[eagle] Early 2008
rwmcgwier at gmail.com
Fri Dec 21 12:54:49 PST 2007
We have several projects right now in engineering and I am looking for
some volunteers to take on some individual pieces of this after Jan. 1.
Please help me recruit talent that can work on these projects for a
short intensive period. The goal will be to demonstrate as much as
possible at Dayton and even more by October. This means that beginning
in January we have to move out smartly. I hope this group will step up
and take on either individual pieces or help recruit volunteers to do
some of this work.
We are taking on two projects with the Suitsat2 hardware should it ever
become available. Suitsat 2 itself, and an on the air demo, to begin
with in Florida through the coordination efforts of Drew. The Florida
demo is easier than Suitsat2 but still requires work. We have hardware
from DEMI (nice, already in Florida!) that will allow us to put an SDX
on a tower there at about the 900 foot level which will cover a huge
piece of Florida. The other project is the HASP balloon project. This
uses the Suitsat 2 hardware, again, assuming availability.
We need to have an SBC to talk to and reload this thing as we update and
upgrade code for the Florida experiment. I have not vetted the Suitsat 2
IHU for this purpose because I have never seen it, can't size it, or
even tell you if it runs. This will be remedied in January.
In addition, we need to get ready for the pursuit of a working prototype
of the full SDX. I talked to Marc Franco a couple of weeks ago. He and
his wife have a beautiful new baby and Marc is working again on the
amplifier. Marc Franco has made steady progress on the driver and
amplifier. He is working through an oscillation problem in the driver
in an attempt to NOT have to solve it by gain reduction (lowering the
overall efficiency). John Stephenson appears to have solved the
critical matching problem for the SAW filter in the 70 cm RX. The goal
for this would be to get it ready for on the air testing in time for
Dayton and then deploy to the Florida site to take over from the Suitsat
hardware. Here we could arrange some torture tests for the Stella.
I have most of the hardware details on Howard Long's version of the SDX.
I still need a late version schematic and the latest code but he has
shared with me many of his parts selections, reasons, etc. Karl has
marked up the P3E transponder in a way that tells Howard how to add SDX
to the mix, right down to voltages, current, impedances, etc. I will
arrange to get the latest code from Howard.
I have two Lyrtech boards which are XC2V3000 Virtex 2's and TMS320C6713
DSP. These boards are to be used to prototype code for the HELAPS
modulator and a small channel version of the ACP.
We need some FPGA work done on the Virtex 2 for SDX and for ACP. The
Virtex 2 is overkill for the SDX. We need it to do rectangular to polar
conversion, a PWM for the modulus or envelope channel, and a few other
The Virtex 2 is a capable part but it will not support the full ACP.
Nevertheless, it will certainly allow us to develop the basic ACP FDM up
and TDM down demod, remod cores we need. The difficulty in dealing with
this card is that it really does have to have expensive tools. I have
them and while Rick has a copy of the Lyrtech, but I am not sure this
is optimal if we can find a volunteer with FPGA experience and the time
to work. Rick has both real work and institutional difficulties in
AMSAT to deal with. Ideally, I would find a different candidate to help
with this. This means that I am looking for someone with a) access to
Matlab and b) FPGA experience and c) access to TMS320C6713/6726
development tools. This is a tall order but it is the fastest way to a
working prototype to "show we can".
There is absolutely no reason we cannot begin the prototype development
of an upconverter and a downconverter for the ACP. I can test the ACP
at IF with the other Lyrtech board being used for ground terminal
development. We need to do work on the modulator, demodulator, FEC,
decoder, etc. for this. But we need to come up with some preliminary
thinking on devices to be used at 3.4 GHz and 5.7 GHz for the generation
and reception of hard limited constant envelope signals and some
prototyping needs to be done.
I would like to call for a meeting as early as possible. I don't care
if we have multiple meetings but we need to organize our activities
around getting some specific tasks and deliverables into our thinking by
not later than mid February. We need to set realistic goals for what
can be accomplished by a) Dayton and b) the annual meeting.
I will be on TeamSpeak on January 8 for a meeting of anyone who wants to
show up and talk about these activities. I hope to report on some
definite progress on many things facing us, including a detailed ITAR
situation report from Rick. That is moving along but we are at the very
hard spot of agreeing on language for the technical assistance
agreements. We need to aim for a serious meeting as early as possible
in and probably early February. Please think about your availability.
This note is an informal heads up to expect a larger and more detailed
mailing to come out while I have 5 days at home.
AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL,
TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair
“An optimist may see a light where there is none, but why
must the pessimist always run to blow it out?” Descartes
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