Re: [Discuss-gnuradio] gnu Radio and Mode S (1090 MHz)

[Andrew Rich]

Thanks Nick

I have some more questions if I may

1) What determines the bandwidth of the daughter boards for USRP ?
2) Where do you connect if you want to bypass the RF board and connect at 
base band ?
3) Will I be able to achieve what I want to achieve on openSUSE linux ?
4) When you talk about "code" what language ?
5) What is a trunk when you talk about gnu ? is that the software base ?
6) I assume I can get an RF board and do 1030 MHz as well ?
7) Can I use perl to do any of this ?
8) Would someone be able to guide me through this.
9) Is a "PC" suitable and quick enough to keep up with the signals ? Does 
the USRP and code lag or is there plenty of time left over ?

Andrew




----- Original Message ----- 
From: "Nick Foster" <address@hidden>
To: "gnuradio" <address@hidden>; <address@hidden>
Sent: Wednesday, March 17, 2010 9:11 AM
Subject: RE: [Discuss-gnuradio] gnu Radio and Mode S (1090 MHz)



Andrew,

Eric Cottrell has written a complete Mode S receiver for gnuradio, using a 
USRP with a DBS-RX daughterboard. I also use a 1090MHz SAW filter and an LNA 
in my setup to get better results. Eric's software has not been ported to 
the current gnuradio architecture and uses the older "blks" interface.

I rewrote Eric's software from scratch last spring to achieve better 
processing at lower sample rates, and to use a more optimal bit slicer for 
coping with FRUIT. I haven't released the software yet -- it is working with 
the latest gnuradio trunk, but I haven't gotten around to cleaning up the 
code to the point where I'm not embarrassed to look at it.

It sounds like you're more interested in sampling data that you already have 
in demodulated PPM form, from a receiver you already own. If that's the 
case, the USRP is probably overkill, but it will certainly work if you use 
an LFRX as the front end board. If you add the DBS-RX to the USRP, you've 
all but obviated the need to use the SBS-1 you have in your current setup.

Nick

________________________________
> From: address@hidden
> To: address@hidden
> Date: Wed, 17 Mar 2010 05:58:40 +1000
> Subject: [Discuss-gnuradio] gnu Radio and Mode S (1090 MHz)
>
>
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>
>
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>
>
>
> Hello
>
>
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> Sorry if this is a duplicate.
>
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> I am using my digital scope to capture data and pipe it to a
> flat file where I can look at it in LINUX (gdsh USB and perl)
>
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> I am attempting to decode 1090 MHz transponder
> signals.
>
>
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> I know what I am looking for. ( I do this for a
> job)
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> I am on the hunt for better hardware and software to do the
> job under LINUX.
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> I simply need a faster better capture soluition that will
> allow me to up the through put of my signal analysis.
>
>
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> Can someone suggest ? I see some work has already been done on
> gnu-radio in this area.
>
>
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> At the moment I am processing csv capture files from the
> scope.But it takes seconds to grab the data from the scope.
>
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> Does gnu-radio have a module or code that would let me sample
> and save ? I can do the rest. Maybe a scope function ? samples vs
> time.
>
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> The data rate is 1 MHz for Mode S.
>
>
>
> I have the 1090 MHz receiver, actually got 2. SBS-1 with video
> out (0-2Volts)
>
>
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> Here are some captures I have done so far.
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> http://vk4tec.no-ip.org/adsb_gds1022/
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> Would the USRP and some LINUX code help me out ?
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> I can program, in perl, python should not be too hard to
> grasp. C, so so .
>
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> Here is my website
>
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> www.tech-software.net
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> Andrew Rich VK4TEC
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>
> 17/03/2010

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