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.
73,
John KD6OZH
----- Original Message ----- From: sco@sco-inc.com To: aMSAT-BB@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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