My error, typo I meant GMSK!! Sent from my iPad
> On May 3, 2016, at 9:31 PM, Kevin McQuiggin <mcqui...@me.com> wrote: > > Hi Henry: > > The narrowest channels are 600 bps MPSK, although in Inmarsat parlance they > call it "A-BPSK". There are 1200, 4800, 10200 bps channels as well, plus > faster ones I have not really considered yet. > > The spec document describes it all. > > I find the signal to be quite strong, perhaps check your polarization or > antenna pointing. You'll want RHCP for Inmarsat. Signals are well above the > noise floor for me. I'm using an Ettus B200. > > Also, check out a program called "JAERO", the web site has lots of relevant > information. > > My program isn't on github yet, I'm an old timer so I'm developing it > locally. I can release it once it's ready! > > Kevin > > Sent from my iPad > >> On May 3, 2016, at 8:31 PM, Henry Barton <kw...@outlook.com> wrote: >> >> So the control channels are the narrow ones? I’m guessing the really wide >> ones are the traffic. (On a side note, I’m kind of surprised that people >> [you and killmore231] can get Inmarsat with a patch. I just barely see the >> signals with 9A4QAV’s helix and an SDRplay. However, Iridium comes in like a >> blowtorch.) Anyway, can’t wait to see your program. Is it on Github? >> >> Sent from Windows Mail >> >> From: Kevin McQuiggin >> Sent: Tuesday, May 3, 2016 10:02 PM >> To: Henry Barton >> Cc: discuss-gnuradio@gnu.org >> >> Hi Henry: >> >> I have an Inmarsat demodulator working for the lower speed control channels. >> I am writing a program to decode the traffic, but this is not a trivial >> task. Think on the order of 1000 lines of C. It is "almost" working, I am >> hoping for valid output in the next week or so, depending on my free time. >> >> My program is currently a standalone program, but once it's done it could >> conceivably be converted to one or more gnuradio blocks. >> >> I suggest the following document to give you background on the channel >> specifications for Inmarsat: >> >> http://www.icao.int/safety/acp/inactive%20working%20groups%20library/acp-wg-m-iridium-8/ird-swg08-wp07%20-%20old_amss_material_ch.4_plus_attachment.doc >> >> The demodulation is fairly easy, read the spec document and the channel >> characteristics are pretty well described. My gnuradio demodulator is based >> on the GMSK demod block. I'm using a home brew patch antenna, and the >> LNA4ALL low noise amplifier. >> >> Kevin >> >> Sent from my iPad >> >> On May 3, 2016, at 12:45 PM, Henry Barton <kw...@outlook.com> wrote: >> >> http://rtlsdrblog.rtlsdrblog.netdna-cdn.com/wp-content/uploads/2015/10/sdrplay_lband-1024x573.png >> I didn’t see the widest signal (bright yellow) from this picture on >> sigidwiki.com. Does anyone know what it is? If so, can it be decoded by >> GNUradio? Thanks. >> _______________________________________________ >> Discuss-gnuradio mailing list >> Discuss-gnuradio@gnu.org >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> _______________________________________________ >> Discuss-gnuradio mailing list >> Discuss-gnuradio@gnu.org >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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