Minikits EME117 Quick Start Manual Download Page 6

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WEATHER SATELLITES: The notes below are to
help the people that are new to Weather Satellite
Reception.

There are currently three Satellites on the

137MHz band that are operational  2/1/11.

Please check status on http://homepage.ntlworld.com/
phqfh1/status.htm

NOAA 15    137.620MHz
NOAA 17   137.500MHz ( On but No images )
NOAA 18   137.9125MHz
NOAA 19   137.100MHz

Only Infrared pictures are available when the Satellites are
going over at night time. Picture quality can be rather
grainy & dark with little colour at dusk or dawn.

ANTENNAS:

A circular polarized antenna like the Quadrifilar Helix or
Turnstile is required to give acceptable signals. An
omnidirectional antenna for the 144 to 148MHz band can
be used, but signals are quite weak as the satellite gets
higher than 20 degrees above the horizon due to the
radiation angle of the antenna. Good noise free signals
have been received on a quadrifilar Helix at only 3 metres
above the ground. Signals however were only receivable
from around 20 degrees above the horizon. Increasing the
antenna height would improve this. With around 10 metres
of low loss RG6 cable, a receive preamplifier should not be
required. If a preamplifier needs to be used, then one with
a tuned input filter is required to reject strong out of band
signals like pagers on 150MHz. To receive low angle
signals a circular polarized cross yagi, & azimuth /
elevation rotator would be required.

COMPUTER:

A PC with a Soundblaster or similar audio card is required
for the processing of the audio signal. Computer
interference has been noted on 137.620MHz. The problem
was radiation from the cables feeding a Scanner.  The
Scanner is now switched off when receiving NOAA 17 on
137.620MHz.  Interference was also able to be minimized
by rotating the antenna for a null.  Antennas like the
Quadrifilar Helix do still have nulls.

SOFTWARE:

1.

The WX software suggested will allow you to get your

Weather Satellite Receiver going easily & quickly.  All
software is available from the www.satsignal.net WEB site.
There are other software packages available but the
WXTRACK & WXSAT are free & easy to use. An
additional audio record level program WXREC may also
be useful.

Load the WXTRACK software & click the SETUP

button & set your location in WXTRACK. The available
Satellites are listed in the SETUP screen. Drag the
required APT Satellites into the Active box. Select Noaa

15, 17, 18, 19, & Meteor 3-5.  Update the satellite KEPS by
clicking OPTIONS & then UPDATE KEPS.  Your
computer will connect to the NORAD web site &
automatically download the latest KEPS.  Make sure that it
has downloaded the weather.txt, & noaa.txt files into the C:/
wxtrack folder. While you are still on the WEB, go to a
search engine & search for the current UTC time. Set your
computers clock to this time.

For decoding & displaying the Weather pictures use

WXSAT. It will allow you to display the picture from the
Weather Satellite, along with being able record & playback
WAVE files. Load the software & click on the
PARAMETERS button & select either NOAA 4+4 or
Meteor depending on the satellite you want to display when
it comes into view. Click the PARAMETERS button &
then the DECODING button & set the selection on the
bottom RHS of the window to N-S or S-N depending on
which direction the Satellite is traveling from. When you
are just starting to receive the signal from the Satellite, click
the RECORDING button & click PICTURE & WAVE
FILE. WXSAT will then start recording the audio from the
receiver as a WAVE file & start displaying the picture on
the screen. A slight adjustment of the fine tuning on the
receiver may be required when you first receive the signal.

The software WXREC can be used to check the audio

record level into the soundcard. Load the software & click
on the icon to start the program. The program will display a
record level indicator that can be set with the mixers record
level. When a satellite is received, set the record level to
NOAA or Meteor depending on what you are receiving

. I

have not found the record level to be accurate, & had to
turn it down slightly.

5. For any Software problems read the information on
the satsignal WEB site as your computer may need extra
files that can be downloaded from there.

REFERENCES:

www.minikits.com.au/down.htm

WxtoImg Software http://www.wxtoimg.com/

WXSAT Ver2.5 Christian H Bock

WXTRACK Ver 3.7.2 David J Taylor
http://www.satsignal.net/

WXREC Satlevel ver1.1.0  David J Taylor

ARRL Weather Satellite Handbook Dr Ralph E Taggart

137MHz Antenna
http://www.jcoppens.com/ant/qfh/index.en.php
http://www.qsl.net/kf4cpj/qha/