For the last 24hrs I’ve had the RaspberryPi2 transmitting WSPR on 20m and 10m connected to my EFHW Vertical antenna. So far not a single spot on the 10m band, I’m assuming the band hasn’t opened in the UK over the test period.
WSPR 20m band reports over the last 24hrs
Results on 20m continue to impress with reports from the USA, West Africa coast and as far east as Georgia.
I’ll check the signal on 10m later today using my IC705 to ensure it is transmitting ok and then will leave it running for another 24hrs to see what happens.
UPDATE:
It appears there’s been a reliable opening on both 10m and 20m to the Canary Islands just off the west coast of Africa so far today.
The Weak Signal Propagation Reporting Network (WSPR) known as “Whisper” in the HAM community is a QRP/QRPp beacon mode that is used by many HAMs around the world to see pretty much realtime propagation on the HF bands.
I first started using WSPR when I lived in France some years ago and it proved invaluable for assessing antenna performance and directivity. It’s not a new mode by any means and nowhere near as popular as it used to be as it’s really been superseded by FT4/8 these days that provides the same functionality but, with QSO capability too.
Having an old RaspberryPi hanging around and reading about the WSPR software that’s available for it now I decided to put the Raspi to good use and build a WSPR beacon for the 20m band that I could leave on 24/7.
Having the EFHW Vertical at the end of the garden means that I can connect it directly to the Raspi without the need for an ATU as it’s fully resonant. (It’s actually resonant on 20m and 10m)
I normally run both my RaspberryPi mini computers completely headless and then SSH in to them from my MacBook Pro and decided this was the best way to go with the WSPR beacon too since the WSPR software is command line based and doesn’t require a GUI.
First thing to do was to upgrade the OS from Debian Buster to Bullseye. It’s been a while since I used the Raspi but, it fired up perfectly and connected to the LAN without issue.
After a little time I had the O/S updated to Bullseye and the Raspi was ready for the software build.
The WSPR program comes in source code only so, this means you have to compile it yourself. This isn’t a big job as it comes complete with a makefile.
Using a terminal run the following commands to download and compile the WSPR source code.
So first thing to do is install git.
sudo apt-get install git
Once git is installed I downloaded the software from the git repository.
It only takes a few seconds to download the software which is stored in a new directory called “WsprryPi”.
Before the code can be compiled there’s a small issue with the includes in one of the source code files that needs to be resolved so that the code compiles without error.
cd WsprryPi
vi mailbox.c
Using your favourite command line editor, ‘vi‘ in my case I added the following line into the include statement at the top of the code.
#include <sys/sysmacros.h>
Once added the full include statement looked like this:
Once done, I saved the file ready for compilation.
Compiling the code is easy, just run the make command and sit back and watch all the compiler messages scroll across the screen.
make
Compiling the WSPR source code
Once compiled without errors, I just needed to install the binary.
make install
At this point the software is ready to go.
I quickly soldered up a lead to go from the RaspberryPi GPIO pins to the Coax cable that is connected to the EFHW vertical antenna in the garden and connected it all up ready to test.
RaspberryPi 2 WSPR Beacon connected to EFHW vertical for 20m/10m bands
Pins 7 and 9 on the Raspberry Pi’s GPIO pins are where the signal is output. Pin 9 is the Ground pin, and pin 7 is the Signal pin. Pin 7 goes to the inner of the coax and pin 9 to the ground side of the coax.
The purple cable is the ethernet cable connecting the Raspi to my local LAN so that I can access it remotely via SSH. I’ve powered the Raspi off of the USB port on the wifi access point in the radio shack which is always on.
Once it’s all connected it’s just a case of starting the WSPR program from the command line as user root.
wspr -s -r M0AWS JO02 10 20m > ./wspr.log &
I run the WSPR program as root user so that it has the correct privileges to access the devices to communicate with the GPIO headers, if you want too start it as your normal user then you’d need to use sudo to gain the root privileges.
The command line options I’ve used are as follows:
-s
Check NTP before every transmission to obtain the PPM error of the crystal
-r
Repeatedly, and in order, transmit on all the specified command line freqs.
M0AWS
My Callsign
JO02
My Locator Square
10
The power being used in dBm
> ./wspr.log &
Redirects all output to wspr.log in the current directory and then puts the program into the background so that it is left running when I log out.
Once the program is started you can monitor progress by using tail on the log file.
tail -f ./wspr.log
The output you will see will be something like this.
Desired center frequency for WSPR transmission: 14.097100 MHz
Waiting for next WSPR transmission window...
TX started at: UTC 2022-07-17 16:06:01.015
TX ended at: UTC 2022-07-17 16:07:51.638 (110.623 s)
Desired center frequency for WSPR transmission: 14.097100 MHz
Waiting for next WSPR transmission window...
TX started at: UTC 2022-07-17 16:08:01.015
TX ended at: UTC 2022-07-17 16:09:51.639 (110.624 s)
Desired center frequency for WSPR transmission: 14.097100 MHz
Waiting for next WSPR transmission window...
TX started at: UTC 2022-07-17 16:10:01.015
TX ended at: UTC 2022-07-17 16:11:51.642 (110.627 s)
Desired center frequency for WSPR transmission: 14.097100 MHz
Waiting for next WSPR transmission window...
TX started at: UTC 2022-07-17 16:12:01.015
TX ended at: UTC 2022-07-17 16:13:51.639 (110.624 s)
Desired center frequency for WSPR transmission: 14.097100 MHz
Waiting for next WSPR transmission window...
TX started at: UTC 2022-07-17 16:14:01.015
TX ended at: UTC 2022-07-17 16:15:51.639 (110.624 s)
Desired center frequency for WSPR transmission: 14.097100 MHz
Waiting for next WSPR transmission window...
TX started at: UTC 2022-07-17 16:16:01.014
TX ended at: UTC 2022-07-17 16:17:51.639 (110.624 s)
Desired center frequency for WSPR transmission: 14.097100 MHz
Waiting for next WSPR transmission window...
Obtained new ppm value: 4.09996
TX started at: UTC 2022-07-17 16:18:01.015
TX ended at: UTC 2022-07-17 16:19:51.640 (110.624 s)
Desired center frequency for WSPR transmission: 14.097100 MHz
Waiting for next WSPR transmission window...
TX started at: UTC 2022-07-17 16:20:01.014
TX ended at: UTC 2022-07-17 16:21:51.638 (110.624 s)
Desired center frequency for WSPR transmission: 14.097100 MHz
Waiting for next WSPR transmission window...
TX started at: UTC 2022-07-17 16:22:01.004
TX ended at: UTC 2022-07-17 16:23:51.628 (110.624 s)
You can pass multiple bands on the command line if you want to hop around bands.
It’s also recommended that you add a low pass filter between the Raspi and coax connection to help suppress any harmonics that may be generated. You can make one easily enough using just a capacitor or there are a number of prebuilt low pass filters specifically made for the GPIO hat on the Raspi online.
With only 10dBm (10mW) output from the RaspberryPi it’s surprising the distances that the signal travels. In no time at all I had reports from all over Europe and as the day progressed reports started coming in from Iceland, the USA and Russia.
Map showing stations that heard M0AWS on WSPR
I used http://wspr.aprsinfo.com WSPR monitoring website to watch progress as the day went on and after 24hrs had been heard by a number of stations over 3000 miles away.
You can also get a more detailed view of reports from the WSPRnet website where you can query the database and create a detailed list of all decodes over a set period of time.
Detailed list of WSPR decodes
Since my EFHW Vertical is resonant on both 20m and 10m I’ll now run it for the next 24hrs on both bands to see what results I get.
I’ve had a few messages of late asking how I generate my WSJT-X log web pages for my website. The answer is pretty simple, I use a little BASH script that I started writing some time back and have gradually improved over the last few months.
If you have a PC running Linux or a RaspberryPi running any of the normal Debian/Ubuntu/Redhat/Fedora based Linux distro’s that are available today then, this script should work just fine.
I originally wrote this program using Python but, a friend of mine bet me that I couldn’t write it in BASH and so, I took up the challenge and this is the result. It’s pretty simple and uses all the normal UNIX command line goodies like grep, sed and awk.
The script also uses WWL to calculate the distance between two Maidenhead locator grid squares and so it’s important to have it installed before running the script. (The script checks for it at runtime and will exit if it is not installed!). You can install WWL using your package manager on your Linux distro or from the command line directly. Details are in the READ-ME.txt file.
Screen grab from my M0AWS WSJT-X Log web page
It’s important that you READ the READ-ME.txt included in the zip file before trying to run any of the scripts included as it details the variables that you need to enter values for to make the script run on your PC/Server. (Example entries are in place as supplied).
The variables are mainly just paths to files on your system and whether you want distances calculated in miles or kilometres. Other than that there’s nothing else required for it to run.
I’ve also included details on how to run the script automatically from a crontab so that your webpage can be updated automatically every few minutes/hours etc.
The script also includes code to add a PNG map file into the generated webpage so that there is a graphical representation of all your QSOs. The map isn’t generated by the script (something I need to add in the coming few months) so you’ll need to generate it yourself and then add it to the website either via the crontab script included in the zip file or manually.
I use the QSOMap website to generate my map image files and then have them uploaded to my web server via the crontab script.
The script processes 100 entries per second on my web server (Headless virtual machine running Ubuntu Server 64bit Edition) and so should be pretty fast on most PCs. It will run somewhat slower on a RaspberryPi so be patient!
You can download the script and associated information using the button below.
Following on from the adi2html v0.5 release I’ve now added a little more code to include a map of the contacts detailed in the wsjtx_log.adi file so that there is a visual representation of the data included in the webpage. (Map must be generated externally and JPEG/GIF/PNG uploaded to website to be included in the webpage).
Following on from my original article where I detailed the adi2htmlBash script that reads in the WSJT-X log and creates an HTML version of the data so that it can be presented in a palatable format on websites (See my WSJT-X log here), I’ve now released v0.5 for public consumption.
In adi2html v0.5 I’ve added colour to the webpage that is generated to make it easier on the eyes and rewritten the function process_log() so that it uses the column name to identify each field instead of the row position.
By making this change it should cope just fine if the order of the fields is ever altered in the WSJT-X log during its development.
As before the code can be downloaded using the link below.
If you use my code please consider leaving the footer in place so I get some credit, thanks!
I had some spare time today so I finished a small BASH program that I started writing yesterday that reads the wsjtx_log.adi file and writes the data out in HTML format so that it can be incorporated into my website (See the Logs Menu).
(Sorry the font is so small but WordPress is crap at displaying code!)
It’s a fairly simple piece of code that anyone who is into Linux and has a basic understanding of the BASH shell will easily be able to comprehend. (Yes there’s a little awk and sed in it just to add to the entertainment value!).
There are a few places where the code can be improved which I’ll address in v0.3 when I have time but, for now I’ll put it online just incase anyone is interested in using it.
If you do use the code please consider leaving the footer in place so I get some credit.
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