[Namaste-dev] Re: Howie's question

Michelle w5nyv at yahoo.com
Fri Jun 13 17:06:25 PDT 2008


Thank you very much for bringing this up. I was not aware that the rules were based on the service employed and not the physical antenna structure. 
There are compelling reasons to use these dishes - they're available and familiar. However, there is a big difference between that compared to basing the system design around them, which is what we have been doing. 
Another advantage of having a fixed component is that it makes for an anchor in the system design, which has been quite useful to me in describing the project, as well as exercising the link budget.
Sounds like to me it's time to list and review the top-level requirements as I understand them, from the presentations back in February. I'll get to work on that over the weekend.-Michelle W5NYV


----- Original Message ----
From: Roger Thompson <rogert at traceroad.net>
To: Bob McGwier <rwmcgwier at gmail.com>; namaste-dev at amsat.org
Sent: Friday, June 13, 2008 11:33:11 AM
Subject: [Namaste-dev] Re: Howie's question

I find this interesting.

"We need the processing gain we get by using the 1/(R^2) loss advantage 
by demodulate decode at the satellite over 1/(2R)^2 path loss we would 
get from a bent pipe."

When I first heard about this project, I wondered right away why so much
complexity was being put into orbit by choice.  Added gain needed from
processing at the satellite explains why, but only if there are constraints
at the ground end of the link that force this design choice.  What are these
constraints?  My opinion so far is they don’t really exist...



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