Re: [amsat-bb] Rotator stops for the southern hemisphere

[Paul Yeager <w4ski@xxxxxxxx>]

Phil:

Here's my guess:

The "south centered" thing is certainly an advantage for those of us in the 
northern hemisphere working A0-40.  The orbit seems to be such that in the 
norther hemisphere, azimuth to A0-40 always ranges between greater than 90 
and less than 270 degrees , and many (if not all) passes include azimuth 
passing through 180.

Having the rotator "south centered" saves having to move through 359 
degrees or so in the middle of the pass.

Now.... if my understanding of the AO-40 orbit is correct, this would not 
be a problem for folks in the southern hemisphere, as (again, if I 
understand the orbit correctly) from the southern hemisphere, azimuth would 
range from greater than 270 to less than 90, with most passes transitioning 
through 0 degrees.  For this, "north centered" would be fine.

As for other satellites, especially LEOs, I'm not sure that there is an 
advantage one way or another.  Perhaps analysis of many orbits with a given 
ground reference might tell.  My gut feel is that it is a tossup.

I recognize that I might have it all wrong, and if so, I sure hope someone 
sets me straight!  We live  and learn!

73

Paul W4SKI

At 08:25 AM 7/31/02 +1000, you wrote:
>Hello All,
>
>The recent discusion about south centred scales has got me thinking. Should
>we, in the southern hemisphere, have our rotators setup with the stop to the
>north (south centred scale) or not? This is the way that mine is setup simply
>because my controller takes an input of 0 and 360 to point north but I could
>always change it if it's wrong.
>
>I'm not sure that it makes a lot of difference either way because there are
>times when a satellite passes through north, or south, which means that the
>rotator will have to reverse to get to the other side of the stop.
>
>Due to ongoing house renovations, which I hope to have completed by October,
>I don't have my aerials installed and I'm still waving them around by hand.
>This is not very satisfactory at all. I hope AO -7 continues to function for
>at least the next couple of months, I'm looking forward to making a contact.
>
>--
>Regards,
>Phil
>phil@spiderweb.com.au
>
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