Using this book: The Hobbyist's Guide to the RTL-SDR: Really Cheap Software Defined Radio is helpful just to have some theoretical background and context ...

I determined that I have a R820T chip. I have a MCX connector.

Able to prove that the hardware works by receiving a FM radio station (NPR KQED 88.5 MGhz here in SF) using ... Gqrx: http://gqrx.dk/ ... also was able to pick up local police and others in the 850 MGhz area ... this site was interesting to get a list of radio frequencies that might have activity in San Francisco.

Installing prerequisites

These are listed here ... we investigated the docker image, but ultimately determined that mounting the SDR radio over USB / audio output from Docker containers, is not very well supported yet, so we gave up on this approach. Instead we had to install everything on OSX. I have OSX El Capitan 10.11.6. I was able to install all this stuff using a combination of brew, pip, and downloading / compiling the Python source manually. The biggest issue I ran into, which took me about 2 hours to figure out, was a conflict between the system Python and the brew installed Python, when downloading & compiling gr-tpms and gr-osmosdr manually. There are instructions on how to fix this, at the bottom of this file.

1. fftw

   brew install fftw

2. gnuradio

   brew install gnuradio

3. rtl-sdr

These instructions pretty much just worked: https://gist.github.com/jheasly/9477732

4. gr-osmosdr

I initially was able to install this with brew, but I came back and installed it from source ... see Git repo and instructions here: https://github.com/osmocom/gr-osmosdr I also had to pip install Cheetah ...

5. crcmod

   pip install crcmod

Building gr-tpms

Followed the instructions here: https://github.com/jboone/gr-tpms#building

Running, fixing errors

When I tried running it:

I got this error:

✗ tpms_rx --source rtlsdr --if-rate 400000 --tuned-frequency 315000000
Traceback (most recent call last):
  File "/usr/local/bin/tpms_rx", line 29, in <module>
    from gnuradio import analog
  File "/usr/local/lib/python2.7/site-packages/gnuradio/analog/__init__.py", line 35, in <module>
    from am_demod import *
  File "/usr/local/lib/python2.7/site-packages/gnuradio/analog/am_demod.py", line 22, in <module>
    from gnuradio import gr
  File "/usr/local/lib/python2.7/site-packages/gnuradio/gr/__init__.py", line 44, in <module>
    from top_block import *
  File "/usr/local/lib/python2.7/site-packages/gnuradio/gr/top_block.py", line 30, in <module>
    from hier_block2 import hier_block2
  File "/usr/local/lib/python2.7/site-packages/gnuradio/gr/hier_block2.py", line 25, in <module>
    import pmt
  File "/usr/local/lib/python2.7/site-packages/pmt/__init__.py", line 58, in <module>
    from pmt_to_python import pmt_to_python as to_python
  File "/usr/local/lib/python2.7/site-packages/pmt/pmt_to_python.py", line 22, in <module>
    import numpy
ImportError: No module named numpy

To fix it, I did

pip install numpy

... then I recompiled and reinstalled.

---

Then, I got another error:

✗ tpms_rx --source rtlsdr --if-rate 400000 --tuned-frequency 315000000
Traceback (most recent call last):
  File "/usr/local/bin/tpms_rx", line 37, in <module>
    import tpms
  File "/usr/local/lib/python2.7/site-packages/tpms/__init__.py", line 44, in <module>
    from tpms_swig import *
ImportError: No module named tpms_swig

I googled and found this: jboone/gr-tpms#3

So, I fixed it by doing:

brew install swig
cmake ..
make
sudo make install

When it reinstalled, I started seeing good messages like:

-- Checking for module SWIG
-- Found SWIG version 3.0.8.
-- Found SWIG: /usr/local/bin/swig  

---

Then, I got another error:

✗ tpms_rx --source rtlsdr --if-rate 400000 --tuned-frequency 315000000
Fatal Python error: PyThreadState_Get: no current thread
[1]    77993 abort      tpms_rx --source rtlsdr --if-rate 400000 --tuned-frequency 315000000

The full stack trace is in the file ./CRASH_gr-tpms.txt

It seems like this is because gr-tpms is pointed at the OSX system Python ... whereas everything else is pointed at the brew installed Python ... this thread was helpful: https://github.com/Homebrew/homebrew-science/issues/3401#issuecomment-213986011

I came up with this as being the right path:

PYTHON_INCLUDE_DIR    /usr/local/Cellar/python/2.7.12/Frameworks/Python.framework/Versions/2.7/include/python2.7
PYTHON_LIBRARY        /usr/local/Cellar/python/2.7.12/Frameworks/Python.framework/Versions/2.7/lib/libpython2.7.dylib

To configure these, from the directory /proj/sdr-linari/gr-tpms/build ... run:

ccmake .. press to 'toggle advanced mode', then hold the to page down through all the options until you get to PYTHON_INCLUDE_DIR & PYTHON_LIBRARY ... you can press , then copypasta the proper values, press again to make them take, then when you are done with both, press to save them

then recompile & reinstall with

cmake ..
make
sudo make install

---

I got another, similar error:

✗ tpms_rx --source rtlsdr --if-rate 400000 --tuned-frequency 315000000
Mac OS; Clang version 7.3.0 (clang-703.0.31); Boost_106100; UHD_003.010.000.000-0-unknown
Fatal Python error: PyThreadState_Get: no current thread
[1]    44017 abort      tpms_rx --source rtlsdr --if-rate 400000 --tuned-frequency 315000000

The full stack trace is in the file ./CRASH_gr-osmosdr.txt

I think, this is the same error as the one I just fixed, except for the gr-osmosdr package (which I had also installed from source) ... so repeat the above fix, to fix and reinstall this one as well ...

Success & hopefully profit

So, after all this, it started ... and, once I moved the antenna to be closer to the street (10 meters transmit range, according to Google), it decoded 5-10 transmissions within as many minutes.

See the transcript of the successfull run at tpmx_rx_running_TRANSCRIPT_AUG_22nd.txt

Other useful links

http://blog.manbolo.com/2014/09/27/use-python-effectively-on-os-x#p1