At 02:49 AM 9/30/2007, Patrick McGrane wrote:

Regarding Miles desire for simplified electronics, I wholeheartedly agree!

I was very disappointed that amsat-na pushed for the SDX on the german P3E. I'm sure its a better receiver but its never flown. P3E was built around a proven AO-13 design.

If someone were to fly a payload a quarter of a million miles to the moon, It should be dramatically simple and long lasting, That means no short life components like batteries.

N2OEQ

Patrick: it is too bad that you were unable to join us here in Hartford, CT this weekend for the TAPR-ARRL DCC ... There were many presentations on SDR, some by AMSAT personnel ...

The hardware does not GET any simpler than in SDX ... the HUGE advantage is that a component with a shifting value (such as might occur in a spacecraft with wide temperature swings) does not degrade the performance/optimization of a device, because if the hardware does age/shift, then that can be compensated for in software ...

By the way, doing an amplifier in DSP/SDR greatly improves the efficiency and power budget too ... you do NOT want to fly today's missions with yesterday's technology ...

I'd encourage you to visit Pittsburgh for the AMSAT-NA annual meeting in October ... you can hear it first hand in the presentations, and talk to the people that build hardware and the others that bang bits !

73,

Dave VE3GYQ/W8 Spencerville, OHJ

President TAPR, INC.

And now I'll take a turn at giving my opinion.

I've been an active member of AMSAT going on four years and a member of Project OSCAR for a little less than that. I'm glad that we, amateur scientists that we are, are using new technologies to produce our "product" to the amateur community.

Amateur radio has changed since the early 1900s where people experimented and built their equipment and learned from their failures and, most importantly, learned from their successes. Ever since the very beginning the world has looked at the amateur radio community, directly and indirectly, for the latest and cutting edge (sometimes bleeding edge) ideas and technologies. Unfortunately since the early ninety's I feel that amateur radio has slipped in this technology arena. No one hardly ever builds anything anymore and too many of us younger crowd expect the older crowd to get everything going for them (not always).

I got involved in AMSAT and Project OSCAR because they were still cutting edge. They still had the world's ear and they were not afraid of trying new things. We have had almost 60 (or maybe more now) "OSCAR" satellites flown since OSCAR 1 was built and launched and we're not done yet. If we want to ever make it in this world and not get run over by the commercial world then we'll have to stay on top of technology and keep developing new ideas. We have to keep building on our successes and fixing our failures or else we'll just have to wait for HRO (Ham Radio Outlet) to start selling satellite parts (or maybe the entire satellite) in order for us to get our satellites in orbit.

Someone mentioned that AO-7 was probably the biggest success in AMSAT's history. I have to say that AO-7 is a very nice satellite and one that I hope to operate on it more in the future. But it should also be noted that AO-7 was silent for twenty-one years before it came back to life to be operational when in the sun's illumination. Before it went silent in 1981 it had been operational for six and a half years which is great. I can only hope that all of our satellites will operate that long and longer in the future.

I think that if we have the opportunity to fly equipment that will allow for a better power budget (something that has always been a problem on satellites and probably always will), that will provide more/better functionality, and that will allow for upgrades later on down the road (it's software after all) then I say go for it. If you haven't had enough time to get a lot of testing on it? Well then fly a second transponder, one that is built smartly using "traditional" technology. That way you can use it as an experimental platform. We can also take advantage short lived LEO satellites and maybe even use the ISS as an experiment platform (as was done with PCSAT2).

If we don't cross the SDX bridge now then when? If you say never then you don't understand what our amateur radio "fore-fathers" were thinking and feeling when they built the very technology and laws that allow us to communicate the way we do today.

73s, Eric Christensen, W4OTN AMSAT Area Coordinator - Southeastern Virginia USA AMSAT Member 35360 http://www.ericsatcom.net

Donate to the Eagle Fund - http://www.amsat-na.com/donation.php?donate=eagle