A New Raspberry Pi for π Day

The Raspberry Pi Foundation has announced the new Raspberry Pi 3 Model B+. This incremental design improvement provides some interesting features.

  • 1.4GHz 64-bit quad-core ARM Cortex-A53 CPU
  • Dual-band 802.11ac wireless LAN and Bluetooth 4.2
  • Faster Ethernet (Gigabit Ethernet over USB 2.0)
  • Power-over-Ethernet support (with separate PoE HAT)
  • Improved PXE network and USB mass-storage booting
  • Improved thermal management
Raspberry Pi 3 Model B+

The 5 GHz wifi and power over ethernet capabilities are especially interesting improvements. The Raspberry Pi is a great experimenter’s computer. Many amateur radio operators and makers are using them in purpose built applications such as digital hotspots and home control. You can see more here.

Update: 03/19/2018 — One difference that I failed to note betwee the RPI 3 Model B and the B+ is that while the RPi 3 Model B sported 1 GB of RAM, the B+ cuts it back down to 512 MB. While 512 MB may be enough for your application, if it is not, you may with to stick with the original RPi 3 Model B.

2018 SWL Fest Talk Links

Here are the links mentioned in my 2018 SWL Fest presentation, “RTL-SDR: more SDR on the cheap!”

Receiving NRSC-5 by Theori
NRSC-5 Proof of Concept Code
NRSC-5-D Standard
Other NRSC-5 Related Standards
NRSC-5 Metadata GUI by K2DLS
dump1090 blog post
Dire Wolf source code
Xastir wiki
Xastir source code
Raspberry Pi Foundation

Other useful links

Digital Signal Decoder+
Virtual Audio Decoder
DAB Player

If you attended my presentation, thank you for your interest. If you have never attended a Winter SWL Fest and are interested in any aspect of radio reception, consider attending next year. All frequencies from DC to Daylight are fair game.

Ham Radio Deluxe Roadmap

I had the opportunity to catch up with Mike Carper, WA9PIE, at the Orlando Hamcation today.  Mike is one of the two current owners of Ham Radio Deluxe, the incredibly popular software used by radio amateurs to control their radios and handle logging and other tasks.  HRD Software LLC went through some rough times in 2016, but Mike reports that 2017 was a great year under reconstituted management.

Mike Carper, WA9PIE, owner of HRD Software LLC

In 2017, Roger Hardin joined the company as a full-time software developer. In 2018, Mike plans to add several developers to address a backlog of bug reports as well as work on new feature releases.  Joining the team on a part-time basis is well known radio amateur Tomas Hood, NW7US.  They plan to follow an 80/20 approach.  Mike anticipates that 80% of the effort will be devoted to correcting software defects and 20% will be devoted to rolling out new features.

In addition to addressing customer concerns around QSL label printing and Cabrillo contest log generation, there is a planned major change around how rig control definitions are handled.  Mike announced at Hamcation that they plan to externalize rig definitions via XML.  This means that end users will gain the ability to tweak features and implement their own definitions.  Watch for this sometime later in the year.

Mike has also instituted a lot of process around documenting customer reported incidents as well as software development and testing.  The process has led to a more transparent approach to product changes.  Any customer can now view a change log to see what issues have been addressed in a particular release via the web.  The User Manual has also been converted to an online wiki format.

Thanks to Mike for the update.  I’m looking forward to continued development of Ham Radio Deluxe.

Update: Monitoring NextGen ATC (on the cheap!)

Note: This article was originally published in March 2017. I’ve revisited and updated it in preparation for a talk that I’ll be giving at the 2018 Winter SWL Fest. I’ve simplified the installation process. While doing so, I learned that Google now requires an API key for the application to have access to their maps. My github fork of the dump 1090 code has been updated to account for this development.

A key component of next generation air traffic control is Automatic Dependent Surveillance – Broadcast (ADS-B). The current FAA mandate is for all included aircraft to output ADB-B transmissions no later than January 1, 2020. But you don’t have to wait to receive and map ADS-B. There is a lot of air traffic to be seen.

dump1090 as viewed via a remote web browser.

Some folks are using complete downloadable images that are set up to feed flight tracking services such as FlightAware. If you’re interested in doing this, The SWLing Post featured an article that you’ll enjoy. I wanted to explore whether I could use some items already on hand to see a map of overhead aircraft on any computer on my home network.

I pulled out an older Raspberry Pi Model B and a 4 GB SD-Card and installed a copy of Raspbian Stretch Lite. The Model B has been retroactively called a Raspberry Pi 1 Model B. It is equipped with 512 MB of RAM, two USB ports and a 100mb Ethernet port.

I decided to use a spare older RTL-SDR stick based on the RTL2832U and R820T chips. This USB device comes with a small antenna that I hoped would be good enough to get me started. It is not in any way optimized for the 1090 MHz signals that are used by ADS-B and is roughly 19 parts per million (ppm) off frequency. It cost a bit over $10 at a hamfest a couple of years ago. The designs have improved since the early models were offered. Newer models include a TCXO (thermally compensated crystal oscillator) for stability and accuracy.

I needed software to take signals from the RTL-SDR stick and plot them on a map. That software is “dump1090”, originally written by Salvatore Sanfilippo. I added an install stanza to the Makefile, along with a systemd service file, for a smooth system install. I also needed to install the RTL-SDR USB drivers. The complete installation runs “headless”, meaning no monitor, keyboard or mouse need be connected. Remote management can be done via ssh.

There is a security change that comes along with Stretch. ssh is now disabled by default. After copying the initial Stretch image to the SD card and BEFORE removing it to place the Raspberry Pi, mount the boot partition and create an empty file named “ssh”. If you are not using ethernet, you could also pre-configure wifi settings.

First, bring the Raspbian Stretch installation up to date.

sudo apt-get update
sudo apt-get upgrade

Add some needed packages.

sudo apt-get install git cmake libusb-1.0-0-dev librtlsdr-dev rtl-sdr

You may test by running rtl_test -t. If the device is properly seen by the driver you should see the following:

Found 1 device(s):
  0:  Realtek, RTL2838UHIDIR, SN: 00000001

Using device 0: Generic RTL2832U OEM
Found Rafael Micro R820T tuner
Supported gain values (29): 0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6 
[R82XX] PLL not locked!
Sampling at 2048000 S/s.
No E4000 tuner found, aborting.

Don’t be concerned by the “No E4000 tuner found” message. The E4000 is an older chipset that is no longer used by today’s RTL-SDR devices.

Compile and install the dump1090 code.

git clone https://github.com/K2DLS/dump1090.git
cd dump1090
sudo make install

Configure dump1090 options.

cd /etc/default
sudo vi dump1090

Here’s what I placed in the file.

# Default settings for dump1090.
DUMP1090_OPTS="--quiet --net --lat xx.xxxxx --lon -yy.yyyyy --ppm 19 --gain -10"

–quiet runs in the background
–net starts a webserver so that you can access via a web browser
–lat set to YOUR decimal latitude (negative for South)
–lon set to YOUR decimal latitude (negative for West)
–ppm if you know the ppm tolerance of your device (otherwise omit)
–gain -10 which sets gain automatically

A full parameter list can be reviewed by typing dump1090 --help.

With an antenna connected you can perform a quick device check by typing dump1090 --interactive. If all is well you’ll see a screen like this:

Hex     Mode  Sqwk  Flight   Alt    Spd  Hdg    Lat      Long   Sig  Msgs   Ti/
A39D11  S                                                         6     1    4
A25D36  S                     1775                                7     4    3
AAA593  S                     2575  205  075                      7     2    7
A25238  S                                                         4     1   12
A0480B  S                    19650                                8    28    3
ACF4DD  S                     3825                                7     2   14
A41F61  S           FDX3018   2800  211  025   40.428  -74.332   23    83    0
A6FFFE  S     1753  LXJ550   30475  371  226                      8    63    0
C060B3  S                     4625                                6    14    1
ACF69B  S                    23250                                6    25    1
A2D27C  S                    24000                               13    42    2
A0BF90  S                     9500  249  257                      5     3    9
A7D30A  S                    40000                                8   111    1
AE0192  S           SPAR958  32675                               22    93    0
ACC040  S                     7825                                8   146    2
ACA5DF  S                    26600                                6    79    0
A80C7B  S                     4550                                9   108    1
A7CC00  S                     7825                               35   123    0
ACF841  S     1507           14425                               50   132    0
A8C802  S           NKS149   23575  332  216   39.995  -74.262   12   160    0
A61949  S           UAL1105   2725                               14    60    0
AC2E20  S     1006           19925                               22   130    0
AB766A  S           DAL1526   8525  216  038   40.444  -74.213   81   249    0
AA4440  S                     5400  253  066                      6     6   13

Control-C exits this screen.

Now start the dump1090.service.

sudo systemctl start dump1090.service

If all goes well, a netstat -an will show that there is a binding to port 8080.

tcp        0      0  *               LISTEN

Now you can start up a web browser from any computer on your home network and see a map of planes overhead. If your router supports internal dynamic DNS you can name the RPi and access via something like http://skynet:8080. Alternatively, use the IP address, which can be obtained via ifconfig.

eth0      Link encap:Ethernet  HWaddr b8:27:eb:12:34:56  
          inet addr: Bcast:  Mask:
          inet6 addr: fe80::1234:5678:8765:abcd/64 Scope:Link
          inet6 addr: fd68:bee:1f21:2221::5/128 Scope:Global
          inet6 addr: fd68:bee:1f21:2221:1234:5678:8765/64 Scope:Global
          RX packets:990830 errors:0 dropped:418120 overruns:0 frame:0
          TX packets:323700 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:87491798 (83.4 MiB)  TX bytes:207659746 (198.0 MiB)

lo        Link encap:Local Loopback  
          inet addr:  Mask:
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

In this case, the URL would be

Once the map appears, re-position it to your part of the world and enjoy learning about what is flying overhead. You can enhance your enjoyment by listening to your closest airport tower or air traffic control frequencies on a scanner. These transmissions use amplitude modulation (AM) and can be monitored an another RTL-SDR stick or a scanner, even a relatively old model.

A New Kelement

I’ve been a fan of internet radio appliances ever since the AE1 hit the market in 2006.  I still find them to be more convenient than using a smartphone paired with a bluetooth speaker.  However, my Grace models, a few years old now, stopped working with Sirius a couple of years ago.  It was the same with a Logitech Squeezebox.  Google Home provides a decent way to access Pandora and TuneIn, but not Sirius.

Our kitchen counter has added a new Kelement WiFi Internet Radio and I like it.  It is an appliance based upon an Android screen and familiar apps, along with two speakers and a subwoofer.  No, the sound won’t blast you away, but it is fine for the $80 I paid during Black Friday/Cyber Monday.  The price on Amazon is now $90, but I would still recommend it at that price.

It is nice to be able to again listen to Sirius while downstairs and the Android touch screen interface makes sense.

November DV4mini Image Update

The K2DLS DV4mini image for the Raspberry Pi 2 and 3 (only!) has been updated to include the October 12 release of the DV4mini Control Panel.  This includes XRF through letter Z and REF up to 100 for the D-Star users.  The image will fit nicely on an 8 GB SD Card.

Become an APRS Weather Alert Station

Most of us are familiar with the SAME codes used by NOAA Weather Radio All Hazards transmissions.  They allow the radio to be unmuted for Warning/Watch/Advisory (W/W/A) announcements for a county or zone.  I thought it would be a good idea to add W/W/A functionality to my existing APRS station.  I have been transmitting and iGating local weather readings via APRS for a number of years as part of the Civilian Weather Observer Program (CWOP).

My APRS station uses aprx software.  aprx runs under Linux, so I run mine on a Raspberry Pi Model B with Raspbian.  aprx supports the ability to run an external program as a beacon.  I wrote my program (noaacap.py) to be run by the aprx beacon exec function.

noaacap uses the NOAA CAP (Common Alerting) protocol and the Atom feeds published by the National Weather Service.  Installation is quick and simple if you have a running aprx system.

This is what my alerts look like after being iGated to APRS-IS.  They also go out over RF to the region.  I can even map the alerts on an APRS GUI such as Xastir.

Weather alert map @ K2DLS-13 during Hurricane Jose

If you’d like to become an APRS weather alert station for your county, consider running aprx and noaacap. You’ll need a 2 meter transceiver, a TNC (hardware or virtual), and an antenna to tranmsit the data feed via RF.  Help keep fixed and mobile stations, especially those using radios with APRS display screens, well informed and situationally aware.  You don’t have to run a high profile digipeater.  If your APRS signal is receivable by a local digipeater, you could even use an HT, a sound card interface, and an RPi to assemble a low cost station and provide this valuable local service via amateur radio.

More information about noaacap can be found on my github page.

DV4mini RPi Image Updated to Raspbian Stretch

The K2DLS DV4mini image for the Raspberry Pi 2 and 3 has been updated to Raspbian Stretch.  The DV4mini client and BMXTG 1.3 start automatically upon boot.  VNC has been updated to RealVNC.  Both VNC and ssh are started by default.

The installation fits nicely on an 8 GB SD card and it looks great on my 7″ touchscreen display.

The default password for the pi user is “raspberry” — please change it immediately!

The image may be found here.

Solar Eclipse Data Collection Project

Between 1600 – 2015 UTC on August 21, 2017, as the solar eclipse swept across the nation, I captured much of the lower 2 MHz of the radio frequency spectrum.  I used a Microtelecom Perseus SDR, a 130′ inverted L with four radials, and lots of disk space.  In doing so, I have created a permanent record of this portion of the RF spectrum during the solar eclipse.

I am making the spectrum capture files available for your analysis and research.  Each file contains a 5 minute segment.  If you download a group of files, they will play in succession.

You can use the demo version of the Perseus software or any other software that can read the Perseus data, such as Linrad or HDSDR.  You cannot use just an audio player to play the files, even though they have .wav extentions.

Should you perform any analysis or otherwise make use of the files, I’d like to hear from you in the comments below.

Special thanks to Jav, K4JH, for donating the bandwidth for this effort.

BMXTG 1.3 released on Github

I’ve added BMXTG to Github and updated it to version 1.3.  File locations have been formalized for consistency and I’ve created a .deb package for easier install.

Brandmeister XTG Dialer v1.3 by K2DLS

If you have a running DV4mini build and want to add BMXTG, grab the .deb file from the link in the README.

To install:

sudo dpkg -i bmxtg-1.3.deb

After installing, copy the desktop file to your Desktop directory.  This will make the desktop icon available.

cp /usr/local/share/bmxtg/bmxtg.desktop ~/Desktop/