[amsat-bb] Re: S band and Eagle: an appeal for more transparency

Bruce Robertson broberts at mta.ca
Fri Sep 8 06:57:03 PDT 2006

Quoting i8cvs <domenico.i8cvs at tin.it>:

> ----- Original Message -----
> From: "Stefan Wagener" <stefan_wagener at hotmail.com>
> To: <brobertson at mta.ca>; <amsat-bb at amsat.org>
> Sent: Friday, September 08, 2006 1:57 AM
> Subject: [amsat-bb] S band and Eagle: an appeal for more transparency
> (was
> Sband and Eagle: an appeal for a higher level discussion)
> > The main problem with the whole discussion is that the majority of
> folks
> > have NOT seen the data. In addition, if the data are as sound as they
> are
> > portrait, why is AMSAT-DL not believing in them and is including
> S-band as
> > a downlink. How is the discussion between ANSAT-NA and AMSAT-DL
> > going on this?
> > 73, Stefan VE4NSA
> Hi Stefan, VE4NSA
> The reverse is true. If the result of the S band as a downlink on AO40
> was
> extremely succesfull why AMSAT-NA is not believing in AMSAT-DL ?
> The decision of AMSAT-DL to reuse the S band for downlink of P3E is
> based
> on already experimented facts using AO40 and there is no question about
> that.
> Is someone in condition to demonstrate that the S band of AO40 was a
> catastrophical affair ?


If I understand the argument from the Eagle Design Team, they are basing it
on current and extrapolated conditions, not trying to make the case that
AO40 S band was a bust, nor reusing the assessments of AMSAT-DL, which I
assume were made a matter of years ago. 

I would love to see the next year's issues of the Journal exploding with
papers tackling this question. I expect Naples would be a super place (i.e.
nice and noisey :-) in which to undertake some experiments that might
refute (or possibly confirm) the Design Team's assessment.

Come to think of it, San Fran. would be a great place, too. Maybe some
local folks who have access to the appropriate test equipment could stage
some experiments at the symposium. It would be a great way to get some data
for us to mull over. (If that happens, I'll have another reason to regret
not being able to go to what sounds like a fantastic time.)

Brainstorming here: might wifi equipment provide a cheap test bed for such
experiments? I'm not sure how well calibrated they are, but these devices
often report noise level and signal level in dBm. Linksys wifi routers can
be hacked with linux to make their signal strength adjustable. I suppose
one problem could be that the card is designed to treat as signal that
which we want to treat as noise, namely other wifi networks. 

> Don't worry about because if P3E will be succesfull in orbit at the end
> of
> 2007 than the S band as a downlink will be again the voice of truth.

If the timing were right, this could be a reasonable approach; but as I
remember, the piece on AMSAT-DL entitled "Launches Speak Louder Than Words"
put the earliest sure launch date in 2008. That might be too late to use
P3E as a test-bed. 

73, Bruce VE9QRP

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