Gentoo-Rpi5 Radio Scanner w/OpenWebRx

[jlpoole]

I want to monitor the nearby air traffic control tower and found this software project that seemed suitable for the task: OpenWebRx. The underlying Github project is located here. Beware: if you "git clone" and later decide to build/run the project, you must switch your cloned repository to the "master" version and not use the high watermark -- I tripped up on that distinction and the code failed, the developer pointed out I was using the development version instead of the specified "master". There is a Groups.IO forum, OpenWebRx, for this project.

There is a service LiveATC.net which publishes live control tower radio conversations and they specify recommended equipment to capture radio transmissions at: Increase Coverage. Accordingly, I purchased from Amazon the official RTL-SDR (official, beware of knock-offs)"V4 R828D RTL2832U 1PPM TCXO HF Bias Tee SMA Software Defined Radio with Dipole Antenna Kit " for $41.95 (PRIME). The receiver is USB connected unit with a coax terminal which hooks up to an antenna.

OpenWebRx's manual installation page can be found at: https://github.com/jketterl/openwebrx/wiki. From there, look under "Setup" on the right for the "Manual installation" link which contains parenthesis and cannot be set forth here on Gentoo's forum. There's a lot of custom software that is not in Gentoo's portage that has to be installed. Here's a listing of the directory where I build out-of-portage packages:

Code: Select all

jlpoole@rpi5 ~ $ date; ls /usr/local/src -1
Thu May 30 11:57:13 PDT 2024
SoapySDR
codec2
codecserver
csdr
digiham
[redacted]
js8py
m17-cxx-demod
openwebrx
[redacted]
owrx_connector
pycsdr
[redacted]
pydigiham
[redacted]
jlpoole@rpi5 ~ $

The Manual Install Guide was written for people using Debian, so I had to study each specified package and correlate them to Gentoo's portage, if they existed. That took about an hour to walk through and analyze. Hopefully, the listing below will help others bypass such an analysis and just install the specified packages below, and then proceed with the out-of-portage packages and you should be okay... at least for the basic required components. Here are the packages, and their dependencies, specified by the Manual Install guide that I ended up adding to my Rpi5:

Code: Select all

jlpoole@rpi5 ~ $ sudo head -n 753 /var/log/emerge.log |tail -n $(echo "753-484"|bc) | awk '{ \
     epoch=$1; \
     sub(/:$/,"",epoch); \
     command = "date --date='\''@"epoch"'\'' +\"%Y-%m-%d %H:%M:%S\""; \
     command | getline hr_time; \
     print hr_time" "$0 \
     }'|grep ">>> emerge"
2024-05-29 16:13:41 1717024421:  >>> emerge (1 of 5) app-crypt/rhash-1.4.3 to /
2024-05-29 16:14:03 1717024443:  >>> emerge (2 of 5) dev-libs/jsoncpp-1.9.5 to /
2024-05-29 16:14:20 1717024460:  >>> emerge (3 of 5) app-arch/libarchive-3.7.2-r2 to /
2024-05-29 16:15:30 1717024530:  >>> emerge (4 of 5) dev-libs/libuv-1.48.0 to /
2024-05-29 16:16:03 1717024563:  >>> emerge (5 of 5) dev-build/cmake-3.28.3 to /
2024-05-29 16:39:12 1717025952:  >>> emerge (1 of 3) dev-libs/libusb-1.0.26 to /
2024-05-29 16:39:35 1717025975:  >>> emerge (2 of 3) virtual/libusb-1-r2 to /
2024-05-29 16:39:42 1717025982:  >>> emerge (3 of 3) net-wireless/rtl-sdr-2.0.1 to /
2024-05-29 16:41:16 1717026076:  >>> emerge (1 of 1) media-libs/libsamplerate-0.2.2 to /
2024-05-29 16:43:27 1717026207:  >>> emerge (1 of 9) media-libs/libogg-1.3.5-r1 to /
2024-05-29 16:43:44 1717026224:  >>> emerge (2 of 9) media-libs/opus-1.4 to /
2024-05-29 16:44:07 1717026247:  >>> emerge (3 of 9) dev-libs/libltdl-2.4.7-r1 to /
2024-05-29 16:44:23 1717026263:  >>> emerge (4 of 9) app-eselect/eselect-mpg123-0.1-r1 to /
2024-05-29 16:44:30 1717026270:  >>> emerge (5 of 9) media-libs/flac-1.4.3 to /
2024-05-29 16:45:12 1717026312:  >>> emerge (6 of 9) media-libs/libvorbis-1.3.7-r1 to /
2024-05-29 16:45:44 1717026344:  >>> emerge (7 of 9) media-sound/lame-3.100-r3 to /
2024-05-29 16:46:25 1717026385:  >>> emerge (8 of 9) media-sound/mpg123-base-1.32.3 to /
2024-05-29 16:47:00 1717026420:  >>> emerge (9 of 9) media-libs/libsndfile-1.2.2-r2 to /
2024-05-29 16:48:46 1717026526:  >>> emerge (1 of 1) net-analyzer/netcat-110.20180111-r2 to /
2024-05-29 18:20:22 1717032022:  >>> emerge (1 of 1) app-portage/gentoolkit-0.6.3-r1 to /
2024-05-29 18:21:17 1717032077:  >>> emerge (1 of 2) virtual/fortran-0-r1 to /
2024-05-29 18:21:24 1717032084:  >>> emerge (2 of 2) sci-libs/fftw-3.3.10 to /
2024-05-29 18:43:56 1717033436:  >>> emerge (1 of 1) dev-libs/protobuf-21.12 to /
2024-05-29 18:56:26 1717034186:  >>> emerge (1 of 1) dev-libs/icu-74.2 to /
2024-05-29 19:09:13 1717034953:  >>> emerge (1 of 2) dev-build/b2-5.0.0 to /
2024-05-29 19:09:24 1717034964:  >>> emerge (1 of 2) dev-build/b2-5.0.0 to /
2024-05-29 19:11:08 1717035068:  >>> emerge (2 of 2) dev-libs/boost-1.84.0-r3 to /
2024-05-29 20:17:55 1717039075:  >>> emerge (1 of 2) virtual/libudev-251-r2 to /
2024-05-29 20:18:03 1717039083:  >>> emerge (2 of 2) sys-apps/usbutils-017 to /
jlpoole@rpi5 ~ $

Building this project took me a couple of hours. While I was able to successfully build all the required components, I was tripped up on one of the options: m17-cxx-demod. There are several more optional items, but I'm not sure whether they would apply to my hardware and, more importantly, what benefit they would offer me. Despite this roadblock, I was able to launch and run OpenWebRx and tune into my local control tower (KSLE at 119.1 Mhz). The instructions for the project presuppose a good knowledge about radio, I found I had to dig a bit and acronyms are plentiful. A key point is that once you have the server up and running, you must configure an "SDR Device and Profile" which, in turn, defines the particular band you are interested in. The default profiles did not match the frequency I am interested in, i.e. 119.1 Mhz, so I had to create a profile specifying such and then I was able to successfully listen in on the air traffic control tower for Salem (KSLE). Bear in mind I used the antenna kit that came with the Amazon kit, so I set up the kit antenna in an enclosed porch and do receive signals. I live 2 miles away from the control tower, and my property is within a runway's flight path. To have superior reception, you are looking at probably $200-250 for a high quality antenna that would be placed outdoors on a structure and then high quality coaxial cable (50' can run $150!), so the antenna and coaxial cable surpass the cost of the Raspberry Pi 5 plus the transciever. And, this estimate does not take into account the installation of a "masthead" (large 2" pipe) that has to be secured to the structure; I'm a woodworker and therefore quite handy and building things, but for someone who is not, this would be an added expense probably worth several man hours to design and attach and run the coaxial cable neatly secured, so $300-600.

Oh, and of course, I am running this software on a Raspberry Pi 5 (with NVRE) using Gentoo Linux. I should note as I built this on May 29, 2024, my portage on the Rpi5 was about 60 days out of sync. I did not want to wait for an update.

I believe that OpenWebRx will allow multiple people to connect to the server and monitor a variety of bandwidths, e.g. police, aircraft &etc., but I'm still learning. Any rate, for Gentoo enthusiasts using Raspberry Pi, the OpenWebRx works and if you want to try scanning, this may be a viable alternative rather than dedicated hardware equipment.

Here is a pretty screenshot of the "waterfall" the web interface presents.

Edit: revised link which contains parenthesis which Gentoo Discussion Forum will not accept.