At 12:29 AM 3/24/2007, Bruce Robertson wrote:
From my reading, and I'm not an expert, SDX technology is predicted to be
indistinguishable from a linear xponder to the ground station: I have read
In its most basic configuration, it will be functionally identical to an analog transponder, except somewhat better filter performance. The performance on the Odyssey transponder being built for SuitSat 2 looks impressive. And in this basic configuration, the ground station need not know the difference.
no account of entailed losses. What it *does* aim to provide is a newly flexible and configurable bent pipe. One obvious application is to limit the amount of output power in a given portion of the passband, thereby reducing the impact of alligator stations. The audio files posted on this list indicate no unnatural artifacts to my ear, and such transponders are routinely built to operate with varying modulation schemes.
That's the real beauty of the technology.
My point is that SDX allows us to dream of these things, and potentially to implement them even after the bird is up. Yes, it entails a risk. We're fortunate to be able to mitigate this risk: SuitSatII will fly with SDX on-board so that we can test this technology. To my mind, the satellite service/hobby is a branch of the hobby that continues to fulfill the experimental origins of amateur radio. We need to do so prudently, given the cost of launching the hardware into space, but I think the SDX concept fits nicely within that curve.
SuitSat 2 is a handy test platform for the technology, that's for sure. It's good to see ham radio continue innovating.
73 de VK3JED http://vkradio.com