Group for Earth Observation

The Independent Amateur Quarterly Publication for

Number 8

Earth Observation and Weather Satellite Enthusiasts

December 2005

Inside this issue . . .
Weatherman: read about
Vierling’s new complete
APT weather satellite
station.
Learn how axial
displacement of the twounequal loops of an RQHA
antenna affects its
performance - Rob
Hollander explains ...
Just how good is yourlocation for the reception of
APT images? Peter
Edwards details how you
can evaluate your location
to optimise your imaging.
Richard Osborne describes
how to construct a battery
operated portable PSU topower your weather
satellite receiver.
John Tellick reports on
GEO’s contribution at the
AMSAT 2005 Colloquium.
Les Hamilton reviews
APTDecoder, a new, free
software package for the
reception and processing of
NOAA APT data.
POVIM - Fred van den
Bosch details thepresentation he made at
Symposium 2005
Plus much, much more ...

AboveComparing radio and opticalhorizons - see ‘Evaluation of
Location’ by Peter Edwards on
page 29.

Right
A preview of a new programfrom David Taylor. This splices
together NOAA HRPT
segments disseminated via
EUMETCast. You can readabout this development on
page 14.

CONTACT INFORMATION

issue we posed the question whether hurricanes could be
Last
expected to intensify as the warming trend over our planet

continues. We could hardly have guessed then that we were about toexperience an all-time record Hurricane Season. Our front coverfeature is an image of Hurricane Katrina; an object of beauty seenfrom above the realm of Earth’s atmosphere but from ground level acataclysm bringing death and destruction on an unprecedented scale
to New Orleans and its environs.
that wasn’t all! For the first time ever, one of the season’s
Andhurricanes,
Vince, forsook the normal route from the eastern

Atlantic across to the Caribbean and headed northeast towards the
Iberian peninsula. Though downgraded to a tropical storm by thetime it made landfall, Vince certainly created a splash in parts of
Spain and Portugal (see our report on page 7). As we go to press,
Hurricane Beta is raging off the coast of Nicaragua.
who monitor APT and welcome a challenge may enjoy
Readerstrying out APTDecoder, new software that both captures andcreates images from NOAA APT. This new program from Patrik Tast
is still under development. Although not really recommended forbeginners, APTDecoder can already produce very worthwhile resultsin the hands of an experienced user. The program is reviewed on
page 15.
issue marks the conclusion of a highly successful second year
This
for GEO. We certainly couldn’t have got where we are without the

support of our hundreds of subscribers world-wide. The entire GEOManagement Team wishes all our readers a most pleasurable Festive
Season and continued enjoyment from your satellite imaging
throughout the New Year.

Contents
GEO Report
Francis BellMy Radio and Weather Satellite Workstation
Mike Stevens
Membership Report
Nigel Evans
Quarterly Question
Francis Bell
Monitoring EUMETCast
David Taylor
Unique Finale to the 2005 Hurricane Season
Improved DAWS Temperature Script
Les Hamilton
Turbocharge your Feng Yun 2C Downloads
Hurricane Forecast Feeds
Peter GreenGEO at the AMSAT Colloquium
John Tellick
News in Brief
APTDecoder
Les Hamilton
Weatherman - A complete APT reception system Les Hamilton

2
3
4
4
5
7
10
10
11
13
14
15
19

GEO Shop Page
NOAA Satellite Predictions for the UK and western Europe
Helplines and Internet Discussion Groups
Copy Deadline for GEO Quarterly No 9 (March 2006)
GEO Membership Renewal Form

i
ii
iii
iii
iv

Construct a Portable PSU for your ReceiverCreate your own 3D Weather Images
Amazing Revelations from Mars Express
Evaluation of Location
Radiation Pattern and Polarisation for an RQHA
Earth Imaging News
POVIM
Advisory on DAWS Scripting
Software Showcase
Publications ... a reminder
To Kill a Mocking Bird

23
24
26
29
32
34
38
41
42
43
44

Richard Osborne
Fred van den Bosch
ESA
Peter Edwards
Rob HollanderPeter Wakelin
Fred van den BoschPeter Edwards
Douglas Deans
Francis Bell
Francis Bell

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
Articles and Images for Publication
Les 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 © 2005
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 8Group for Earth Observation

December 2005

Francis Bell
Readers’ receiving stations in many partsof Britain have been experiencing serious
interference on NOAA-18’s 137.9125 MHz
APT downlink because of commercial
pager transmissions within the UK, which
use an adjacent frequency. I wanted toknow if other countries experienced
interference on this frequency. So when I
recently spent some time travelling in theeastern Mediterranean, Black Sea andUkraine, I took my hand-held scanner withme as I wanted to judge the situation inthese parts of Europe.
I did not attempt to record or display
images but I did listen to the audio fromNOAA’s satellites on 137.50, 137.62 and137.9125 MHz. Without a satellite in thesky these frequencies were silent. With asatellite in the sky I received a strong
signal. Lucky Europe!
Travelling with Prediction Tables
While carrying out these tests, I used thetable of predictions published in our
Quarterly, which I had taken with me. I
should have known in advance, but I
quickly realised that the table GEO
publishes is applicable from anywhere in
the world—with one additional piece of
information. You need to know your local
offset from the published times.
The prediction table relates to a latitude
and longitude close to the centre of theUK, but when I was in the Ukraine the local
time was three hours in advance of GMT
while the latitude and longitude were bothvery different. This scarcely matters as, forany given position in the world, all you
have to know is your local time offset andthe table will remain basically correct. At
my temporary location in the Ukraine theoffset was 27 minutes from their local time,and knowing this figure, the entire table forall the satellites fell into place. Of course,
do check your offset for both ascending
and descending satellites
Thanks to our Editor who produces thesetables. Yes, I do know about Keplerianelements and running them on a computer,but I still value the table GEO publishes.
Notes about my recent travels havereminded me about Istanbul where we
stayed briefly: the Blue Mosque, bazaars,

2

viewing two impressive suspension
bridges connecting Europe with Asia anddrinking beer overlooking the Bosphorus.
All quite straight forward but I didn’t realise
how many people lived there—about 17
million!
Meteoquake
Here is the connection with GEO. We haverecently been asked to act as consultants
to Meteoquake. This is a new group who
are researching into the possible
prediction of earthquakes from cloudformations above an earthquake area thatis judged to be at risk. I have no idea of the
background science involved. I’m a little
sceptical but hope this sort of prediction ispossible. I’m sure we have seen TV
coverage of the earthquake in SE Asiawith the subsequent Tsunami and themore recent earthquake in Pakistan. The
location of Istanbul is particularly sensitive
because a series of earthquakes appears
to be progressing across Turkey, making
Istanbul with its seventeen million people
vulnerable. Meteoquake may submit anarticle about their programme to GEO for
possible publication in a future Quarterly.
On the subject of potential disasters,
please don’t follow me around theworld. Places I have visited havebeen followed within a year or two by
hurricanes (several places in the
Caribbean and Gulf of Mexico),
terrorism (Egypt and Sir Lanka), a
Tsunami (Sir Lanka), an earthquake(Australia), a military coup (Gambia)
and bubonic plague (India).
On a serious note: our planet is subject to‘natural’ disasters, so we should be as
vigilant as possible, hence our own GEOGroup. I remember walking down Bourbon
Street in the French quarter of New
Orleans and listening to the jazz. Following
hurricane Katrina, that area finished under
5 metres of water which will not drain awayeasily.
Administrative Matters
As a registered company, GEO must
submit accounts (which are in the publicdomain) to Companies House. Accounts
for our first year, which ran from November
24, 2003 to November 30, 2004, have now
been filed. The accounts were quite
www.geo-web.org.uk

straightforward. Income came frommembership subscriptions and the main
costs were printing and distribution. There
were only a few other small items. To
check that I had everything in the rightform and that the figures were correct, I
asked a good friend, who is an accountant
and very skilled in these matters, to have alook at my figures, bank statements andinvoices. He agreed on everything except
one point: I had valued our stock andassets for the first year as zero. My
accountant friend said: ‘you do have somestock of back Quarterly issues and you
should value them,’ and we agreed on afigure of £1700. My view is that stock isn’t
worth anything unless you can sell it. So
here comes the sales pitch!
I believe GEO members should be much
more ambitious in buying back issues ofthe printed Quarterlies which we hold instock. This will help GEO’s finances:
remember we have to be financially viable
otherwise there will be no GEO. Suchaction may also help inform otherindividuals and groups if these back issues
fall into the right hands.
Here are some suggestions
everybody comes out a winner.

where• Buy back some back issues tocomplete your own collection.
(Stocks of our Launch issue i.e.
Quarterly number one are
exhausted.)• Buy one or more issues and givethem to your local radio club
• Buy sets of back issues and givethem as Christmas or birthday
presents. That may be cheaper thata book token.
• Buy one or two back issues and justgive them to your friends.
• I like this one very much; it would begreat if it happens. Every member
buys one additional copy of ourlatest Quarterly and then takes it andgives it to their local library.
• If you are a school, university,
business or any organisation with areception area, buy a back issue foryour reception area (this would
provide more interesting reading
than the average doctor or dentist’s
waiting room offers).

December 2005

Group for Earth Observation

GEO Quarterly No 8

Symposium and other Conferences
GEO’s plans for next year include our own
symposium on April 29, 2006 at the
National Space Centre in Leicester. Do
please put this date in your diary. Details
concerning this, our third symposium, willappear in our March 2006 issue.
We also hope to be represented in
Helsinki during June 2006 at the
EUMETSAT conference and I alreadyhave a draft paper ready for presentation,subject to its acceptance. Though a datehas yet to be fixed, the next NOAA
conference is likely to be held in the USA
during 2007, and GEO will try to be there.
It is important that we represent the UK
and our international membership at these
events.
Multi-Language Flyer
On the international dimension, GEO haveproduced a short document briefly
describing our group, its membership andthe benefits of membership. This has beentranslated into Spanish, French, Dutch,
German, and Portuguese. Each occupies
about a single A4 side of paper. The text ofthese documents should be on our website by the time this Quarterly reaches you.
Encryption
I still find the subject of encryption
frustrating. I am opposed to encryption of
weather satellite data. Nobody has everpresented me with an argument that it is arational policy to use public money to build
launch and operate a superb satellite withsophisticated instruments, with dedicated,skilled people on the ground looking after
the dissemination of data, and then to
encrypt the data. The logic defeats me. I
may be in trouble for writing the previous
few sentences but I don’t care. I havebeen in trouble before with my views about
encryption but I have broad shoulders andI’m not going away! The philosophy ofencryption is alien to me. It is profoundly
wrong.
In Conclusion ...
As usual I will finish this piece with athanks to our supportive membership andthose who contribute copy to thisQuarterly. I would also like to extend an
invitation to others to share theirexperiences, images and technical skills
with our group. Every contribution orquestion relating to weather satellites,
whether from experts or absolutebeginners, is valued.
And do please remember to renew yourmembership and encourage your friends
to join. A statement of the obvious: nomembers, no GEO.

Mike Stevens. G4CFZ
If you read my articles
in GEO Quarterlies 3
and 4 you will realisethat I have extensive
interests in the fields ofboth amateur radio andweather satellite
imaging. Since we arealways encouraged tosend in articles
describing in detail ourworkstations and how
we achieved them, I
decided to do just that.
I hope the following
description of how I
organise everythingmight be of interest toother readers.
My workstationconsists of a Proscan
receiver for polar
orbiting satellites, thesignal from which is fed
to an Acer 233 laptop
where images areproduced using either
WXtoImg or WXsat. My
Meteosat-8 system
consists of a 60 cm
satellite dish (now pole
The combined workstation, housed in a neat wooden cabinet
mounted and more rigid
than previously following
last years storms) which feeds the
The next section down contains my two
TechniSat receiver which in turn sends
amateur radio rigs with the Yaesu on
its output into the E-Machine PC. All
the left hand side. To the right of thesesoftware for image production is by
is the E-Machine main console with theDavid Taylor.
Proscan on top of it and, below thatagain, are the power supply system andI have separated GeoSatsignal from the
PC printer. The laptop is located on themain PC. With the network system that very top of the cabinet.
operates on the Acer laptop running all
the time in conjunction with the MSGI am located on the Isle of Portland at
Animator software, everything runs
about 500 feet above sea level where itvery smoothly.
is very exposed to winter conditions,but reception is excellent and so far I
The photograph shows my workstation,
have no interference with NOAA 18,
enclosed in a smart cabinet so thatwhich is a bonus. I hope this has been
everything is hidden when the doors
of interest to you all. I am sure there
are closed. On the top shelf inside theare many people out there who havecabinet sits the PC monitor, alongsidemuch more interesting stations. If so
my scanner with the satellite receiver
let’s hear about them—it’s all part ofat the top right. The keyboard andour fantastic hobby, sharing
mouse occupy the narrow shelf below.
experiences and ideas.

www.geo-web.org.uk

3

GEO Quarterly No 8Group for Earth Observation

Nigel Evans
As at October 11, 2005, the current paid
up members number 524. Of the members
who have chosen not to renew, 32 havememberships which have only just expiredso these are members who may haveforgotten to renew. Around 100 have notrenewed for the current year having
received the first issue for 2005; there isno direct feedback from these members.
Since the beginning of this year GEO has
attracted 137 new members and thecurrent membership is:• UK membership• Europe• Rest of world

375
79
70

I am not altogether surprised by theturnover of membership as other similarclubs have similar experiences. This
indicates that GEO will have to continue
with its drive for new members just to
maintain the current membership level,
which is necessary to support the qualityof service we provide. It also indicates that
our membership seems unlikely to reach1000 members, and GEO will have tobudget for a membership income in therange 500 - 600 members per annum but
recognising that there will be additional
income from GEO’s shop.

combine the laws of Coulomb andAmpere into a single action-at-distanceforce law. The ratio between these units
had the dimension of a velocity andWeber and Kohlrausch published thefirst accurate measurement in 1856. It
first appeared with the symbol ‘c’ inWeber’s Force Law, and has beenreferred to in numerous subsequent
papers by German physicists as‘Weber’s constant’.

And now the question. 'With respect to the
Earth's mean sea level, what is thesurface level of the water in the Caspian
Sea?’ Answers, either in imperial or metricunits (and I will take answers plus or minus
a little) to me via e-mailIt later transpired that this constant,divided by the square root of 2, was very
close to the velocity of electrodynamic
waves. Subsequent workers such as
Maxwell and Drude subsumed thisconversion factor so that ‘c’ now became
the symbol for the speed of light itself(Maxwell having shown that light wasitself an electrodynamic wave).

A clue:– the answer will surprise you! It
surprised me.

Throughout the later years of the 19th
century, a dichotomy persisted, where
the symbol ‘v’ was applied specifically tothe velocity of light, and ‘c’ to the velocityof electrodynamic waves. Around theend of the 19th century, influential
workers in the field, such as Planck andLorentz started to use ‘c’ to symbolise
the velocity of all forms ofelectrodynamic radiation. In 1907,
Einstein, who had originally formulated
his law as E = mv2 (squared), switchedfrom v to c, leading to its adoption as thestandard symbol for the speed of all
forms of electromagnetic radiation
through a vacuum.
It does, therefore, seem that the origin of
the use for ‘c’ as lightspeed was no morethan a fortuitous choice of a constant byWeber, many years ago.

Francis BellThe Quarterly competition in our last
publication did attract entries. To remind
you of the question, it related to Einstein's
famous formula E = mc2. The question
was: ‘Why use a lower case c to represent
the speed of light?’ The commonest
answer I received was that it was derived
for the Latin 'celeritas' meaning speed. I
have heard this answer given before
which is why I asked the question and it
was the answer I expected. Whether it'strue or not I just don't know.
I did receive the following comprehensive
entry from our editor, Les Hamilton.
The Speed of Light - ‘c’There is a popular belief that thisphysical constant derives from the word‘celerity’ (Latin celeritas - meaning
speed), but this is almost certainly little
more than an urban myth propagated by
Isaac Azimov.
During the 18th century, a number ofGerman physicists including Gauss(1835) and Weber (1846), attempted to4

December 2005

Our hobby deals with electromagnetic
radiation: visible light , IR and radio sosome background history of theirdiscovery is always interesting to know.

Quarterly Question 8
I know I said I wouldn't do this but I can't
resist. Recently my travels took me
through the eastern Mediterranean andbeyond into the Black Sea. I took with me
my hand-held scanner to listen to weather
satellites although I did not attempt todownload the images. I also took with me
a map of the area. Looking at the map I
was astonished by a statistic for the
Caspian Sea which was not far away. In
the past I have received images of the
Caspian Sea from Russian weather
satellites at my home in SW Surrey UK
but the NOAA satellites I am currently
receiving are in orbits too low for me toreceive images from the area of the
Caspian Sea directly. Perhaps some of our
Italian friends could send in an image forus. That is a request!
www.geo-web.org.uk

francis@geo-web.org.uk
or my postal address. I will pick a winneron December 25, 2005.

The reward will be free admission to our
symposium in Leicester next April for thewinning entry or to their nominee.

Cover Images
Front coverThis NOAA-17 channel-2 HRPT image shows
Hurricane Katrina poised over New Orleans at
16:24 UT on August 29, 2005.
Image: NOAA CLASS Library
Processing: HRPT Reader/Groundmap
Projection: Orthographic

Inside Back Cover (top)Rob Denton was intrigued by two of the cloudfeatures in this NOAA-18 image which heproduced from the 12:23 UT pass on
September 27, 2005. Rob wrote: ‘I found it
interesting because the low pressure over thewest of the Black Sea has been rotating in thesame place for two days now. Note also theunusual straight line of cloud to the north if Italy.’
Received at Worksop, Notts, England on a
Dartcom System II receiver with Wimo crossed
dipole antenna - processing: WXtoImg.

Inside Back Cover (foot)
DAWS temperature chart for the north Atlantic
at noon on September 16 - see note on page
10.

Back cover (top)Antarctica’s Erebus glacier protrudes from thecoast of Ross Island to form a 12 km long ice
tongue stretching across the ice-covered
McMurdo Sound in this NASA ASTER image
from November 30, 2001.
NASA image created by Jesse Allen, Earth
Observatory, using data provided courtesy ofNASA/GSFC/METI/ERSDAC/JAROS, and the
U.S./Japan ASTER Science Team.

Back cover (foot)Hurricane Katrina crossing the Louisiana
coastline, as viewed from GOES-12 at 16:15
UT on August 29, 2005.

Erratum
Captions to the rainfall analysis maps on
page 25 of GEO Q7 should have read‘winter’ for figure 1 and ‘summer’ for figure 2.

December 2005

Group for Earth Observation

GEO Quarterly No 8David Taylor (e-mail: davidtaylor@writeme.com)
A chance remark by Arne van Belle recently, alerted me to theavailability of a program that would read out the status of a
SkyStar card (used for receiving EUMETCast via the Hot Bird-6
satellite) and return the results in text format. Of course, thiscapability is already available in graphical format with theprograms supplied by EUMETSAT, but having the data in text
format meant that I could use my own software to graph it. Even
better, I could add the graphing to my automated data collection
so that no daily effort was required. One limitation is that the datais only sampled at 5-minute intervals, so any very rapid changes
will not be seen. There are three parameters which I choose toplot, and a fourth which I cannot:• Signal Quality - this is a percentage scale relating to thequality of the signal. A signal could have a high SNR (seebelow) but still be of poor quality—has anyone ever seen
examples of this?
• Signal-to-noise ratio (SNR) - typically less than 10 dB on
my system.
• Bit Error Rate - the instantaneous error rate prior to any
correction. Typically the SkyStar hardware will perform one
level of correction, and the higher-level TelliCast protocols
a further level of protection against errors.
• Uncorrected blocks - it would be nice to plot this, but as
the B2status.exe [1] program resets the count each time it’srun, you can’t get an accumulated uncorrected block count.
Discussion of some interesting days
It was just by chance that Arne’s discovery was made about thetime of the Autumn 2005 solar outage period, and I started
running the monitoring code just one day after my maximum solar
outage. Solar outage occurs when the sun is in line with the Hot
Bird satellite as seen from your antenna. Consequently, yoursystem receives not only the wanted signal from Hot Bird, butalso the energy radiated by the sun at 11GHz. Indeed, if yoursystem is very poorly designed, this solar heat energy can melt
the low noise block (LNB) at the antenna focus! Solar outages
occur twice a year, around the Equinoxes.
Friday, October 14
The three graphs in figure 1 represent a screen shot from theWeb page
http://www.david-taylor.myby.co.uk/mrtg/Eumetcast.html
and show the throughput of the SkyStar-2 card: from top tobottom• The quantity of data it sent to the TelliCast receiving
software• The bit-error rate (BER)• The signal Quality and SNR.
Whilst the throughput is an accurate total, the Quality, SNR and
BER are snapshots taken every five minutes, so are not trueaverages. Nevertheless, the data is quite interesting.
The top graph (throughput) shows a clear increase in data at the
middle of the day. This is to be expected, as the data is losslessly
compressed so that night-time visual channel data with large darkareas will compress better than daylight data and hence produce
smaller files and lower throughput.

Figure 1 - Friday, October 14, 2005

The middle graph (BER) shows a peak just at the time when thesolar outage is predicted. With the sun behind the satellite, thenoise in the receiver bandwidth is greater and therefore the error
rate of the data is greater. As a matter of interest, the error
correction scheme is such that no uncorrected blocks or missing
segments were observed. The maximum BER is around 400
errors per million, or 0.0004%. Although there appears to be asmooth peak in the data, I think that the MRTG plotting routinesmoothes the data, so don’t read too much precision into thesevery narrow peaks.
As you would expect, at the same time as the noise increases
both the SNR and signal quality take a dip, which shows clearlyin the bottom graph. There is no significance in the fact that
Quality is plotted with solid bars and the SNR as a line. MRTG
plots two variables that way, and it means that I don’t need to ask
the Editor for colour pages for this note! To allow the Quality and
SNR to be plotted with the same scale, the SNR is multiplied by
10 and therefore the 0 - 100 scale can be read as 0 - 10 dB SNR.
Thursday October 13
The three graphs shown in figure 2 indicate much the same story
as Friday’s. However, there are differences. Just as solar outages
affect your reception from Hot Bird, they also affect the downlink
between Meteosat-8 and its EUMETSAT ground station. Just
because they have a bigger antenna doesn’t mean they aren’taffected—while the sun is in the antenna beamwidth the bigger
antenna simply picks up more noise! OK, it’s more complex thanthat, but now is not the time to delve deeper. The net result is that
EUMETSAT may lose data from Meteosat-8 too, when the sunpasses behind that satellite. As Meteosat-8 is located at 3.4°W
and Hot Bird at 13°E, any outage will occur about one hour later
for Meteosat-8 than for Hot Bird.

www.geo-web.org.uk

5

GEO Quarterly No 8Group for Earth Observation

December 2005

used the B2status.exe program$ntp_str = `b2status -ti`;from the B2C2 SDK [1] which$ber = (split(/\n/,$ntp_str))[6];
can return a snapshot of the$ber = (split(/ +/,$ber))[3];$ber = int (1000000 * $ber);status of the DVB card. This
print “0\n”;
program can take commandprint “$ber\n”;
line parameters to limit the disprint “0\n”;
print “0\n”;
played data, so I run this withthe -TI parameter. The first line
File: SkyStarBER.plof each Perl script invokes thecommand and processes theoutput from the program into a$ntp_str = `b2status -ti`;$qual = (split(/\n/,$ntp_str))[4];four-line response as required$qual = (split(/ +/,$qual))[4];by MRTG. There are two sepa$snr = (split(/\n/,$ntp_str))[5];rate scripts—one to get the$snr = 10 * (split(/ +/,$snr))[3];
Quality and SNR, the other to$snr = int ($snr);
print “$qual\n”;
get the BER. To make the valprint “$snr\n”;
ues sensible integers for MRTG
print “0\n”;
to plot, the SNR is multiplied byprint “0\n”;
10 so that both it and Quality
File: SkyStarQualSNR.pl
become values in the range
0..100 (at least on my system),and the BER is multiplied by 106 so that it becomes an integer‘parts per million’ value.
Figure 2 - Thursday, October 13, 2005

• the Meteosat-8 / EUMETSAT outage is clearly shown on
the throughput graph (top), where the lack of data for the
12:00 and 12:15 UTC scans shows as a large drop in thethroughput at 13:00 - 13:30 clock time (MRTG uses local
time, UTC + 1 hour in my case, for display).
• the BER plot shows a peak at local solar outage time, andit’s larger than Friday’s peak because the sun-satellite
separation was less (0.57° on Thursday compared to 0.94°
on Friday, according to my WXtrack program).
• the Quality and SNR plots also show the dip due toincreased solar noise. However, there also seems to havebeen a drop between 02:00 and 02:30 UTC, with a slightblip in the BER during the same period. I have no idea
what caused that drop. In periods of very heavy rain you
do see drops like this but I don’t recall there being bad
weather around at that time (there had been two days
before, though).
How to add your own SkyStar data to MRTG
MRTG is a free tool widely used on UNIX systems for monitoring
network activity and there is a version available for Windows as
well. It comprises a Perl script for data collection, and a program
called from the Perl code which amalgamates the data. You candownload MRTG from:http://people.ee.ethz.ch/~oetiker/webtools/mrtg/mrtg.html
and Perl (also free) from:http://www.activestate.com/
Look for ‘ActivePerl’. You should also enable the SNMP service
on your Windows system if you wish to monitor network
throughput. There are a couple of steps to adding the signal
statistics to your MRTG reports: to write two very small Perlprograms to convert the output of the B2status.exe
program [1] into the correct four-line format for MRTG, and to add
the lines to your MRTG.cfg file to cause the Perl scripts to becalled and the data to be plotted.
You can also use MRTG to plot a variable which can be obtained
from the command-line by running a program which writes it
results to ‘standard output’, i.e. a normal command-line output. I

6All of these files are available by cut-and-paste from my website
so there’s no need to type them in. Look for this page:
http://www.david-taylor.myby.co.uk/mrtg/Eumetcast.html
Once the values are available as integers they can be plottedwith MRTG. Plotting the Quality and SNR requires a fixed 0..100
scale. Plotting the BER is best done on a log scale. I’m not anexpert in MRTG, so if any GEO Readers have suggestions for
improvements of the code below I would welcome them!
Reference
1 The ‘B2C2 SDK’ is the Software Development Kit for the SkyStar cards,
and it can be downloaded from:http://www.technisat.com/?site=service/download.php&produktID=1281
The Zip download includes the B2status.exe program. Neither the
SDK nor the B2status.exe file is supplied by EUMETSAT on their CD.
#-----------------------------------------------------------------------------------------------Target[SkyStar_Stamsund_BER]: `perl SkyStarBER.pl`
MaxBytes[SkyStar_Stamsund_BER]: 1000000
Title[SkyStar_Stamsund_BER]: SkyStar V2.3 card on Stamsund
Options[SkyStar_Stamsund_BER]: gauge, nopercent, growright, logscale, withzeroes
YLegend[SkyStar_Stamsund_BER]: BER ppm
ShortLegend[SkyStar_Stamsund_BER]: ppm
LegendI[SkyStar_Stamsund_BER]:
LegendO[SkyStar_Stamsund_BER]: BER:&nbsp;
Legend1[SkyStar_Stamsund_BER]:
Legend2[SkyStar_Stamsund_BER]: Bit Error Rate (BER) in parts per million
PageTop[SkyStar_Stamsund_BER]: <H1>SkyStar BER snapshots - Stamsund</H1>#-----------------------------------------------------------------------------------------------Target[SkyStar_Stamsund_SNR]: `perl SkyStarQualSNR.pl`
MaxBytes[SkyStar_Stamsund_SNR]: 100
MaxBytes2[SkyStar_Stamsund_SNR]: 100
Unscaled[SkyStar_Stamsund_SNR]: dwmy
Title[SkyStar_Stamsund_SNR]: SkyStar V2.3 card on Stamsund
Options[SkyStar_Stamsund_SNR]: integer, gauge, nopercent, growright
YLegend[SkyStar_Stamsund_SNR]: Quality, SNR*10
ShortLegend[SkyStar_Stamsund_SNR]: .
LegendI[SkyStar_Stamsund_SNR]: Quality %:&nbsp;
LegendO[SkyStar_Stamsund_SNR]: 10 * SNR dB:&nbsp;
Legend1[SkyStar_Stamsund_SNR]: Signal Quality (0..100%)
Legend2[SkyStar_Stamsund_SNR]: SNR * 10 (0..10.0dB)
PageTop[SkyStar_Stamsund_SNR]: <H1>SkyStar Quality & SNR snapshots - Stamsund</H1>#------------------------------------------------------------------------------------------------

www.geo-web.org.uk

Lines to add to MRTG.cfg

December 2005

During 2004, GEO reported on the firstever Atlantic hurricane to make landfall inSouth America. Now, just 18 months later,
the first ever Atlantic hurricane developed
close by European waters.
Hurricane Vince
Events started to unfold on October 8 thisyear with the appearance of tropical storm
Vince some 200 kilometres north-west ofMadeira. Initially, windspeeds around theeye of this slow-moving storm, tracking
northeast at around 10 kilometres per hour(kph), were just 80 kph; but during theafternoon of the following day they briefly
exceeded the 117 kph hurricane thresholdand prompted the NOAA National Hurricane Center (NHC) to elevate Vince tothe status of a Category-1 hurricane. The
colour image on page 9, acquired by the
MODIS instrument aboard NASA’s Aqua
satellite, clearly shows the clear eye in thecentre of the storm at the time when it wasat its most powerful. The Canary Islands
and the coast of northwest Africa arevisible at the lower right.

Group for Earth Observation

The arrival of Vince made this year’s
hurricane season the second busiest on
record with 20 named storms, a record
previously dating back, jointly, to 1887 and1995, each with 19 storms. At this time therecord was still held by the 1933 season
which produced 21 storms (NHC records
stretch back to 1851). Vince was also thefirst storm in the Atlantic Basin to begin
with the letter ‘V’ since the naming system
was introduced in 1953.
Hurricane Wilma
This year’s list of names was completed
when tropical storm Wilma materialised on
October 16 to equal the 1933 tally; andjust three days later she had become afull-blown category-5 hurricane with winds
reaching 280 kph and a minimum eye
barometric pressure of just 882 millibars.

GEO Quarterly No 8

the Mexican offshore islands of Cancun
and Isla Mujeres.
Wilma, though soon downgraded to a
Category-3 hurricane, pulverised theYucatan peninsula with sustained 200 kph
winds and gusts up to 240 kph, whichripped away storefronts, peeled off roofs
and forced tourists and residents alike toseek shelter in upper floors of buildings.
Moving at little more than 10 kph, Wilma
forced Mexico’s Caribbean coastline toendure hurricane conditions for some 48
hours, during which time some regions
experienced over a metre of rainfall.
At length, Wilma picked up speed andgained strength over the warm waters of
the Gulf of Mexico before smashing into
Florida with 200 kph winds and inflicting a

Vince, which had a diameter of only some
180 kilometres, formed farther east andfarther north than any tropical Atlantic
storm in recorded history. Hurricanes
normally form off west Africa where thesea-surface temperature is 27°C or
greater. It is extremely unusual for atropical storm to form off Madeira where,on the date in question, the sea surface
temperature was a mere 23°C at noon.
This latitude more commonly spawns
subtropical storms which are fed byclashing horizontal layers of cold and hot
air in the upper atmosphere rather thanwarm sea surface water and humidity.
Vince was soon downgraded to a tropicalstorm again and its centre, where winds
continued to gust to 75 kph, made landfall at the extreme southwest of Spain, justnorth of Cadiz, on the morning of
October 11, bringing 35 mm of rainfall tothe surrounding region in a two-hour spell.
Vince also gave rise to rainfall totalling
50 mm in Morocco, 40 mm in Andalusia,
26 mm in central Portugal but only
between 5 and 15 mm across the droughtstricken Costa del Sol.

Hurricane Wilma making landfall on Mexico’s Yucatan peninsula at 19:20 UT on October 20, 2005
in this NOAA-18 channel-2 HRPT image. At this point, Wilma was a category-4 hurricane.
Image: NOAA CLASS archive

At that point Wilma was the most powerfulhurricane ever recorded in the Atlanticbasin having escalated from category-2 tocategory 5 in just 6 hours! This prompted
the evacuation of some 100 000 people
from low-lying coastal areas around Cuba
and another 33,000 holidaymakers fromwww.geo-web.org.uk

Processing: HRPT Reader

four-hour pounding that cost at least four
lives, cut power to millions of homes andcaused billions of dollars in damage.
Wilma flooded the low-lying Florida Keys,
then hit the mainland south of the fastgrowing retirement city of Naples before

7

GEO Quarterly No 8Group for Earth Observation

December 2005

Meteorological Organisation, of which NOAA isan active member. You can find the lists for the
next five years at:
http://www.nhc.noaa.gov/aboutnames.shtml
A listing of retired names can be consulted at:
http://www.nhc.noaa.gov/retirednames.shtml
Names are given to tropical cyclones when theyreach tropical storm status (sustained winds of atleast 63 kph) and are maintained should thetropical storm be upgraded to a hurricane(sustained windspeed of 117 kph or greater).
Of the 22 named storms that have formed since
the June 1 start of the 2005 hurricane season, 12
have become hurricanes, six of these major. Thisis double the long-term average, which is 10
named storms and six hurricanes (two major)
per season. The Atlantic hurricane season
officially closes on November 30.
Image Credit
The colour image on the opposite page was
acquired by the MODIS instrument aboard
NASA’s Aqua satellite. The 250-metre resolution
image shows Hurricane Vince at its most activeat 14:10 UT on October 9, 2005.
Credit: MODIS Land Rapid Response Team, NASA GSFC.

The twin record-breakers, Hurricane Wilma (left) and Tropical Storm Alpha (lower right),
pictured in this NOAA 18 channel-2 HRPT image at 18:45 UT on October 23, 2005.
Image: NOAA CLASS archive

speeding across the Everglades to the
populous Miami-Fort Lauderdale areaon the Atlantic Coast, blasting windows
out of high-rise buildings, destroying
mobile homes and flipping cars.
Tropical Storm Alpha
Amidst all the turmoil surrounding
hurricane Wilma, Tropical Storm Alpha
became the record 22nd Atlantic tropicalstorm of the season when it developed
south of Puerto Rico, incredibly, on
October 22. This exhausted the list of
storm names for the first time ever andnecessitated use of the Greek alphabet
to continue the series. At its peak, as it
approached the Caribbean island of
Hispaniola, Alpha was producing windsof up to 90 kph which necessitated theevacuation of thousands of residents inboth the Dominican Republic and Haiti.
After making landfall, winds subsided toaround 55 kph, accompanied by torrential rainfall. Some places received
over 35 cm of rain and hundreds ofhouses in Haiti were destroyed by flash
floods. In a suburb of the capital, Port
au Prince, 23 homes were washedaway when a rain-swollen river over-8

flowed its banks. The flooding andmudslides triggered by the heavy rainscaused at least 26 deaths, some after
individuals were overwhelmed by flash
flooding. Never in danger of escalating
to hurricane proportions, Alpha peteredout after just two days.
Naming Atlantic Storms
Starting from 1953, Atlantic storms
were allocated girls’ names but, from1979, male and female names wereassigned alternately. Five ‘awkward’
letters (Q, U, X, Y and Z) are notincluded in the lists which operate in a
six-year cycle. Hurricanes that produce
major loss of life or property, such as
Charley, Frances, Ivan and Jeannefrom the 2004 season, and doubtless
Katrina and Wilma from the current
one, are ‘retired’ and replaced.
As a contingency, should yet morestorms develop, they will be named
using letters from the Greek alphabet(alpha, beta, gamma ...). The recent
tropical storm Alpha was the first everinstance when this has occurred. The
list of storm names is maintained by aninternational committee of the World
www.geo-web.org.uk

Hurricane Wilma pictured over Florida at 18:35 UT on
October 24, 2005. NOAA-18 channel-2 HRPT
Image: NOAA CLASS archive

GEO Quarterly No 8Group for Earth Observation

Les Hamilton
As explained in last quarter’s article by Fred van den Bosch [1], Digital
Atmosphere Workstation (DAWS) cannot handle directly negative
temperature values from synoptic data files. A work-around waspresented which offered a solution by adding a temperature offset to allvalues. Although this works, it does have the side effect of making thescript hard to interpret because the actual temperatures being plotted do
not in fact appear within it. Below is an alternative script which achieves
precisely the same display, but at all times references the actual
temperature values being displayed.

ERASE# -----------------------------------------------------------------# Place actual temperature value in Slot No 1
ANALYZE,STOR=1 TEMP
# -----------------------------------------------------------------# Store ZERO - (TEMP/1000 is approximately ZERO) in Slot No 2
analyze,STOR=2 SDVC=1:1000# -----------------------------------------------------------------# SDIF 2:1 subtracts Temp from 0 (changes -T to +T)# SDIF 1:2 subtracts 0 from Temp (leaves +T unchanged)# ---------------------------------------------------------------ANALYZE,OVER FILL COLOR=000:239:255 GRTN=0 SDIF=2:1
ANALYZE,OVER FILL COLOR=000:255:209 GRTN=0 SDIF=1:2
ANALYZE,OVER FILL COLOR=000:154:255 GRTN=5 SDIF=2:1
ANALYZE,OVER FILL COLOR=159:255:000 GRTN=5 SDIF=1:2
ANALYZE,OVER FILL COLOR=000:080:255 GRTN=10 SDIF=2:1
ANALYZE,OVER FILL COLOR=255:255:000 GRTN=10 SDIF=1:2
ANALYZE,OVER FILL COLOR=082:000:255 GRTN=15 SDIF=2:1
ANALYZE,OVER FILL COLOR=255:204:000 GRTN=15 SDIF=1:2
ANALYZE,OVER FILL COLOR=179:000:255 GRTN=20 SDIF=2:1
ANALYZE,OVER FILL COLOR=255:161:000 GRTN=20 SDIF=1:2
ANALYZE,OVER FILL COLOR=242:000:242 GRTN=25 SDIF=2:1
ANALYZE,OVER FILL COLOR=255:097:000 GRTN=25 SDIF=1:2
ANALYZE,OVER FILL COLOR=204:000:204 GRTN=30 SDIF=2:1
ANALYZE,OVER FILL COLOR=255:014:014 GRTN=30 SDIF=1:2
ANALYZE,OVER FILL COLOR=153:000:153 GRTN=35 SDIF=2:1
ANALYZE,OVER FILL COLOR=255:110:110 GRTN=35 SDIF=1:2
ANALYZE,OVER FILL COLOR=122:000:116 GRTN=40 SDIF=2:1
ANALYZE,OVER FILL COLOR=255:153:153 GRTN=40 SDIF=1:2#basemap
ANALYZE,CONT CINT=5 COLOR=100:100:100 LINE=1
ANALYZE,CONT COLOR=255:255:255 EQUA=0 LINE=1
A north Atlantic chart produced in this way (but with 2°C contours) isshown on the inside back cover of this issue.
Each temperature is first placed in the first storage slot. As DAWS does
not permit the user to place the value zero into a slot directly, the second
section of the script improvises, dividing the temperature by a thousand
and placing the result (which is almost zero) in Slot No 2.
When negative temperature values drawn from the synoptic datafile are
subtracted from zero (i.e. 0 - Temp) a positive value is created and plottedon the chart in a ‘cool’ colour. When a positive temperature from thesynoptic datafile has zero subtracted from itself, (i.e.Temp - 0) it isunchanged and can be plotted on the chart in a ‘warm’ colour.

References

December 2005

Last issue [1] we described how you can download raw
Feng Yun 2C telemetry data from China’s National Satellite
Meteorological Centre (NSMC) and process it yourself.
Unfortunately, since then, Internet data transfer rates from theOrient have plummeted to unacceptable levels. But thanks toFred van den Bosch, who has ‘discovered’ a download manager
called FreshDownload, transfer rates can now be increased up to
eightfold.
FreshDownload is a download manager which can be obtained
free (as a 1.5 Mb download) fromhttp://www.freshdevices.com
The program, though free, does require registration if you are touse it beyond its 11-day trial period; but the good news is that
registration is also free!
The secret behind this program’s speed is that it can open up to
eight simultaneous HTTP connections to retrieve a file.

The main FreshDownload window

Setting up a DownloadYour first action will probably be to increase the default number ofsimultaneous connections. Click <View/Fresh options/Connection>and change the value to 8. Next, visit the NSMC site at
http://www.nsmc.cma.gov.cn/SCB/F2C/HDF/
and right-click on the file you require and, on the pop-up menu,
click ‘Copy link address’. Next open FreshDownload and click the‘Add’ button followed by Ctrl-V on the keyboard. The address for
the HDF file will immediately appear in the ‘URL’ field. Finally,
click ‘OK’ (or press the ‘Enter’ key) to start the download.
In practice, most HDF files (which weigh in at 133 Mb) can be
downloaded in 90 minutes or less. Fred claims a ‘record’ of under
20 minutes!
On days when connections are particularly slow, download
channels can time-out. If so, exit the program, then reload anddouble-click on the filename (see image above) to resume. Thereis also an option to increase the time-out value.

1 Using Scripts with DAWS, GEO Quarterly No 7, page 30.

Reference

2 Advisory on Daws Scripting, this issue, page 41.

Processing Images from Feng Yun 2C, GEO Quarterly No 7, page 26

10

www.geo-web.org.uk

December 2005

Group for Earth Observation

GEO Quarterly No 8

Peter Green
This article describes a small program that can keep you up to datewith hurricanes through the forecasts available from the NOAA
National Weather Service Hurricane Centre as well as other
weather and image related sites. The National Hurricane Centre(NHC) can be found at
http://www.nhc.noaa.gov/
where you can obtain the latest news regarding the forecast anddevelopment of hurricanes as well as ongoing informed discussion.
The website also provides a host of images as well as details about
hurricane formation, tracking and forecasting. You can have
hurricane advisories delivered to your desktop via RSS newsfeeds!
What is RSS?
RSS (Really Simple Syndication) can provide lightweightsummaries of the latest news in a form that can be read using news
aggregator software. The idea is to provide the latest news andupdates in a headline or news digest format.
Figure 1 - Newsfeeds listed on the NOAA NHC web page

What do I need to use RSS Newsfeeds?
To use our RSS newsfeeds you must have a feed reader or news
aggregator installed on your computer. These programs can be set
to read the newsfeeds on a recurring basis, from as little as every 5
minutes up to several hours.
What are the NHC Feed Addresses?
The NHC currently offers three basin-wide aggregate feeds plus a
new innovation for the 2005 Hurricane Season, a series of feeds,
each relating to a specific active storm (figure 1).
BlogExpress
To take advantage of the RSS feeds I use BlogExpress which isavailable as a free download from:http://www.usablelabs.com/productBlogExpress.html
BlogExpress is a full-featured .NET application for content
syndication (also called a news aggregator or blog reader) which
supports all RSS versions. It can read contents from any websitesthat provide XML files for content syndication. BlogExpress is asmall download (560 kb) which just runs in the backgroundcollecting the latest news items for you.

Figure 2 - Copying the newsfeed web address

Inserting Hurricane Feeds into BlogExpress
Once you have installed BlogExpress you must add the NHC feed
addresses to the list of feeds in the reader. It’s a good idea to startby adding a new category for your feeds: just click <File → New
Category> and type in ‘Hurricanes’.
Next, open the NOAA NHC web page in your browser and click on
the orange coloured ‘XML’ icon labelled ‘RSS feeds’ in the left-handmenu panel (this icon is used across the Internet to indicate that an
RSS feed is available). This opens a page containing the various
RSS feed addresses (figure 1). Right-click the mouse on any of thelinks shown and select ‘copy link address’ from the popup menu thatappears (figure 2).
Back in BlogExpress, click <File → New Subscription> , click on the‘Subscription address’ field and paste in the address (by typing
Ctrl+V on the keyboard) as illustrated in figure 3. Click 'Check'then 'Finish' and the job is done. Next time you run BlogExpress
you will find the hurricane news flooding in.
www.geo-web.org.uk

Figure 3 - Adding a new feed to BlogExpress

11

GEO Quarterly No 8Group for Earth Observation

December 2005

Figure 4 - Hurricane Hilary imaged in true colour by NASA’s Aqua satellite on August 22, 2005

E-mail Delivery
If you prefer, the menu on the NOAA NHC web page has an
option where you can receive the same advisories by e-mail.
Hurricane Hilary
The August 20 advisory on Hurricane Hilary stated:‘EXPANDING AREA OF CONVECTIVE
CLOUD TOPS COLDER THAN -80C’
This is illustrated in figure 5, a screenshot taken from David
Taylor’s MSG Animator program which shows Hurricane
Hilary as viewed from NASA’s GOES-12 geostationary
satellite. One of Ton Lindemann’s colour lookup table palettes
has been applied to show the regions of greatest convective
activity. Ton’s CLUTs can be downloaded from the ‘Satsignal’
page at:www.satsignal.net
Thanks to both Ton and David for making their software
available.

12

Figure 5 - Hurricane Hilary as imaged in David Taylor’s MSG
Animator on August 20, 2005

www.geo-web.org.uk

December 2005

Group for Earth Observation

GEO Quarterly No 8

John Tellick
GEO was once again pleased to be invited toattend this year’s AMSAT-UK Colloquium, held
between July 29-31 at the University of Surrey,
Guildford, where we manned three stands
devoted to the reception of both geostationary
and polar orbiting weather satellite images, plus
information about the hobby.

was not too difficult to achieve seemed to begetting across more.
At last year’s Colloquium, the chairman hadcommented on the average age of attendees
and how amateur radio was suffering from alack of recruitment of young members? This

On the first stand there were no fewer than
three MSG systems (run by Francis Bell, David
Taylor and John Tellick) demonstrating live
Meteosat-8 reception. Real-time animations
and other imaging from these were projected on
to a big screen in the exhibition area, justoutside the lecture theatre.

year it was very encouraging to see so many
young people—many of them involved withbuilding micro-satellites—in attendance. Long
may this continue! GEO, AMSAT and allamateur radio groups have to find ways ofenthusing youngsters and interesting them inscience and the many aspects of amateur radio.
There was lot of space-oriented content thisyear which proved very interesting. One of themain presentation was on the Cassini-Huygens
mission to the Saturnian system. This included
much detail about the Huygens landing on Titan
and was delivered by Professor John Zarneckiof the Open University, the principal investigator
for the surface science package on Huygens.
Other presentations were concerned with thedesign and construction of spacecraft, spacequalification for hardware, orbital dynamics,
future and imminent amateur satellite projects
and the design of electronics for space andspace hardware.

Owing to the building’s location, our Hot Bird
reception dish had to be ‘planted’ in a garden
area behind some railings but worked wellnevertheless. David Simmons provided his
expertise in setting up the dish for us as well as
answering queries, and the signal was thendivided, using a simple T-splitter, to allow us tofeed two PCs from the same antenna.

David Taylor installing the EUMETCast
software on his laptop

The display area where live images
were projected on to a big screen

David Simmons (left) and Francis Bellsetting up the dish for Hot Bird/Meteosat-8

Two of the APT satellite receivers
on display on the GEO standDavid Taylor dealt with software set-up queries
and demonstrated various weather satellite
programs on his laptop, and also demonstrated
a quick laptop setup of the EUMETCast USB
hardware and software with a SkyStar USB box.

David Taylor gave a talk on the near future ofweather satellites, concentrating on the AVHRR
and MetOp data that will soon be disseminatedon EUMETCast.

On another stand devoted to APT reception,
Francis Bell managed to demonstrate
successful NOAA 18 reception on an RX2
receiver despite pagers being very audible on
his scanner. Our comprehensive display ofbrochures, technical documents and satellite
photos, kindly donated by EUMETSAT and
BNSC, created great interest, as it always does.
And John Tellick provided some examples of
GEO Shop products as well as details andadvice to those interested in setting up a
EUMETCast system.
The people who visited the GEO displays andspoke with us were well-informed and many
were interested in getting a live weather feed forthemselves. The message that MSG reception

There was also discussion of projects with the
ISS to get schools (and thereby the younger
generation) interested and involved with space.
GEO clearly has a role here since the receptionof EUMETCast data by amateurs and schools
can help to achieve this on many levels.

There was also a presentation on satellite
tracking software during part of the Colloquium
which generated a lot of interest in David’s
WXtrack program.
The Colloquium provided a most interesting andworthwhile three days and considerable interest
was shown in the GEO live EUMETCastdemonstrations and the space/environmental
related information freely available todelegates.
Acknowledgements
Delegates browse through theliterature on the GEO standwww.geo-web.org.uk

Thanks to David and Cecilia Taylor for allowing
us to make use of some of their photographs;
also to David for his contributions to this report.

13

GEO Quarterly No 8Group for Earth Observation

December 2005

Coming soon ...
HRPT via EUMETCast
The lower image on the inside front
cover of this issue is a screen-shot froma program in development by David
Taylor, and shows what HRPT AVHRR
data, which will soon to be available via
EUMETCast, will offer users.
Data from the polar orbiting satellites
such as NOAA-18 (and, in the future,from MetOp) is collected from multiple
receiving stations (Maspalomas in Gran
Canaria and Tromso in Norway in thisexample) then transmitted over the
EUMETSAT EUMETCast service in
one-minute chunks. The data thus
covers a full swath stretching all theway from the Equator to slightly beyond
the North Pole, a feat which would be
impossible for any single ground station.
In the new combiner program, all the
one-minute segments are displayed on acommon polar stereographic map
format, making a continuous image. The
segments are also combined to form asingle large file which can be displayed
and analysed using programs like HRPT
Reader. The full 1.1 kilometre ground
resolution of the HRPT data ismaintained and the image size of thisexample is 9972 lines of 2048 pixels.
It is EUMETSAT’s intention to makethis data available to users before theend of 2005, and the same type ofdissemination will be used for the new
MetOp satellite next year. The greatthing for users of the EUMETCast
system is that no new hardware isrequired: just some low-cost software to
decode and assemble the segments. Soeven people who can not erect thesteerable antenna previously needed toreceive HRPT data will soon be able toenjoy the higher resolution and quality
provided by this format through themedium of EUMETCast. Exciting times
indeed!

WEFAX/PDUS Extension
As we go to press comes news that theoft-postponed launch of the MSG-2
satellite may take place on December 20
this year. Inevitably, this has resulted ina knock-on effect on the new satellite’scommissioning, and WEFAX and PDUS
transmissions from Meteosat-7 haveconsequently now been extended until
June 14, 2006.

14

NOAA-18 image from the 13:35 UT pass on September 24
Processed by Bill Cutler using Spacetech/Archimedes A5000

MetOp-2 NewsThe latest date for the launch of
EUMETSAT’s first polar orbiting
weather satellite in the MetOp series iscurrently June 20, 2006.

Imaging on Archimedes
Way back in the late ‘80s, when amateur
weather satellite imaging was still verymuch in its infancy and most PC users
were still firmly entrenched in DOS, acompany called Spacetech produced thefirst weather satellite decoding softwarewith a ‘windows’ style interface. This
innovative package, called Weatherdesk,ran on the Acorn ‘Archimedes’ microcomputer. Bill Cutler still uses his
Spacetech decoder podule in an
Archimedes A5000
computer,andrecently sent GEO some examples of his
images, including this rather nice
NOAA-18 one he acquired on September
24 this year.
www.geo-web.org.uk

Bill lives in Battersea, London and has
no problems with pagers. He uses an
RX2 receiver, first of all recording thesatellite audio on a mains cassetterecorder then decoding it on his
Archimedes.
Bill tells us that he has in the pastexperienced interference from aneighbour’s electronic low-voltage
outdoor lighting, and has repositioned
his turnstile antenna to the bottom of
his garden to minimise this.

RSS Feed for GEO-Subscribers
If you plan to take up Peter Green’s
advice and tap into RSS newsfeeds, you
might like to add the GEO-Subscribers
mailing list to your portfolio.
Just add a subscription to this address:
http://rss.groups.yahoo.com/
group/GEO-Subscribers/rss

December 2005

Group for Earth Observation

GEO Quarterly No 8

Les Hamilton
Some months ago, Patrik Tast of Västervik in Finland
released APTDecoder, a software package that allows you to
capture NOAA APT audio, convert it into weather images,
then subsequently process these to add colour, remove noise,create a weblog and much more. Although still undercontinuous development, APTDecoder already offers a host offeatures which make it a powerful rival to establishedfavourites in its field, like WXsat, WXtoImg and Satsignal.
Obtaining and Installing APTDecoder
APTDecoder is free software and is available both from theSoftware Library and by direct download from:http://www.ptast.com/apt/decoder/
The single installation file will, by default, install APTDecoder
in the folder ‘C:\APTDecoder’ although it does offer a ‘browse’
button that allows you to select your own preferred location.
The first time you run APTDecoder, it is a good idea to openthe <Help → About> menu and click where it says ‘Create adesktop shortcut’.
Preparing APTDecoder for Imaging
APTDecoder offers a host of user options. Here are just a few
that you are recommended to modify before starting to use theprogram.
• Click <Settings → General settings> and in the General tab
check ‘Enable auto recording and processing’ so thatsatellite passes will be captured automatically.
• Open <Settings → Ground station> and type in yourlatitude, longitude, altitude and station name.
• Make sure you are on-line then open <Satellite → Keplerianelements> and click ‘Download’ to import the latest 2-line
elements.
• Open <Satellite → Active APT satellites> and place a check
mark against the names of those satellites from which
you wish to create images. Note: If no satellite is checked,
the program will not do anything!

Figure 1 - The APTDecoder main screen

Figure 2
The APTDecoder
folder tree

Capturing your first image
Now just leave APTDecoder running. The legend at the top of
the screen announces which satellite is approaching andcontinually updates its azimuth and elevation, as well as
stating the maximum elevation and AOS (Acquisition Of
Signal—the time when the satellite rises above your horizon).
Signal capture then commences (figure 1), the image
displaying in real-time as it builds up. Note the floating
overlay which shows full details of the satellite pass; thisoverlay does not appear on the saved images. Once the pass iscomplete the satellite audio, the decoded image and an
information file are all saved automatically
Setting Recording Volume
If you already have other software such as WXsat or WXtoImg
working satisfactorily on your PC, the recording level should

Figure 3 - The Image Enhancement Window

http://www.ptast.com/apt/decoder/15

GEO Quarterly No 8Group for Earth Observation

December 2005

prove satisfactory for APTDecoder and your images should show
a full range of tones. Otherwise, wait until a satellite image isforming and click <Tools → Recording control>. Check the ‘Select’box for the input channel that you connected to your receiver(‘line-in’ or ‘microphone’ as appropriate) and adjust its volumeslider until the decoding NOAA image shows a good range of
tones without ‘burning out’ the cloud detail.
Filing System
APTDecoder creates a new data folder each year, containing a
subfolder for each month and a further subfolder, as required,for each day of the month (figure 2). Every NOAA pass
generates three files: a WAV file containing the satellite audio,
a jpeg image in the standard NOAA format of two side-by-side
images, and a text file which contains full details of the pass(satellite name, times of AOS and LOS, station details and the2-line element set). All these are saved in the current ‘day’
folder, every file with a convenient generic stem filename basedon the date and time:

Figure 4 - The satellite pass information window

yymmdd_hhmmss_NOAA_nn
Optimising Image Reception
Even though you take the trouble to set the recording level
carefully, you may well discover that your images still lack thebrightness and contrast that you desire. APTDecoder has builtin tools for modifying its default image parameters under the

Figure 5 - Gamma correction in the <Enhance> menu

<Settings → General settings → Image properties → Enhancements>

menu (figure 3). Any changes made here will become thedefaults for all future satellite images. You can actually changethese parameters during image acquisition then store thechanges by clicking ‘OK’.
Pass Thresholds
Unless you have a particularly clear horizon you will probably
find that the beginning and end of each pass is of poor quality
and not worth decoding. The <Settings → General settings → Passthresholds> tab allows you to select, by either elevation orpathloss (in dB), when during a NOAA pass imaging starts andends.
Modifying Images
Once a basic twin-channel NOAA image has been captured it
can be processed in a variety of ways. The two channels,
Video-A (daytime visible channel-2) and Video-B (infrared
channel-4) may be displayed individually or further improved
using the tools in the <Enhance> menu. False colour can beapplied in several ways, both as a colour-composite image andas colour enhanced IR. The full range of image possibilities
available in the <Images> menu is:
•
•
•
•
•
•
•
•

*
*
*
*

Normal - the basic twin-channel NOAA transmission
Video A - visible channel-2 by day, channel-3 IR overnightVideo B - channel-2 infrared
False colour (A,B)
False colour temperature enhanced (ch 2+4)
False-colour low temperature enhanced (ch 2+4)
IR brightness temperatures (ch 4)
IR low temperature enhanced (ch 4)

scalable window showing the region beneath the cursor at up
to 500% enlargement; the ‘Reduce noise’, ‘Median filter’,‘Despeckle’ and ‘Sharpen’ options all work well; others such as‘Enhance’, ‘Emboss’ and ‘Find edges’ are of dubious usefulness
in this field.
Selecting a Colour PaletteFour of the image modes listed above (asterisked) can each be
assigned its own individual colour palette through the<Settings → Color lookup tables> menu (figure 6). Click theyellow folder icon adjacent to the mode for which the palette
is to be changed, select a new one from the pick-list that isdisplayed, then click ‘OK’. If you wish to see the immediate
effect of a new palette, load an image of the appropriate mode,
select a new palette and click the appropriate ‘eye’ icon. Thisway you can check various palettes before making a final
decision as to which you wish to be the default for that mode.
APTDecoder also features an editor where you can create
palettes of your own (<Tools → Color Lookup Table Editor>).
Imaging from Archived WAV Files
APTDecoder can be used to create images from archived WAV
files. Because these will often be stored on a CD or DVD,writing the images to the same folder as the WAV file is no

An additional useful option in the <Images> menu is called<Spacecraft → Passinfo> which displays a screen showing thecontents of the logfile produced at the time of acquisition (seefigure 4).

The <Enhance> menu provides tools to normalise and equalise
the image, as well as to adjust contrast and modify the gamma
setting (figure 5). The <Effect> menu offers additional tools,
some more useful than others. The ‘Magnifier’ opens a small

16

www.geo-web.org.uk

Figure 6 - The colour palette selection window

December 2005

Group for Earth Observation

GEO Quarterly No 8

Figure 7 - APTDecoder’s Flat Earth Monitor (satellite tracking screen)

Figure 8 - NOAA 17 at 11:37 UT on July 7, 2005, processed in APTDecoder using a customised palettewww.geo-web.org.uk

17

GEO Quarterly No 8

longer possible—but there is aningenious solution. APTDecoder createsa new folder called ‘raw’ inside its ‘audio’
folder, and deposits the images there.
The format in which the images are
stored (JPG, BMP, GIF etc.) can beselected from <General settings → Image
properties>
by using the ‘RAW
Image format’ drop-down menu. Thissetting also determines the format ofimages saved during direct reception
from the satellites.
Flat Earth Monitor
A satellite tracker called the Flat Earth
Monitor is an integral feature of
APTDecoder. It operates continuously inthe background but can be displayed
from the <Tools> menu (figure 7). The
satellites you display, and whether you
choose to draw footprints and display
the positions of the sun and moon, are allcontrolled under the <Settings> menu.
Daily Log
APTDecoder can prepare a web page
containing any, or all, of the images thatyou process during the day. This is avery elegant HTML page (index.html),
stored in the ‘APTdecoder\html\daily’folder, which displays a thumbnail copyof each image along with a neat table
listing full details of each satellite pass.
Clicking on any thumbnail reveals thefull-size image. To generate the Log justcheck ‘Create an html log’ on the Generaltab. If you wish, the program will also
upload the Daily Log to your FTP
server—an ideal way to keep your web
page of satellite images up to date.
At the start of each day, APTDecoder
erases the previous day’s Log and starts
a new one so you don’t have tocontinually delate old images.
Radio Control
APTDecoder supports radio tuning
control for the RX2, R2FX, and EMGO
weather satellite receivers.
RSS Reader
Another valuable feature of APTDecoder
is its in-built RSS Feed reader (see Peter
Green’s article on page 11). Not only
does this connect with updates on the
APTDecoder Forum, you can also
program in RSS feed addresses forNASA, NOAA, GEO_Subscribers and soon.
Other Features
In a program as feature-laden as
APTDecoder, it is impossible to cover
everything in a single article. Other
useful attributes are a Pass List table,
Footprint Overlap predictor, Orbit Data
table (expanded display of the 2-line

18

Group for Earth Observation

element data), Satellite swath display
plus a feature to check and update yourcomputer clock via the Internet.
The APTDecoder Internet Forum
The APTDecoder software is underconstant development and one of its
strengths is the availability of a
dedicated forum where users can ask
questions, make bug reports, offer
suggestions, and generally benefit fromeach others’ experiences. The forum canbe accessed directly through the<Help → Community>
menu, or bypointing your Internet browser to:
http://www.ptast.com/apt/decoder/and clicking the Community button at
the top of the page.
Questions and bug reports are generally
dealt with promptly. Unfortunately,
APTDecoder does not yet possess a Help
File. No doubt this will appear in time,
but meanwhile, why not join theInternet Forum and share yourexperiences with other members. You
should find that this Forum goes a long
way towards meeting all your program‘help’ requirements.
Conclusions
Although still very much a work inprogress, APTDecoder is already an
impressive program for capturing APT
weather satellite transmissions. The
software is really easy to use: just enableauto-recording and sit back and await
results. High-quality images are createdat the time of acquisition and theprogram also saves the WAV file so thatprocessing in other software can beundertaken later if desired.
Julian Moss has been an enthusiastic
user of APTDecoder since it was
launched, and his appraisal of thesoftware can be read in the gray sidepanel at right.
It is worth noting that APTDecoder is amulti-threaded application and manages
the CPU demands of its own modules,
and any other high-priority software
running at the same time, in an
intelligent manner. For example, if Flat
Earth Monitor is open when a satellite
pass becomes due it slows down as therecording thread takes priority. Whenthe recorder is inactive, more time isdevoted to Flat Earth Monitor. This canresult in several seconds delay when
closing down modules such as Flat Earthmonitor and the Radio Control tunerprogrammer; the module may appear to‘hang’ for several seconds before
vanishing from the screen.

www.geo-web.org.uk

December 2005

Julian Moss has been involved intrialling and testing APTDecoder since
it first appeared, and many of the
CLUTs (colour palette files) distributedwith the program were created by him.
Here is Julian’s appraisal of
APTDecoder.
“I am extremely pleased with thissoftware. I am now using it exclusively,
instead of the full version of WXtoImg
which I not so long ago paid for. I findthat APTDecoder produces much finerand more natural looking images than
WXtoImg, though as with SatSignal it
is not tolerant of poor quality telemetry
and cannot produce an image from apass recorded using a narrow bandreceiver (at least, not in myexperience.) APTDecoder cannot (yet)add overlays to an image, but this iscurrently being developed and I amvery excited about what I have seen sofar.
“I find that APTDecoder produces
images that are as good as those
produced by SatSignal. But it has the
major advantage over SatSignal that it
is a fully integrated package that
automates the whole process, fromrecording the satellite pass to
uploading decoded images to a web
server.
“I suppose I should add that
APTDecoder has the advantage ofbeing free, but as someone in thesoftware business I have no problem
with the idea of paying for software.
!I have customised my own colour
look-up tables for false colouring myimages. I started this some time ago
when APTDecoder did not provide
much control over the appearance ofimages. I find that by increasing thecontrast of the look-up bitmaps in apaint package, I can produce brighter
images that are more to my liking.
However, if you do this, then it is nolonger possible to edit the bitmaps
using APTDecoder’s built-in CLUT
editor, and any other changes must be
made manually.
“I have found Patrik Task to be
extremely responsive to suggestions.
Several of the features in the program,
such as the ability to run minimised in
the system tray, and to produce an
XML RSS feed of new images, weresuggestions I made. I really hope that,as a result of this article, more APT
enthusiasts from around the world will
begin using Patrik’s program, so that I
can add their RSS feeds to my feed
reader and start seeing weather
images from other places as soon as
they are created.”December 2005

Group for Earth Observation

GEO Quarterly No 8

Les Hamilton
Vierling Communications GmbH, based in
Ebermannstadt, some 50 km north of Nurnberg inGermany, have recently launched a new productcalled WEATHERMAN, a complete APT weather
satellite station. WEATHERMAN is aimed at mobile
users as well as the home and education markets
and comprises a 137 MHz APT receiver with power
supply unit, connecting leads and a QFH antenna kit
plus recording, imaging and control software.

Meteor (almost certainly obsolete) and NOAA-18(these frequencies are programmed into a PIC).

I have been using WEATHERMAN daily since earlyAugust and have found it to produce excellent
images from all the NOAA satellites. In the case of
NOAA-18 it is only marginally outperformed by theRX2 regarding its ability to reject UK pagers on
137.91 MHz. For readers thinking of investing in a
new APT system, or even just a quality receiver or
QFH, Vierling equipment is well worth considering.

The QFH antenna comes disassembled, as a kit, but
is easily constructed in under an hour. Everything isscrewed or bolted in place—you don’t have to solder
anything at all. The QFH is of the ‘tall/narrow’ design
with each filar making a half-turn around the mast.
Don’t make the mistake that I did first time by giving
the filars only a quarter-turn. The centre-leftphotograph at right shows a part-built QFH with twoof the filars correctly located. Being of all-metal
construction (alloy/brass), and with the downlead
connections protected by a weatherproof cap, thisantenna should prove ideal for outdoor use.

The Package - What you get
WEATHERMAN is delivered in a package that
includes the 40 x 1500 mm alloy mounting mast andthe four brass filars of the quadrifilar helical antenna(QFH) kit. Three boxes contain the APT receiver, its
9-volt plug-top power supply unit and the various
bits and pieces required to complete construction of
the QFH. One end of the 15-metre length of antenna
downlead comes ready fitted with tags to attach it to
the filars and there is a standard bayonet connector
at the other to mate it with the receiver—nosoldering is required. The supplied CD installs allnecessary software and PDF user guides for setting
up the system.
The Receiver
The Vierling APT receiver is housed in an attractive
plastic case 155 x 80 x 35 mm. At its lower end are
a 9-volt power input socket and a 9-pin D-type serial
port connector for computer control; at the upper
end are the bayonet antenna connector and two
3.5 mm jack sockets. One socket connects thesignal from the receiver to the ‘line-in’ socket of thecomputer soundcard while the other canaccommodate headphones to monitor the satellite
signal. The fascia supports a green power-on LED
and an orange LED that illuminates when a satellite
signal is being received. An LCD status display
indicates the frequency being received.
The receiver has a 30 kHz bandwidth and includes
automatic frequency correction (AFC) circuitry tocompensate for the Doppler frequency offset of thesatellites as they orbit. The receiver has a very highinput sensitivity which renders a mast-top preamplifier unnecessary with an outdoor antenna.
Tuning runs in 100 kHz steps from 137.10 MHz to
137.90 MHz, with additional 137.62, 137.85 and137.91 MHz frequencies for NOAA-17, Russian

The 9V power supply has a European ‘shuko’ 2-pin
mains fitting so you will need an appropriate adaptor
to use it; because it is also fitted with a non-standard
9-volt connector, you cannot readily substitute a
typical PSU designed for UK use.
The Antenna

The Vierling APT receiver

Setting up WEATHERMAN
Setting up WEATHERMAN for use took just a few
minutes. For initial tests I attached the QFH to the
top of a 2.5 m tall washing post in a clear situationnear the foot of my garden. The antenna downlead,
PSU and audio lead from the ‘signal’ jack were allconnected and, within seconds, the receiver’s LCD
screen stated ‘NOAA scan-mode’ and displayed thefrequency stepping through the pre-programmed
settings. As soon as a NOAA satellite arrived within
range the orange LED lit up, scanning ceased, andthe LCD pronounced ‘NOAA aktiv’. When a set ofheadphones (or a small speaker) was attached, thecomforting NOAA ‘clip-clop’ tone was clearly heard.
The Vierling receiver possesses no manual controls
although a specific frequency can be selected undersoftware control from the PC (see Appendix A). In
practice I found the default scanning mode to be
perfectly adequate for almost every situation;
software control is only required to select between
two satellites when their passes overlap.
Software
The software includes WaveTrace, Vierling’s own
wave-file recording program and WetterSat, thereceiver control software. Also supplied are David
Taylor’s Satsignal for converting the saved WAV files
into images and WXtrack for tracking the satellites
and predicting their passes. These provide thenovice with a fairly foolproof method of producing
images (see Appendix B). However, if you alreadyhave your own recording and imaging programs
installed on your PC, you can continue to use thesewith WEATHERMAN.

http://www.vierling-group.com/weatherman/

The
Vierling
QFH
antennaDuring construction (left),showing the half-turn ofeach filar and completed(right)Close-up of the LCD
display on the Vierling
APT receiver

19

GEO Quarterly No 8Group for Earth Observation

December 2005

Wettersat, in scanning mode, has locked on toa 137.62 MHz NOAA-17 pass. Both ‘NOAA’and ‘Receiver’ windows show green.

Wettersat, set to 137.50 MHz under computer
control awaits NOAA 12. The green ‘receiver’
window shows that the receiver is active on thisfrequency; the red ‘NOAA’ window shows thatthe satellite signal is not yet being received.

Wavetrace in action

20

The NOAA 18 pass from 13:04 UT on September 27, 2005, captured in Aberdeen, Scotland using
WEATHERMAN (Vierling APT receiver with outdoor QFH antenna) and processed with WXtoImg.

http://www.vierling-group.com/weatherman/

December 2005

Group for Earth Observation

Setting the Recording Level
It is vital that the recording level of your PC soundcard is set up
correctly. If it is too high the images will be too white and clouds inparticular become ‘bleached’; too low and images will be very dark.
Recording level is adjusted using a program called sndvol32.exe.
Click on your computer’s START button; select ‘Run’ and type‘sndvol32’ in the 'Open:' field. Click ‘OK’ and the program will openwith the legend 'Volume Control' in its title-bar. Click <Options>then <Properties> and check the ‘Recording’ radio-button; makesure that the ‘line-in’ and ‘microphone’ options are ticked then click‘OK’ to reveal the Recording Control panel (below).

GEO Quarterly No 8

My Experiences with theVierling ‘Weatherman’
Clive Finnis
I have used the Vierlingreceiver in place of my RX2
for a few days of passes now.
I have not used the QFH
antenna that comes with it
but stuck to the Paul Hayes
QFH I have installed in myloft. Due to planning
regulations around here I
cannot use an externalantenna.
Initial Impressions
The Vierling receiver is
supplied in a small, almost
hand held size case, which
looks
very
neat
and
professional,
and
gives
confidence that it will be
reliable in use.
In UseThe soundcard recording control showing the ‘line-in’ input
muted by the volume slider (left) and activated (right).

WEATHERMAN will normally be connected to the soundcard’s‘line-in’ socket, so this must be activated by checking the 'Select'box in the 'Line-in/Balance' panel and then raising the volume
control slider to around mid-scale. Once a live NOAA signal isbeing received, observe the blue audio-level bar in WaveTrace;
adjust the ‘line-in’ volume slider in Recording Control until thisstretches approximately 80% across the WaveTrace window (ifthis bar touches the far edge of the window, your level is too high).
If you find that the signal level remains low even with Recording
Control at maximum you can, instead, connect the ‘headphone’
output from WEATHERMAN to the soundcard ‘line-in’ socket. In
this case the audio level can be adjusted both at the receiver(using a small screwdriver to adjust the recessed ‘volume’ grubscrew immediately above the ‘Power’ LED on the front panel) andin Volume Control.
With some soundcards you may find that you get better results byconnecting to the ‘microphone’ input socket instead (be sure toclick its ‘Select’ box to activate this audio channel).
Producing Weather Satellite Images
The most rewarding and exciting way of imaging from weather
satellites, specially for newcomers to the hobby, is to use
soundcard software that actually displays the images on the PC
screen at the same time as the satellite is passing overhead. If you
already have soundcard capture software such as WXtoImg,
WXsat, or APT Decoder installed on your PC, I would certainly
recommend that you continue using it instead of WaveTrace. All
these programs decode both WAV files and images. This meansthat a particularly good pass may be reprocessed following
capture using any of these programs, or SatSignal, to produce
images of the highest quality.
The Results
As far as reception and imaging from the NOAA satellites that use
the 137.50 and 137.62 MHz frequencies are concerned, there are

The first problem was that
the Vierling does not supply
d.c. at the aerial socket topower a preamplifier (theRX2, Timestep Proscan andDartcom receivers all havethis facility). I know thatpreampsareseenasunfashionable, but with myantenna being indoors I findthat a Dartcom Preamp close
to the QFH definitely gives
me longer passes and better
quality images. I climbed to
the loft and disconnected thepreamp.
Two alternatives present
themselves if you really want
to use a pre-amp with theVierling receiver:
1 use a bias-T close to thereceiver (Minicircuits dothem for about $30 to$80 each) or
2 provide a separate d.c.
feed to the pre-amp via
a feedthrough capacitor.
I did neither and relied on astraight through connection
from Antenna to receiver.
Second problem: Using the‘Line In’ socket on my soundcard, I could barely getenough input for WXtoImg
despite setting the Volume
Control on Windows Control
Panel to maximum.

http://www.vierling-group.com/weatherman/

Changing to the ‘Mic In’
socket I reduced the Volume
Control to minimum, yet still
got an overload on WXtoImg.
Catch22—too little on one,
too much on the other (seethe main article for a
possible solution).
A third problem was thesoftware bug Les discovered:
the software crashes if theVierling is connected during
a re-boot. Hopefully this will
prove an easy fix forVierling.
Results
Unfortunately, mine weredisappointing. When I first
unpacked the Vierling I was
so impressed that I wasreaching for my cheque bookto buy one; but I now think
the good old RX2 willcontinue to be my mainstay
for the time being. The main
problems were reduced
lengths of passes and serious
pager interference, possibly
due to the lack of a pre-amp
to compensate for the indoor
antenna, I suspect.
I suffer very minor NOAA18
pager interference here with
my RX2, showing only at thestart and end of the passes.
With the Vierling it was all
the way through the pass.
This cannot be due to thedownlead or the aerial asthese were unchanged. It
could be the lack of Dartcom
Preamp, or it could be a
problem with the Vierlingreceiver itself.
Conclusion
I would like to spend moretime with the Vierling andinvestigate some options
regarding the pre-amp andinput levels to the PC. It
seems such a nice piece of kit
and I feel it should give
betterresults
thanI
achieved. Unfortunately I’ve
had to do it on a ‘five minutes
here, five minutes there’basis due to various home
and work commitments.

21

GEO Quarterly No 8Group for Earth Observation

no issues. WEATHERMAN produces results comparable withany other receiver I have used—bar none! Even with NOAA-18 at
137.91 MHz, results are very good indeed.
The colour composite NOAA-18 image reproduced on page 20
was captured from a pass with a maximum elevation of 70° using
WEATHERMAN with the QFH mounted outdoors. It provides afull eleven minutes of flawless imagery. True, the extremities ofthe pass—where the satellite signal is at its weakest—show
distinct evidence of pager breakthrough: over north Africa and to
the Far North where a hillside further compromises my horizon—
but I’ll accept this any day! My RX2 receiver, also fed from an
outdoor QFH, imaged the same pass and showed exactly thesame pager bands (though marginally less prominently).
The performance of WEATHERMAN, as with my RX2, isdependent on receiving the strongest possible signal fromNOAA-18. Anything that attenuates the satellite signal seems
to increase pager intrusion (here in the UK). When the QFH
was mounted in my loft, beneath the eaves of the house, there
was a major increase in pager interference with both receivers.
I also discovered that passes with a maximum elevation below
20° suffered severe pager banding over most of their length.
Clive Finnis evaluated the WEATHERMAN system from his homein Dorset (see right-hand panel on page 21) and made similar
observations.
Conclusions
WEATHERMAN is the only complete APT weather satellite
imaging solution currently available. If you are starting out on thehobby for the first time, it comes strongly recommended, with ahigh-quality computer-controllable receiver and a durable allmetal QFH antenna. A CD of useful software is also provided.
Overall, I was extremely impressed with the Vierling APT receiver
which produced images every bit as good as those from any of
my other receivers under identical conditions. Even for NOAA-18,
which has defeated the efforts of a number of high-quality
receivers (see our review of the excellent German-built R2FXAPT receiver in our previous issue), results were surprisingly
good. Before testing it I had feared that the Vierling receiver might
struggle on this frequency but my doubts were almost completely
dispelled as it came a very close second to my RX2, widely
considered to be the best receiver at 137.91 MHz.

December 2005

Warning
At the time of writing there is a ‘bug’ in this software. If the Vierlingreceiver is already powered on and connected to the PC while
the latter is booted up, a ‘port not available’ error occurs. The
simple solution is to remove either the power lead or the serial
lead from the receiver while the PC boots up then reconnect oncethe computer is running.
Appendix B
The Wavetrace program can also be found in the <Program
files\Weatherman folder> on your PC. Create a shortcut for easeof use. The WaveTrace screen window is illustrated in the bottom
left illustration on page 20. Detailed help is available on clicking
the button labelled ‘Hilfe’. This help is in English, and in common
with all the WEATHERMAN documentation, is an Acrobat PDF
file—so you need Acrobat Reader installed on your computer.
I used the program without modification and results wereexcellent. All you require to do is click the ‘Start’ button;
everything else is automatic, and every time a satellite is picked
up by WEATHERMAN, an audio wave (WAV) file is saved on thehard drive.
The WEATHERMAN installation includes a shareware copy ofDavid Taylor’s SatSignal to convert your WAV files into images. (Itis located inside the <Program files\Weatherman\WXtrack> folder).
Run SatSignal, load one of the saved WAV files, then watch yourimages unfold. (For a more detailed article on the use of
SatSignal, see GEO Quarterly No 3, page 46).
Obtaining WEATHERMAN
At the time of writing, WEATHERMAN can be ordered from
Vierling, through their website. The direct link appears at the footof this page. If you follow the link ‘Information material’ you will beable to download an English-language version of the
WEATHERMAN brochure (1.5 Mb PDF file).
If you require further information, or wish to enquire aboutordering from Vierling, click the link ‘Prices & more information’ toe-mail your request/order to them. There is no problem withlanguage, as the Vierling team are proficient in English.
Prices for GEO Members are as follows:
Item

Appendix A
Software control of the Vierling receiver can be achieved bymeans of the small program called Wettersat.exe. After installing
all the WEATHERMAN software, you should find this in the<Program files\Weatherman> folder on your PC. It is a good idea todrag this on to the Desktop using the right mouse button andcreating a shortcut there.

Complete WEATHERMAN(No. 70351.001)
Vierling Receiver only
(No. 70351.002)
QFH Antenna only
(No. 70351.6003)

PricesEuro
Sterling(ex VAT) (inc VAT)
336 euro£280

215 euro£180

150 euro£125

To use the program you will require a 9-pin D-type serial lead toconnect the receiver to your PC. By default, Wettersat opens in‘scan’ mode. The ‘receiver’ window shows green to indicate that
WEATHERMAN has been detected; the ‘NOAA’ window will alsochange from red to green as soon as a satellite signal is received(see the upper left-hand image on page 20).

To complete payment for my system I had to pay an additional£22 bank charge for the currency conversion and cash transfer.
However, by the time you read this, GEO may be able to supply
WEATHERMAN through the GEO Shop, which would allow
payment by credit card or personal cheque and avoid thesecharges.

To select a particular frequency, uncheck the ‘scan’ box and click
either the ‘NOAA+’ or ‘NOAA-’ button to cycle through the stored
list to the one that you require. The receiver will remained tuned
to this frequency until you alter it once more. If the receiver ispowered off (by unplugging its PSU), it always starts up again in‘scan’ mode. The centre image on page 20 shows the receiver
awaiting a satellite on 137.50 MHz.

Do check the GEO Shop page on our website (or send the
Shop an e-mail) before ordering. The URL is:22

http://www.geo-web.org.uk/shop.html
Above prices in euros are as quoted to GEO by Vierling, and do
not include VAT. Approximate prices in Sterling, including VAT arelisted for comparison. All prices include P&P.

http://www.vierling-group.com/weatherman/

December 2005

Group for Earth Observation

GEO Quarterly No 8

Manager: Clive Finnis
e-mail: shop@geo-web.org.uk
FAX: +44 (0) 1202 893 323

PRICE LIST

TechniSat SkyStar 2 PCI Card

EU

RoW

TechniSat SkyStar 2 PCI Card49.50 51.00
Technisat Skystar USB box
109.50 121.50
Telestar 80 cm dish with LNB
49.00
Telestar Ku band universal LNB
11.00 12.50
Technisat Satfinder alignment meter 21.50 24.50
Dartcom high quality QFH antenna 259.00 279.00
Turnstile APT antenna
36.00
GEO-PIC 1.0
7.00
7.40
GEO/Dartcom EPROM v 1.3
10.00 10.75
GEO 2004 CD (back issues)
8.00
8.40
GEO 2005 CD (back issues)
8.00
8.40

UK

8.30
11.25
9.30
9.30

Printed Back Issues
GEO Quarterly No 2
GEO Quarterly No 3
GEO Quarterly No 4
GEO Quarterly No 5

5.10
5.10
5.10
5.10

3.50
3.50
3.50
3.50

4.20
4.20
4.20
4.20

A 'free to air' DVB satellite TV and data
receiver card as recommended by
EUMETSAT. This card requires
installing inside the computer andcomes with comprehensive installation
instructions and CD-ROM of driver
software.

TechniSat SkyStar USB Box
If you do not feel confident about
installing cards inside your computer
you can use the external USB version.

Telestar 80 cm dish (or similar model)
and Ku-band LNB

All prices are in £ sterling and include postage and packaging

HOW TO PLACE YOUR ORDER
Orders should clearly state your name and address, including
postcode, and contact telephone number and e-mail addressin case we need to contact you about your order. Items orderedshould be clearly described and quantified.
It is preferred that you submit your order on a copy of the official
Shop Order Form, which you can download from the GEO
website at:
http://www.geo-web.org.uk/Orderform.pdf(Of course, we will also accept handwritten or typed orders)
Please mail your orders to:
GEO ShopPO Box 1375
Christchurch BH23 9AS
EnglandTechniSat SatFinder
Alignment Meter
A very useful and sensitive
meter which is a great help insetting up and aligning the dishfor maximum signal. The metercomes with full instructions

GEO PIC 1.0 for
RX2

GEO/Dartcom
EPROM v 1.3

This PIC comes
programmed withthe two new
frequencies to be
utilised by theforthcoming NOAA18 and NOAA-19
satellites.
Note: Check yourRX2 synthesiser
chip before ordering(see GEO Quarterly
No 5, page 16)

Recent tests haveshown the Dartcom
APT receiver to be
one of the best
regards pager
immunity in the UK.
This NEW EPROM
for the Dartcom
APT receiver adds
the two new NOAA
frequencies to thescan list in memory
page 0.

If you are paying by credit card, you can FAX us your order to:+44 (0) 1202 893 323
Turnstile APTantenna

TERMS AND CONDITIONSPayment Methods

Payments from UK Members can be accepted by Personal
Cheque, Postal Order, Credit Card and Debit Card. Paymentsfrom EU and Rest of World members can be accepted by Credit
Card or Debit Card.
Cheques and Postal Orders must be made payable to ‘Group for
Earth Observation’
VISA, Mastercard, Switch and Switch Solo are all accepted, butplease note that you must state• the cardholder’s signature• the type of card, card number and expiry date
• the issue number (for Switch and Switch Solo only)

Dartcom
QFH antenna

GEO 2004 CD
Back issues in PDF
format - so that new
members can catchup on last year.

All credit cards are authorised before goods are despatched.
Please include your e-mail address or telephone number in case
we need to contact you about your order. In the event ofproblems with items purchased from GEO-Shop, please contact
Clive Finnis (contact details at top of page).
Ordering and Shipping
We will ship by post, so please allow 28 days for delivery although wehope UK and EU orders will take just a few days; orders to the Rest of
the World may take a few weeks.

www.geo-web.org.uk

Items from the GEO shop are available only to
paid up GEO membersi

NOAA 12NOAA 15NOAA 17NOAA 18

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

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

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

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

NOAA 12NOAA 15NOAA 17

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

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

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

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

Mar 01 05:48 07:28 15:34 17:14 05:34 07:14 15:23 17:01 11:02 12:43 20:50 22:30 01:58 03:39 11:51 13:31
Mar 02 05:23 07:03 15:10 16:49 05:11 06:51 16:37 18:18 10:39 12:20 20:27 22:06 01:48 03:29 11:41 13:21

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

ii

NOAA 18

December 2005

Group for Earth Observation

GEO Quarterly No 8

MSG-1
A forum dedicated to Meteosat-8 (formerly MSG-1), where members
can share information about the reception hardware and software.

GEO Helplines

e-mail: MSG-1-subscribe@yahoogroups.com

Douglas Deans, Dunblane, Perthshire, SCOTLAND
All aspects of weather satellites from APT, HRPT to Meteosat-8
DVB/EUMETCast systems.
• telephone:(01786) 82 28 28• e-mail: douglas@dsdeans.freeserve.co.uk
John Tellick, Surbiton, Surrey, ENGLAND
Information about the hardware required to receive Meteosat-8 andadvice about registering for the various MSG services. John will also‘field’ any queries of a more general nature about any aspect of receiving weather satellite transmissions.
• telephone: (0208) 390 3315
• e-mail: info@geo-web.org.uk

Weather Satellite Reports
A group providing reports, updates and news on operational aspects ofweather satellites.
e-mail: weather-satellite-reports-subscribe@yahoogroups.com

WXtoImg
Users of the WXtoImg software package for capturing and imaging
NOAA APT can air their problems, discuss its features and ask questions about it.
e-mail: wxtoimg-subscribe@yahoogroups.com

Copy Deadline

Keith Holland, London, ENGLAND
Specifically, help for APT users (137 MHz band) and Meteosat-7 wefax.
• e-mail: geo@koholland.plus.com
David Strickland, Truro, Cornwall, ENGLANDDavid has set up his own wireless network system of three computers.
He has interests in electronic design and prototyping, general computing, microchip processors with various facilities and of course MSG
satellite imaging. He will be happy to discuss any of the above topics,
and to help anyone local, including viewing his setup.
• e-mail: David@Strickland.uk.com
Geoff Morris GW3ATZ, Shotton, Flintshire, NE WALES
Geoff has lots of experience aerial, coax,connectors, mounting hardware etc. Also done a lot of work with the orbiting satellites. Geoff isknow his way with most of David Taylor’s software. He has recently
started with MSG, so should be able to share his experiences with othernewcomers to this branch of the hobby.
• Tel: (01244) 818252• e-mail: gw3atz@btopenworld.com
Guy Martin G8NFU, Biggin Hill NW Kent, ENGLAND
Guy is prepared to advise anyone who wishes to receive MSG underWindows 2000. He also runs Meteosat-7 SDUS.
• agm@tonbridge-school.org
Hector Cintron, San Juan, Puerto Rico, USA
Hector is prepared to field enquiries on HRPT, APT, WEFAX, EMWIN
and NOAAPORT• Phone: 787-774-8657• e-mail: n1tkk@hwic.net
E-mail contact can of course be made at any time, but
we would ask you to restrict telephone contact to theperiod 7.00-9.00 pm in the evenings.

for GEO Quarterly No 9

Tuesday, January 31, 2006
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• Construction projects• Weather satellite images• Reports on weather phenomena• Description of readers’ satellite imaging stations• Activities from overseas• Letters to the Editor• Problems and Queries for our experts to answer
Contributions should of course be original and, where possible, should
be submitted to the editor in electronic format (floppy disc, e-mailattachment, CD). But we will also accept handwritten or typed copy
should the need arise.
Please note, however, that major articles which contain large numbersof satellite images, photographs or other illustrations should be submitted well before this date so that they can be prepared and made up
into pages in time for publication.
Images and Diagrams

Useful Internet
Discussion Groups

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 and diagrams are preferred in
Windows metafile and postscript formats.

There are a number of Internet-based discussion groups available toweather satellite enthusiasts. You can join any of these by sending an
e-mail to the appropriate address, with a request to subscribe. Indeed,a blank e-mail containing the word ‘subscribe’ in its Subject line is all thatis required. Some of the more useful groups and their contact addresses are listed below.

We can also scan original photographs, negatives and slides.
If your article submission contains embedded images and diagrams,
please note that we do also require, in addition, individual copies ofeach image or drawing which is not embedded within the article, formake-up purposes.

GEO-Subscribers
This is a group where GEO members can exchange information relating
to either GEO itself or Earth observation satellites and related matters.

Submission of Copy

e-mail:GEO-Subscribers-subscribe@yahoogroups.com

Satsignal
An end-user self help group for users of David Taylor's Satellite
Software Tools including the orbit predictor WXtrack, the file decoders
GeoSatSignal and SatSignal, the ATOVS and HRPT Reader programs,
the remapper GroundMap, and the MSG Data Manager
e-mail: SatSignal-subscribe@yahoogroups.com

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 to the following e-mailaddress:
editor@geo-web.org.uk

Large attachments (1 Mb to 10 Mb) are best sent to:lesw.hamilton@gmail.com

www.geo-web.org.uk

iii

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iv

www.geo-web.org.uk

December 2005

Group for Earth Observation

GEO Quarterly No 8

Richard Osborne

Figure 1

The RX2 receiver is designed for a 12 V
supply at about 100 mA. In the house, aregulated plug-top power supply can beused but this is not possible for portable
operation. My answer to the problem is
to power the RX2 from a step-up DC to
DC convertor powered by four nickel
metal hydride (NiMH) rechargeable
batteries.
I built a DC-DC convertor on Veroboard
together with a simple charger circuit forthe batteries and packaged the lot insidea small plastic instrument case. The
circuit diagram of the supply is shown in
Figure 1.
The core of this circuit is the Maxim
MAX761 DC-DC convertor, which boosts
the 5 V supplied by the batteries to the
12 V required to operate the receiver.
The circuit can deliver a current up to
150 mA.
The design also contains a comparator
that can be used to monitor the voltageof the battery pack and drive an LED
when the voltage falls below a pre-set
value to indicate that the batteries needcharging. The comparator is set to trip at
about 4.8 V.
When a charging supply is connected thebatteries are constantly charged intrickle mode using an LM317 as a simple
constant-current source. ZD1 prevents
the output from the LM317 rising too far
if, for any reason, the battery packcircuit goes open circuit. I recommend
the use of a resettable fuse in series withthe batteries as they can deliver a large
quantity of current under short-circuit
conditions.
With the simple charger circuitdescribed, the batteries could become
overcharged if left on charge for too long.
Some mains powered plug-in timers
incorporate a timer feature that could be
used to good effect. For morecomprehensive charging functions, theMaxim MAX712 could be used as awww.geo-web.org.uk

basis. Alternatively, use a box with abattery compartment and charge thebatteries externally.
When designing DC-DC convertors, auseful tip is to obtain two identicalinductors and fit the second in series
with the output. This gives a substantial
reduction in switching noise at theoutput resulting in a very smooth output
supply.
The components are all readily available
from suppliers such as Farnell. The
inductor needs to have a minimum
current rating of 1.25 A.
Another use for the convertor is to poweran LNB in conjunction with a satellite
finder meter, useful for locating Hot Bird
to receive MSG-1 transmissions.
Acknowledgement
Thanks to Norbert Puetz of Erding,Germany, for the photograph of his
customised RX2 receiver.

23

GEO Quarterly No 8Group for Earth Observation

December 2005

steps, in order.
• Run Bas Relief to reveal the screen
shown in figure 2.
• Load the same satellite image into
both the <Image> and <Depthmap>
windows.
• Now click the <Smooth> button.
This reveals the ‘Segmentationsmoothing’ pop-up window (figure 3).
• First, click the <Create outline image>
button. As soon as the outline
appears (figure 4), click <Close>.
• Next, click the <Smooth depth map>
button to create a rather hazygreyscale image (figure 5) then click<Close>.
• Finally click <Open depth map> toplace this image in the ‘Depthmap’
window of the main Bas Relief
window. Click <Close> to clear the
pop-up screen.
On the main screen (figure 2) try a value of‘20’ for <Parallax between views>, select<Colour Red-Cyan> and then click on the<Anaglyph image> button. Once you
supply a suitable filename in the <Saveimage> input box your anaglyph is created.

Fred van den BoschIn this article I describe how you can make3D anaglyphs from your weather satellite
images. An anaglyph is a special kind ofimage which produces a 3-dimensional
appearance when viewed throughcoloured glasses. A freeware program
called Bas Relief is used to generatethese anaglyphs.
Introduction
The registered version of WXtoImg, theprogram which I use for APT-images,
contains options for the creation of 3D
anaglyphs. These must be viewed throughcoloured spectacles with a red filter to theleft and a blue-green one to the right.
Because MSG images are flat, just likethose from NOAA APT, it should bepossible to make anaglyphs from themtoo.
Initially I was disappointed. Searching theInternet turned up a large quantity ofprocedures using photosoftware such as
Photoshop and Paint Shop Pro, but theimplementation of these methods was
generally extremely laborious and theresults inconsistent.
In order to learn more I summarised myexperiences on the Satsignal Internet
forum under ‘How to make anaglyphs.’
Following these depressing experiences I
searched for software that could create ananaglyph directly from an image.
TheoryFirst of all a little theory. A traditional way ofpresenting two different stereo images ofan object is convert them into a coloured

24

anaglyph. Such an anaglyph contains theinformation from the left-hand image in the
red channel and that from the right-hand
image in the green and blue channels of
the colour image (figure 1). The image isthen viewed through coloured glasses.
The red filter over the left eye contains
only information from the left image; thegreen or blue filter over the right eye
contains only information from the righthand image. Now you see a 3D image!
Bas Relief
Bas Relief is a program for making all
kinds of manipulations to 3D images. The
free demo version is fully functional in one
specific area—creating anaglyphs.
Bas Relief can be downloaded from :http://www.3dphotopro.com/
software.html.
You have to register for the free newsletterto gain your download password, but you
can unsubscribe later at any time.
Operation
The operation of the Bas Relief software is
as follows. The program works on theassumption that all light coloured parts of
the image are relatively close to theobserver while all dark parts are moredistant. This information is used to make a‘depthmap’. The anaglyph is then createdby combining the original image with thisdepthmap.
Procedure
Making a 3D-image is in fact very simple
indeed. Just work through the following
www.geo-web.org.uk

Disadvantages
Although creating an anaglyph image as
explained above is a very simple process,it is nevertheless quite a lot of work using
Bas Relief. Does anyone see any
possibility of automating the process?
A second disadvantage is connected withthe premise that the light parts of theimage are the nearest to the observer.
This means that light-coloured areas suchas the Sahara will appear closer (in MSG
images). However as long as Europe isselected as the region of interest, thisdisadvantage is not as bad as I expected.
Alternatives
Anyone who would like yet more programs
to experiment with can download ‘2D to
3D RedBlue converter’ [1]. This program
creates, from a single image, both lefthand and right-hand stereo images bymanipulation of pixels.
These can be used to make a black-andwhite anaglyph, or using a program suchas Anaglyph Maker [2], a coloured one.
Because these programs require evenmore work than Bas Relief, they are notdiscussed further here.
References
1 2D to 3D RedBlue Converter

http://www.programurl.com/
2dto3d-redblue-converter.htm
2 Anaglyph Maker

http://www.stereoeye.jp/index_e.html

December 2005

Group for Earth Observation

GEO Quarterly No 8

Figure 2 - the main Bas Relief screen

Figure 3 - the smoothing pop-up window

Figure 4 - the outline image

Figure 5 - the greyscale depth map
Figure 1 (upper left) - the main Bas Relief window
Figure 6 (lower left) - the final colour anaglyphwww.geo-web.org.uk

25

GEO Quarterly No 8Group for Earth Observation

December 2005

The
EuropeanSpace
Agency’s
Mars Express has now been orbiting the
Red Planet for a year and a half, during
which time it has taken some of the mostspectacular and detailed images ever ofthe planet. The mission will image theentire surface of the planet at a resolutionof 10 metres per pixel, and can also image
selected areas at 2 metres per pixel. The
satellite occupies a highly elliptical,
7 hour 42 minute orbit which ranges from
298 km to slightly beyond 10000 km. Hereare presented just a few of the spectacular
images that have so far been returned
from the High Resolution Stereo Camera(HRSC) aboard Mars Express.
Coprates Chasma
Coprates Chasma (figure 1) is a major
trough located roughly in the centre of theValles Marineris canyon system whichappears at the north (right-hand side) of
the image; it ranges between 60 and 100
km wide and extends 8 to 9 km below thesurrounding plains. Coprates Catena lies
parallel to Coprates Chasma and can beseen in the south (left) of the image as
three troughs; these range from just a few
kilometres up to 22 km wide and are up to
5 kilometres deep. Ground resolution isapproximately 48 metres per pixel.

Figure 1 - Coprates Chasma

Nicholson Crater
Nicholson Crater (figure 2), which measuresapproximately 100 kilometres in diameter, islocated at the southern edge of Amazonis
Planitia, north-west of a region called Medusae
Fossae. This image shows the central part of
Nicholson Crater with a ground resolution of
approximately 15 m/pixel (north is to the right).

Ice and Dust at the Martian North Pole
Figure 3 shows layers of water ice and dust for
the first time in a perspective view of part of theMartian north polar icecap. The cliffs are almost
two kilometres high and the dark material in thecaldera-like structures and dune fields could be
volcanic ash.

Figure 2 - Nicholson Crater

PhobosEvery so often, Mars Express passes close to
Phobos, one of the planet’s two tiny moons,
about one hour before the orbiter attains thelowest point in its orbit. For several minutes theorbiter can be commanded to turn its camera
away from Mars and towards the moon. Images
obtained of Phobos, which has a maximum
diameter of just 28 kilometres, have surpassed
any obtained from previous Mars missions, and26

show a global network of regularly spaced
grooves which extends from near the equatoras far as the north pole of the satellite’s Marsfacing surface (figure 4). The image shows theMars-facing side of the moon and has aresolution of approximately 7 metres/pixel. It
was taken from a distance of slightly less than
200 kilometres on August 22, 2004.

www.geo-web.org.uk

The Future for Mars Express
It was announced on September 22 that theMars Express mission will be extended by one
Martian year from the beginning of December
2005 (about 23 months). This decision, taken
by ESA’s Science Programme Committee, willallow the spacecraft to continue building on its
many scientific successes to dateDecember 2005

Group for Earth Observation

GEO Quarterly No 8

Since the start of science operations in early
2004, Mars Express has revealed anincreasingly complex picture of Mars. New
aspects of the Red Planet are emerging almost
every day, including its present-day climate
system and its geological diversity. Mars
Express has also started mapping water in its
various states.
Among its discoveries so far, Mars Express has
established that volcanic and glacial processes
are much more recent than had been expected,
confirmed the presence of glacial processes inthe equatorial regions and mapped water andcarbon dioxide ice in the polar regions.
Mars Express has also detected methane in theplanet’s atmosphere, which suggests either
current volcanic activity on Mars, or, more
excitingly, the possibility that there are currently
active ‘biological’ processes. This hypothesis
may be reinforced by the fact that Mars Express
has established that the distribution of water
vapour and methane, both ingredients for life,
substantially overlap in some regions of theplanet.
All images: ESA, © ESA/DLR/FU Berlin (G. Neukum).

Water ice near the Martian north pole

Figure 4 - The Mars-facing surface of Phobos

www.geo-web.org.uk

27

Netherland’s Dykes
Along the southwest coast of the Netherlands,
sediment-carrying rivers have created a massive
delta of islands and waterways between the
coastal dunes. Following a devastating storm
which flooded the region on January 31, 1953,
the Dutch built an elaborate system of dykes,
canals, dams bridges and locks to hold back the
North Sea. This simulated natural color image
was produced from the Aster instrument aboard
NASA’s Terra satellite on September 24, 2002.
Image: NASA/GSFC/METI/ERSDAC/JAROS,
and U.S./Japan ASTER Science TeamDecember 2005

Group for Earth Observation

GEO Quarterly No 8

Peter J Edwards MW5ARR - e-mail: marion@trevland.freeserve.co.uk
It is often desirable to assess equipment,
set up and location to satisfy oneself thateverything operates as best as possible
within the limitations of location andreceiver alignment. This article describes
my own experiences evaluating homebuilt equipment using readily available
weather satellite reception software.
Building the Hardware
My satellite receiver was assembled
quickly and easily using a kit from
Emgo [1]. After much investigation ofavailable literature inferring ease of
construction and lack of nulls in elevation
acceptance I decided to construct a QFH
antenna.
The QFH was built fromreadily available 8 mm
copper central-heatingtubing with solder-type
elbow connectors at thecorners, using dimensions available on several websites. The useof 8 mm tubing madethe construction easy
due to the softness ofthe copper, allowing
Figure 1
bending of the elements
The QFH in the
without creasing. The
attictubing used for support
was 32 mm plastic waste pipe. Initially theantenna was installed in the attic of mybungalow approximately 5 metres above
ground.
SoftwareSatellite reception was made using WXSat
software and results were reasonable, but
it became clear following analysis using
David Taylor’s WxTrack [2] prediction
program that many passes were not being
recorded to their full length.
I assessed the problem using David
Taylor’s NOAA Plot [2] program, which can
produce polar plots of signal-to-noise ratio(SNR) along a satellite’s path across theheavens. Figure 2 shows the output
obtained from NOAA Plot with the systemdescribed above. I included passes fromNOAA-12, -15 and -17 over a one-weekperiod. The white lines indicate where the
SNR is 30 dB or greater. It was clear thatthe receiver was only recording the end ofeach pass; therefore it was assumed,
correctly as it later turned out, that it was
tuned on the low side of the signal and thatthe approaching satellite was outside thecapture range of its passband and/or
discriminator.
After the receiver had been realigned andthe front-end amplifier peaked by use of asignal generator, a second series ofrecordings
showedanenormous
improvement though results were still far
from optimum. NOAA Plot showed that the
SNR was still only just above an
acceptable value for low noise images andazimuth plots showed deep nulls incoverage. This was not unexpectedconsidering the indoor location of the QFH
in my attic.

Figure 2 - Polar plot for the attic mounted QFHPreamplifier
The next stage was to attempt to improve
the overall SNR by installing a mastheadpreamplifier. I found a 144 MHz pre-ampof the type fitted inside 2-metre radios
many years ago. The design utilised a‘cheap and nasty’ transistor: although nota state-of-the-art low-noise device thisproved more than adequate for satellite
reception. High-tech, state-of-the-art
devices are expensive and not required as
signal levels are generally high once thesatellite is above the radio horizon. I
consider that low noise devices become
an unnecessary overkill at 137 MHz. The
pre-amp was installed in a plastic box andpeaked using the faithful signal generator.
The addition of the pre-amp resulted in aconsiderable improvement (figure 3) andthis set-up was used for over a year
without problems. When the day came toservice my existing outdoor antennas it
was an obvious time to relocate thesatellite antenna to the outside mast.
Positioning the QFH at the top of the mast
added approximately 3 m of additional
elevation and ensured that it was clear of
any obstructions. NOAA Plot indicated afurther 10 dB improvement in SNR(figure 4). Figure 5 shows plots of average
SNR as a function of satellite elevation ateach stage in the improvement sequence.
How do you use NOAA Plot?
NOAA Plot requires data files generated
by SatSignal and WXtrack, two more of
www.geo-web.org.uk

Figure 3 - Polar plot with added pre-amplifier

Figure 4 - Polar plot with outdoor QFHDavid Taylor’s programs, before it canoperate. These files have the form
xxxtelem.dat (created by SatSignal) and
xxxpass.dat (generated by WXtrack),
where ‘xxx’ is the standard ‘mmddhhmm’
time-code filename stem relating to a

29

GEO Quarterly No 8Group for Earth Observation

December 2005

low as 4° is normal in most directions yet, with rising ground on
all sides, the minimum elevation would appear to be 8-10°,
especially to the south. Therefore, the reception must arise fromreflection and diffraction of the satellite signal: living in a rural‘hole in the ground’ is not as bad as it might first appear.
As an experiment to confirm my poor location I used an Ordnance
Survey map to help me to draw some 2 kilometre elevation
profiles around my home. Profiles were plotted using EXCEL anddrawn to scale. The northeast-to-southwest profile (figure 6)
shows clearly that, although my house lies 270 m above sea
level, it is located in a depression where the surrounding terrain
rises to more than 400 m, especially to the south and west (mylocation is marked on the chart as ‘QTH’).
Creating a Radio Horizon in WXtrack
Figure 5 - Average SNR as a function of satellite elevation,
showing sequential improvements

particular satellite pass recording. The ‘telem’ file from Satsignal
contains the noise-level information for the image; the ‘pass’ filefrom WXtrack provides spatial details of the actual pass.

In order to make a more precise assessment of my situation I now
needed to determine the actual elevation angles of my horizon in
every direction. I did this by analysing the EXCEL charts
produced from Ordnance Survey map data. Details of the method
and calculation appear in the sidebar on page 31.
The outcome was a table of results like this:Creating mmddhhmmtelem.dat→Save NOAAOpen SatSignal and make certain that <Options→noise stats> is ticked: then process a WAV file recorded using
WXSat and save the images. Next, load the saved image (the‘main image’ containing the two NOAA channels side by side)back into Satsignal and the telemetry datafile will automatically besaved into your WXtrack folder.

Note: you require a registered version of Satsignal for this, andmust, of course, have WXtrack installed on your PC.
Creating mmddhhmmpass.dat
Open WXtrack and make sure that the ‘Save track listing as’ field
is checked in <Options → What to save>. On the ‘Setup’ tab,double-click the pass relevant to the WAV file you just processed;
this takes you to the ‘Ground Path’ tab where you must click the‘Make Picture’ button. WXtrack now saves the pass datafile inside
its own folder.
You must now copy both these datafiles into the NOAA Plot folder
before running NOAA Plot to produce the analysis.
At first sight there might appear to be much work involvedin creating a week’s worth of ‘telem’ and ‘pass’ files andcopying them all into NOAA Plot. But yet another of David
Taylor’s programs, SatBatch [2] comes to the rescue, as
it can be used to fully automate the process.
The Effect of Local Topography
The diagrams produced by NOAA Plot (figures 2-4) show nulls invarious directions. Some of these are due to the topographyaround my QTH but the charts also show that reception ispossible well below my visible horizon. Reception at elevations as

Direction

N

NE

E

SE

S

SW

W

NW

Elevation

4.0°

5.4°

1.6°

2.9°

13.1°

7.9°

6.9°

5.2°

WxTrack contains a feature which allows the user to define his
own horizon profile by entering specific elevation angles for
azimuth value. This information is held in the file horizon.dat.
Azimuth v elevation figures obtained as described were edited
into the existing horizon.dat file which was then saved. Now,
when WXtrack is run, and provided that <options → Show → Radio
horizon> has been checked, the expected radio horizon based on
the optical horizon measurements from Ordinance Survey
mapping is shown around your QTH.
After examination of the NOAA Plot polar diagrams it became
clear that reception from well below the optical horizon had
indeed been obtained, as previously mentioned.
Comparing the Actual and Optical Horizons
My next step was to compare my optical horizon with the horizon
indicated in the NOAA Plot diagrams. Figures obtained from both
Ordinance Survey plotting and NOAA Plot polar diagrams wereinserted into an EXCEL spreadsheet and plotted in ‘radar’ form to
produce figure 7.
As can be seen from the radar plot, reception at elevation angles
below the optical horizon occurs at most azimuths but the mostinteresting are those between 140° and 260°. In these directions,a large hill less than a kilometre distant rises more than 150 m
higher than my QTH. Under normal consideration it would bepresumed that no reception would occur from that direction, yet
the figures computed by NOAA Plot indicate that reception has

Figure 6 - The 2 kilometre elevation profile around the QTH

30

www.geo-web.org.uk

December 2005

Group for Earth Observation

GEO Quarterly No 8

Determination of Elevation Angles
Elevation angles for creating a radio horizon were obtainedby analysing a number of elevation profiles created in
EXCEL. The method is explained using part of the elevation
profile from figure 6. The vertical scale has been
exaggerated for clarity.

Figure 7 - ‘Radar’ Plotindeed occurred. At the time of writing this is assumed to result
from diffraction and not reflection, as there are no buildings orother structures in the neighbourhood.
Data from NOAA Plot representing the ‘real’ reception horizon
were edited into horizon.dat and a map showing the real or
obtained horizon was produced. Reproduced inside the front
cover of this issue, the map was created in Paint Shop Pro byoverlaying WXtrack screen grabs resulting from use of the twodifferent versions of the horizon.dat file. Using the new horizon
file has allowed more accurate predictions to be obtained thanwould have occurred without the necessary investigation.

I drew a line from my QTH to the first location where thehigh ground would intercept a satellite signal and noted thehorizontal displacement. In the example illustrated above it
is 840 metres.
The actual height of this obstruction is easily calculated bysubtracting the altitude of my QTH (270 m) from thealtitude of the obstruction (350 m). This gives a verticalobstruction height of 80 m.
The theoretical minimum elevation angle for reception is
now defined by the gradient of this line. Mathematically,
this is the tangent of the required angle.
To work out this angle

In Conclusion
The moral to this is that good satellite reception is easily achieved
with minimal outlay. Receivers can be bought or assembled,
antennas such as the QFH are not difficult to fabricate at home,
software is available, and when registered has outstanding
facilities. I had for a long time suspected that reception at mylocation was far better than could be predicted and it was
satisfying to be able to optimise my station using readily available
software, and to be able to confirm the improvements.

Calculate the gradient, which in this case is

Reception is azimuth dependant but images as distant as the
Crimea to the east, Algeria in the south, Svalbard to the north andto the west of Greenland are all normal from my location.

There are two ways to do thisThe theoretical maximum SNR being 58.9 dB, it is assumed thatlittle if any further improvement could be made—other than tomove location!
Few problems are insurmountable and even living in what would
at first sight appear to be a poor location, surprisingly goodresults can be obtained. My present system includes recording
and processing using WXtoImg [3], reviewing the day’s images
followed by reprocessing using SatBatch and SatSignal if
required.
References:
1 Emgola APT receiver kit - www.emgola.cz
2 David Taylor’s software - www.satsignal.net
3 WXtoImg APT software - www.wxtoimg.com

height of obstruction
displacement of obstruction

=

80
840

= 0.095

All that is now required is to identify the angle whose
tangent has a value of 0.095.

• Look it up in a book of mathematical tables• Use a scientific calculator
The former should require no further explanation.
With a scientific calculator, you have to evaluate the term
tan-1 (0.095), the inverse tangent of the gradient.
Calculators do differ in their operation, but generally:• Press the ‘2nd function’ key• Press the ‘tan’ key• Enter 0.095• Press the ‘ANS’ key
In this case, the angle is calculated to be 5.4°

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31

GEO Quarterly No 8Group for Earth Observation

December 2005

by Rob Hollander
Every now and then constructors of a
Resonant Quadrafilar Helical Antenna(RQHA) ask me what the effect is of anaxial displacement of the two loops ofsuch an antenna. The construction of aself-phasing RQHA, with two loops ofdifferent size, can be made simpler byshifting the centres of both loops in theaxial direction in order to get the loop
terminals at the top in one plane. The
actual shift of the loop centres depends
on the design parameters: like centre
frequency, number of turns, pipe
diameter and the ratio of the diameter ofthe cylinder of the helical part and theaxial length of the RQHA.
For an antenna for APT at 137.5 MHz,
with a half-turn helix, a pipe diameter of
12 mm and a ratio of helix diameterover length of 0.444 (the design
parameters that I use), the displacementof the centres will be 18 mm. In terms ofwavelength (218 cm at 137.5 MHz), this
18 mm is less than 1%. This means anoverall small shift in phase of the fieldsof the two loops in the axial direction. In
the radial direction there is almost nophase shift due to an axial displacement.
If there is any effect at all, then we
expect to see it in the axial direction.
To explain the effects it is often easier toconsider the RQHA to operate as atransmitting antenna. Instead of thesensitivity pattern we have a radiation
pattern of the same shape. The radiation
pattern and polarisation of an RQHA are
the result of a delicate balance of the
fields of the two loops with currents
90 degrees out of phase. The field at a
certain place r and time t is the result of
the addition of the fields generated by
the currents in the different parts of the
RQHA.
For the purpose of calculations, theantenna is divided into very small
current elements. We have to take into
account not only the strength and thephase of the current in each element but
also the phase due to the fact that the
speed of light is not infinite and thedifferent path-length from each current

32

element to the point r where the field isconsidered. Therefore, if the RCP fieldsof an RQHA where both loops have thesame centre cancel in the downward
axial direction, then we expect that thisis no longer the case for the same RQHA
when the centres of the two loops are
axially displaced However, the radiation
pattern is not the only thing that willchange; the circular polarisation willchange too!
The 100% RCP in the axial direction
upwards will become less than 100%.
The question is: ‘How much less?’
For a small displacement of 1% of awavelength you may guess that thesechanges in pattern and degree of RCP
will be small. Nevertheless, I decided to
calculate the effects to see how far we
can go with an axial displacement of thetwo loops.
Figure 1 shows how the polarisation
patternchanges
as
the
axial
displacement increases from zero to 1, 2,
5 and 10% (from top to bottom).
The degree of circular polarisation isexpressed as Axial Ratio (AR), definedas the ratio of field strengths.
(RCP – LCP)
(RCP + LCP)The AR is +1 for pure RCP, -1 for pure
LCP and zero for linear polarisation(where RCP=LCP.) The absolute valueof AR is shown in Figure 1. From thehorizon there is little effect. The Axial
Ratio from above (at zenith) drops, but
remains better than at the horizon,
where the Axial Ratio should be as close
to +1 as possible to avoid noise bands in
the APT pictures.
Figure 2 illustrates the corresponding
radiation patterns. The radiation
patterns are shown as RCP sensitivity(in blue) and LCP sensitivity (in red),
relative to the maximal RCP sensitivity
as 30 dB. It is clear that a 1% shift has
virtually no effect but that a 10% shiftwww.geo-web.org.uk

Figure 1
Axial Ratio graphs for (top to bottom)
0, 1, 2, 5, 10% axial shift

December 2005

Group for Earth Observation

GEO Quarterly No 8

Figure 3a
Sensitivity for RCP and LCP as a function of the axial displacementin three directions: from the horizon, from above and from below.

Figure 3b
Polarisation shown as AR at zenith and at the horizon as a function of the axial displacement.

has a distinct effect. Especially, the RCP
pattern changes. The RQHA becomes alittle bit sensitive for RCP from below!
Figure 3 shows the same results in adifferent way. Figure 3a (top) shows how
the sensitivity for RCP and LCP changes
with axial displacement in three
directions: from the horizon, from above
and from below.

Figure 2
Radiation patterns for (top to bottom)
0, 1, 2, 5, 10% axial shift

The sensitivity from the horizon increases
slightly with the axial displacement. The
sensitivity from above is constant and thesensitivity from below rises with axial
displacement. Figure 3b (bottom) shows
how AR at zenith and at the horizon
depend on the displacement. The
conclusion is that the ~1% axial
displacement, needed to get the terminals
of a self-phasing RQHA in one plane, does
www.geo-web.org.uk

not change the radiation pattern and thepolarisation noticeably.
Addendum
Another constructional problem
Some people would like to have theantenna terminals at the bottom of their
RQHA. This is possible. Just put your
RQHA upside down and your RQHA
remains a RCP sensitive antenna.
However, to bring the radiation patternback to the upper hemisphere you have tochange the phase of one loop by 180
degrees. I already mentioned this in myarticle GEO-Q3 page 28, where you canfind more details. This upside-down
version would be useful if you wish to use
your own favourite balun construction,
without the need for the co-ax to run downfrom the top of the antenna.

33

GEO Quarterly No 8Group for Earth Observation

December 2005

Peter Wakelin

AIRS Data Improves Weather Forecasts
Although the majority of GEO members probably look upon
the visible and infrared imagery as the most important data tocome from weather satellites, it is the huge amount of datafrom other instruments that has made the biggest
contribution to improved forecasting accuracy over the lastfew decades.
40 years ago, balloon-borne radio sondes released from a few
thousand land stations and a handful of ships were theprimary source of upper air measurements of wind,temperature, and humidity. Sounding the atmosphere fromsatellites has improved steadily both in spatial resolution
around the world and in the accuracy of vertical profiling.
AIRS has taken this one stage further.
The Advanced Infrared Sounder (AIRS) is an experimental
instrument on board the Aqua satellite, which uses 2,378
distinct spectral channels to collect data about the Earth.
AIRS uses microwave data from other instruments on Aqua totake into account the effects of clouds, which results in much
improved vertical temperature measurements through theatmosphere.
Two years ago, the European Centre for Medium Range
Weather Forecasts in Reading, UK, started to incorporate
AIRS data into their numerical global forecast model andnoticed a marked improvement, especially in the southernhemisphere. Now, NASA and NOAA scientists at the Joint
Center for Satellite Data Assimilation in Camp Springs, MD,
USA, have reported similar improvements in forecasts up to
six days ahead.
For more information on AIRS see:
http://airs.jpl.nasa.gov

Two British-Built Imaging Satellites Launched
The Russian company Polyot launched several small satellites
on a single Kosmos-3M rocket from Plesetsk, northern Russia,
on October 27. The payloads included Beijing-1 and Topsat,
two satellites built by Surrey Satellite
Technology Ltd, Guildford, UK. Beijing-1
is part of the Disaster Monitoring
Constellation and will be operated by
Tsinghua University for a Chinesecompany, Beijing Landview Mapping
Information Technology Ltd. Its 31 cm
aperture telescope has a resolution of four
Beijing-1
metres. Topsat is an imaging spacecraft
Drawing:
SSTL
for UK military research.
Also on board was the first Iranian satellite, Sinah-1, built by
Polyot, Omsk, Russia. The 160 kg experimental payload
carries remote sensing equipment. The other payloads were
SSETI-Express, a student-built satellite sponsored by theEuropean Space Agency, Mozhaets-5, carrying a laser

34

An artist’s conception of the SSETI Express satellite flying over Europe in Earthorbit. Credit: Morten Bisgaard, Aalborg University

communications experiment and Rubin-5 which is atechnology/communications payload.
More on this and other recent launches can be found on
Jonathan McDowell’s informative website at:
http://www.planet4589.org.jsr.html

ESA’s Cryosat Fails to Reach Orbit
The European Space Agency’s Cryosat spacecraft fell into the
Arctic Ocean shortly after launch on October 8 when thesecond stage of the Rockot launch vehicle failed to shut down
as planned and did notseparate from the upperstage. The Rockot is based ona converted SS-19 missile
from the Soviet era with amodern Breeze upper stage
added. The failure has been
provisionally attributed to aflight guidance software
problem but ESA, theRussians and Eurockot, thejoint Russian and German
developers of the Rockot
vehicle, are each carrying out
separate investigations into
the failure. All six previous
launches of similar Rockots
since 2000 were successful.
The Rokot launcher

Cryosat was intended to carryout long-term measurements of polar ice and sea-ice
thicknesses to look for the effects of global warming. A
replacement craft may be built but a launch before 2009 isunlikely.

www.geo-web.org.uk

December 2005

Group for Earth Observation

Meteosat-7 to Move East
Provided that the launch of MSG-2 (now expected in
December) and subsequent commissioning are successful, it isanticipated that in mid-2006 Meteosat-7’s orbit will be loweredslightly so that it drifts eastwards at about one degree a day
to its new location over the Indian Ocean. Meteosat-5 currently
operates the Indian Ocean Data Coverage service at 63
degrees east longitude but its fuel is almost depleted and its
orbit inclination continues to increase (it is now almost eight
degrees). Following the manoeuvre, Meteosat-5 will be boosted
upwards out of the geostationary orbit to eliminate thepossibility of a collision.
DMSP-17 Launch Expected in December
The next spacecraft in the Defense Meteorological Satellite
Program’s polar-orbiting series is scheduled for launch from
Vandenberg Air Force Base in California on December 1st.
Like the civilian equivalents in the NOAA series, the DMSP
craft have undergone significant developments in the last 30
years. DMSP-17 is similar to DMSP-16 launched in October
2003, which was the first in the latest Block 5D-3 series ofspacecraft. DMSP-17 will be lifted into orbit by a Delta 4M
rocket whereas the remaining three craft are to be launchedon Atlas 5 vehicles. Although the instrumentation is quite
different to that on board the civilian NOAA satellites, theaccompanying US Air Force picture clearly shows that thesame spacecraft bus is used for the two classes of satellite.

GEO Quarterly No 8

the strongest lightning emission feature within the cloud-top
optical spectra produced by the neutral oxygen line at
777.4 nm.
Infrared Sounding (IRS) mission
The primary objective of this mission is to support numerical
weather prediction by providing more frequent information on
vertical temperature and water-vapour profiles, and to derive
improved wind data from the tracking of three-dimensional
water-vapour patterns.
UV/Visible Sounding (UVS) mission
This mission is designed to detect and measure changes in thecomposition of the Earth’s atmosphere, and applications
would include air quality monitoring and forecasting, thedetection and surveillance of pollution clouds and ultraviolet
radiation monitoring and forecasting.
Further studies and approval processes will last until 2009
when development and testing of the MTG system will begin.
The first launch is planned for 2015.
This is a brief extract from ‘Meteosat Third Generation- The
Future European Geostationary Meteorological Satellite’,
which appears in the August 2005 issue of ‘ESA Bulletin’. The
authors are Jean-Loup Bézy, Donny Aminou & Paulo Bensi(ESA Directorate of Earth Observation) and Rolf Stuhlman,
Stephen Tjemkes & Antonio Rodriguez (Eumetsat). For more
information on ESA publications see:
http://www.esa.int/publications

Artist’s impression of DMSP-17 in orbit

Meteosat Third Generation Progresses
Meteosat Third Generation (MTG) activities started five years
ago following the decision by EUMETSAT’s Council to proceedwith a Post-MSG User Consultation Process. Following theconsolidation of user requirements and the assessment ofobserving techniques, five observation missions for MTG were
proposed:
High-Resolution Fast Imaging (HRFI) mission
This mission expands MSG’s High Resolution Visible mission
to five channels with 500-1000 m resolution and a five minuterepeat cycle. The coverage is limited to selectable fractions of
the full Earth disk with a coverage equivalent to one-third of
the full disk.
Full-Disk High-Spectral-Resolution Imagery (FDHSI) mission
This mission is an evolution of MSG’s SEVIRI imager withmore spectral channels, spatial resolution improved to 1-km
(visible) and 2-km (infrared) with a 10 minute repeat cycle.
Lightning Imagery (LI) mission
The observation technique selected is based on the detection ofNASA’s Cassini mission to the planet Saturn has been returning
stunning images of its moons for well over a year now. The
spectacular image above shows the 360 km diameter, craterriven features of Hyperion, imaged by Cassini’s narrow-angle
camera from a distance of 62 000 km on September 26, 2005.

www.geo-web.org.uk

35

Snow across Patagonia
250 m resolution MODIS image
from NASA’s Aqua satellite
on October 10, 2005.
Image: MODIS Rapid response System

December 2005

Group for Earth Observation

GEO Quarterly No 8

Rob Denton has a passion for collecting postal memorabilia relating toweather satellites. The First Day Cover illustrated above was mailed from
Cape Canaveral on November 12, 1977 to commemorate the impending
launch of Meteosat-1 (which took place on November 23).
At right is one of the final NOAA-15 images of the autumn, obtained at
07:40 UT UT on October16. Northern hemisphere early-morning sunlight is at
a premium but enough remains to highlight the North Sea and lakes in
Sweden with glint. (Image: Les Hamilton, Vierling receiver, Satsignal).

Laurent Deblangy from Juilles, near Toulouse in France, captured this HVR Meteosat-8 image at 08:30 UT on October 16, 2005.
The image segment shows the French Alps with low stratus cloud over the valley of the River Po in Italy.
Image © EUMETSAT 2004

Processing: GeoSatsignal-5, using channels 9 and 12

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37

GEO Quarterly No 8Group for Earth Observation

December 2005

Fred van den Bosch
Background
I made a presentation at the GEO 2005 Symposium under theabove title and in this article I will develop one of its
components more fully. POVIM is a framework for Product
Oriented Video, Images and Maps. It provides the functional
design for:• the automation of computer programs• a separate reception PC• a master folder containing a hierarchy of sub-folders• a convention of systematic filenames throughout• everything in a logical and consistent structure.
A number of hints are provided for implementation as well as
a number of ideas for the future.
Introduction
The primary reason for development of the above measures is
simple: my system was starting to get into a bit of a mess. I
continually had to search out where specific files had been
stored. So I decided to tackle the matter in a structured way
using SDM (System Development Methodology), a system I
had learned previously. SDM has been around for a while now
and is not so useful for the majority of modern systems but itworks well for POVIM.
In turn, I carried out the following steps:

Problem Inventory and Analysis
After an inventory of all problem points I was able to sum up
the most important matters as follows:• I am lazy
• everything is stored on a single system• satellite images and Digital Atmosphere maps werestored in several different folders ...
• ... and under a variety of non-systematic names• no form of documentation had been maintained.
The next step is the analysis of these problems:
I am lazy
Because there is no available therapy to put into practice I
have decided to automate as much as possible. For David
Taylor’s programs [1] this is easily achieved by creating batch
files. Digital Atmosphere Work station (DAWS) offers thepossibility of scripts and its own scheduler.
This has a number of consequences:38

In the foreseeable future a separate reception PC will be
required. But at the time of writing I am thinking over myneeds. Broadly, there are two possibilities:• A simple PC which is exclusively used for reception. Allother work would take place on the main (large) system.
• A higher specification system where, in addition to
reception, it is used to create images of several areasusing GeoSatSignal in batch mode etc.
I am now at the testing stage with my large system to find out
which programs can be run together. The results are notentirely reliable because I have only 512 Mb of internal
memory and there are still other items to be installed
Images and Maps in several Folders• problem inventory• problem analysis• functional design• implementation and testing.

Everything is stored on one system• VPN and the Tellique software do not work at the sametime.
VPN (Virtual Private network) is a program which I use
to connect my home computer with the one at my work.
As soon as VPN is started up it automatically blocks allother network traffic: this is to guarantee a safe
connection to my company computer. Consequently, theTellique software is prevented from working.
• Poor response times
On my 2.67 GHz system these are very similar to those of
my 300 MHz laptop. Not really ideal therefore.

The cause of the problem here is of course clear. Most
programs, except David Taylor’s, have absolutely no
consistency with each other. Files are therefore generally
installed in the folder which the software designer considered
the best, and using default filenames. To improve this a logicaland consistent folder structure must be devised.
Storage with Non-homogeneous Filenames
The solution is simple: to design conventions for naming anduse filenames.
Documentation
Well! Even in professional circles this tends to become‘forgotten’. It is therefore a good idea to document the entire
system. Think about tackling:• where the program has been installed• input/output• registration codes• everything else that is important
In short, there is considerable work to be done.
DesignUsing the above information, a framework can be devised(figure 1). The basis of this is a central folder called‘PRODUCTS’. Within this folder, each type of product (image,www.geo-web.org.uk

December 2005

Group for Earth Observation

Figure 1
www.geo-web.org.uk

GEO Quarterly No 8

39

GEO Quarterly No 8Group for Earth Observation

December 2005

map, animation) is gathered into its own sub-folder. For
example, the channel 1-11 Meteosat-8 images are 11 products;
DAWS maps with isobars are another, etc. If desired, you cancreate a hierarchy of sub-folders within ‘PRODUCTS’: e.g.
‘DATA’, ‘MSG’, ‘DAWS’ and so on. Additional sub-folders foreach product are then added. Figure 2 shows the mainprinciples of my own classification. Naturally everyone canuse their own ideas. The most important thing is that thestructure is logical and consistent. Every product has a fixedname of type:

find out the theory of this from the Internet [5]. Input consistsof two different products and the output is saved as a separate
product.

YYMMDDHHMM-XXXXX

Autoget and SeaIceViewer [1] come to mind, amongst others.

Bas Relief [6] is a program to make 3D anaglyph images. How
to do this is described in a separate article [7].
ImageToAvi [8] is a program which I use to create a video froma series of anaglyphs.
Other Software

where• YY = year
• MM = month• DD = day• HH = hour
• MM = minute• XXXXX = an optional extra
The only deviation from this convention occurs for animations,which often cover several entire days. Again, everyone canmake their own rule here.
Now follow a few observations concerning some of thecomponent parts of the framework.
Software Running on my Reception PC
The software descriptions described below are based on myown experiences. I do not exclude future modifications basedon experiences gained in using the reception PC.
Tellique Software
The Tellique program makes use of a RamDisk [2]. This limits
writing to the hard disk and offers very many advantages.
MSG Data Manager
The output of image files from this program can be collected ina sub-folder within ‘PRODUCTS’ (e.g.’ DATA’).
GeoSatSignal

Figure 2

A separate GeoSatSignal job is defined for each type of fileexported. At the same time a batch file is written for each job
to export its output to ‘PRODUCTS’. I myself have created aseparate sub-folder called ‘MSG’ which contains further subfolders for each job.
MSG-Animator
The animations are stored in their own folder.
WXtoImg or WXSat
Programs to decode APT signals, each with there own (sub)folders.
Software run on my Large System
DAWS (Digital Atmosphere Work Station [3]) uses images
from the MSG folder as backgrounds and then stores the
products in ‘DAWS’, its own sub-folder within ‘PRODUCTS’.
The ‘DAWS’ sub-folder contains further divisions by region:
Netherlands, Europe, World, Vietnam etc., each containing its
own series of sub-folders for products. You can see how thisworks for the region ‘Wereld’ in figure 2.
PhotoFiltre [4] is a program with which you can perform
arithmetical operations on images; for example, images fromtwo MSG channels can be subtracted from each other. You can

40

Implementation
How can you switch over to this structure? For those who havestill to begin setting up their MSG system it is simple: use thestructure described above on each installation. However, forthose who have already installed a lot it will require more timeand effort. Here’s a step-by-step plan.
• Create the desired structure: a folder ‘PRODUCTS’ andthe desired sub-folders.
• Give every folder a meaningful name! Consider the
structure you want and keep following it. Think wellabout this in advance: modifying it later is a considerable
task.
• For ‘MSG’ you can think of the region or the channels you
are going to make use of; for ‘DAWS’ the displayedmeteorological phenomena (e.g. wind and temperature).
• Make the necessary adjustments to each software
program.
MSG Data Manager• Make sure that you create a folder called ‘DATA’ inside‘PRODUCTS’.

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December 2005

Group for Earth Observation• Open MSG Data Manager or click on the ‘Stop’ button and
go to the Setup tab. Enter the location of this ‘DATA’
folder as your ‘Processed image files location’.
• Click the ‘Start’ button to run MSG DataManager and all
the necessary additional sub-folders will automatically becreated by the program itself (within ‘DATA’).
• Check that the sub-folders have been created and files are
written to it.
• Copy all files from the existing structure to the DATA
folder.
GeoSatSignal.
• Try out the first GeoSatsignal job and test it interactively.
• If everything goes well, then test the associated batch file.
DAWS
Check every script carefully.
Testing in general• Test every program separately.
• Test every program step separately, e.g. with DAWS eachscript and with GeoSatSignal each batch file. Record, on
paper or in a spreadsheet, which programs, batch files,
scripts etc. have been adapted and tested.
Product Manager
At the present time I use Picasa [9] as a temporary viewer. The
advantage of this program is its ability to display thumbnailsof all the folders—in which the modifications are continually
being updated—on the screen. Next you can choose which
image to zoom in to.
In the long run a program, lets call it ‘Product Manager’, will
be required which will be able to present everything in a moremeaningful manner. As this program does not yet exist, I am
going to have to build it myself. Learning a suitable
programming language is therefore high on my list ofpriorities. Here is what I require this program to do.
Products
Product Manager will have to be able to cope with all thevarious products held in the ‘PRODUCTS’ folder. Its record foreach product should include

GEO Quarterly No 8

files to be deleted are stored and the number of days thatyou wish to retain, all older files are removed.
• Starting Programs
This would allow a simple one-click option to run any of
the software packages used on the system.
• Starting up Temporary Batch FilesAll batch files could be started up by means of a task
manager (e.g. the Windows Task Manager). It can be
useful to be able to start a batch file, in a simple way, at
any time.
• Refer to the ‘Manual of Synoptic Satellite Meteorology’
This manual [10] exists of three CDs. Within the CDs you
are regularly referred to other CDs and you feel a bit likea DJ! For this reason I have copied all three CDs into afolder in such a manner that all the references work.
• Start ‘PowerPoint Presentations Eumetsat’
Eumetsat [11] have a whole series of PowerPoint
presentations concerning everything you can do with
MSG images. I have placed a number of the mostimportant of these on my hard disc so that I can consult
them rapidly.
• Documentation
Above I have indicated what can be stored. If there isenough interest, I will publish a more detailed checklist of
my own public documentation.
SummaryThis article describes the functional specifications for a system
to automate the whole process. Of course everybody is free to
use parts of it and how to fill in the technical details. In afollowing article I will explain how to build and start batchjobs.
References
1 David Taylor

http://www.satsignal.net

2 EUMETCast Reception using a RAM Disc

Arne van Belle, GEO Quarterly No 6, page 14

3 DAWS

http://www.weathergraphics.com/

4 Photofiltre

http://www.photofiltre.com/

5 Theory arithmetic

http://wolves.dreamhost.com/web/arith/

6 BasRelief

http://www.3dphotopro.com/software.html

7 BasRelief article

GEO Quarterly No 8, page 24 (this issue)

8 ImagetoAVI

http://www.aswsoftware.com/products/

9 Picasa

http://picasa.google.com/

10 Observing the weather with MSG-1

Robert Moore, GEO Quarterly No 3, page 44

11 EUMETSAT

http://www.eumetsat.int• a short name to characterise each product• a type which describes the nature of the product (e.g.
MSG image, DAWS map/chart, etc.)• the path leading to the folder containing each file• the relevant geographical area for the product (e.g.
Netherlands, Europe etc.)

Advisory on DAWS Scripting

Product Manager will also have to possess facilities to selectand display the various data products. First, it must be able toselect one or more products plus a start date and time; then all
the products for the selected time would be presented, each inits own window. These windows would be designed to remain
synchronised whenever any one of them was scrolled. And it
goes without saying that you would be able to zoom in and outof the various images.

I have come across a minor error, that could could cause
confusion or concern, in Fred van den Bosch’s GEO Q7 article‘Using Scripts in Digital Atmosphere Workstation’. The article itself
is excellent and Fred should be congratulated in explaining
scripting so well. But, should anyone copy the scripts as shown,
they will not work correctly. The reason is that the DAWS
commands must be spelt using American English. The example
in question is the ‘COLOR’ command, which must be spelt ‘color’and not ‘colour’ as published. If you use the English spelling‘colour’, the command will not work properly in DAWS.

Product Manager would also have to contain certain‘housekeeping’ features such as:

Editor’s Note

• Removal of Old Files
Old files in the ‘PRODUCT’ folder would have to be
regularly removed. David Taylor’s website [1] contains the
program TrimTree. This program can run from a batch
file. If you provide this program with the folder where thePeter Edwards

I must point out that Fred is in no way responsible for thisunfortunate error. His submitted scripts were correct, and were
tested prior to publication. Unfortunately the British English
spell-checker used on the text of GEO Q7 recommended thechange in spelling and I was not observant enough to realisethat this was a ‘special case’ which should remain unmodified.

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41

GEO Quarterly No 8Group for Earth Observation

December 2005

Douglas Deans - douglas@dsdeans.freeserve.co.uk
As I have stated before, I will take theopportunity from time to time, when new or
upgraded software is in short supply, toremind readers, some of whom may be
new to the hobby, of the contents of theshowcase CDs. This is one such time. This
quarter we will take a look at GS4 and also
review an image processing program withan interesting optional extra.
GS4 was primarily produced to help thosewith either a slow or pay-as-you-go
Internet connection or, indeed, no Internet
connection at all. The outcome was a CD
full of remarkable images taken fromLandsat 7, the Space Shuttle, MODIS,
weather satellites and a collection fromNASA's Earth Observatory. Of course,
readers who use the Internet regularly willrealise there is an endless package ofsuch wonderful images produced on adaily basis and covering every conceivabletopic. I have tried to choose ones that areboth interesting and timeless, and where
possible, I have chosen large images thatwould be more difficult for some todownload. For each image in the group
there is a corresponding text file with a fulldescription of the image and its source. In
addition I have provided a folder with anumber of incredible weather satellite
animations from MSG-1. Even for thosewith a broadband connection this could bea handy composite CD with over 700 Mb
of images and descriptions ready to use.

channels/wavelengths are available. Of
course Meteosat 8 with its twelve channels
is the prime example.

PhotoFiltre v 6.1.5

PhotoFiltre is a freeware program or, as itsays, is ‘free for private, non-commercial
or educational use’; otherwise registrationis required. The program has all the usual
features associated with image processing
software but its forte does seem to be theretouching of photographic images. I must
confess that photography has never beena hobby of mine so my use of such
software is inevitably associated withsatellite imagery and this is where theprogram has a very useful optional extra.

You might consider this to be yet anotherimage processing program but there arecertain features of this software which arevery attractive to those dealing withweather satellite imagery where multiple

For readers who receive the multiple
channels from Meteosat-8 there are many
wavelength combinations along with RGB
colour options that can help to accentuate

GS1 All David Taylor's weather satellite programs and libraries, including the current releases of WXtrack, Satsignal, HRPT Reader, GeoSatsignal, GroundMap, RX2
PassControl and many other program extras. This disc also contains a large quantity of sample files, many of high-resolution data, for use with these programs.
WXtrack
Satellite Tracking Programv 3.5.0
SatSignal

Creates images from wave files

v 4.2.0

HRPT Reader

Converts raw HRPT data files into images

v 2.6.2

GroundMap

Rescales satellite images

v 1.3.8

RX2 PassControl

Computer control program for the RX2 receiverv 3.0.6

GS2 A wide range of software for all aspects of weather satellite reception, including tracking, receiving, monitoring and image manipulation. Content is detailed
below but many other extras are provided. Titles correspond with folder names. * implies a DOS program.
Collection D02
Recall (wave file recorder), Palette (modifies Wxsat colour palettes).
Collection D03

Scanner recorder v 1.8 (wave file recorder), *NOAA95/*FENG99 (software for the NOAA 95 HRPT project)

Collection D04

Wxsat (wave file recorder/decoder), Satmon (wave file recorder).

v 2.59AGSatTrack

Satellite tracking programv 1.33

APTDecoder

Program for capturing APT audio and processing images

CirkitDocuments for the Cirkit Wxsat receiver and the UOSat receiver (PDF format)

v 1.0.2.68

Element Manager

2-line element manager

v 1.59

Footprint

Satellite tracking programv 2.10Irfan View

Image/slideshow viewer

v 3.80

JVcomm32

Evaluation version (APT/FAX/SSTV decoder)Macintosh kepler editor

Edits verbose AMSAT format elements. Mac OS X and OS9 only.

NeoPaint

Image processing program (30 day evaluation)

OrbitronSatellite Tracking Program

Paintshop Pro

Image processing program (30-day evaluation)

v 3.60

PhotoFiltre

Image retouching program with many extras

v 6.1.5

Satscape

Satellite tracker and wave file recorder

v 2.02

Space-Track TLE Retriever

Generates TLE files in 'Celestrak' style from data sets recovered from Space Track

Splitter

Utility program for splitting and reuniting large files

World Wind (NASA)

View anywhere on Earth from satellites

v 1.3

WXtoImg

WAV file recording and decoding program with many options.

v 2.5.11

GS3 3DEM Package for 3D Terrain Visualisation
This CD includes the full set of GLOBE Tiles to allow you to produce excellent images and flybys from HRPT inages. Also included is a selection of Mars MOLA
files, sample images and helpful guides by Ed Murashie.
GS4 Image CD
A wide selection of high-resolution remote images from a range of satellites, including stunning imagery from the Space Shuttle missions. A full description andsource if provided for each image.
GS5 Mars Rover Panoramics
A chronological account, in panoramic images, of the NASA Mars Rovers' progress across the Martian Terrain

42

www.geo-web.org.uk

December 2005

Group for Earth Observation

GEO Quarterly No 8

certain meteorological conditions. David Taylor's program
GeoSatSignal 5 (which I hope to review in GEOQ 9 and 10) has
all the facilities to enable you to combine arbitrary channels ofMeteosat-8 data by mapping the channel to either the red, green
or blue component of the output image. The combinations areendless.
However, there are times when it may also be necessary tosubtract channel images to help differentiate a feature such as
snow or night-time fog. This is now possible with PhotoFiltre as
an arithmetic plug-in can be downloaded and added to theprogram. This plug-in is also freeware. I know David has plansto add channel subtraction to GSS5 and so, along with thealready fully working RGB option this will make GSS5 thecomplete package for such work.
One of the best guides for this kind of work is EUMETSAT's
MSG Interpretation Guide which is full of wonderful informationon the use of RGB techniques and channel subtractions for alarge range of applications related to weather analysis andforecasting, ocean and land surface, and many other topics. The
Guide can be downloaded in sections from the Internet andhundreds of megabytes of material is available.
http://oiswww.eumetsat.org/
WEBOPS/msg_interpretation/and I believe it can also be ordered from EUMETSAT on DVD.
Use of the plug-in is straightforward and is as simple asunzipping the file's content into PhotoFiltre's 'plugins' folder.
Thereafter, when using the program, select tools > plug-in andthen ‘Arithmetic’. There are many other plug-ins freely available
for other operations and if installed they will also appear intools > plug-in.

Francis Bell
Members who received ourlaunch issue in February 2004
may recall a few paragraphs I
wrote about some otherpublications which relate toweather satellites. I indicatedsome of these publication which I
receive without any cost tomyself.
This reminder has been prompted
because, a few days ago, I
received my latest copy theEuropean Space Agency’s August
2005 ESA Bulletin. It is acomprehensive publication
containing about 100 pages
covering ESA’s science,technology, engineering andspace missions. The latest issue,
number 123, I found particularlyinteresting because of its
coverage of the Meteosat
programme. I don’t always readthe ESA Bulletin from cover tocover; I usually read the abstracts
and then the items relating toweather satellites. The latest
edition was very informative.
ESA also produce the publication
Earth Observation Quarterly. Its
title is descriptive. It generally
consists of between 8 and 16
pages and covers topics relating
to Earth imaging—not justweather satellites.
Both of the above two publication
are available free of charge. Write
to the address below, giving yourname and address, and ask to be
put on the mailing list for thesetwo particular publications.
ESA Publications Division
PO Box 299
2200 AG Noordwijk
The Netherlands

PhotoFiltre and the Arithmetic plug-in is available on GEO
software CD GS2 or for more information and to download theprogram go to :http://www.photofiltre.com/
APTDecoder v 1.0.2.68
I do not intend to review this program as an excellent one has
been provided by Les Hamilton on page 15 of this quarterly
issue.
The program is available on GEO software CD GS2 or, for more
information and to download go to :Flight models of MSG-2 and MSG-3 in the clean roomat Alcatel Space in Cannes

http://www.ptast.com/apt/decoder/

Image: ESA - reprinted from ESA Bulletin, August 2005

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
the appropriate amount. Nothing else is required.
The cost includes the CD, packaging, posting and a small
donation towards the cost of overheads. No fee is asked
from overseas members although an exchange of softwareor interesting satellite 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.

The other publication I receive,
which is 8 pages long, is Image,which comes from EUMETSAT,
and describes a range of theiractivities plus brief reports. It also
gives a global summary ofoperational weather satellites. I
find it a useful document. Again
it’s available free of charge. Write
to the address below and ask to
be put on their mailing list.
EUMETSAT Information
Division
Am Kavalleriesand 31
D-64295 Darmstadt
Germany

www.geo-web.org.uk

Some of the above information isavailable via the Internet although
in many cases I prefer the printed
copy.

References
ESA Bulletin
http://www.esa.int/
SPECIAL/.ESA_Publications/
Image
http://eumetsat.int/
Follow the link to ‘Publications’
then click ‘Image’.

43

GEO Quarterly No 8Group for Earth Observation

December 2005

Francis BellWe cared for them by trying not todisturb them and ensuring the stable
door was always open.
It was delightful to hear them on asummer evening when they were on myaerial. There was more audio output
from the aerial than any RF which went
downs its coax. To twitter is the mostdescriptive verb I can think of todescribe the sound. We hope they will beback next year.
This experience and David's photographgave me an idea for a competition. Thereis no time limit just send your entry to
GEO's editor—a brief description and aphotograph—when you consider you
have an entry.

Duties dispatched me to Tobago, which
is a small island close to South America.
As usual, in a spare moment, I had aneye on telecommunications and thoughtthat GEO readers might be interested ina photograph I took of a satellite
receiving dish. It looked totally out ofplace against a background of coral seas,sand and palm trees.
While walking along the beach, Nadineand I crossed between a rather old hotel
and a strip of shacks of mixed
residential, shops and beach services.
None of these looked as if it could
withstand a storm. However, between
the hotel and its adjacent house was a
6-metre diameter satellite dish. I was
astonished to see it there; it did looktotally out of place. Closer inspection
revealed the age of the dish and it hadprobably been out of service for many
years. The hint about the ‘out of service’
was the almond tree growing throughthe perforated dish mesh.
The dish’s antecedents looked only justpost Harper Lee’s Pulitzer Prize winning novel ‘To Kill a Mocking Bird’
which was about the racially charged
southern USA.
I was seen taking photographs of thedish and invited into the garden of theadjacent ‘house’. The friendly residents
were ambiguous and coy about theownership of the large dish but they didtell me about its current use. They told
me that the dish supports the almond

44

tree and that the tree provides nestingsites for mocking birds and sugar birds.
I smiled and thanked them for theirtime.
Two thoughts passed through my mind.
Is this the biggest birds’ nest I have everseen? And could the focussed RF provide
enough energy to incubate the birds
eggs—or would the birds be better off
just sitting on the eggs? There may besome natural balance here; could the RF
incubate a bird’s egg or be enough to‘Kill a Mocking Bird?’

Birds
A Competition
For most of us, Earth Observation is ahobby with a technical challenge but
this is a light-hearted digression fromour usual perspective.

The categories for entries I have thoughtof are:• The greatest number of birds (fifteen
or more to beat David).
• The largest number of species (mymodest entry here could be two fromtwo different sites)• The largest bird (I have a crow foran entry in this category).
• The rarest, most exotic, mostcolourful or any other category you
decide appropriate.

I was enchanted by David Taylor's
photographs of starlings on his 137 MHz
turnstile aerial which was published in
GEO Quarterly 6. I live on the edge of avillage and have many birds living orvisiting the area. Some of these birds
also use my 137 MHz antenna on whichto perch.

Any aerial will count - HF to microwave.

The photograph shows a family ofswallows on my aerial. I know they werea family because the parents nested inour stable and produced four fledglings.

Entries to the editor please - time-scale
open ended. There is no prize as such:
just the satisfaction of seeing your photo
published in GEO Quarterly.

www.geo-web.org.uk