[amsat-bb] Re: LVB tracker questions

[Bruce Robertson]

On Jan 9, 2008 6:45 PM, Howard Long <howard at howardlong.com> wrote:
> Hi Kevin and Andrew
>
> >  1) the LVB does its calibration in software, no variable supplies.
> >  2) it keeps accepting commands and acting on them.
> >  3) on the right side is the desired location, left side is the actual
> location.
> >  4) I know it works with the GS-232a protocol   W135 035  W (az)  (el)
> >   maybe someone else knows.
> >  5) Howard has mentioned this before on the bb and I believe its in his
> > write-up on the tracker that he does multiple samples and averages them
> > to get a more stable reading.
> >  6) I think the diodes you are referring to go to the plus voltage for
> > the position pots and to ground, if those are the ones you are talking
> > about then they are there to limit any spikes on the az or el position,
> > any negative voltage gets shunted to ground, any positive voltage greater
> > than the supply gets shunted there.
>
> That about sums it up!
>
> As well as the GS-232A protocol it also supports Easycomm I. It looks at the
> command sentences and automatically knows from their structure what protocol
> is in use. Smart eh? ;-)
>
> The GS-232A seemed to be the most widely supported protocol at the time, and
> I've not had any complaints yet that it should support anything else.
>
> Note that there are some esoteric GS-232A scheduling commands that are not
> supported. Also calibration is performed differently. The reason calibration
> is done in software was so that I didn't need to have to keep adjusting the
> G-5500 trimpots every time I changed the rotator controller interface.
>
> As Kevin has already alluded to, the movement of the rotor is monitored
> simultaneously as commands are accepted. All commands are acted upon
> immediately whether or not the rotor is already moving. So you can override
> a previous command immediately simply by sending another. This is how a real
> GS-232A works.
>
> Note that the LVB Tracker does not detect a stalled rotor by itself - this
> is a job for your favourite tracking software.
>
> 73, Howard G6LVB
>
>


This is a wonderful addition to the stable of AMSAT-related project.
As I've been toying around with designing a track-box for Tony AA2TX's
iRotor interface, I've learned quite a bit by reading the articles in
the Journal relating to the LVB Tracker.

You mention GS-232A protocol and Easycomm I. I have my code parsing
the GS-232A, which is easier because the parsing can be done by
character position. But I was hoping to use serial-line rotor command
protocol that included the name of the satellite being tracked so that
that info could also be displayed. Does anyone know of such a beast,
especially if it is supported by SatPC32? I went through that
program's manual but had no joy.

73, Bruce
VE9QRP