Re: [amsat-bb] Problem with Sat Tracker

["Dave Lamont" <lamontd@xxxxxxxxxxxxxxx>]

Hi Jim,

I have no idea about the Sat Tracker pin outs but be aware that unless
the Sat Tracker has been reworked for the 450 degree G-5500 rotator,
you have a problem.

The feedback voltage on G-5400, G-5500, and G-5600 systems is
nominally 5 Vdc at full clockwise rotation. This voltage is feed normally
to an 8 bit A to D convertor.  (5 divided by 256)

Presumably the Sat Tracker divides 360 degrees by 256 ( 8 bits)
and uses the resulting constant to match up satellite bearing with
rotator feedback position. This all goes "belly up" when  you need
to divide 450 degrees of the G-5500 by 256 to obtain the same
relative position. The problem is further compounded by the additional
90 degrees to the East that the G-5500 has and which the Sat Tracker
probably  knows nothing about.

Another possible problem is the postioning of the mid meter scale point.
Most 5400/5600 units to my knowledge are centred on North, whereas
the G-5500 is centered on South West. This wll also confuse the original
Sat Tracker algorithms.

Have a look at my web site   www.qsl.net/zl2amd/   My Uni_Trac 2000
system caters for ALL G-5xxx series units as well as providing user
configuration for the G-5500 so that the 450 degrees available can
be used more efficiently.

73
Dave Lamont     ZL2AMD
----- Original Message -----
From: Jim White <jim@coloradosatellite.com>
To: <amsat-bb@AMSAT.Org>
Sent: Saturday, March 11, 2000 8:04 PM
Subject: [amsat-bb] Problem with Sat Tracker


> I'm having trouble getting a SASSI Sat Tracker to work with a Yaesu G 5500
> rotor (the new one).  When we run the ROTOR program to do the calibration
> we find the following problem:  When we turn the rotor in az with the
> switch on the front of the control box we get no indication on the
> ROTOR.EXE graphic readout.  When we turn the rotor manually in elevation
we
> see both the elevation and az indicators move on the graphic
> readout.  Smells like crossed wires, but we are using the cable that came
> with the Sat Tracker.
>
> Anyone have this problem?  Is there a difference in the pin out of the
> connector on the back of the control box that would cause this?  Is there
> some software setup in the ROTOR.EXE that I haven't found which tells it
> this is a 5500 not at 5400 or ?
>
> Any info appreciated.
>
> jw
> wd0e@amsat.org
> jim@coloradosatellite.com
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