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Re: Fodtrack

Hi Rodrigo, Bill,

Ignacio (CE2MH) asked me to provide my input on this:

>     I had similar problems. When you turn Fodtrack ON, the DAC has 0x00 in
> his digital input so, its output will be 0 Volt. At the YAESU control box
> this means rotating to the left edge. If you have the left wire changed with
> the right wire then, the control box will rotate right.

Not necessarily. The state at switchon is undefined, so the value it
assumes is random. It can be zero, full scale, or in some cases anything
in between. So the above is no sure indication of a misconnected wire.

>     I solved that installing the switch to stop the Fodtrack while my
> tracking software is not working.
>     So do not activate fodtrack outputs, unless the software is already
> working.

That's the normal operation. I used to leave my sat station running 24
hours a day, so the unclean switch-on was no problem. Nowadays I run my
station only occassionally, so I move the switch to OFF until the
software sends some commands to the interface.
>         When the software is working normally, elevation works fine, but
> azimuth sometimes starts going -180? . Then receives the next data, and
> returns to the normal azimuth position. But this occurrs +/- every
> 10secs.
> Very strange. I still haven't found what the problem is.

If it happens REGULARLY at a fixed interval, the most likely cause is
interference on the parallel port caused by some software that is
accessing the port between FodTrack accesses. Check what programs are
resident on your PC, and throw out any paralell port scanner drivers,
intelligent printer handlers, and so on!
If the problem occurs at irregular intervals, there is a chance that the
port is extremely slow to recover its rest state. In such a case some
pullup resistors on the strobe and Az/El selection lines will help.

> > When I turn the Fodtrack unit on ( there is an on off switch ) it
> > immediately moves the antennas to 180f ( both azimuth and elevation ) .

It is normal. Use the Calibration function of the Fodtrack program to
send test values to the interfase. If the rotator follows those
commands, all is fine. 

The random values at switch-on could only have been avoided in hardware
by a rather complex reset circuit involving around half a dozen
additional chips. That's why I just left the interfase to start up with
random values.

If you need any further info from me, please include mmornhin@gmx.net in
the destination, since I'm not subscribed to the list.


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