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Eagle SDR prototype on the air, SDR and IHU-3 for Phase 3E, ETC.

At the labs of CNS Systems, Inc. in Md.  (W2GPS business), W2GPS, W3IWI, and N4HY finished cobbling together the SDR prototype transponder today.  We sucessfully conducted a three way QSO in the 45 Khz wide Mode A transponder.  Mode B, software selectable, will be added during the coming week on a trip to Down East Microwave.

The SDR transponder is based on the software designed and written by AB2KT, Frank Brickle, AMSAT's newest member and a serious polymath, along with Bob, N4HY.  We have been concentrating on the SDR-1000 as most nearly fitting our early needs.  Today's prototype demonstration was done using two SDR-1000's
(see http//www.flex-radio.com)

For the software used into today's first success please see:


This is not the latest code, but the latest, along with the fully functional transponder code will be uploaded as soon as Frank and I argue about the directory structure and fix a few gotcha's that can only be found out by trying the code!

For the hardware, we used two SDR-1000's and a DEMI transverter for 2 meters.  This coming week, Bob N4HY, will travel to DEMI and 70 cm will be added.

At the AMSAT annual meeting in Louisiana,  we will have both the Mode B and the Mode A transponder fully functional and usable by all.   We will show the power of using software defined radio for the transponders by having 1/2 of the transponder divided into two or three FM channels and the other half fully linear whilst adding 400bps AMSAT standard beacon in the middle, AND on command, switch it to fully linear, etc.  Given today's success we will proceed with development of fully functional SDR equipment that can be adapted to multiple missions that MIGHT be flyable on Phase 3E but will absolutely be on 
AMSAT Eagle.

We will incorporate the Stella  algorithms developed by Howard, G6LVB, adapted to our hardware for the demonstration in Lousiana.  Expect to be able to conduct SSB, CW, FM, etc. QSO's on Mode A, Mode B and Mode LS if time permits (see next paragraph).

If time permits, we will also be attempting to use GnuRadio USRP, with its dedicated L band receiver and S band transmitter module for an LS transponder.  This will be possible only if the S band module is available and functional in time for us to develop the software for the USRP.


(The jumble of wires will disappear by Lousiana!  If not, we might trip over them!).
Thanks to Rick and Elaine Hambly for allowing this to go on for weeks!

It is hoped that with this demonstrated versatility, it will be easily understood why SDR is an important technology for AMSAT to be using.  Karl Meinzer, DJ4ZC, is an early adopter of SDR technology for spacecraft.  For Phase 3E, the telecommand uplinks will be a software defined radio receiver.   In addition to the standard telecommand link, we will be using a Turbo code based system licensed by AMSAT-DL for use on the Phase 3E spacecraft to test its efficacy for Karl's and AMSAT-DL's great dream:  P5A, a mission to Mars.

In order to make this possible, AMSAT-DL has been getting some design and software work done by KK7P, Lyle Johnson, Chuck Green, N0ADI, Frank Brickle, AB2KT, and Bob N4HY. We worked together for several days at the home and offices of Lyle, KK7P on the IHU-3.  The IHU-3 test code came up and ran and Bob, N4HY is very close to having IPS running on the IHU-3 (expect that announcment to be made from AMSAT-DL in a few days after we get a few bugs worked out).   


(These photos are by N0ADI and N4HY)

and you may visit the AMSAT-DL IHU meeting photo's at 


A MUCHSIMOS GRACIAS goes out to Heather Johnson for putting up with this group for several days while we prepared an IHU-3 for radiation testing by Stacey Mills, W4SM.

A paper by Lyle Johnson, Chuck Green and Bob has been prepared for the annual meeting.

This annual meeting in Louisiana is shaping up to be one on demonstrable achievement on all sides of the AMSAT world.  I hope to see you there.

Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
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