[amsat-bb] Re: Eagle Ground Station Pak

John B. Stephensen kd6ozh at comcast.net
Sat Oct 7 18:34:32 PDT 2006

The more sources for equipment the better. The ACP design team has a lot of 
work to do in designing communications protocols and picking coding schemes 
but there are clearly items that need to be developed that are independent 
of those design decisions and generally useful. Dual-band feeds for 2 foot 
and larger diameter dishes are required. There are commercal and surplus 
power amplifiers for 3.4 GHz available but they can proably be made more 
inexpensively with MMICs and FETs designed for WiMax.

Beyond that, we know that the uplinks and downlinks will be wideband PSK and 
that the baseband signals will have to be generated and processed on a PC. 
Uplink signals will be up to several hundred kHz wide and dowlink signals up 
to a few Mhz wide. These could be generated and detected at 2 meters to use 
existing transverters or at other frequencies. There are image-reject mixer 
ICs available that convert 5.85 GHz directly to a low IF frquency that can 
be digitized. There are also quadrature modulator ICs that will convert 
2-wire baseband signals directly to 3.4 GHz.



----- Original Message ----- 
From: <sco at sco-inc.com>
To: <aMSAT-BB at amsat.org>
Sent: Sunday, October 08, 2006 00:46 UTC
Subject: [amsat-bb] Eagle Ground Station Pak

> Does anyone have any idea what will be in the proposed Eagle Ground
> Station package that has been proposed to be provided from Amsat?
> I assume this is for the digital transponder, correct? Might it be a
> patch antenna combo for S/C that would attach to a dish antenna?
> Would it include the upconverter and downconverter required to work
> S/C digital?
> Depending on what is included I might be interested in building such
> a kit/package for users.
> Les W4SCO
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