FYI,
Eric
So I decided, after Eric posting to spend part of the Sunday taking care
of ADS-B, and started doing some thinkering and frequency monitoring.
From the links read I thought I should expect bursts of radiofrequency
at 1090MHz whose duration is 0.5 microseconds, differently spaced
depending on whether I am getting the preamble or the bits.
I have tried to monitor 1090MHz using DSB rx, but I could not see any
carrier at all - my discone antenna is not really suited for 1090MHz, so
I guess that either I do not have signals in my zone (quite strange, as
I am close to 2 international airports), or my antenna does not do the
job. Is there anyone on the list interested in the subject that could
provide a recording of some ADS-B bursts?
regards
Matteo iz2eeq
From the links read I thought I should expect bursts of radiofrequency
at 1090MHz whose duration is 0.5 microseconds, differently spaced
depending on whether I am getting the preamble or the bits.I have tried to monitor 1090MHz using DSB rx, but I could not see any
carrier at all …
I can’t hear it on my discone either, but I have an SBS-1 and swapped
antennae with my IC-PR1500 and recorded this:
http://infothecary.org/jordan/tmp/20061105-SSR.wav
I’ve read that you should be listening in SSB, so the first half of the
recording is that way; however, it seems simple AM is the better way,
and the 2nd half of the recoding is done that way.
Let me know when you’re ready to release some code to decode it! 
/jordan