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Re: Observed AO-40 FEC coded telemetry ?



Hi Kazu and Group,
    I ran the .wav file through Phil's (ka9q) FEC demodulator and it 
comes out as 37 blocks of gibberish :-[  .
I await developments with interest.

        73 de Geoff vk2tfg

JJ1WTK, Kazu Sakamoto wrote:

>Hi all,
>
>On Saturday June 7th 2003 around 03z, 
>I am sure that I observed the experimental transmission of FEC coded
>telemetry of AO-40 on the S2 beacon.
>
>Normally, the bird have been sent the blocks in the sequence of
>A,E,A,K,A,E,A,L,A,E,A,M,A,E,A,N and then repeat them. However, on that
>day, the IHU-2 turned on around 0245z, and a new sequence initiated since 0252z.
>The sequnce I observed was an ordinally A block in 13 seconds first,
>then (possibly) a FEC coded A block in around 13 seconds followed by
>idle 28 seconds. The two LEDs of 'CAR' and 'CLK' on 'the Phase 3 400bps
>PSK demodulator mkII' designed by James G3RUH were always active even
>FEC coded blocks were sent. Unfortunately since I'm not ready to decode
>the FEC coded blocks, I coundn't confirm what contained in the 13 seconds. 
>
>I logged the sound into some .wav files by AO40Rcv written by Moe
>Wheatley, AE4JY and placed them below. 
>
>http://www.ne.jp/asahi/hamradio/jj1wtk/
>
>The waterfall pattern is so interesting. After the conventional A block,
>the many peaks around 1600Hz turned broad ones. I think it means the
>scrambler in the onboard FEC encoder works well.
>
>
>
>73, Kazu Sakamoto, JJ1WTK   kazu@jj1wtk.jp
>----
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>
>  
>



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