[amsat-bb] Re: Eagle Ground Station Pak

Edward R. Cole al7eb at acsalaska.net
Sat Oct 7 22:51:53 PDT 2006

Les, Paul...

At 07:02 PM 10/7/2006 -0700, Paul Williamson wrote:
>At 8:46 PM -0400 10/7/06, sco at sco-inc.com wrote:
>>Does anyone have any idea what will be in the proposed Eagle Ground
>>Station package that has been proposed to be provided from Amsat?
>In short, no, nobody has any concrete idea yet. It's just an 
>intention at this point.

Exactly, Les you are asking to soon for details that have yet to be worked
out to specific details, schematics, hdwr...
The board just held a meeting to make significant changes to the Eagle band
plan.  I would guess it will be months/years till those will be determined
in any detail.

>What's completely clear is that a digital solution for accessing the 
>ACP (Advanced Communication Package) would have to be made available 
>to users. It's not something most people would be able to homebrew 
>and there's no off-the-shelf equipment for it. So at least that 
>unique part of the system would have to be made available. There's an 
>explicit goal that this device be made affordable. Beyond that, the 
>details are yet to be designed.
>I would hope to see that any other unusual or difficult-to-obtain 
>system component would also be made available. The dual-band feed you 
>mentioned would be a good example.

I would expect that this item will be designed by the microwave community.
Paul Wade, W1GHZ, has made dual-band waveguide feeds for 10/24-GHz.  Others
have manufactured dual-band mw feedhorns for other bands.  I may give it a
try for 1268/3400 MHz by scaling Paul' s design.  I would assume that the
dishes would be centerfed with f/d ~ 0.375.  Offset feed dishes would
require a feed horn with narrower beamwidth.

>It might turn out to be feasible to build an antenna that requires no 
>mechanical positioning. A phased array of some sort, presumably. If 
>we come up with a good solution for that, I expect it would also be 
>made available through AMSAT.

A dual-band design might be a bit tough, but single band phase tracking is
Ed - KL7UW 
BP40iq,  Nikiski, AK      http://www.qsl.net/al7eb
Amsat #3212
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