I know that a while back there was a grc flowraph of op25 that handled DES. Any chance of a pybombs recipe for op25 that handles RC4 as implemented in Advanced Digital Privacy?
If anyone is experimenting with the latest Max branch and the new rx.py app, you may have noticed that phase 2 tdma audio isn't working yet. I have some quick and dirty code that implements the missing bits if anyone wishes to try it out. The three modified files can be found in my google drive:
https://drive.google.com/open?id=0B-...DFrTGx4Vkh3em8https://drive.google.com/open?id=0B-9lC78gYedOMDFrTGx4Vkh3em8
p25_frame_assembler_impl.cc
p25p2_tdma.h
p25p2_tdma.cc
Drop them into the op25/op25/gr-op25_repeater/lib directory, perform a 'make install' (from the build directory) and then add "-2" into the rx.py command line to enable tdma decode.
Hi all,
OP25 (specifically scope.py) doesn't seem to work out of the box with
the latest version of GNU Radio, seemingly because it relies on
deprecated components (WX widgets). Today I was able to massage the
code to get it semi-functional with 3.7.11 using my own custom flow
graph, which was reverse engineered from the scope.py application. When
I tune it to a voice channel of a Phase I system I am able to hear
audio, which I consider a success.
The changes I made to the code base are located here[0], and attached
to this email is my flow graph. I hope that this is helpful to people
new to the project.
I do have some questions though:
1. How can this flow graph be optimized? I am not a radio expert by any
means, and while this flow graph works, I don't know *why* it works.
Importantly, the MPSK Receiver block is deprecated and set to be removed
in a future release[1], so I'd like to change it to something more
idiomatic.
2. What do the veriables "beta", "gain_mu", "alpha", "gain_omega",
"if_rate", and "symbol_deviation" mean? How were they chosen? Why do
they work?
--
Alex
[0] https://github.com/centromere/op25
[1] https://github.com/gnuradio/gnuradio/issues/1083
Trying to get op25 on a new latop that has 12.04 (tried to install 10.04
but network drivers wont load).
Installed with the :
http://op25.osmocom.org/trac/wiki.png/wiki/InstallInstructionsPage
First issue was math header was not found, included it in
op25/gr-op25_repeater/lib/gardner_costas_cc_impl.cc
The with the new gcc naowing became an error so I disabled it with
make CXX_FLAGS="-Wno-narrowing"
Which got me to what seems to be libboost cant be linked.
[ 65%] Linking CXX shared library libgnuradio-op25_repeater.so
/usr/bin/ld: CMakeFiles/gnuradio-op25_repeater.dir/vocoder_impl.cc.o:
relocation R_X86_64_PC32 against symbol
`_ZN2gr13op25_repeater12vocoder_implC1EbbiPcib' can not be used when making
a shared object; recompile with -fPIC
/usr/bin/ld: final link failed: Bad value
collect2: error: ld returned 1 exit status
op25/gr-op25_repeater/lib/CMakeFiles/gnuradio-op25_repeater.dir/build.make:593:
recipe for target 'op25/gr-op25_repeater/lib/libgnuradio-op25_repeater.so'
failed
make[2]: *** [op25/gr-op25_repeater/lib/libgnuradio-op25_repeater.so] Error
1
CMakeFiles/Makefile2:644: recipe for target
'op25/gr-op25_repeater/lib/CMakeFiles/gnuradio-op25_repeater.dir/all' failed
make[1]: ***
[op25/gr-op25_repeater/lib/CMakeFiles/gnuradio-op25_repeater.dir/all] Error
2
Makefile:127: recipe for target 'all' failed
make: *** [all] Error 2
Any ideas. Seems like I need to rebuild libboost?
Thanks,
Dylan
Hello,
Let's say you're scanning the airwaves in the frequency range of a
known P25 system and come across a spike in power at one particular
band that never shuts off.
* You should think that you've located a control channel, correct?
* If so, is it safe to say that the upstream and downstream channels
are side-by-side (one contiguous frequency band)?
* What is the most accurate way of determining whether what you've
discovered is a Phase I or Phase II system?
* When someone keys up a radio, is the following sequence of events
accurate?:
1. The radio sends a packet via the upstream control channel
indicating that it wishes to speak.
2. The fixed site sends a packet via the downstream control channel
indicating a frequency X on which it wants the speaker to transmit.
3. The fixed site sends a packet via the downstream control channel
instructing all radios in the talk group to tune in to a frequency Y.
4. The speaker transmits on frequency X, and the fixed site acts as a
repeater, re-broadcasting the audio to frequency Y.
--
Alex