AtmoSphere - pages/geogra01.html

Geography Department's Base Station

The Geography Department's Base Station and how to use it

The geography department has a "Base Station" capable of receiving weather satellite images from the meteosat weather satellite. Meteosat is in geostationary orbit around the Earth at a distance of 22,300 miles (35,900 km). Every four minutes, a separate image is beamed down to Earth and anyone with suitable equiment (such as the geography department) can receive these images. These images are also available from the AtmoSphere images page, live from the Nottingham University base station. This page describes how to receive images using the geography department's base station.

Aiming the antenna
Meteosat is positioned in geostationary orbit over the Greenwich meridian. King's School is fairly close to the Greenwich Meridian and so the antenna must face almost due south. The satellite is at an angle of 30^o elevation from the horizon. (See diagram below).

Position of MeteoSat

This has already been done for you. Do not alter the direction in which the antenna is pointing.

Receiving an Image
What follow are instructions for receiving an image from Meteosat. For ways of improving this image or receiving images from other satellites, consult the Timestep manual.

Every four minutes Meteosat sends a new image according to the Meteosat Dissemination Schedule. Use this schedule to plan which images to receive when. A good five minutes before you wish to receive an image, follow the procedure below:

Before turning on the computer, ensure that:

the base station has:
- its power supply plugged in and switched on
- its setting switch set to A1
- its speaker plugged in
- its amplification set to 2 o'clock on the dial.
- its ribbon cable plugged into the back of the interface card.
the interface card:
- is plugged properly into the back of the computer
- has it's selection switch switched towards the ribbon cable
the computer:
- has no disk in the disk drive
- has the monitor plugged in
- has the mouse properly plugged in (underneath)

The speaker plugged into the base station should be making a noise. First adjust the gain control on the front of the base station so that the LED on the front just flashes. Adjust the volume control until this noise is at a comfortable level. Do not turn the volume RIGHT down. If necessary, unplug the speaker. Now turn on the computer and put the Meteosat disk in. When an image appears on the screen, double click on the picture of the disk drive. Now double click on the picture of the satellite dish marked "Zoomdisk".

Make sure that the autotracking menu item

Turn autotracking off

is set. If not, double click on it to change. Now click on

Download into memory

some text should appear on the screen saying

Searching

Nothing will happen for up to four minutes. At the time on the dissemination schedule, the message will change to

Image found Loading Line : 800

This will not change for a bit. The speaker should then start to make a pinging noise. Each ping should be accompanied by the line number falling by one on the screen at a rate of four per second. When the line number reaches zero, the image should appear full screen on the monitor.

This is not the full resolution of the image. If the image that has just appeared is the one you want, press [ESCAPE] on the computer keyboard and click on

View the Full Image

to see the image at full resolution. (If it is not the image you want, simply wait for the next one to be received.)

If you wish to keep the image, put a different disk in the disk drive and press [ESCAPE] and click on

Save the Image