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Re: C Band



Wow.  Good ideas.  If I got this right, the 5 deg inclination of AO-40
means that for the most of apogee, it is mostly always 5 degrees higher
than the GEO arc (TV sats).  SO take your 10 foot dish and TV activator,
use the EL TWEAKER to bump it up about 4 degrees, and  you should be
able to track AO-40 for hours... with only the longitude control!

Of course, once it has its attitude correct, you wont need a 10' dish...
But the bwamwidth at 2.4 GHs is on the order of 3 or 4 degrees so it
should work fine.. without re-tweaking the EL adjustment (except to watch
TV)...

 de WB4APR
On
Thu, 19 Apr 2001, Edward R.
Cole wrote:

> Robert,
> 
> That is a very innovative idea, and one that anyone who still uses a large
> sat-TV dish could do.  I have switched to the small ku-band sat-TV system
> but intend to upgrade to a 1m [4-foot] offset dish in a couple weeks as the
> 33 inch dish is too small for up here [fortunately the store will give me
> full trade-in credit].  It would not be as useful as a c-band dish that
> tracks across the "Clark-Belt", though.
> 
> I also have an 8-foot dish that could be used when I get the az-el drive
> restored to operation.  It is destined for eme use eventually, but may be
> required for AO-40 depending on the final orbit-status.  But back to your
> original idea:
> 
> Finding the pointing coordinates by measuring is one approach.  Though, as
> you point out, not entirely satisfactory.  If you have NOVA it has several
> of the geocentric c-band satellites listed.  So all that is needed is to
> load them into a view and record their az-el coordinates.  Now you have a
> list to compare with AO-40's movement.  Since AO-40 is inclined only 6
> degrees from the equatorial plane it will travel close to the geocentric
> coordinates often, I would guess.  You might even be able to track it for a
> short period by moving the TV dish, though coincidence of the two orbits
> would extend only for a short duration [ a few degrees?].  One could
> analyze this a bit more to be sure.
> 
> Ed
>  
> 
> >From: "Robert Jewell" <ac9r@home.com>
> >Have you ever looked at how often AO-40 passes in front of your existing C
> >Band satellite dish?
> >
> >Tomorrow, April 20, 2001, at about 1343Z to 1443Z, AO-40 will be near 210
> >deg in AZ and 45 deg EL, + / -
> > (in NASHVILLE). (MA= 224 - 237)  I made 11 elevation measurements from 160
> >deg AZ to 245 deg  AZ(the limits of my dish), here in Nashville, TN.  ( EM
> >66).  Azimuth is difficult to measure with a compass, elevation was measured
> >with a one degree inclinometer (?):
>  
> 
> 
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de WB4APR@amsat.org, Bob

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