quinta-feira, 22 de março de 2007

Hardware do SUITSAT-2 ganha forma

Segundo a AMSAT, pela voz de Bob McGwier, N4HY, o hardware do Suitsat-2 começa a ganhar forma.

Transcrevemos a sua comunicação.

"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, W2GPS, lab, with Tom, 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.

Detected audio in an SDR-IQ SDR as well as captured IF from the SDR-IQ of the transponder can be downloaded and heard from: http://www.cnssys.com/~w2gps/amsat_files/suitsat/

We have to balanced for image and do DC offset correction but the thing works and sounds great as you can hear for yourself!"

Additional details and pictures of the hardware can be found at:


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