[amsat-bb] Re: Why do the amsats get more and more complex?

Steve Meuse smeuse at mara.org
Tue Sep 19 10:38:48 PDT 2006

Jason White expunged (jason at jason.white.name):

> Anyway, I'm just curious why it seems that every new satellite project 
> proposed seems to be bigger and more complex than the last? I keep 
> hearing about exotic modes and uplink/downlink bands for P3E.. software 
> defined transceivers, etc. etc. and what it looks like to me are more 
> and more failure points. I understand the need to push the limits of 
> technology as a justification for our very existence, but personally I 
> feel like the designs are overly complicated and highly priced. I'm not 
> ready to switch my earth station to SDRs, for instance.. I'm dubious 
> about putting one into orbit.. then again, I'm not skilled enough to 
> make those sorts of decisions.

A minor note of clarification, the Software Defined Transponder (SDX) does not require groundstations to run SDRs. It's a new method to implement the traditional linear transponder design in software. 

Now, as for the bigger/better issue, I'll make some observations:

- P3E is purpose built as a technology testing platform for a very specific Mars mission, I don't see it as all bells and whistles. (bigger better for the sake of bigger better)

- The Eagle design, as it's turning out, *seems* to be much less complicated than a AO-40 or P3E, at least in the number of bands and functions. 

Then there are the basics, like FCC Part 97 rules:


§97.1 Basis and purpose.

(b) Continuation and extension of the amateur's proven ability to contribute to the advancement of the radio art.

(c) Encouragement and improvement of the amateur service through rules which provide for advancing skills in both the communications and technical phases of the art. 

> What I'm getting at is that Oscar 7 proved how reliable older technology 
> can be..  For the price of one of the  phase 3 birds  it seems like 
> several Mode B linear transponder sats could be put up, or a few more FM 
> sats. I personally would much rather see a modest mode B sat in AO-40s 
> intended orbital pattern than to try to wrangle parts for microwave.

I've talked about this before, but it's important to remember that AMSAT is not a serivce provider. We don't exist to provide a continual supply of mode X transponders in Y orbit. We're here to advance the state of the art, IMHO.

(of course, I still hold the right to throw a temper tantrum over mode S downlinks)

> Wouldn't it be better to separate out some of the more experimental 
> stuff from the old standbys? That way a failure of one whole sat would 
> still leave something usable for the same money spent.  My vote would be 
> to piggyback a completely independent analog satellite onto P3E "just in 
> case".

If you want to build an "old standby" sat, go for it!

The people who are actively building sats aren't interested in that. I don't blame them either. But remember, AMSAT isn't stopping ANYONE from putting a team together to build a new sat. 

> If someone could help me understand why the direction is the way it is 
> maybe I could get excited about the bigger sats, but I think you get 
> more "bang for the buck" with the smaller less complicated birds. My 
> favorite so far is PCSat I. Mostly off the shelf hardware and I had a 
> very easy time digipeating APRS through it. One of those in an 
> elliptical orbit would be a hoot!

Of course, you would likely need a more robust equipment set to work HEO :) It's a give and take, there isn't a perfect solution. 


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