[hpsdr] Odyssey Siren A success

Robert McGwier rwmcgwier at gmail.com
Tue Mar 13 14:35:37 PDT 2007


We had a complete breakthrough on the Odyssey Siren in the past two 
weeks.  It will be used in Suitsat 2, in a terrestrial linear repeater 
experiment by Viktor Kudielka OE1VKW and friends, who supported its 
development, and we are already leaping all over the place to applications.

Frank Brickle and I will be doing our SDR code on it over the next 
several days.  The board as shown in the schematic needs some 
modifications to fix the 3 - ish volt power supply for the Codec and a 
modified oscillator circuit but we are certain it will all work now.

On the 10.7 MHz IF,  I measured 0 dBm max into a 50 ohm load and less 
than -120 dBm MDS and > 80 dB dynamic range.  This is with a BOM of < 
$50 in parts and about a $20 dsp pic chip!

Yesterday in Rick's lab, with W2GPS, K3IO, we made the above 
measurements, hacked on code and turn the thing into a bent pipe 
transponder.  I also did the hilbert transform to make it an inverting 
transponder.  It all worked perfectly.

http://www.cnssys.com/~w2gps/amsat_files/suitsat/

has detected audio in an SDR-IQ SDR as well as captured IF from the 
SDR-IQ of the transponder.  We have to balanced for image and do DC 
offset correction but the thing works and sounds great as you can hear 
for yourself!

73's
Bob
N4HY


-- 
AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL,
TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair
"Taking fun as simply fun and earnestness in earnest shows
how thoroughly thou none of the two discernest." - Piet Hine



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