Building HAM Clock on an old RaspberryPi

I’ve got a couple of old RaspberryPi computers on the shelf in the shack and so decided it was time for me to put one of them to good use. The first model on the shelf is the oldest and is one of the very first RaspberryPi 1 computers that was released. (It’s the one with the yellow analog video signal output on the board!). This particular model is extremely slow but, I hang onto it just as a reminder of the first SBC in the line.

The second one is a RaspberryPi 2, a quad core machine that is only slightly faster than the first model but, it’s powerful enough to run HAM Clock.

It didn’t take long to install a vanilla Raspbian Desktop O/S and get it configured on the local LAN. I installed a few packages that I like to have available on all my Linux machines and then started on the HAM Clock install.

The first thing I needed to do was install the X11 development library that is required to compile the HAM Clock binary. To do this, open a terminal and enter the command below to install the package.

sudo apt install libx11-dev

You will need to type in your password to obtain root privileges to complete the installation process and then wait for the package to be installed.

The HAM Clock source code is available from the HAM Clock Website under the Download tab in .zip format. Once downloaded unzip the file and change directory into the ESPHamClock folder ready to compile the code.

cd ~/Downloads/ESPHamClock

Once in the ESPHamClock directory you can run a command to get details on how to compile the source code.

make help

This will check your system to see what screen resolutions are available and then list out the options available to you for compiling the code as shown below.

The following targets are available (as appropriate for your system)

    hamclock-800x480          X11 GUI desktop version, AKA hamclock
    hamclock-1600x960         X11 GUI desktop version, larger, AKA hamclock-big
    hamclock-2400x1440        X11 GUI desktop version, larger yet
    hamclock-3200x1920        X11 GUI desktop version, huge

    hamclock-web-800x480      web server only (no display)
    hamclock-web-1600x960     web server only (no display), larger
    hamclock-web-2400x1440    web server only (no display), larger yet
    hamclock-web-3200x1920    web server only (no display), huge

    hamclock-fb0-800x480      RPi stand-alone /dev/fb0, AKA hamclock-fb0-small
    hamclock-fb0-1600x960     RPi stand-alone /dev/fb0, larger, AKA hamclock-fb0
    hamclock-fb0-2400x1440    RPi stand-alone /dev/fb0, larger yet
    hamclock-fb0-3200x1920    RPi stand-alone /dev/fb0, huge

For my system 1600×960 was the best option and so I compiled the code using the command as follows.

make hamclock-1600x960

It’s no surprise that it takes a while to compile the code on such a low powered device. I can’t tell you how long exactly as I went and made a brew and did a few other things whilst it was running but, it took a while!

Once the compilation was complete you then need to install the application to your desktop environment and move the binary to the correct directory.

make install

Once the install is complete there should be an icon on the GUI desktop to start the app. If like mine it didn’t create the icon then you can start the HAM Clock by using the following command in the terminal.

/usr/local/bin/hamclock &

The first time you start the app you’ll need to enter your station information, callsign, location etc and then select the settings you want to use. There are 4 pages of options for configuring the app all of which are described in the user documentation.

M0AWS - HAM Clock running on RaspberryPi Computer
M0AWS – HAM Clock running on RaspberryPi Computer

Once the configuration is complete the map will populate with the default panels and data. I tailored my panels to show the items of interest to me namely, POTA, SOTA, International Beacon Project and the ISS space station track. I was hoping to be able to display more than one satellite at a time on the map however, the interface only allows for one bird to be tracked at a time.

You can access the HAM Clock from another computer using a web browser pointed at your RaspberryPi on your local LAN using either the IP address or the hostname of the device.

http://<hostname>:8081/live.html

or

http://<ip-address>:8081/live.html

You can also control the HAM Clock remotely via web browser using a set of web commands that are detailed on port 8080 of the device.

http://<hostname or ip-address>:8080/

M0AWS - HAM Clock remote command set
M0AWS – HAM Clock remote command set

This is a great addition to any HAM shack especially if, like me you have an old HDTV on the wall of the shack that is crying out to display something useful.

More soon …

A venture into the world of Meshtastic

Meshtastic is a relatively new thing in the internet of things (IOT) world and is gaining traction in the U.K. at the moment.

So what is Meshtastic?

Meshtastic is an open source, off-grid, decentralised mesh network built to run on affordable, low-power devices on the 868Mhz industrial, scientific, and medical (ISM) band. (Some devices can also run on the 433Mhz 70cm HAM band.)

The ISM band is licence free but, has limits on the RF power levels that can be used. The one plus over the HAM bands is that you can legally transfer encrypted messages over the ISM band making it secure.

The best way to think of Meshtastic is a radio version of the online decentralised Matrix chat system but, without the large server requirements and ever growing database!

Heltec ESP32 v3 Wifi, Bluetooth and 868Mhz device for Meshtastic
Heltec ESP32 v3 Wifi, Bluetooth and 868Mhz device for Meshtastic

There are quite a few Meshtastic compatible devices on the market today with many costing around the £20 mark whilst others like the LillyGo T-Echo costing over £100 in the U.K. even though they are less than half the price in the USA.

Since I’m just starting out on my Meshtastic adventure I thought I’d start with a pair of Heltec ESP32 v3 devices that are normally readily available on Amazon but, due to the current push to build a U.K. wide mesh, they are currently out of stock pretty much everywhere.

Loading the Meshtastic firmware onto the devices is fairly straight forward and can be done using the web installer via either the Edge or Chromium web browsers.
(Note: If using Windows O/S you will need to install some drivers from the Meshtastic website to be able to communicate with the devices)

Having neither of the two browsers and being a Linux command line junkie I decided to use the Python programme to load the firmware onto the two devices. It’s worth noting that you don’t need any drivers to be able to communicate with the devices if you’re using either Debian or one of the many Ubuntu flavours of Linux O/S.

Using the Python command line program sounds like a more complicated approach but, in reality it’s super simple, extremely reliable, quick and if like me you use a Linux PC in the radio shack then you most likely already have most of what you need to get the job done. Just follow the simple steps as laid out on the Meshtastic web site and you’ll have the firmware loaded in no time at all.

Installing the Meshtastic firmware onto my Heltec ESP32 v3 using the Python command line tool
Installing the Meshtastic firmware onto my Heltec ESP32 v3 using the Python command line tool

The firmware takes less than a minute to copy across to the Heltec device and is automatically rebooted ready for configuration once the transfer has completed.

It is possible to configure the device via the command line tool however, since there is a nice GUI app for both Apple iOS and Android devices I decided to install the Meshtastic app on my iPad and connect to the device via Bluetooth to configure it.

Once you’ve got the Meshtastic app installed on your device and have connected via Bluetooth you’ll be ready to start configuring the device to join the mesh. The first thing you want to do is set the region. This is different in each country but, in the UK we use the EU_868 region settings. This will set the device to use the 868Mhz ISM band which is the band being used to build the U.K. wide mesh.

View of the Meshtastic app on iOS showing the configuration options for the Heltec ESP32 v3
View of the Meshtastic app on iOS showing the configuration options for the Heltec ESP32 v3

There is a multitude of configuration options within the app which I will go into in greater detail in a series of articles at a later date.

Heltec ESP32 v3 running Meshtastic Firmware
Heltec ESP32 v3 running Meshtastic Firmware

For those of you that, like me aren’t near any other nodes you can connect the devices to the internet and use the Meshtastic MQTT server to communicate with other nodes. This of course isn’t off-grid but, it will get you started until the mesh grows into your local area at which point your device will automatically start communicating with the other nodes over radio.

Meshtastic MQTT connectivity
Meshtastic MQTT connectivity

Once you are connected to either the MQTT server or other nodes via radio you will see the other node details appear in the Meshtastic app. It’s interesting to look at the information and see signal strengths and traffic levels etc for each node.

View of the Meshtastic app on iOS showing Nodes in the Mesh and Device Metrics for the M0AWS-1 Node
View of the Meshtastic app on iOS showing Nodes in the Mesh and Device Metrics for the M0AWS-1 Node

There are a multitude of cases available for the Heltec v3 devices, especially if you have access to a 3D printer. One of the nicest cases I have seen is the Bender from IKB3D (I know, it’s a strange name!) but, it really is a super little case for the Heltec series of devices.

You can either buy the 3D print files for £8.99 and print it yourself or just order a pre-printed and assembled case directly from the website although, due to demand there is a long lead time currently.

More soon …

Whispering around the world

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.

git clone https://github.com/JamesP6000/WsprryPi.git

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:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <assert.h>
#include <stdint.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/sysmacros.h>

#include "mailbox.h"

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.

More soon …