[amsat-bb] Re: rotator questions

[Bill Howell]

Joseph,
Check out this page:
http://www.thecompassstore.com/decvar.html#
There's a link on that page to plug in your Zip code and figure  
declination, or
you can use the handy map on the main page.
For Austin, the magic number is 4 degrees.

If I recall correctly (it's been a few years), I set the rotor  
control box to North, went up on the roof and rotated the *mast*  
until the ants pointed to magnetic north (using a compass). Note that  
the compass will read inaccurately if held near a metal mast.
Then I rotated the mast a bit more so the ants were pointing about 4  
degrees *West of magnetic North*.

That's the way I remember doing it.

Bill N5AB

On Aug 12, 2009, at 10:28 AM, Joseph Armbruster wrote:

> Hey everyone at the amtat-bb!
>
> I spent a good portion of the day sick in bed yesterday and only  
> naturally
> got to thinking about quite a few things.  I figured i'd pop on  
> here and
> start asking questions.  Here's some background information on my sat
> experience; my rig consists of a TH-F6A (handheld, not full-duplex)  
> and an
> arrow antenna.  I have been successfull at manually trakcing the  
> ISS and
> AO-51, but I have been unsuccessful at making a contact.  I went  
> out to
> field day (in Oviedo Florida) and was able to check out the rig the  
> LMARS
> club uses.  This got me wondering about sat tracking software, the  
> internals
> and what definition of "North" that is used.
>
> I'm familiar with the IGRF (from my day job as a GIS guy) and was  
> wondering
> if any of these apps use the IGRF for calculating magnetic  
> declination:
> http://www.ngdc.noaa.gov/IAGA/vmod/igrf.html
>
> I've thought about creating my own rotator and started wondering  
> about the
> configuration used.  When you buy a rotator and put it out in the  
> yard, i'm
> guessing you have to orient the base 'correctly'.  How is the base  
> of a
> rotator usually aligned?  Do you get a compass out and use local  
> magnetic
> north (without compensating for the declination from the IGRF).
>
> I'm still in learning mode and very new to the world of sat, so if  
> these are
> really dumb questions, my apologies!
>
> I am open to any reading materials you can suggest on the matter.
>
> Joseph Armrbuster, KJ4JIO
> _______________________________________________
> Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the  
> author.
> Not an AMSAT-NA member? Join now to support the amateur satellite  
> program!
> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb