 
             
            Hi all,
Firstly, thank you to Max for the Slashdot mention!
I'd like to continue the ultra-cheap SDR theme with this video that demonstrates the RTL2832 USB DVB-T dongle successfully receiving an encrypted P25 signal, which is then decrypted and decoded by OP25 (represented by the new 'OP25 Decoder' GRC block in gr-baz http://wiki.spench.net/wiki/gr-baz#rtl_source_c ), and sent to the soundcard:
http://www.youtube.com/watch?v=wShOLgW2tmI
The block lets you specify a key to enable DES-OFB decryption of an incoming stream. As Matt Robert suggested, this could be further developed by having a 'key map file', that contains the correct key for a specific AlgID/etc.
All the RTL2832 code is in gr-baz. The patch enabling decryption support is from a rather old version of the source (r219), so if anyone would like to make it current for submission into the repo, please let me know and I can send it out!
I also added another new block called 'Message Callback', which is used to trigger callbacks in the GRC generated code based on messages sent by other blocks to messages queues. If you watch the video or visit my wiki, you'll see all the tuning/channel selection/filtering/audio is done by the appropriate blocks in GRC - separate from the OP25 code (this is different from it all being in the one Python file, e.g. audio_p25_rx). You may recall the FSK4 block outputs auto-tuning messages to the Frequency Translating FIR filter (channel selection block) before the FSK4 block. This feedback loop is handled internally in the existing stand-alone Python files, but needs to be replicated in GRC - hence the new block. The 'Message Callback' block connects to the 'tuning' output of the OP25 Decoder block, and is told about the 'auto_tune_freq' GRC variable to update when a message arrives with a new value. This GRC variable is subsequently used to update the Centre Frequency in the Frequency Translating FIR filter (channel selection block) to fulfil the FSK4 block's request.
If you're into GNU Radio, I just posted a much longer update with the latest RTL2832 developments (including a completely re-written 'librtl2832++') to the GNU Radio Discussion list.
Kind regards,
Balint @spenchdotnet http://twitter.com/spenchdotnet
From: op25-dev@yahoogroups.com [mailto:op25-dev@yahoogroups.com] On Behalf Of ikj1234i Sent: Sunday, 1 April 2012 10:20 PM To: op25-dev@yahoogroups.com Subject: [op25-dev] congrats to Balint: on Slashdot ! ! !
http://hardware.slashdot.org/story/12/03/31/1914217/software-defined-radio-f or-11
 
            Firstly, thank you to Max for the Slashdot mention!
Ha ha, it's a pleasure to see this project move forward.
The cheapest one I've ever built was for $1.00 - picked up an old crystal scanner at a hamfest that happened to have a crystal in it on the proper frequency for a local P25 station. It only needed a disc-tap using parts from the junkbox...
Max
 
            LOL, I thought someone might say that J
Nice work at that price!!!
From: op25-dev@yahoogroups.com [mailto:op25-dev@yahoogroups.com] On Behalf Of ikjtel Sent: Friday, 6 April 2012 12:07 AM To: op25-dev@yahoogroups.com Subject: [op25-dev] Re: World's cheapest P25 receiver: $20 RTL2832 dongle + new OP25 Decoder block with DES-OFB for GRC!
Firstly, thank you to Max for the Slashdot mention!
Ha ha, it's a pleasure to see this project move forward.
The cheapest one I've ever built was for $1.00 - picked up an old crystal scanner at a hamfest that happened to have a crystal in it on the proper frequency for a local P25 station. It only needed a disc-tap using parts from the junkbox...
Max
 
            Hi,
I've just tried building the gr-baz module on a couple of different systems but I'm encountering a make error along the lines of: ./baz_swig.cc: No such file or directory
I note someone else has also encountered the same error and pasted their make output to pastebin (http://pastebin.com/y6dUAxC1). This is the same error I'm getting. Anyone got any clues? Is this a generated file that isn't being generated, or a file that hasn't been included in the svn repo?
Thanks
Cheers Richard
On 6 April 2012 02:14, Balint balint256@hotmail.com wrote:
**
LOL, I thought someone might say that J****
Nice work at that price!!!****
*From:* op25-dev@yahoogroups.com [mailto:op25-dev@yahoogroups.com] *On Behalf Of *ikjtel *Sent:* Friday, 6 April 2012 12:07 AM *To:* op25-dev@yahoogroups.com *Subject:* [op25-dev] Re: World's cheapest P25 receiver: $20 RTL2832 dongle + new OP25 Decoder block with DES-OFB for GRC!****
Firstly, thank you to Max for the Slashdot mention!****
Ha ha, it's a pleasure to see this project move forward.
The cheapest one I've ever built was for $1.00 - picked up an old crystal scanner at a hamfest that happened to have a crystal in it on the proper frequency for a local P25 station. It only needed a disc-tap using parts from the junkbox...
Max****
 
            Hi all,
This is a known issue - unfortunately I just haven't had the time to make necessary modifications (will do so now), but the temporary work-around is to symlink:
/usr/local/include/gnuradio/swig/gruel_common.i -> /usr/local/include/gruel/swig/gruel_common.i
The new version will be in the gr-baz repo hopefully very soon.
Thanks for the report,
Balint
From: op25-dev@yahoogroups.com [mailto:op25-dev@yahoogroups.com] On Behalf Of Richard Clarke Sent: Friday, 20 April 2012 8:24 AM To: op25-dev@yahoogroups.com Subject: Re: [op25-dev] Re: World's cheapest P25 receiver: $20 RTL2832 dongle + new OP25 Decoder block with DES-OFB for GRC!
Hi,
I've just tried building the gr-baz module on a couple of different systems but I'm encountering a make error along the lines of: ./baz_swig.cc: No such file or directory
I note someone else has also encountered the same error and pasted their make output to pastebin (http://pastebin.com/y6dUAxC1). This is the same error I'm getting. Anyone got any clues? Is this a generated file that isn't being generated, or a file that hasn't been included in the svn repo?
Thanks
Cheers
Richard
On 6 April 2012 02:14, Balint balint256@hotmail.com wrote:
LOL, I thought someone might say that J
Nice work at that price!!!
From: op25-dev@yahoogroups.com [mailto:op25-dev@yahoogroups.com] On Behalf Of ikjtel Sent: Friday, 6 April 2012 12:07 AM To: op25-dev@yahoogroups.com Subject: [op25-dev] Re: World's cheapest P25 receiver: $20 RTL2832 dongle + new OP25 Decoder block with DES-OFB for GRC!
Firstly, thank you to Max for the Slashdot mention!
Ha ha, it's a pleasure to see this project move forward.
The cheapest one I've ever built was for $1.00 - picked up an old crystal scanner at a hamfest that happened to have a crystal in it on the proper frequency for a local P25 station. It only needed a disc-tap using parts from the junkbox...
Max
 
            Awesome, thanks for that.
Cheers Richard
On 20 April 2012 10:58, Balint balint256@hotmail.com wrote:
Hi all,****
This is a known issue – unfortunately I just haven’t had the time to make necessary modifications (will do so now), but the temporary work-around is to symlink:****
/usr/local/include/gnuradio/swig/gruel_common.i ->/usr/local/include/gruel/swig/gruel_common.i****
The new version will be in the gr-baz repo hopefully very soon…****
Thanks for the report,****
Balint****
*From:* op25-dev@yahoogroups.com [mailto:op25-dev@yahoogroups.com] *On Behalf Of *Richard Clarke *Sent:* Friday, 20 April 2012 8:24 AM *To:* op25-dev@yahoogroups.com *Subject:* Re: [op25-dev] Re: World's cheapest P25 receiver: $20 RTL2832 dongle + new OP25 Decoder block with DES-OFB for GRC!****
Hi,****
I've just tried building the gr-baz module on a couple of different systems but I'm encountering a make error along the lines of: ./baz_swig.cc: No such file or directory****
I note someone else has also encountered the same error and pasted their make output to pastebin (http://pastebin.com/y6dUAxC1). This is the same error I'm getting. Anyone got any clues? Is this a generated file that isn't being generated, or a file that hasn't been included in the svn repo?
Thanks****
Cheers****
Richard****
On 6 April 2012 02:14, Balint balint256@hotmail.com wrote:****
LOL, I thought someone might say that J****
Nice work at that price!!!****
*From:* op25-dev@yahoogroups.com [mailto:op25-dev@yahoogroups.com] *On Behalf Of *ikjtel *Sent:* Friday, 6 April 2012 12:07 AM *To:* op25-dev@yahoogroups.com *Subject:* [op25-dev] Re: World's cheapest P25 receiver: $20 RTL2832 dongle + new OP25 Decoder block with DES-OFB for GRC!****
Firstly, thank you to Max for the Slashdot mention!****
Ha ha, it's a pleasure to see this project move forward.
The cheapest one I've ever built was for $1.00 - picked up an old crystal scanner at a hamfest that happened to have a crystal in it on the proper frequency for a local P25 station. It only needed a disc-tap using parts from the junkbox...
Max****
-- *SCOTT ADAMS: Normal people believe that if it ain't broke, don't fix it. Engineers believe that if it ain't broke, it doesn't have enough features yet.*****
 
            Hi all,
A couple of updates:
. gr-baz (git & SVN) now contains the fix to the issue regarding the 'gruel_common' compilation error (thanks Alex Csete).
. The OP25 block now first tries to use the op25.fsk4_demod_ff, and then falls back to fsk4.demod_ff if the former is not found.
. For those experimenting with OP25 and the RTL DVT-B USB dongles, I've started a Google Group https://groups.google.com/forum/#!forum/ultra-cheap-sdr for discussion surrounding the device, and its use with gr-baz/GNU Radio/plugin on Windows.
Regarding the error seen by 'allanjs1986' in GRC:
Type "msg" is not a possible type.
I'm a little worried about this - are you using the latest GRC? I thought message queues (specified by the 'msg' type) were still around. does anyone know more?
If you need a workaround, then just comment out/delete the last <source> block (name: 'tune', type: 'msg') in gr-baz/grc/op25.xml, do a sudo make install, restart GRC, and remember to set 'Output auto tune' to 'No' in the OP25 decoder block properties.
From: op25-dev@yahoogroups.com [mailto:op25-dev@yahoogroups.com] On Behalf Of Balint Sent: Friday, 20 April 2012 8:58 AM To: op25-dev@yahoogroups.com Cc: 'Richard Clarke' Subject: RE: [op25-dev] Re: World's cheapest P25 receiver: $20 RTL2832 dongle + new OP25 Decoder block with DES-OFB for GRC!
Hi all,
This is a known issue - unfortunately I just haven't had the time to make necessary modifications (will do so now), but the temporary work-around is to symlink:
/usr/local/include/gnuradio/swig/gruel_common.i -> /usr/local/include/gruel/swig/gruel_common.i
The new version will be in the gr-baz repo hopefully very soon.
Thanks for the report,
Balint
From: op25-dev@yahoogroups.com [mailto:op25-dev@yahoogroups.com] On Behalf Of Richard Clarke Sent: Friday, 20 April 2012 8:24 AM To: op25-dev@yahoogroups.com Subject: Re: [op25-dev] Re: World's cheapest P25 receiver: $20 RTL2832 dongle + new OP25 Decoder block with DES-OFB for GRC!
Hi,
I've just tried building the gr-baz module on a couple of different systems but I'm encountering a make error along the lines of: ./baz_swig.cc: No such file or directory
I note someone else has also encountered the same error and pasted their make output to pastebin (http://pastebin.com/y6dUAxC1). This is the same error I'm getting. Anyone got any clues? Is this a generated file that isn't being generated, or a file that hasn't been included in the svn repo?
Thanks
Cheers
Richard
On 6 April 2012 02:14, Balint balint256@hotmail.com wrote:
LOL, I thought someone might say that J
Nice work at that price!!!
From: op25-dev@yahoogroups.com [mailto:op25-dev@yahoogroups.com] On Behalf Of ikjtel Sent: Friday, 6 April 2012 12:07 AM To: op25-dev@yahoogroups.com Subject: [op25-dev] Re: World's cheapest P25 receiver: $20 RTL2832 dongle + new OP25 Decoder block with DES-OFB for GRC!
Firstly, thank you to Max for the Slashdot mention!
Ha ha, it's a pleasure to see this project move forward.
The cheapest one I've ever built was for $1.00 - picked up an old crystal scanner at a hamfest that happened to have a crystal in it on the proper frequency for a local P25 station. It only needed a disc-tap using parts from the junkbox...
Max
 
            Hi this may fix your worries I'm running the 3.2.2 GRC so a bit old. Its the only one i can seem to get installed and running.
--- In op25-dev@yahoogroups.com, Balint <balint256@...> wrote:
Regarding the error seen by 'allanjs1986' in GRC:
Type "msg" is not a possible type.
I'm a little worried about this - are you using the latest GRC? I thought message queues (specified by the 'msg' type) were still around. does anyone know more?
 
            I've just accepted the git pull request submitted by Alex Csete (thank you!) to fix the build issue on v3.6 of GNU Radio (tested by 'zignig'), so if you grab the latest, hopefully this issue will disappear!
(If other people have encountered this problem, please let them know too.)
From: op25-dev@yahoogroups.com [mailto:op25-dev@yahoogroups.com] On Behalf Of Richard Clarke Sent: Friday, 20 April 2012 8:24 AM To: op25-dev@yahoogroups.com Subject: Re: [op25-dev] Re: World's cheapest P25 receiver: $20 RTL2832 dongle + new OP25 Decoder block with DES-OFB for GRC!
Hi,
I've just tried building the gr-baz module on a couple of different systems but I'm encountering a make error along the lines of: ./baz_swig.cc: No such file or directory
I note someone else has also encountered the same error and pasted their make output to pastebin (http://pastebin.com/y6dUAxC1). This is the same error I'm getting. Anyone got any clues? Is this a generated file that isn't being generated, or a file that hasn't been included in the svn repo?
Thanks
Cheers
Richard
On 6 April 2012 02:14, Balint balint256@hotmail.com wrote:
LOL, I thought someone might say that J
Nice work at that price!!!
From: op25-dev@yahoogroups.com [mailto:op25-dev@yahoogroups.com] On Behalf Of ikjtel Sent: Friday, 6 April 2012 12:07 AM To: op25-dev@yahoogroups.com Subject: [op25-dev] Re: World's cheapest P25 receiver: $20 RTL2832 dongle + new OP25 Decoder block with DES-OFB for GRC!
Firstly, thank you to Max for the Slashdot mention!
Ha ha, it's a pleasure to see this project move forward.
The cheapest one I've ever built was for $1.00 - picked up an old crystal scanner at a hamfest that happened to have a crystal in it on the proper frequency for a local P25 station. It only needed a disc-tap using parts from the junkbox...
Max




