[eagle] Re: Another idea on phased array configuration

Matt Ettus matt at ettus.com
Sat Apr 28 12:56:17 PDT 2007


Louis McFadin wrote:
> Bob,
> I am very worried about this huge requirement for power. I am 
> concerned that we are making a satellite that that AMSAT will not be 
> able to afford.
>> We also need to resolve the question of how much power needs to be 
>> supplied during the worst case eclipse scenario. This has a major 
>> impact on the amount of energy storage is required.
> Another question is whether we are going to stay with the requirement 
> of being sun angle neutral. These are all drivers for the size of the 
> spacecraft and the structure.

What I'm most worried about is that no decision is ever final. 

What I'm most worried about is that questions which were quite settled 
are now being reraised. 

What I'm worried about is that nobody seems to remember what we 
concluded at past meetings.

What I'm worried about is that a simple question about the phasing 
system for the patch array has become an opening to question the shape, 
size, and power of the satellite.

What I'm worried about is that  in late April 2007 we are repeating 
discussions from 2004.


The decision was 36 patches at 1/2 to 1 Watt apiece.  The link budgets 
were done assuming just a little bit more than 1/2 watt apiece.

For 1/2 watt each, we get 18 W of RF, and assuming 40% efficiency, 45 
Watts DC.  Maximum heat load = 27W.

For 1 Watt each, we need 90 Watts DC input to generate 36 output.  
Maximum heat load = 54W.


Matt



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