[amsat-bb] Re: Tracking - End-stop Problem

[Mark L. Hammond]

Hi Dave,

A user of the LVB Tracker, SatPC32, and a Yaseu G-5500 *can* do 450 AZ
and 180 EL if they choose to.  It's all configurable.  The LVB Tracker
must be calibrated with either 360 or 450 for azimuth , and either 90
or 180 for elevation.  From there, the operator just has to make sure
the SatPC32 rotor setup "matches."   Users can pick and choose
whatever combination matches their station needs or desires (450/90,
360/180, 450/180, 360/90).

I tend to use 90 deg because it's simpler from a "coax hanging"
perspective.  And I also use 360; in my hands, the 450 seems to "lack
linearity" if that makes sense.    By that I mean, if I calibrate to
450, it's like 360 isn't quite really 360....   So, I just use 360 and
it's fine.

73,

Mark N8MH

On Mon, Feb 8, 2010 at 7:14 AM, David Johnson <dave at g4dpz.me.uk> wrote:
> Hi Clive,
>
> Dave is correct about MacDoppler, it works a treat.
>
> What Don (the writer on MD) and I do for GENSO is set a rotator dead
> spot and indicate to the software that it should allow the
> elevation to flip the rotators 180 degrees before the pass. The
> prediction algorithm then knows that if the azimuth passes through the
> dead spot during the predition, it should flip the rotators beforehand
> and output the adjusted azimuth position.
>
> I'm sure that some of the windows trackers do this.
>
> AFAIK none of the existing programs allow for the 450 degree rotation.
>
> 733
>
> Dave, G4DPZ
>
> On 08/02/2010 10:59, Dave-K7DAA wrote:
>> Clive:
>>
>> If you're running Windows, this won't help you, but MacDoppler does
>> this easily, and without operator intervention.  I'm using the same
>> equipment you are, but with a MacBook Pro laptop, and it works
>> beautifully.
>>
>> 73,
>>
>> Dave - K7DAA
>>
>>
>> On Feb 8, 2010, at 2:17 AM, Clive Wallis wrote:
>>
>>
>>> Hi,
>>>
>>> A problem that I've had for many years is how to track when the
>>> satellite's azimuth crosses across the rotator's end-stop,  ie. when
>>> the
>>> azimuth changes from 0 to 359 degrees.
>>>
>>> My rotator turns between 0 and 450 degrees, so it should be possible
>>> to
>>> use  angles between  360  and 450  to  overcome a sudden  transition
>>> from  0 to 360 degrees.
>>>
>>> As the pass data is  available within the tracking program, it
>>> should be
>>> feasible to deal with the problem in the program.   Do any tracking
>>> programs include this feature?
>>>
>>> A possible solution would be to use a small PIC between the computer
>>> and
>>> tracker, which could modify the commanded azimuth.
>>>
>>> I'm using a Yaseu 5500, LVB tracker, Sat_Explorer tracking program and
>>> WinXP.
>>>
>>> Any help,  suggestions or comments would be most welcome.
>>>
>>> 73     Clive    G3CWV
>>>
>>> Hitchin, North Hertfordshire, UK
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>
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-- 
Mark L. Hammond [N8MH]