Thames Amateur Radio GroupThames Amateur Radio Group Slide 1 SWL’ing – For WeatherFax, NOAA APT and RTTY
Revision 1.2
Ken M0XKG
Thames Amateur Radio Group Slide 2 SWL’ing – For WeatherFax, NOAA APT and RTTY
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- What to expect
- The kit needed
- Q & A
Thames Amateur Radio Group Slide 3 SWL’ing – For WeatherFax, NOAA APT and RTTY
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License free…
With general communications receivers that cover the
MF and HF bands, from 30 kHz to 30 MHz, receive:
- Weather Fax Transmissions (WeFax)
- NAVTEX (SITOR = RTTY + FEC ) marine weather
With 2 m WFM receiver (such as SDR)
- NOAA APT (Weather satellite pictures)
Thames Amateur Radio Group Slide 4 SWL’ing – For WeatherFax, NOAA APT and RTTY
Revision 1.2
Weather Fax
represent black
- 3885 kHz and 7880 kHz from DWD – The Deutscher
Wetterdienst have best signal
- The picture takes 11 to 20 minutes to receive – as a
telephonic fax though slower
- Typically decoded with software such as JVComm32
Thames Amateur Radio Group Slide 5 SWL’ing – For WeatherFax, NOAA APT and RTTY
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DWD Pinneberg Antennas
Thames Amateur Radio Group Slide 6 SWL’ing – For WeatherFax, NOAA APT and RTTY
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Weather Fax
to receive
Thames Amateur Radio Group Slide 7 SWL’ing – For WeatherFax, NOAA APT and RTTY
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Surface Analysis Chart
Thames Amateur Radio Group Slide 8 SWL’ing – For WeatherFax, NOAA APT and RTTY
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https://www.ebay.co.uk/itm/Understanding-Weatherfax-A-Guide-to-Forecasting-the-Weather-fro- 9780713661224/253830120604?epid=92004620&hash=item3b1974449c:g:qkcAAOSwSA5eB5ux
Thames Amateur Radio Group Slide 9 SWL’ing – For WeatherFax, NOAA APT and RTTY
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“OK” peak
Thames Amateur Radio Group Slide 10 SWL’ing – For WeatherFax, NOAA APT and RTTY
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“Sharp” peak – Nice!
Thames Amateur Radio Group Slide 11 SWL’ing – For WeatherFax, NOAA APT and RTTY
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Iceberg Chart
Thames Amateur Radio Group Slide 12 SWL’ing – For WeatherFax, NOAA APT and RTTY
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Sea Surface Temperature Chart
Thames Amateur Radio Group Slide 13 SWL’ing – For WeatherFax, NOAA APT and RTTY
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Surface Prognosis Chart from GYA Northwood
Thames Amateur Radio Group Slide 14 SWL’ing – For WeatherFax, NOAA APT and RTTY
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Satellite image on Weather Fax – US Station
Thames Amateur Radio Group Slide 15 SWL’ing – For WeatherFax, NOAA APT and RTTY
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Precipitation and Visibility Chart, GYA Northwood
Thames Amateur Radio Group Slide 16 SWL’ing – For WeatherFax, NOAA APT and RTTY
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2018 Christmas Greetings from DWD
Thames Amateur Radio Group Slide 17 SWL’ing – For WeatherFax, NOAA APT and RTTY
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FAX, with “Mark and Space” tones
- Tones (similar to Morse keying) represent letters
- 4583 kHz and 7646 kHz from DWD – The Deutscher
Wetterdienst
contents @ 50 Baud
decoder
- Output is a stream of plain text
Thames Amateur Radio Group Slide 18 SWL’ing – For WeatherFax, NOAA APT and RTTY
Revision 1.2
RYRYRYRYRYRYRYRYRYRYRYRYRYRYRZRYRYRYRYRYRYRYRYRYRYRYRYRYHYRYRYRY
RYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRY
WEAZHER AND SEA BULLETIN FOR EPUTERN MRBITERRANN SEAORVISSUED XG MARINOLWEATHEGC
SERVICX HAMBURG
DEEPENING, MOVING SLOWLY NORPEAST. 7498&# 180,,IONIANLAEA, 3-(3,8,&. LARGE HIG
1=&=8CENTRAL EUROPE, MOVING
FURTHER RIDGE 1030 ALGERIA, STATIONARY. LOW 1023 JUST WEST
OF MOROCCO, NEARLY UNCHANGED.
ADRIA-NHGKYN(:4,0=, 13.1E) SST: 15 C
MO 30.,12+: N 3-4 0.5 M N GX
MO 3#. 18Z:,NW-N 4-5 =.5:H N //
TU 31. 00Z: W-NW 4 ,0.#.M //
TU -1. 06Z: W
NW NM8 ,,,8(=.=1RSISNN //
RTTY Decoded with
be seen
Thames Amateur Radio Group Slide 19 SWL’ing – For WeatherFax, NOAA APT and RTTY
Revision 1.2
ADRIA-NHGKYN(:4,0=, 13.1E) SST: 15 C
MO 30.,12+: N 3-4 0.5 M N GX
MO 3#. 18Z:,NW-N 4-5 =.5:H N //
TU 31. 00Z: W-NW 4 ,0.#.M //
TU -1. 06Z: W
NW NM8 ,,,8(=.=1RSISNN //
CENTR.ADRIA (42.9N 15.4E) SST: 17 C
MO 30. 12Z: NE 4-5 1.5 M //
MO 30. 18Z: N 2-3 1 M //
TU 31. 00Z: NW-N 3-4 0.5 M //
TU 31. 06Z: NW-N 4, 1 M //
TU 31. 12Z: NW 4-5 1 M //
TU 31. 18Z: NW 4-5 1 M //
RTTY Decoded
with PAKRATT PK-232
Thames Amateur Radio Group Slide 20 SWL’ing – For WeatherFax, NOAA APT and RTTY
Revision 1.2
- This mode uses a frequency shift keyed signal, as RTTY,
with “Mark and Space” tones though includes FEC –
Forward Error Correction. Called SITOR-B or AMTOR-B.
- 490 kHz and 518 kHz in most areas
(490 kHz for Inshore Waters Forecast)
- Messages a couple of minutes long though depends on
contents @ 100 Baud
some thought
decoder with plain text output
Thames Amateur Radio Group Slide 21 SWL’ing – For WeatherFax, NOAA APT and RTTY
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ZCZC UV87
MB DEG KTS NM C
SULE SKERRY - - - - -
FOULA - - - - -
LOSSIEMOUTH 1020 200 13 19 11
DYCE - - - - -
BOULMER 1028 180 10 - 10
DONNA NOOK 1034 180 13 7 8
WEYBOURNE 1035 200 15 11 8
SHOEBURYNESS 1038 200 6 5 8
MANSTON 1038 160 7 4 7
SANDETTIE 1038 170 13 5 8
NNNN
ZCZC TE34
ORIGINE METEO-FRANCE.
BULL_TIN SUD MER DU NORD ET EST DE MANCHE DU 28/12/2019 A 18 UTC
VENT EN BEAUFORT. MER EN ECHELLE DOUGLAS.
PAS DE BMS.
SIT GEN LE SAMEDI 28 DECEMBRE 2019 A 12 UTC B-PRES ATL AU SW DE ISL DECAL EN MER
DE NORVEGE DIMANC. TLWG ASSOC CIRCULANT DE W DES ILES BRIT N DE LA MER DU N.
H-PRES 1040 AU S DE LA SCANDINAVIE DECAL EUROPE CENTRALE. DORS ASSOC SE MAINTE
NANT GOLF GASC.
NAVTEX Decoded with
Some minor errors though
better due to FEC
Thames Amateur Radio Group Slide 22 SWL’ing – For WeatherFax, NOAA APT and RTTY
Revision 1.2
ZCZC UV87
MB DEG KTS NM C
SULE SKERRY - - - - -
FOULA - - - - -
LOSSIEMOUTH 1020 200 13 19 11
DYCE - - - - -
BOULMER 1028 180 10 - 10
DONNA NOOK 1034 180 13 7 8
WEYBOURNE 1035 200 15 11 8
SHOEBURYNESS 1038 200 6 5 8
MANSTON 1038 160 7 4 7
SANDETTIE 1038 170 13 5 8
NNNN
PAKRATT PK-232
Thames Amateur Radio Group Slide 23 SWL’ing – For WeatherFax, NOAA APT and RTTY
Revision 1.2
APT (Analogue Picture Trasnismssion)
or 137.9125 MHz depending on Satellite (NOAA
19/15/18)
- Needs a specialist receiver or SDR to receive due to
wide FM bandwidth
in the receiver bandwidth
- Turnstile antenna due to circular polarisation
Thames Amateur Radio Group Slide 24 SWL’ing – For WeatherFax, NOAA APT and RTTY
Revision 1.2
APT (Analogue Picture Trasnismssion)
monochrome and daylight
Comm32) can make a false colour
image
show satellite position
Thames Amateur Radio Group Slide 25 SWL’ing – For WeatherFax, NOAA APT and RTTY
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WX Track - showing satellites and day-night intersector
Thames Amateur Radio Group Slide 26 SWL’ing – For WeatherFax, NOAA APT and RTTY
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WX Track - Using “Ephemeris” to show best satellite passes
Thames Amateur Radio Group Slide 27 SWL’ing – For WeatherFax, NOAA APT and RTTY
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NOAA APT signal as received
Thames Amateur Radio Group Slide 28 SWL’ing – For WeatherFax, NOAA APT and RTTY
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NOAA APT signal following processing. Note “false colours”.
Thames Amateur Radio Group Slide 29 SWL’ing – For WeatherFax, NOAA APT and RTTY
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NOAA APT signal being received. Listen to the “clock and ping” noise.
Signal is 920 km away – don’t
expect S9!
Thames Amateur Radio Group Slide 30 SWL’ing – For WeatherFax, NOAA APT and RTTY
Revision 1.2
Thames Amateur Radio Group Slide 31 SWL’ing – For WeatherFax, NOAA APT and RTTY
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Thames Amateur Radio Group Slide 32 SWL’ing – For WeatherFax, NOAA APT and RTTY
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- Basic PC (see mine) for decoding
software
(TNC) like AEA PAKRATT PK-232
- A general purpose communications
most things
2m band coverage for NOAA APT and
ideally an APT turnstile antenna,
though a 2m dipole will pick up!
https://www.amazon.in/HP-t5740-computer- Embedded-Standard/dp/B01A1WAZA6
https://wiki.radioreference.com/i ndex.php/IC-PCR1000
https://www.universal- radio.com/catalog/tnc/pk232.html
Thames Amateur Radio Group Slide 33 SWL’ing – For WeatherFax, NOAA APT and RTTY
Revision 1.2
What kit do I need?
Long-wire for RX. About 14 m total length, 5 m up at highest point. Note: 7 to 8 m (even just at 2 m horizontal) will do fine for most things.
I could also use the 7 m vert you see here, though that is for 40m/20m TX
16/0.2 thin wall wire
Thames Amateur Radio Group Slide 34 SWL’ing – For WeatherFax, NOAA APT and RTTY
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What kit do I need?
2 m Turnstile Antenna at M0XKG Home QTH, 4 m elevation on fishing pole + speaker stand tripod
Matt black for
Safety triangles – per design from Ben M6JNX
Thames Amateur Radio Group Slide 35 SWL’ing – For WeatherFax, NOAA APT and RTTY
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Practical Demostration
syfy.com, https://muppets.disney.com/
Thames Amateur Radio Group Slide 36 SWL’ing – For WeatherFax, NOAA APT and RTTY
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Any questions?
Thames Amateur Radio Group Slide 37 SWL’ing – For WeatherFax, NOAA APT and RTTY
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centre frequency half-way between the White and Black
tones
- The actual tune used will depend on the rig and software.
On my ICOM PCR 1000, the tune for 7880 kHz, with
JVComm32 software is 7878.15 kHz
- For RTTY / NAVTEX, the same logic applies. Experiment
with different “shift” (and also reverse) settings on the
decoder and remember the correct Baud rate.
Thames Amateur Radio Group Slide 38 SWL’ing – For WeatherFax, NOAA APT and RTTY
Revision 1.2
- An exact match is not needed – this is general reception
- The DWD signals are 10kW ! Expect a good S9 to S9+10dB
on your meter in the best conditions. Minimum of S7
suggested
- A random 7 to 10m wire will RX most things
- Reception quality – especially on Fax – will be a function
of conditions and time of day, as with normal HF
Thames Amateur Radio Group Slide 39 SWL’ing – For WeatherFax, NOAA APT and RTTY
Revision 1.2
Receiver-Balun/1573184022
LWB Mk2 is general purpose and good from 1 MHz to 30 MHz. It is a bit deaf
below 1 MHz.
8m will work fine.
your own?)
Communications Receiver Suggest with CAT control or software control such as ICOM PCR 1000, a
little expensive though nice receiver.
Avoid ICOM PCR 100 – this does
not have SSB
JVComm32 Software Decoder http://www.jvcomm.de/dlframee.html
2009 is latest build, 2.01. Demo is free though puts “DEMO” on images.
Nice features for tidying up received images
Can also decode SSTV
decode
Hardware Decoder (RTTY, NAVTEX) Try AEA PAKRATT PK-232. From £ 50 on auction sites.
See also “(boat) shack in a box” decoders like Fastnet FMD55
Older kit – so may have dodgy
caps!
SDR Dongle Generic with HF from £ 10 +, though get a stable TCXO (1ppm) if possible Find your favourite (free)
software to use with the dongle. I
use HDSDR.
Specialist Powered Antenna – NAVTEX https://www.nasamarine.com/product/518khz-navtex-antenna/
“out of the box”, this is single frequency. Dual frequency antennas can
only be used with the dedicated Nasa receivers. For a generic receiver,
you need a “Bias T” or a receiver like the Clipper that includes the power
feed.
loudest noise) to 490 kHz, even on
a 518 kHz antenna.
Understanding Weatherfax – Mike Harris https://www.ebay.co.uk/itm/Understanding-Weatherfax-A-Guide-to-Forecasting-
too.
Annex – References – HF RX
Thames Amateur Radio Group Slide 40 SWL’ing – For WeatherFax, NOAA APT and RTTY
Revision 1.2
JV Comm32 Software Decoder http://www.jvcomm.de/dlframee.html
2009 is latest build, 2.01. Demo is free though puts “DEMO” on images.
Nice features for tidying up received images
UK Licence from
Also need to download DLLs.
SDR Dongle Generic with HF from £ 10 +, though get a stable TCXO (1ppm) if possible You will need a turnstile antenna
or UHF for HRPT as below.
You can also with the right
software and SDR use the IQ
BPSK/QPSK signal to receive HRPT
signals (high resolution) from
is specialist stuff.
NOAA APT Turnstile Antenna From £ 50, tuned to 137 MHz to 138 MHz. Two is better than one, crossed
with combiner lead. Best is Quadrafilar though can be expensive.
At a push can use simple 2m
dipole…
Communications Receiver Suggest with CAT control or software control such as ICOM PCR 1000. A
little expensive though nice receiver.
Avoid ICOM PCR 100 – this does
not have SSB