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Your data file will have been stored in the Directory in which you have stored the
InstantTrack program. Usually this is called “IT”. You can look there for your data file using
Explorer, and examine it using a simple word program such as WordPad or NotePad.
The data file controls.
The program is designed to read the output data files produced by either
InstantTrack
or
Nova for Windows
. When you click the ‘Send an ephemeris to the controller’ button, a file
window opens to allow you to select the ephemeris data file produced by one of these
programs. The default file type is one which ends in ‘.out’; for example, ‘ao40.out’, ‘moon.out’,
etc. However, you can have it look for files of any type by clicking the down arrow in the file
name box. After you have selected the appropriate file, the program may take a second or two
to apparently digest this file. It is, in reality, parsing the data in the file and writing it to internal
memory and then sending it to the controller. The program does some elementary data
checking and it can make a guess at detecting files that are not produced by either
Nova for
Windows
or
InstantTrack
. However, this ability is pretty rudimentary and shouldn’t be relied
upon – in other words, it is best to make sure the file you select is truly either an
InstantTrack
or
Nova for Windows
output file.
If the controller has previously been loaded with some data for an existing pass, you
can upload data for subsequent passes by opening the data file and sending it to the controller
as described above. It will be loaded into the controller’s memory after the data that is already
there. However, the controller only has the capacity to remember 50 data points and if you
exceed that limit, the subsequent data will be lost. You may clear the controller’s memory by
clicking the ‘Clear the buffer’ button in the rotor controls section of the window. You would
normally do this before starting the upload of a series of passes into the controller or when you
wish to erase the data already in the controller for any reason.
The remaining rotor control button, ‘Go to first stored position’, instructs the controller to
immediately go to the first data position stored in its memory. This is useful for a satellite pass
that will take place sometime in the future when the satellite appears over the horizon. It will
cause your antennas to be pointed to that location right now and not wait until the predicted
time of the satellite appearance before starting to move. This instruction also enables the
subsequent automatic motion of the rotors at the times for each successive position.
A hint about ephemeris data files.
The Sat
EL
rotor system only moves in steps of ten degrees in either azimuth or
elevation so the
AzElControl.exe
program automatically rounds off satellite azimuth and
elevation into steps of ten degrees. In order not to fill up the controller memory with unneeded
data points, it only sends those times and positions when the azimuth or elevation have
changed by ten degrees.
Ten degree steps are sufficiently fine for amateur radio satellites, because antenna
beam angles are typically not narrower than about 20 degrees. With 10 degree steps, the
antenna is assured of never being more than 5 degrees off in elevation plus 5 degrees off in
azimuth, for a worst-case error of ~7 degrees. This error is small compared to the typical 20
degree or more of the antenna beam width.
Low orbit satellites move across the sky in times of just a few minutes while Phase 3
Satellites move much more slowly. For this reason, when creating the ephemeres by either
Содержание Az-EL
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