aproblem because of its depressed location;in this case placing the indoor display
unit at a higher level enabled the signal
from the outdoor unit to be received.
Experiences with the WMR-968
Over the five year period I have had theweather station it has performed well,although I have had to replace the winddirection/speed sensor unit and the indoor
temp/humid/baro unit. In the former case,the sensor stopped indicating wind speed,in the latter, although the sensors
continued to work well, the RF link would
only work over a distance of a few
centimetres! Both units failed after the
one year warranty was up but within two
years of purchase. The rest of the kit andthe replacements have worked flawlessly.
SoftwareAt the same time as I bought the weather
station, I also bought the Ambient
Software program Virtual Weather
Station (VWS). This is a great piece ofGroup for Earth Observation

software and is well worth its low price,especially as you get regular free
upgrades. I originally purchased version 4
and it is now up to v 12.07, with all sorts
of additional bells and whistles which
weren’t on the original. Recent versions
have the capability to upload the weather
station data to your website on acontinuing basis, if that is what you need.
The best thing about VWS is that itallows you to display the data from theweather station on your computer screen
in a number of ways, including graphing
it over the last few days, distribution ofwind direction, etc. You can also display
more data simultaneously than there isroom for on the display unit (figure 7),
and of course, the computer can store andretrieve the data. VWS also producessummaries each day, month and year in
NOAA format, a sample of which isshown in the table below. I keep thesesummaries in a folder and find them very
useful for comparing one year withanother. The online database can be
consulted at any time for any specified
date of interest and, as the database isstored as a .csv file, it can be imported
into an EXCEL spreadsheet andmanipulated in whatever manner you
wish. In this way you can keep years ofweather data to the nearest two hours, alleasily available at the click of a mouse.
I run the VWS software on an old IBM
ThinkPad T20 notebook computer via theserial link. The computer runs 24/7 andthe battery back-up built into themachine is useful to carry me over short
power outages. Outages longer than the

www.geo-web.org.uk

GEO Quarterly No 10

battery capacity result in the computer
going into hibernation mode, but theweather station console stores a certain
amount of data which is automaticallyuploaded when the computer comes backon again. Such computers are readily
available second hand at very reasonable
prices.
As mentioned above, VWS can be
configured to upload weather data to yourweb site automatically. I have not used
this function, as I don’t feel that my data
is of general interest, but if you are
driven to publish all your data, thissoftware allows you to do so.
Summary
After five years use of the station, it has
become part of my life. I always check thereadings first thing in the morning andlast thing at night and frequently during
the day. Being a receiver of weather
satellite imagery (now MSG-1), I often
compare what I see on the images withwhat the weather station is indicating
and draw my own conclusions (whichmight be to turn on or off wateringsystems, add more cloth to vulnerable
plants, and so on). The cable-freecapability is very nice to have as therunning of cabling around masonryhouses is a very tedious business, somuch so that it discourages you frominstalling systems or making changes tothem. All in all, I can thoroughly
recommend the WMR-968, but, as I
mentioned, there may be other makes
today which offer as good or better
capability or reliability.

29

GEO Quarterly No 10Group for Earth Observation

Background
Imaging from geostationary Earth observation satellites has
made great strides in recent years, most notably in implementing
the transition from low-resolution WEFAX imagery to the muchhigher resolution digital LRIT. In the USA, the National Oceanicand Atmospheric Administration (NOAA) initiated a timesharing phase commencing August 2003, during which WEFAX
and LRIT images were disseminated alternately from its GOES
platforms. GOES-E finally ceased transmitting WEFAX
altogether on March 1, 2005, and when GOES-W followed suit on
October 3 of the same year the transition to digital was complete,leaving thousands of enthusiasts without a low-cost option toaccess the data. Meteosat-7 will cease WEFAX transmission on
June 14, signalling the end for WEFAX enthusiasts in Europe.
In Europe, a similar scenario at one time seemed likely when
EUMETSAT commenced commissioning trials of their MSG-1
satellite (now named Meteosat-8) in late 2002. However, in one of
the most bizarre strokes of bad/good luck, one of the power
amplifiers concerned with transmitting the digital data from thesatellite failed. This forced EUMETSAT to explore a new, and, in
this context, hitherto unthought of transmission method, DVB-S(Digital Video Broadcasting from Satellite). The outcome was the
EUMETCast system, where MSG data is transmitted to end
users via the commercial Hot Bird-6 satellite, whose primaryfunction is the provision of satellite-TV.

June 2006

warnings, plus other meteorological data from various NWS
facilities are processed to create products. These are then sent to
the Network Control Facility (NCF) which routes them to one of
the four NOAAPORT channels for uplink and retransmission.
And from June 7 this year, NOAA polar orbiter data will be
added to the service on a pass by pass basis. The major
operational components that feed data to NOAAPORT are
shown in simplified form in figure 2.

Figure 2 - Simplified NOAAPORT System Overview

For over three years now, ever since the EUMETCast service
commenced in late April 2003, enthusiasts in Europe have beenable to enjoy superb digital geostationary satellite imagery fromaround the globe. All that is required to achieve this are an 85 cm
offset TV dish fitted with a standard digital TV LNB, anappropriate DVB receiver card or USB unit, twin computers forreceiving and processing the data (or a single high-poweredmodern PC), plus appropriate acquisition and processing
software, and a licensed hardware key. The total cost of all this(PC excepted) is unlikely to exceed £300 ($550)

The NOAAPORT Receive System
In March 2005, the transmission mode for NOAAPORT data
streams changed to Digital Video Broadcasting via Satellite(DVB-S), ‘ ... allowing inexpensive equipment to be used todemodulate the data ... ’, according to NOAA. ‘Inexpensive’ isobviously open to interpretation: at present there are only ahandful of commercial vendors supplying NOAAPORT systems.
These cost a minimum of $10,000 and, depending on options, asmuch as $20,000 or even more. Even if you are prepared to build
your own system, as explained by José Nieves (see opposite), thecost is still likely to be several thousand dollars, many times thecost of a EUMETCast DVB system.

NOAAPORT
Only a very few of our American readers are fortunate enough tohave access to EUMETCast through its C-band service. This istransmitted via the Atlantic Bird-3 satellite, whose footprint
just touches the easternmost parts of the USA. For the majorityof Americans, digital geostationary satellite images are now only
available for direct download using the NOAAPORT service,
which is operated by the National Weather Service (NWS) of the
National Oceanic and Atmospheric Administration (NOAA).

In order to receive NOAAPORT, end-users require to purchase a
DVB-S receiver, a 10-foot (3-metre) dish and a second network
interface card for their reception PC, as well as installing new
software to read and process the received data. The requirement
for the 10-foot dish is driven by the necessity to use C-band(with its lower susceptibility to rainfall attenuation) and by theclose spacing of satellites in the American C-band belt: the large
dish size is required to achieve a narrow beamwidth tominimise interference from adjacent satellites.

Superficially, there are many
similarities between NOAAPORT and
EUMETCast. NOAAPORT provides
one-way broadcasting of NOAA
environmental data and information,in near-real time to end-users, on
C-band, using the commercial
GE Americom GE-4 satellite (alsoknown as AMC-4) located at 101°W(figure 1). Digital telemetry from boththe GOES-E and GOES-W satellites,
environmental sensor informationfrom the GOES Data Collection
System (DCS) [1], radar products,
observations, forecasts, watches andInevitably, this forces up the cost in comparison with domestic
satellite TV. The NOAAPORT satellite broadcast is operated by
the US government and does allow users to enjoy unrestricted,
royalty-free use of the data. The only cost is the one-time
investment in the ground station. But the costs of the system,
perhaps coupled with Internet access to much of the data, has
undoubtedly resulted in much lower take-up of the system by
the amateur community to date.

Figure 1 - AMC-4
Credit: NOAANOAAPORT Product Dissemination
One feature that will surprise most GEO readers is the fact thatNOAAPORT is data driven and there is no set schedule for any
specific meteorological product. Rather, prevailing weather
conditions determine what data is made available and which
products are created and disseminated. When operating
continued on page 43 ...

30

www.geo-web.org.uk

June 2006

Group for Earth Observation

GEO Quarterly No 10

Jose F Nieves
Department of Physics, University of Puerto Rico

GEO are delighted to have received thisvery comprehensive and detailed guidewhich covers everything a prospective
user of NOAAPORT requires to know
about setting up a system. GEO is mindfulthat NOAAPORT is not accessible to thevast majority of our readership, so just asynopsis is presented here. The entire
article is available as a PDF downloadfrom the GEO website atwww.geo-web.org.uk/sats.html

from the section headed ‘The American
NOAAPORT System’.
Synopsis
Following a brief overview of the
NOAAPORT system, focussing on thecollection of meteorological data fromvarious sources and the subsequentrouting of products through the system,
José explains how switching to the
DVB-S transmission format and open
specification now allows an end user toassemble a receiving station from off-theshelf parts for a fraction of what it costjust a few years ago. Early in 2005 Josélearned that the NOAAPORT signal
could be received from his location at San
Juan in Puerto Rico. Very little was thenknown about it but, convinced that ausable signal could be received, José
erected his own dish and embarked on a
project to write the necessary software toreceive and process the data. Since then,
José has been constantly working on his
system, which has now reached a maturelevel. The article continues by describing
his experiences, the equipment that isrequired to receive NOAAPORT data, thenecessary computer hardware andsoftware needed to process it, and how
these can be used.
The Dish Antenna
To receive the signal, a C-band dish, withan associated LNB and an appropriate
DVB-S receiver are required. There has
been much discussion about the best dishto use and the consensus is that thesmallest reliable one measures 10-feet;
7-foot dishes have been experimented
with but these did not provide a signalthat was strong nor stable enough. The
LNB used with the dish is less critical. It
is also explained how it can be useful toinstall an actuator (motorised arm) sothat the dish may be aligned by remotecontrol. José concludes this section bydescribing at length how he installed his
dish.

The Receiver
José recommends the Novra S-75 receiver
which costs around $350 and is available
from satellite equipment dealers. He also
discusses PCI receiver cards that can beinstalled inside your computer but
stresses that it is advisable to use thesein a separate dedicated receive PC
because processing the NOAAPORT data
is very resource-intensive. Trying toachieve both capture and processing on
the same PC ‘is a recipe for disaster’.

The Novra S75 receiver, under 12 cm wide

The receiver has two connectors on theback, one for the downlead from the dishand the other an ethernet port forcommunication with the computer.
Configuration of the receiver,accomplished with the aid of softwarefrom an accompanying Windows CD is
explained, followed by hints on how best
to connect it to the processing computer.
Two options are discussed: using acomputer equipped with two ethernet
ports and employing a crossover ethernet
cable, or alternatively connecting boththe computer and the receiver to an
ethernet switch.
Software
The choice of computer is very muchdictated by the software it is planned touse, and José describes at length the
NBSP (NOAAPORT Broadcast System
Processor) software package which he has
been developing. Previously the only
software that had been available were
LDM (Local Data Manager) and an
associated decoding and display package
from Unidata called Gempak. It is notedthat LDM and Gempak run only on
UNIX or Linux operating systems. In
addition, Gempak constrains the user tostore satellite images and other data files
in particular formats that cannot beviewed or used immediately with othersoftware, including Web browsers. As thiswas far from ideal, José designed NBSP,
which is distributed free. NBSP is underconstant development on a computerwww.geo-web.org.uk

running FreeBSD. Whenever a newversion is ready, compiled binary
packages for FreeBSD, the Fedora Core
distribution of Linux and the Cygwin
environment for Windows are madeavailable. Both the software and themanual may be downloaded from:http://www. noaaport.net

There follows a lengthy and somewhat
high-powered description of NBSP’s
features and system configuration—hardto follow if you are unfamiliar withNOAAPORT but essential reading foranyone involved with setting up theirown NOAAPORT system.
System Configuration
This section discusses a structure fordefault directories to store both
downloaded and derived products;
numerous screenshots and charts areprovided to illustrate the types of productthat can be achieved using the data
downloaded via NOAAPORT. Much use ismade of Digital Atmosphere Workstationin this respect, and the author concludes
with a sample DAWS script for producing
a colour temperature fill.
Finally, there is a unit describing the
distribution of files over the Internet
using an NNTP server.
The entire article is available as a PDF
download from the GEO website atwww.geo-web.org.uk/sats.html

from the section headed ‘The American
NOAAPORT System’.

A typical GOES-W full disc visible image
downloaded via NOAAPORT
Credit: SSEC, University of Wisconsin-Madison

31

GEO Quarterly No 10Group for Earth Observation

Antarctic ice shelves periodically experience calving events which
produce quantities of sizeable icebergs. One such event occurred in
March 2000 when the Ross Ice Shelf in western Antarctica released anumber of large fragments. These have been drifting around the Ross
Sea ever since and include the large tabular B-15A iceberg (GEO Q1,
page 24, GEO Q5, page 27) and a smaller 55 x 18.5 km fragment known
as C-16.
Virtually immobile after grounding itself north of Ross Island, C-16 finally
freed itself early this year, since when surface ocean currents have been
carrying it north towards the floating Drygalski Ice Tongue (GEO Q6,
page 11), an 80-kilometre protuberance from the David Glacier. Should
this tongue break loose completely, scientists fear that major changes to32

June 2006

both ocean currents and local climate could ensue. Finally, on March 30,
2006, C-16 collided with the tip of this ice tongue, breaking off its
easternmost corner and forming a new iceberg measuring 13 x 11
kilometres and now designated C-25.
The Advanced Aperture Synthetic Radar (ASAR) aboard ESA’s Envisat
satellite (GEO Q1, page 22) acquired this wide swath image of the
March 30 collision, providing spatial resolution of 150 metres.
ASAR, which has the ability pierce through clouds and image even in total
darkness, is capable of differentiating between different types of ice.

www.geo-web.org.uk

Image: European Space Agency. All rights reservedJune 2006

Group for Earth Observation

GEO Quarterly No 10

Peter Wakelin
MetOp-2 Shipped to Launch Site
Europe’s first polar-orbiting weather satellite, MetOp-2, arrived at
the Baikonur Cosmodrome in Kazakhstan on April 18 aboard an
Antonov-124 transport aircraft flight from Toulouse, France. Launchis scheduled for 1626 UTC on July 17, on a Soyuz ST / Fregat
vehicle operated by Starsem, to a planned 837 km sunsynchronous orbit. Spacecraft have been launched to sunsynchronous orbits from Baikonur before but always in a southwesterly direction; this will be the first to head out on a northwesterly trajectory taking it across Greenland and central USA on
the initial orbit, a trajectory which, not so many years ago, might
have had extremely undesirable consequences.

enhancing the tracking of ice in Canada’s navigational waters andsupporting safe shipping in the Great Lakes, the St Lawrence
Seaway and along Canada’s coastlines. The constellation will also
support Canada’s contribution to global disaster management andrescue efforts by detecting oil spills, monitoring floods, landslides
and eruptions and aiding forest fire-fighting. The satellites will becapable of imaging day and night and in all weather conditions.
More on this and other activities of the Canadian Space Agency
can be found at:
http://www.space.gc.ca/asc/index.html

Geostationary Lightning Mapper Contracts Awarded
Contracts for the formulation phase for a new instrument to be
flown on the the next-generation GOES spacecraft have been
awarded to Lockheed Martin Space Systems Company Advanced
Technology Center of Palo Alto, California, Ball Aerospace &Technologies Corporation of Broomfield, Colorado and to ITT
Industries Space Systems Division of Fort Wayne, Indiana.
The Global Lightning Mapper (GLM) comprises a high-speed
optical detector and associated electronics to provide a real-time
map of lightning activity over the full disk. The first GLM isscheduled to fly on GOES-R in six years’ time.
Sich-1M Burns Up
Sich-1M was launched in December 2004 but the engine burn tocircularise the orbit was unsuccessful, leaving the spacecraft in an
eccentric orbit with a perigee below 300 km. Atmospheric drag at
this altitude was too great for the gravity-gradient stabilisation
system to cope with and little or no useful imagery was received.
US SPACECOM sensors predicted burn-up time at about
2050 UTC on April 15 which is in good agreement with the re-entry
sighting by an observer in central France at 2054 UTC.
Replacement CryoSat to be Built
The launch of CryoSat in October 2005 was unsuccessful due tothe failure of its Rockot launcher but approval for a replacement,
CryoSat-2, was announced in February by ESA’s Earth
Observation Programme Board.
Cryosat-2, expected to be launched in March 2009 on a three year
mission, will carry SIRAL (SAR/Interferometric Radar Altimeter) to
precisely measure changes in elevation and thickness of both landand sea ice to within about 200 km of both north and south poles.
Precise measurements require knowing the spacecraft’s orbitalparameters to a very high accuracy and, to achieve this, a laser
retro-reflecting system and an onboard ranging instrument called
DORIS (Doppler Orbitography and Radiopositioning Integrated bySatellite) will be incorporated into the payload. In addition, there
will be three star trackers to maintain precise radar antennaorientation.
Canada to Build Three More Radar Satellites
Canada’s Radarsat-1 was launched in 1995 and Radarsat-2, withimproved resolution, is being tested at the Canadian Space
Agency’s David Florida Laboratory in Ottawa prior to its shipment
later this year to the Baikonur launch site in Kazakhstan.

Canada’s Radarsat-2 resolution will be better than that seen in thisRadarsat-1 image of British Columbia

Design and mission definition work has now started on aconstellation of three small Earth-observation radar satellites tocomplement the Radarsat programme. They will provide more
timely and comprehensive data than is currently available,

First Meteor-M Spacecraft Launch Planned for August
The Meteor-M series of spacecraft is based on the proven
Resurs-01 series unified platform and the first may be launched assoon as August. As well as a low-resolution (1 km) six-channel

Image credit: Canadian Space Agency.

www.geo-web.org.uk

33

GEO Quarterly No 10Group for Earth Observation

scanning radiometer, there will be an imager with 50 m or 100 m
resolution at a swath width of 400 km or 900 km, a 29-channel
atmosphere temperature and humidity sounder and an onboard
radar complex.
Raw data will be transmitted at about 8 GHz but there will be direct
readout in the new LRPT format on 137.1 MHz or 137.9 MHz and
HRPT (not AHRPT) on 1700 MHz. The quoted 2 MHz bandwidthand 665kb/s data rate for HRPT are similar to those used by
NOAA.
Fifteen Years of Radar Altimetry
In March, oceanographers, glaciologists, hydrologists andgeodesists gathered in Venice for the 15 Years of Progress inRadar Altimetry symposium organised by ESA and the French
Space Agency (CNES).
As it is now feasible to measure radar return pulse times to muchbetter than nanosecond accuracy, it is possible to measure ocean
surface levels to an accuracy of around two centimetres over vast
oceans—a feat quite impossible by conventional sea-levelmeasuring techniques. Meteorologists have long recognised theimportance of knowing sea surface temperatures but, as there is a
close correlation between atmospheric pressure and the height ofthe sea surface, a new tool has been added to their range to better
predict such events as El Nino, for example, which can have sucha huge impact over large parts of the Earth.
Rossby waves were first identified in the atmosphere in 1939 byCarl-Gustav Arvid Rossby and will be familiar to meteorologists as
the large-scale meanderings of the polar jet-stream, whose
restoring force is the variation in the Coriolis effect with latitude.
Similar waves were theorised to exist in the oceans but, as theiramplitude is only about 10 cm and their wavelength several
hundred kilometres, their existence was not confirmed until theadvent of radar altimetry from space.
In the ocean, Rossby waves are responsible for the asymmetry ofcirculatory vortices; an important effect for us in Western Europe is
the resultant intensification of the western arm of the North Atlantic
vortex that powers the Gulf Stream which keeps us warm in winter.
It is possible that decreasing salinity in parts of the North Atlantic
caused by the influx of fresh water from a warming Arctic region
could influence the circulation in the North Atlantic, and radar
altimetry satellites will help to detect any changes in thiscirculation.

Jason-2 will be similar to this artist’s impression of Jason-1.
Image credit: NASA

Satellites launched in the 1970s proved that radar altimetry fromspace was possible but routine, precise measurements of oceanlevels started in 1991 when ESA’s ERS-1 satellite was launched.
Further European radar satellites followed in 1995 (ERS-2) andEnvisat was launched in 2002. TOPEX-Poseidon, a joint
CNES/NASA project, carried an altimeter in 1992 with a follow-up
mission, Jason-1, in 2001. An improved Jason-2 is to be built for aplanned launch in 2008. A good starting point for further
information on radar altimetry is:
http://sealevel.jpl.nasa.gov

34

June 2006

MetOp Data Denial Implementation Plan Agreed
NOAA and EUMETSAT have signed a Data Denial Implementation
Plan which secures the continued flow of real-time data from the
NOAA-provided instruments on the MetOp spacecraft to public
duty users in the US and EUMETSAT Member States during
episodes that might otherwise require data denial. If, in a time ofcrisis or war, NOAA requests denial, then EUMETSAT will continue
to provide real-time data to an agreed list of essential users.
Satellites Help Detect Deep-Ocean Whirlpools
Researchers from NASA’s Jet Propulsion Laboratory, the Universityof Delaware and Ocean University in Qingdao, China, havedeveloped a method of detecting submerged, salty eddies called‘Meddies’ using data from several US and European satellites.
Meddies, first identified in 1978, are so named because they areformed by the flow out of the Mediterranean Sea through the Straitof Gibraltar. Due to its high salt content, the outflow through theStrait is more dense than the colder North Atlantic so this river ofdense, salty water sinks to depths of more than 1000 m along thecontinental shelf and separates into clockwise-flowing eddies,typically a kilometre in depth and 100 km in diameter. These
submerged meddies spin slowly westwards for many hundreds ofkilometres and may last for more than two years before dissipating.
“Since Meddies play a significant role in carrying salty water from
the Mediterranean into the North Atlantic, new knowledge about
their trajectories, transport and life histories is important tounderstanding their mixing and and interaction with North Atlantic
water,” said Professor Xiao-Hai Yan of the University of Delaware,reporting in the April issue of the American MeteorologicalSociety’s Journal of Physical Oceanography. “Ultimately, we hope
this will lead to a better understanding of their impact on global
ocean circulation and global climate change.”
Radar altimeters flying aboard the NASA/CNES Topex/Poseidon
spacecraft, NASA’s Jason-1 and ESA’s Envisat measured theheight of the sea surface compared to average sea level, revealing
the difference in altitude where a Meddy entered the Atlantic.
Specialised microwave radars called scatterometers on Japan’sMidori-1 and the SeaWinds instrument on NASA’s QuickScat
spacecraft, measured the surface wind over the ocean, providing
the data needed to remove the surface variability ‘noise’ caused by
the wind blowing over the ocean’s surface.
While the technique is not yet 100 percent accurate, Yan and hiscolleagues are continuing to refine it and are exploring its
application to other areas of the world. They are currently
examining salinity variations in the East China Sea before andafter construction of the Three Gorges Dam, the largest dam in theworld.
Improved Accuracy Sea Surface Temperatures now Available
Sea surface temperature (SST) is an important variable forweather and ocean forecasting and is increasingly seen as a key
indicator of climate change. ESA’s Medspiration project combines
data from multiple satellite systems to produce a robust set of sea
surface data for the waters around Europe and the Atlantic Ocean.
These products are generated speedily for near-real time ingestion
into forecasting models, and a high-resolution SST map focussed
on the Mediterranean Sea with an accuracy better than 0.3°C is
now produced daily.
Satellite instruments can only measure the temperature of thesurface ‘skin’ of the water rather than the bulk SST beneath, which
is what meteorologists and oceanographers want. However,
especially in areas of light winds such as the Mediterranean Sea insummer, insolation can create a significant temperature gradientnear the surface which dissipates at night with mixing.
Medspiration products now use SST measurements aquired only atnight, and have recently improved the spatial resolution of SST
maps by incorporating data from higher resolution sensors as well
as data from the polar-orbiting and geostationary weather

www.geo-web.org.uk

June 2006

Group for Earth Observation

satellites. In addition to the Advanced Along Track ScanningRadiometer on ESA’s Envisat, which can measure to 0.2°C, data
are used from a pair of Japanese-built instruments, the Advanced
Microwave Scanning Radiometer (AMSR) on NASA’s Aqua
satellite and the TRMM Microwave Imager (TMI) on the JAXANASA Tropical Rainfall Measuring Mission (TRMM) satellite.
These improved results from the Medspiration project also feed
into an even more ambitious scheme to combine all available SST
data into a worldwide high-resolution project known as the Global
Ocean Data Assimilation Experiment (GODAE) High-Resolution
Sea Surface Temperature Pilot Project (GHRSST-PP).
More on the Medspiration project can be found at:
http://www.esa.int/esaEO/SEM1XXNVGJE_index_0.html

GEO Quarterly No 10

It is envisaged that the data-dissemination satellites would besituated at five or six locations around the globe but, initially,
commercial communications satellites near to the present five main
DB weather satellites would be utilised.
At present, the most advanced implementation is EUMETSAT’s
EUMETCast system but India is making data from its Metsat
spacecraft available to other countries in the area through acommercial satellite and China has quickly developed aretransmission service through the ChinaStar-1 commercial
satellite. China’s Shine Tek system retransmits data not only fromthe Feng-Yun-1D, FY-2C, MTSAT and the NOAA polar- orbiters but
also high-resolution imagery from the MODIS instruments on
several other satellites. At present, this service is not available
outside China.
The Study phase of NOAA’s ADM system began in 2003 and has
now progressed to the development phase, in which the primaryconcern is to demonstrate the viability of the system and to provide
specific descriptions of what the ADM should consist. A partial
operational service may begin in 2007. However, it is clear thatNOAA will not be abandoning Direct Broadcast transmissions in
the foreseeable future; a Multi-Constellation User Terminal (MCUT)
is being developed to receive and process signals from a range ofdifferent polar-orbiting as well as geostationary satellites. The
reception of high-resolution imagery from the forthcoming NPOESS
polar-orbiters in X-band will require a precisely-steered antenna atleast 2 m in aperture.
Four Earth-Observing Spacecraft Launches in April
It is well known that radio signals are affected by passage throughthe atmosphere and Formosat-3 was launched on April 15 by an
Orbital Sciences Minotaur vehicle from Vandenberg, USA,
specifically to measure the effect of the atmosphere on GPS
satellite signals. The joint US/Taiwanese spacecraft, which isalternatively known as COSMIC (Constellation Observing System
for Meteorology, Ionosphere and Climate), consists of six small
62 kg satellites each carrying a GPS receiver which, over a periodof several months, will be moved to equally-spaced planes aroundthe globe inclined at 72° to the equator.
Israel can launch satellites only in a westward direction over theMediterranean Sea so the Russians put their latest imaging
spacecraft, EROS B, into a polar, sun-synchronous orbit from their
far eastern Svobodniy launch site in Amur region on April 25. The
Israeli company, ImageSat, which is part-owned by the state-run
Israel Aircraft Industries, said the 280 kg spacecraft has aresolution of 70 cm. The Russian news agency, ITAR-TASS,
reported that the camera ‘will permit Israeli intelligence to observe
important Iranian targets in the most minute detail’.
China’s 47th successful launch in a row
since October 1996 placed the 2,700 kg
Yaogan research satellite into the planned
orbit. The Long March-4B rocket carried
the payload—which will be used forsurveying, crop yield estimates anddisaster forecasts—from the launch site at
T’ai Yuan on April 27.

Amazing resolution of sea temperature variations near Spain’s Balearic Islands
Image credit: ESA

Global EUMETCast-Style System Takes ShapeIn view of the requirement for cost-optimised access to increasing
volumes of data and products, access to satellite data will bethrough a composite system consisting of both Direct Broadcast(DB) and Advanced Dissemination Methods (ADM). As part of theIntegrated Global Data Dissemination Service (IGDDS), ADM
would be the baseline while DB reception would serve as a limited
backup and for those without access to the ADM service.

The CloudSat/CALIPSO mission was to havebeen launched in 2005 but technical problems
and the strike at Boeing, the makers of the
Delta II launch vehicle, delayed the launch until
April. Scheduled for lift-off during a one-minutelaunch window on April 21, the launch wasaborted due to a technical problem. On
successive days the launch was postponeddue to technical problems, inclement weather
or the non-availability of a support aircraft. The
spectacular night-time launch from Vandenberg finally took place at 1002 UTC on
April 28, and the two satellites are flying inNight-time launch offormation in their planned sun-synchronous
CloudSat/CALIPSO
orbit. A more detailed account of thisCredit: Boeing / Thom Baurmission will appear in the next issue.

www.geo-web.org.uk

35

GEO Quarterly No 10Group for Earth Observation

June 2006

check whether or not the images weresatisfactory. The final images were
processed at home.

Goa

Ruud Jansen
Translation by Chris van Lint

Following our visit to Brazil (KM2005-1
and GEO Quarterly No 6), my wife and I
planned to revisit Goa, India’s smallest
state. Goa is a former Portuguese colony
and enjoys special status within India:
taxes are lower, beer is cheaper and theaverage standard of living is higher
compared to the rest of India. This ismainly due to the presence of bauxite,
which is used in aluminium production,
and at the coast, on the river mouth near
the township of Panjin, bulk carriers areloaded with this ore by means of a large
number of small barges.
The privileged position of
Goa is responsible for thefact that on Sundays andother public holidays, dozens
of buses from otherprovinces and from the cityof Mumbai discharge theircargo of day visitors at
various beach locations. The
most popular of these is thevillage of Calangute, whichboasts a beachapproximately 20 kilometreswide, dozens of shops, big
markets, small hotels andrestaurants.

aware that, when you ask an Indian aquestion and he or she replies whilst
shaking their head in a ‘no’ fashion, he or
she means ‘yes’. This will avoid quite afew problems when bartering in themarket!
Satellite Imaging
Although my wife and I had alreadyvisited Goa for two weeks last December,
we went there again in February/Marchfor a few weeks. This latest time I
brought along my weather satellite gear,

For both recording and imaging I used
Craig Anderson’s WXtoImg software. I
chose the NOAA-18 satellite so that I
would not have to get out of bed early, or
have to wait at the beach until late in theevening. The aerial was partially hiddenfrom sight and was hung under the roofof a so-called ‘shack’ (a beach tent with astraw and corrugated iron roof, situatedclose to the dunes). Notwithstanding this,I still attracted a large gathering of
inquisitive locals. I had attached a pieceof paper to my aerial on which I had
written ‘Danger - Radiation’ in English inorder to prevent touching, disassembly or
distortion of my PITA137. I also had avisit from an angry shack owner who
complained that I was scaring his
customers away because of the radiation
danger!
When the satellite was approaching, I
would head for the aerial with my gear,
connect it to my receiver,
start the minidisk recorderand in the meantime drinka Kingfisher (local beerbrand, named after one ofthe prevalent birds). By thetime my bottle was empty,
the satellite would havedisappeared behind thedunes and I could
disconnect my gear andreturn to my wife, followed
by a cooling bath in the sea(28°C) as a fitting
conclusion.
I have made a few images
in this fashion. The mosteasterly pass (just behindthe dunes) covered Thailand
and the western point of
Sumatra (Indonesia). The
next pass was nearly
overhead India and thefollowing one produced
images of the Arabian
Peninsula. Unfortunately
most of my images are
marred by sun reflections(sun glint) on the sea
surface. This is one of theunpleasant consequences ofbright sunlight and almost
no clouds (just a joke – theother consequences are a
big thirst and a suntan).

Although one sometimes
nearly breaks one’s necktripping over stinking heapsof garbage and has to becareful not to step on theholy cows which roam freeeverywhere, a lot of
resources are expended toensure the streets andbeaches are clean. On thepart of the beach mostfrequented by tourists, ateam of women ensures thatthe whole area is free fromsnippets of paper, empty
bottles and other rubbish.

Even smoking is prohibited
The Arabian peninsula - NOAA-18 at 09:49 UT on March 2, 2006
in the public areas of theconsisting of the KECIL137 receiver, thebeach. The shops recommend bringing
By placing all the images I have madePITA137 aerial and a minidisk recorder,
your own plastic bags to carry yourduring my various holidays next to each
together with a small Sony notebook
groceries, as the ones purchased from theother, I can cover an overlapping area
computer.
shops are relatively expensive.
from west Greenland to the south east
coast of Australia. I also still have an
The notebook was used to calculate theTo put it in a nutshell, Goa is a niceimage of part of South America (GEO Q
pass times of the NOAA-18 satellite,
holiday destination providing you areNo 6). In order for me to cover the wholeusing David Taylor’s WXtrack program,sensitive and aware of local culture. This
world a few more holiday trips will be
as well as for saving the minidisk soundmeans no topless appearances on therequired, so there is still plenty to do inrecordings. This would also enable me tobeach and no shopping in a bikini etc. Be
the future.

36

www.geo-web.org.uk

June 2006

Group for Earth Observation

GEO Quarterly No 10

This splendid image of India was acquired by Ruud Jansen at 08:08 UT on March 2, 2006
KECIL137 receiver, PITA137 antenna and WXtoImg software
www.geo-web.org.uk

37

GEO Quarterly No 10Group for Earth Observation

June 2006

Peter J Bradley G4BZEOver many years of receiving weather satellite images I have
marvelled at how certain lighting conditions can enhance theirability to detect features on the surface of the Earth. Given thatthe ground resolution at the sub-satellite point is approximately
one kilometre for both the NOAA HRPT and MSG HRV, how is it
possible that rivers, for example, which may be much narrower
than 1 km, can be seen when the sun is in an appropriate position?
Sunglint and shadows, particularly when the sun is at a low angle,
can reveal structures, both on the Earth’s surface and in clouds,
that might otherwise not be discernable.
The concept of ‘angle of incidence equals angle of reflection’
explains very simply the reason for this happening. When asatellite is in such a position that rays of light from the sun reach
the Earth’s surface at the same angle as the reflected rays travelback to the satellite, especially from a still body of water (sea, lake,river), that surface acts like a mirror to produce an artefact in thesatellite image that is generally described as sunglint. Thissituation is shown in figure 1.

Figure 2 - Meteosat-8 at 06:00 UT on March 23, 2004
Image © EUMETSAT 2004

Figure 1 - The geometry of sunglint

Anyone who regularly collects weather satellite images will haveseen examples of the larger manifestations of sun glint on APT,
HRPT, the old PDUS and the new MSG-1 over the years. Figure 4
on the facing page is a prime example, a NOAA-14 channel-2
HRPT image received at 08:00 UT on April 17, 2003, which showsmajor sunglint over a large section of Europe east of the UK: note
particularly the rivers Oder, Elbe and Rhine. It also shows a highpressure region centred over Britain with a more distant low
pressure area on the southwestern side of the jet stream.
Lake Victoria
Figures 2 and 3 show two Meteosat-8 segments from the same
region of eastern Africa, centred on Lake Victoria. A close
examination reveals some most interesting features fromsurprising sources. In figure 2, acquired at 06:00 UT, the firsttraces of sunglint make Lake Victoria prominent but otherwise theoverall scene is a relatively flat and featureless landscape with the
exception of a single mountain (Mt Elgon) to the north and theseries of rift valley lakes to the east. 45 minutes later, with the sun
at just the correct angle (figure 3), an amazing river system (which
could be described as one of the sources of the Nile) is revealed;
little evidence of it was apparent in the earlier image.

Figure 3 - 06:45 UT on March 23, 2004
Image © EUMETSAT 2004

38

www.geo-web.org.uk

Figure 4 - Sunglint on a NOAA-14 HRPT image

GEO Quarterly No 10Group for Earth Observation

June 2006

Figure 5 - Mt Longonot

Figure 10 - Steam plume from a French nuclear power station

Figure 6 - The Webuye waterfall

Figure 11 - NOAA 17 composite image showing contrails

Figure 7 - Cloud stretching north from the Pyrenees

Figure 12 - The same contrails, photographed by the author

Figure 8 - Pyrenees from France

Figure 9 - Pyrenees from Spain

40

Most of the rivers you see areconsiderably less than one kilometre
across and therefore do not show up in
the earlier image. When such subkilometre detail is revealed, the sunEarth-satellite geometry is such as tomirror sunlight from the surface of thewater directly towards the satellite
and saturating some of its sensor
elements, thus revealing the hitherto
invisible river system. If one looks at
an animated sequence of images it isvery easy to see the sun glint crossing
from east to west showing up manysub 1-km water course in the process.
Notice also, at lower right in theimages, the apparent rows of cumulus
humilis (fair weather clouds) whichwww.geo-web.org.uk

come right up to the edge of the rift
valley escarpment but not beyond. Also
notice the huge storm cell developing
over the western side of Lake Victoria
itself, quite common during March.
When looking at some of these satellite
images one might just wonder how
early explorers would have felt hadthey known that, in the future, a few ofthese images could have shown them
the total route of the Nile without theneed for years of exploration in thisvast and fascinating continent.
The White Nile flows from Lake
Victoria through Lake Kyoga, apapyrus surrounded lake, then into
Lake Albert, through a narrow gap

June 2006

Group for Earth Observation

GEO Quarterly No 10

only seven metres wide in
the surface rock at Kabelega
Falls (Murchison Falls).
Figure 6 is a photographshowing another waterfall,at Webuye, which can beseen just above the glistening spot on one of the rivers(figure 13). From there, theNile continues up throughUganda and southern
Sudan, then the Sudd region(a vast papyrus swamp) andfinally north to Khartoum
where it meets the Blue Nile
(from Lake Tana in
Figure 13 - Waterfall at Webuye
Ethiopia) before flowing
through Egypt to the Mediterranean.
Mt Longonot (figure 5) is a dormant volcano, photographedfrom the position marked ‘x’ near the right-hand edge of
figure 3. Mt Longonot was formed in the base of the rift valley
and can be seen just south of Lake Naivasha. This lake isdistinguished by having a small crater lake protruding from its
southwestern shore.

Figure 15 - Meteosat-8 HRV - 05:45 UT on April 5, 2004
Image © EUMETSAT 2004

Images acquired at weekly intervals as the sun moves north or
south of the equator show different reflections. Figure 15 is aninteresting example. The main region of sunglint encompasses
the southern Red Sea and part of the Gulf of Aden; there arenotably strong reflections around the Gulf of Tadjoura in
Djibuoti, and inland from Lake Tana, the largest lake in
Ethiopia. Sunglint also makes it possible to see the small islandin Lake Tana and the outflow of the infant Blue Nile. Though
no mean river (it can extend to 400 metres in width when inflood), the Blue Nile is well below the normal resolution
capability of Meteosat-8 HRV.
Cloud Features
Another example of how the satellite can image features thatcan be seen from the ground is that of the clouds to the north of
the Pyrennes. The MSG image in figure 16 shows thisphenomenon clearly; there is no cloud cover to the south of themountains on the Spanish side but a considerable amount on
the French side. Figure 7 was photographed while standing inbright sunshine just to the south of the clouds, from the top of
one of the ridges on the Pyrennes and shows this cloud effect.
These clouds hold a great deal of water which is deposited on
the French side (figure 8) producing the lush vegetation
whereas, on the Spanish side south of where the French photo
was taken, there is very little rain (figure 9) and the landscapeis very yellow and parched.
On one occasion, when in the Loire region, I was intrigued by acloud which appeared to vary in size but stayed in exactly thesame place every day (figure 10). It’s shape changed depending
on how strongly the wind was blowing and the air temperature,
but always remained on station. When I enquired as to why thecloud remained there the response was something like ‘nuage
nuclear’. I was told that the cloud would sometimes rise

Figure 14 - NOAA 17 HRPT, 10:28 UT on December 12, 2005

Figure 16 - Meteosat-8 HRV at 12:00 UT on June 4, 2005
Image © EUMETSAT 2005

hundreds of meters, particularly in the colder months of the year.
It didn’t take long to track down the cloud which was above the
Nuclear Power station (EDF Centre Nucleaire) at the confluence of
the Loire and the Visse just south of the small town of Bourgueil.
Curious to see whether this cloud was large enough to appear on
any of the satellite images, I looked at some archived HRPT
material. Figure 14 shows the cloud on a satellite image, verysmall but present. It is quite possible that similar images could beseen over Drax, Ferrybridge or similar power stations in the UK.
Aeroplane Contrails
My final example of what can be seen simultaneously from satellite
and the ground is shown in figures 11 and 12. Two aeroplane
contrails cross each other above the eastern edge of Dartmoor andthey show up clearly in both the satellite image and thephotograph. The contrail across the image can be seen above it’s
shadow which lies slightly to the east.
Figure 11 is a Photoshop composite of a NOAA-17 pass using
channels 1,2 and 5, and was created in order to show both thevapour trails and the shadows—which do not show up well on any
single channel. Channel-1, which showed the trail well, wasassigned to the red image, channel-2, which showed the shadow
well became the green image and channel-5 provided the blue
component of the image. When combined, the composite gave an
acceptable colour image.

www.geo-web.org.uk

41

GEO Quarterly No 10Group for Earth Observation

June 2006

Douglas Deans - dsdeans@tiscali.co.uk

The exciting news this quarter is the
addition to the library of three newprograms from David Taylor, whom many
will know as the most prolific weather
satellite program writer around. These are
all programs associated with the reception
and use of data from the EUMETCast
system but will also work with data fromothers sources such as the Internet.

into images but gives the user control ofwhat is to be processed: what should be
kept and for how long. In addition, theprogram saves and manages lots of othermeteorological images and data forsubsequent viewing and processing in otherprograms. There is a vast array of user
options and it would be difficult not to find a
set-up suitable for everyone’s use.

Whilst these programs have been about forsome time they have never been available
as Shareware; although David was often
happy to allow new users a trial licence toevaluate the software, it was not
appropriate to include them on the CD.
However, the structure of the programs has
now been changed and allows users a built
in 30-day trial period. This means thatsoftware will now work straight from the CD
for the evaluation period, making it anexcellent candidate for the library.
Registration is required for the software towork beyond the trial period.

MSG Animator v 2.5

Software charges are, in my opinion, very
good value for money, especially with theunrivalled support that David provides. In
addition there are some excellent
composite packages with great savings,
MSG-1 Toolset Plus being one that comesto mind.
The programs being added are MSG DataManager, MSG Animator and AVHRRManager. A brief outline of each of the
programs is provided below and you canread more about AVHRR Manager on
page 9 of this issue. I do hope that
separate, more comprehensive reviews will
be possible in future GEO publications. All
the programs are now included on GS1.
This CD is devoted exclusively to David
Taylor’s software and also contains lots ofimages and test data. You can find more
information about these programs, anddownload them, from:http://www.satsignal.net

MSG Data Manager v 2.5
MSG Data Manager processes andmanages the files received from the MSG
satellites through the EUMETCast system,
where data can be easily received using an
inexpensive Digital Video Broadcasting(DVB) card and a domestic satellite dish.
The program will, of course, also work withother sources of this data when they
become available.
The huge amounts of high resolution digital
imagery and meteorological data now
available means that management isalmost as important as reception. DataManager not only processes the raw data

42

MSG Animator is a fully automated programproviding real-time animations of images
processed and saved with MSG DataManager, including Meteosat 5 and 7 aswell as all the foreign satellite feeds. Up to
30 different animations can be configured
although automatic updating of all thosemight be rather onerous on the computer!
The software provides lots of user-defined
options, including number of frames,
location of image within the full disc, fulldisc if required, palette choice and video
processing options, smooth animations andmany more—too numerous to mention
here. For more complex animations with reprojections, weather chart overlays andmany other combinations, GeoSatSignal
should be used. However Animator is amust for quick, fully automated, up to dateanimations from MSG with no user input
required after the initial set up.
AVHRR Manager v 1.2.2
AVHRR Manager is a relatively new program(see page 9) and has been written to deal withan exciting new addition to the EUMETCast
system known as EARS-AVHRR. As many ofyou will know, HRPT is the digital 6-channel
1-km resolution data from the NOAA satellites
provided by the AVHRR instrument (from which
APT is derived as a sub-product). There are
already many stations in Europe and America
feeding the ATOVS data to EUMETSAT for
distribution via EUMETCast. HRPT is now being
added from about five of those stations in
Europe, Svalbard and Greenland.
When MetOp comes into service with similardata, EUMETSAT plans to distribute wholeworld AHRPT data via EUMETCast. This will bea fabulous service although we may have to getbigger computers and hard drives! The data issent in 1-minute segment files and the program,which is still under development, handles all thefollowing functions and more.

• Decompresses and assembles thesegmented data into composite
AVHRR files ensuring that any out-oforder segments are correctly dealt
with.
• Each completed pass is overlain on aquick-look map, and there are options
to change the quality of the map.
• You can select audible warnings for
new passes and new segmentswww.geo-web.org.uk• There is an option to view a list ofpasses for each receiving station andyou can also add the location of thosestations to the map.
The assembled file can be viewed in David’s
HRPT Reader program and there is a direct linkto this (assuming you have it installed on yourcomputer) via AVHRR Manager. The program isstill under development and I expect that by thetime you read this there will have been anumber of new features added.

The only catalogue additions and changes
this quarter are to CD GS-1, as listed
below. The full catalogue appeared in GEO
Quarterly No 9.
All David Taylor's weather satellite programs and libraries,
including the current releases of WXtrack, Satsignal, HRPT
Reader, GeoSatsignal, GroundMap, RX2 PassControl andmany other program extras. This disc also contains a large
quanti ty of sample fi les, many of hi gh-resoluti on data, foruse with these programs.
Processes and manages
AVHRR Manager
the files for HRPT via
v 1.2.4
EUMETCast
Manipulates
GeoSatSignal
Geostationary weather
v 6.0.0
satellite images
Rescales satellite
GroundMap
v 2.0.0
imagesConverts raw HRPT
HRPT Readerv
2.6.4
data files into images
Automatic animation of
MSG Animator
MSG images following
v 2.5.0
reception
Processes and manages
MSG Data Manager the files received fromv 2.5.0
MSG satellites
Computer control
RX2 PassControl
program for the RX2
v 3.0.8
receiver
Creates images from
SatSignal
v 5.0.0
wave files
S
a
t
e
l
l
i
t
e
T
r
a
c
k
i
n
g
WXtrackv 3.5.4
Program

How to Purchase CDs
Write to the address below requesting
GS1, GS2, GS3, GS4 or GS5. Prices
are £5 for any single CD, 2 for £8, 3 for£11, 4 for £14 or all 5 for £17. Please
enclose cash or cheque (made payable
to Douglas Deans—not GEO) for theappropriate amount. Nothing else isrequired.
The cost includes CDs, packaging,posting and a small donation towards
the cost of overheads. No fee is asked
from overseas members although an
exchange of software or interestingsatellite images is always welcome.
Orders are normally dispatched on the
day of receipt.
Order your CDs from:
Douglas Deans, 17 Montrose Way,
Dunblane, Perthshire FK15 9JL,
Scotland.

June 2006

Group for Earth Observation

GEO Quarterly No 10

Robert Moore
The ‘Mars Express’ article in GEO Q8 reminded me of my trip to
Arizona. On my way to Grand Canyon at the end of October I
had to stay overnight in the town of Flagstaff, the location of oneof the world’s most famous astronomical observatories. The
location was chosen because Flagstaff is high up and very dry
with no cities nearby, thus making it possible to observe all theyear around. Whilst Flagstaff has grown since the late 19th
century, its observatory still enjoys good conditions because thecity has signed up to the International Dark Skies Agreement.
Lighting in the city is carefully controlled; there is enough of it,
but not too much, and no energy is wasted in lighting up the sky.
The founder and first Director, Percival Lowell (1855–1916),
came from a wealthy family and took to astronomy only in his
late 30s when, in 1894, he established the observatory in orderto study Mars. Lowell was convinced that the patterns on thesurface of Mars resulted from the activities of intelligent beingsand he is forever linked in the popular imagination with life on
Mars. However, he also searched for a ninth planet, which hebelieved must lie beyond the known planets in the solar systembecause of irregularities in the orbit of Neptune. Lowell madecalculations of the size and orbit of this planet and, although henever saw Pluto (which was finally spotted in 1930), he started
the search for it. Appropriately, Pluto was eventually identified
at Flagstaff.

naked eye but I saw it as thousands of stars, more and more
densely packed towards the centre of the cluster. The image
reproduced above will give you some idea of what I saw. It canbe viewed, in colour, on the web page
http://seds.lpl.arizona.edu/messier/more/m015_more.html

where it is the seventh and final image.
Whatever its scientific importance, this cluster is a very
beautiful object, whose light takes nearly 34,000 years to reachus. Through a ten-inch reflector I had a look at Mars (which was
almost at its closest to Earth). The disc was very large and sodazzling that is was not possible to pick out surface details—theoperator did not have an appropriate filter available. So I did not
see Lowell’s beloved ‘canals’. Lowell would no doubt be as
intrigued and amazed by the images from Mars Express as weare. Breathtaking seems too mild a description of theobservations we can now make. Perhaps one day a GEO reader
will write us a first hand description of a visit to Mars. I suspect
rather few of today’s readers will be here to enjoy that report.
There is lots to see and do at the Flagstaff Observatory; families
with children are made very welcome and there appears to be anarmy of very expert ‘amateur’ astronomers around to guide
visitors, answer questions and operate the telescopes. So if you
happen to be passing that way – do drop in. Alternatively havea look at:
http://www.lowell.edu/

Reference
Oliver Morton (2002) Mapping Mars, Fourth Estate (London
and New York) ISBN 1-84115-669-8... continued from page 30

NOAAPORTOver 33 000 light years distant and 120 light years across,
M15 in Pegasus is one of the more conspicuous globular
star clusters, on the threshold of naked eye visibility. This
picture was made from CCD images taken at the KPNO
0.9-meter telescope in July and September of 1998.
Image: NOAO/AURA/NSF

The original observatory buildings, now an official National
Monument, are mainly a museum and educational institution
but both on site and at a centre a few miles away, serious
research continues, mainly on the Kuiper Belt and the Moon.
Lowell scientists collaborate with other institutions and haveaccess to some of the world’s largest telescopes.
I had the opportunity to look through two telescopes, although
not Lowell’s 24-inch Clark telescope (that would have beensomething—but it was not in use that night!). Through the
McAllister 15-inch telescope I observed the star cluster M15
near the centre of the Milky Way. This is barely visible to theroutinely, GOES does follows a standard scan pattern which
creates certain products at approximate intervals, thus giving
an appearance of ‘scheduling’. But when particular weather
conditions arise—hurricanes for example—NOAA will change
the satellite’s scan pattern and imaging rate to observe theevent in greater detail. This changes the flow of data sent tothe system for product creation: different products are now
produced, disrupting the apparent ‘schedule.
Further information on all aspects of NOAAPORT can be foundon the NOAAPORT User Page on the Internet [2].
References
1 The GOES Data Collection System (DCS) is a relay system used tocollect near real-time environmental data from earth-based
platforms known as data collection platforms (DCPs) located inremote areas where normal monitoring is not practical. These
platforms, which can be located on fixed sites on land as well as
aircraft, ships, balloons and buoys, can be placed in remotelocations and left to operate with minimal human intervention. They
are used to monitor seismic events, volcanoes, tsunami, snow
conditions, rivers, lakes, reservoirs, ice cover, ocean data, forest fire
control, meteorological and upper air parameters, and to provide
ground truth information. Transponders aboard the satellites detect
these signals and retransmit them to the Data Acquisition (CDA)
station in Wallops Island, Virginia.
2 NOAAPORT Users’ Page
http://www.nws.noaa.gov/
noaaport/html/noaaport.shtml

www.geo-web.org.uk

43

GEO Quarterly No 10Group for Earth Observation

June 2006

John Wills - email: veejay@uk2.net
In the last issue of GEO Quarterly, Francis Bellrequested an image of the Caspian Sea area. Well, I
thought I would send you some that I have received
here in Cyprus over the last few months. At the sametime, I’ll take the opportunity of including a brief
description of my setup.
I moved to Cyprus just over a year ago and am
situated on the south coast, about 1000 feet above sea
level, where I have unobstructed views all around:
except to the south where a small hill just prevents megetting images stretching as far south as the Horn ofAfrica.
My aerial, illustrated opposite, is of the Sykes-Cobey
QFH design, which works very well as can be seenfrom some of the low elevation images reproduced
here. The receiver is from Dartcom, and has had a
GEO/Dartcom EPROM fitted to enable me te receive
NOAA-18. During last Summer I was using theTimestep ProSat for Windows software but have now
installed WXtolmg. I have just completed building an
RX2c which is now my standby receiver.
The images on this page were both captured fromNOAA-17 last summer using the Prosat software. The
upper one, which provided 11 minutes of almost
perfect viewing from north of the Caspian Sea down to
the Red Sea, started to fade out just before the Horn ofAfrica would have come into view. The satellite signal
has been cut off, due to the small hill to the South ofme. The lower image shows just about as far east as I
can get, displaying the Indus River snaking back to
the Hindu Kush. The maximum elevation for this pass
was only 5.2 degrees.
During late summer 2005 I transferred my activities
to WXtoImg and the colour image opposite wasproduced from a NOAA-18 pass acquired at 10:29 UT
on April 17, 2006.
My Satellite Imaging Setup
The uppermost colour image opposite shows myweather satellite equipment. At the extreme left, next
to the oscilloscope, stands a home-made variable,
double power supply, with, to its right, my Proscan
Receiver sitting atop the Dartcom unit. A generalcoverage shortwave receiver can be seen on the desk,along with the computer; to the right of this again is a
module which connects, via a dish, to a satellite for myInternet connection—we do not have a phone line
here.

NOAA-17 at 07:38 UT on September 17, 2005 showing not only
the entire Caspian Sea but the Persian Gulf and Arabian Peninsula.

The uppermost small colour photograph shows my
Sykes-Cobey QFH. Below, another shows it mounted
on my roof in a wider view looking north that
illustrates my vantage point nicely. The final
photograph shows a beautiful sunset over my westernhorizon, across the Mediterranean Sea.
I do not suffer from any paging problems here in
Cyprus. But now and again on 137.62 MHz I do get anoccasional voice transmission. It seems to be a phone
conversation between two ladies, all in Greek; they doseem to have a lot to say to each other!

44

NOAA-17 at 06:45 UT on September 19, 2005 showing
the Indus river snaking back to the Hundu Kush.
www.geo-web.org.uk