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Re: [Discuss-gnuradio] Mode S and ADS-B
From: |
Martin Dvh |
Subject: |
Re: [Discuss-gnuradio] Mode S and ADS-B |
Date: |
Fri, 06 Jul 2007 01:44:14 +0200 |
User-agent: |
Icedove 1.5.0.12 (X11/20070607) |
Eric A. Cottrell wrote:
> Hello,
>
> I finally checked in the infamous Mode Select code to
> branches/developers/wb1hbu/wip and I am glad this portion is done.
>
> I spent a couple of days cleaning the code up a little. I also added
> some features. Likely I missed using a few neat gnuradio functions.
>
> There is a usrp_oscope_ms.py program that displays the Mode Select
> signal, Reference Level, and Attributes. Triggering off of channel 2
> (Reference Level) allows the display of Mode Select waveforms. I made
> the attributes go negative so they are more visible. I was surprised at
> the results.
>
> The usrp_mode_s_logfile.py program outputs Mode Select frame information
> to a log file. It does no decoding of the data. It logs the data bits
> and other attributes of the signal and error correction. It is a good
> program to run if you are in a heavy air traffic area and want to
> generate megabytes of text within an hour.
Hi Eric,
I tried out your code.
Does it run on your machine in realtime?
I have a dual-core athlon X2 3800 and both processor go to 100 % when I run it.
(I didn't know gnuradio could use both processors , I though we still had the
single-threaded-scheduler)
This gives me a lot of USRP overruns (UoUoUo) so it doesn't work very well this
way.
Does mode-s really need a samplerate of 8000000
Another question.
I know 1090 Mhz is the frequency they use in the US.
I googled for info on frequencies for mode-s and ads-b and it seems multiple
frequencies could be used.
Does anyone know of an overview of the actual frequencies in use, at which
places.
(I live in the netherlands)
Greetings,
Martin
I tried increasing the decimation but then the code refuses to run (requires
8000000 sps)
>
> 73 Eric
>
>
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