A couple of years ago I built a Matrix Synapse server and connected it to the decentralised global Matrix chat network that is federated world wide by enthusiasts who host their own Matrix servers. Due to the enthusiasm for a decentralised network the Matrix has grown exponentially and is now an established force in the world of Opensource global communication services.
When I built my server and configured it online my aim was to bring together an enthusiastic group of Radio Amateurs (Radio HAMs) who could build a friendly, welcoming community where people could share, learn and have fun with other liked minded individuals without all the nonsense you see on commercial social media platforms.
Overtime we’ve increased the number of rooms available in the HAM Radio space and the number of subjects covered. This has grown organically as our community has grown and we’ve ventured together into new areas of the hobby.
Global Matrix Ham Radio Space hosted on the M0AWS Matrix Server
From the community a number of projects have spawned including the Opensource.radio Wiki that Mike, DK1MI is sponsoring that aims to detail all the Opensource HAM Radio software, Hardware and projects in one centralised site on the internet. This is a great project and one I am very happy to contribute to.
Thanks to Mike, DK1MI we now also have our own Matrix AllStarLink node available. This is a great resource for the community as it is often not possible for all of us to communicate via the radio waves due to geo-location, time zones, local planning regulations etc. Having this 24/7 internet based resource makes it a lot easier for the community to chat at any time even when propagation on the HF bands isn’t in our favour.
We also have a very active satellite room with regular nets on the QO-100 satellite. With such a great range of rooms and subjects there’s plenty to read and talk about with the community.
If you fancy being part of this growing, enthusiastic group of Radio Amateurs and Short Wave Listeners (SWLs) then click on the link below and come and say hello, a warm welcome awaits!
I get quite a few emails from readers of my blog asking how my QO-100 satellite station is put together and so, I thought perhaps now is a good time to put together an article detailing the complete build.
My QO-100 satellite ground station is built around my little Icom IC-705 QRP transceiver, it’s a great little rig and is ideal for the purpose of driving a 2.4Ghz transverter/up-converter.
Of course all the software used for the project is Opensource and freely available on the internet.
M0AWS QO-100 Ground Station Build Visual (Click to Enlarge)
The station comprises of the following building blocks:
QO-100 Ground Station Dashboard developed using Node-RED
LMR400-UF/RG58 Coax Cable
M0AWS QO-100 1.1m (110cm) off-set Dish with IceCone Helix antenna and Bullseye LNB.
To get a good clear view of the QO-100 satellite I have the dish mount 3.2m above the ground. This keeps it well clear of anyone walking past in the garden and beams the signal up at an angle of 26.2 degrees keeping well clear of neighbouring gardens.
The waterproof enclosure below the dish houses all the 2.4Ghz equipment so that the distance between the feed point and the amplifier are kept to a minimum.
The DXPatrol amplifier is spec’d to run at 28v/12w or 12v/5w, I found that running it at 28v produced too much output for the satellite and would cause the LEILA alarm on the satellite to trip constantly. Running the amp at 12v with a maximum of 5w output (average 2.5-3.5w) is more than enough for me to have a 5/9+10 signal on the transponder.
The large 1.1m dish gives me quite an advantage on receive enabling me to hear the very weak stations with ease compared to other stations.
2.4Ghz ground station enclosure ready for testing
The photo above shows the 2.4Ghz equipment mounted in the waterproof enclosure below the dish. This photo was taken during the initial build phase before I rewired it so, the amplifier is shown connected to the 28v feed. To rewire the amp to 12v was just a matter of removing the 28v converter and connecting the amp directly to the 12v feed instead. This reduced the output from a maximum of 12w down to a maximum of 5w giving a much better (considerate) level on the satellite.
It’s important to keep all interconnects as short as possible as at 2.4Ghz it is very easy to build up a lot of loss between devices.
For the connection from the IC-705 to the 2.4Ghz Up-Converter I used a 7m run of LMR-400 coax cable. The IC-705 is set to put out just 300mW on 144Mhz up to the 2.4Ghz converter and so it’s important to use a good quality coax cable.
Once again the output from the 2.4Ghz amplifier uses 1.5m of LMR-400-UF coax cable to feed up to the 2.2 turn Icecone Helix Antenna mounted on the dish. This keeps loss to a minimum and is well worth the investment.
Bullseye 10Khz High Stability Unversal Single LNB for 10.489-12.750Ghz
The receive path starts with a Bullseye LNB, this is a high gain LNB that is probably one of the best you could use for QO-100 operations. It’s fairly stable frequency wise but, does drift a little in the summer months with the high temperature changes but, overall it really is a very good LNB.
The 12v feed to the LNB is via the coax and is injected by the Bias-T device that is in the radio shack. This 12v feed powers the LNA and associated electronics in the LNB to provide a gain of 50-60dB.
Bias-T to inject 12v feed into the coax for the Bullseye LNB
From the Bias-T the coax comes down to the NooElec SmartSDR receiver. This is a really cheap SDR device (<£35 on Amazon) based on the RTL-SDR device but, it works incredibly well. I originally used a Funcube Dongle Pro+ for the receive side however, it really didn’t handle large signals very well and there was a lot of signal ghosting so, I swapped it out for the NooElec SDR and haven’t looked back since.
The NooElec SmartSDR is controlled via the excellent Opensource software GQRX SDR. I’ve been using GQRX SDR for some years now and it’s proven itself to be extremely stable and reliable with support for a good number of SDR devices.
To enhance the operation of the SDR device I have added a Griffin Powermate VFO knob to the build. This is an old USB device that I originally purchased to control my Flex3000 transceiver but, since I sold that many moons ago I decided to use it as a VFO knob in my QO-100 ground station. Details on how I got it working with the station are detailed in this blog article.
Having the need for full duplex operation on the satellite this complicates things when it comes to VFO tracking and general control of the two radios involved in the solution and so I set about creating a QO-100 Dashboard using the great Node-RED graphical programming environment to create a web app that simplifies the management of the entire setup.
M0AWS QO-100 ground Station Control Dashboard built using Node-RED.
The QO-100 Dashboard synchronises the transmit and receive VFO’s, enables split operation so that you can transmit and receive on different frequencies at the same time and a whole host of other things using very little code. Most of the functionality is created using standard Node-RED nodes. More info on Node-RED can be found on the Opensource.radio Wiki or from the menu’s above.
I’ll be publishing an article all about the QO-100 Dashboard in the very near future along with a downloadable flow file.
I’m extremely pleased with how well the ground station works and have had well in excess of 500 QSO’s on the QO-100 satellite over the last last year.
With the recent explosion of artificial intelligence (AI) art generators that are making the news of late for all the wrong reasons, I decided to see if I could put it to good use and design some futuristic QSL cards.
Having recently been contacted by the Special Callsigns QSL Manager and being advised that there were 18 QSL cards waiting for me, I decided it was time to create some QSL cards of my own for future use.
Having never used any form of online AI and not having any artistic abilities I was amazed how easy it was to create images using nothing more than a paragraph or so of text to describe what it was I wanted to create.
Since all the QSL cards I received were for contacts on the QO-100 satellite, I set out to create a visually futuristic QSL card that was based around a radio HAM operator and satellite communications.
M0AWS – 1st attempt at creating a futuristic QSL card image using AI Art
To my surprise the results of my first image generation were surprisingly good. The AI generated an image that resembled the simple text that I entered, although I never requested a one legged HAM operator!
Pleased with my very first attempt I gradually improved the description of what I was looking for, adding more and more detail to the text and including things that I wanted to see in the image. Over a fairly short period of time this approach started to generate some very interesting images.
M0AWS – AI Art QSL Image attempt 2M0AWS – AI Art QSL Image attempt 3M0AWS – AI Art QSL Image attempt 4
With each iteration I gradually got closer to what I was trying to achieve but, never quite got exactly what I wanted so, I decided to rewrite the descriptive text adding even more information than before. The text was now a full blown paragraph with quite specific things described including the angle at which the scene was being viewed from.
The other option I wanted to try out was the theme functionality that the AI offered. This allows you to set a theme for the image from things like steampunk, cartoon, manga, real world and many more. The results were quite impressive and added yet another angle to the image generation.
M0AWS – AI Art QSL Theme 1M0AWS – AI Art QSL Theme 3M0AWS – AI Art QSL Theme 2
I disappeared down the theme AI Art generation rabbit hole for quite some time and generated some very interesting and fun results. The best by far though was the Thunderbirds themed image, this did put a smile on my face!
M0AWS – AI Art QSL Thunderbirds Themed
At the other end of the spectrum I tried the Salvador Dalli theme, it produced an image that was very like the work of the famous artist but, wasn’t quite what I was looking for.
M0AWS – AI Art QSL Salvador Dalli Themed
After much fun I eventually settled on the image I was after, a futuristic scene of a radio HAM with a satellite ground station over looking a mountain range and city below.
M0AWS Satellite QSL Card generated using online AI
I’m really pleased with the results from my ventures into AI generated art. The next challenge is to create a QSL card for HF bands Contacts.
This solution has worked incredibly well from the outset and over time I’ve added extra functionality that I’ve found to be useful to enhance the overall setup.
The latest addition to the ground station solution is a Sennheiser Headset that I picked up for just £56 on Amazon (Much cheaper than the Heil equivalents at the HAM stores!) and have found it to be excellent. The audio quality from both the mic and the headphones is extremely good whilst being light and comfortable to wear for extended periods.
M0AWS – Sennheiser SC 165 Headset
To incorporate this into the ground station the headset is connected to my Kubuntu PC and the audio chain to the IC-705 is sent wirelessly using the latest version of WFView. This works extremely well. The receive audio comes directly from the GQRX SDR software to the headphones so that I have a full duplex headset combination.
Audio routing is done via pulse audio on the Kubuntu PC and is very easy to setup.
Since I no longer have a mic connected to the IC-705 directly I found that I needed a way to operate the PTT wirelessly and this is where the latest addition to my NodeRed QO-100 Dashboard comes in.
Adding a little functionality to the NodeRed flow I was able to create a button that toggles the IC-705 PTT state on and off giving me the ability to easily switch between receive and transmit using a simple XMLRPC node without the need for a physical PTT button.
M0AWS – Additional NodeRed PTT Flow
The PTT state and PTT button colour change is handled by the Toggle PTT function node shown in the above flow. The code to do this is relatively simple as shown below.
M0AWS – NodeRed Toggle PTT Function to change button colour
The entire QO-100 Dashboard flow has grown somewhat from it’s initial conception but, it provides all the functionality that I require to operate a full duplex station on the QO-100 satellite.
M0AWS – NodeRed QO-100 Dashboard complete flow
This simple but, effective PTT solution works great and leaves me hands free whilst talking on the satellite or the HF bands when using the IC-705. This also means that when using my IC-705 it only requires the coax to be connected, everything else is done via Wifi keeping things nice and tidy in the radio shack.
M0AWS – Updated NodeRed QO-100 Dashboard with PTT button
The image above shows the QO-100 ground station in receive cycle with the RX/TX VFO’s in split mode as the DX station was slightly off frequency to me. The PTT button goes red when in TX mode just like the split button shown above for visual reference.
As you can probably tell, I’m a huge fan of NodeRed and have put together quite a few projects using it, including my HF Bands Live Monitoring web page.
Since I’ve been using my Icom IC-705 on the QO-100 satellite I’ve been getting no end of unsolicited great audio reports with one Op even saying I have the best audio he’s ever heard on the satellite.
Most people are surprised when I tell them that I am using the stock fist mic that comes with the radio. It’s nothing special, in fact it’s rather cheap and plastic, not particularly good quality however, it does seem to have a good sounding mic insert.
The other great thing about the IC-705 is that it has a two channel parametric equaliser built into the radio. Many people don’t realise this and miss out on the massive improvement they can make to their transmitted audio with just a few simple adjustments.
The stock fist mic has a very flat response across the audio frequency range out of the box and doesn’t sound particularly inspiring. Many see this as a negative and often just replace the mic with either a headset (probably from Heil), a boom mic (again probably from Heil) or another, better quality fist mic. All of these options cost varying amounts of money when in reality none of them are necessary.
Starting from a flat audio response is actually a good thing as it makes the equaliser adjustments more pronounced, making it easier to adjust the settings to suit your voice.
We all have different voices but, there is one thing that is pretty much the same for everyone and that’s the frequency range in which the articulation of the words and sounds we make can be found. It’s this part of the voice that is often lacking when we struggle to understand what the DX station is saying.
It’s become common place on the HAM bands these days for stations to boost the bass frequencies and reduce the mid and high frequencies with the net result of a horrible bass ringing sound and muddy mid range often making it very difficult to understand what is being said.
Having spent some considerable time watching the great videos on audio from the late Bob Heil, K9EID it’s clear that the most important frequencies to enhance are those around 2.5khz as this is where all the articulation is in the human voice.
To this end I set about setting up the audio on my IC-705 QRP radio so that my voice sounded such that it is easy to comprehend even in the most difficult of situations on air. This doesn’t mean that it has to be very harsh and overly bright, quite the opposite in that to be heard clearly in all conditions on air one’s audio needs to be balanced across the frequency range with an enhancement in the 2.5Khz frequency range.
M0AWS IC-705 Transmit audio settings – part 1
To reduce the unwanted, muddy bass the first thing to do is change the transmit bandwidth for the “Wide” setting to 200-2900Hz. This will cut off the bottom 100Hz from the voice reducing the overall bass output from the standard fist mic that comes with the radio. This will ensure a 2700Hz wide SSB signal, the recommended max for QO-100 operations and the preferred bandwidth on the HF bands.
On top of this I made a further reduction of 2dB on the TX Bass setting to help balance out the overall audio response of the mic insert.
Next I set about enhancing the higher frequency response of the mic insert and found that it required an increase of 4dB to bring out the articulation of my voice. This enhanced my audio considerably compared to the standard output from the fist mic and improved the intelligibility of my voice considerably, especially in difficult band conditions.
To complete the setup I set the compression to 3 and mic gain to 35 so that the overall drive level is increased slightly giving a greater average output from the radio.
M0AWS IC-705 Audio Settings – part 2
Once I’d got the audio setup correctly I enabled the configuration by setting the Transmit Bandwidth (TBW) to the “Wide” config in the IC-705 Function menu so that the correct settings were made active.
Ever since making these relatively easy changes I have had no end of unsolicited great audio reports from stations asking me what mic I am using and how I’ve managed to get such good audio from the IC-705. Many are surprised that I am using the OEM fist mic that comes with the radio and I’m sure there are those who don’t believe me!
Of course all voices are slightly different and these settings may not be perfect for your voice but, all those that have tried these settings have told me that their audio sounds better than ever and that DX stations often comment on how good their audio is.
I also went through the same exercise with my Yaesu FTDX10 with it’s standard fist mic and again achieved excellent results with it’s 3 channel parametric equaliser. I’ll go through the somewhat more complicated setup for the FTDX10 in another article soon.
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
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
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.
After initially finding that I couldn’t tune the 868Mhz ground plane antenna with the radials bent down at 45 degrees I decided to experiment to find out why.
Initially I had the radials connected to the 4 corners of the base of the chassis mount N Type socket. This works great if you have the radials completely horizontal and gives an SWR of 1.1:1 but, with the radials bent down at 45 degrees the best SWR is around 2:1.
M0AWS 868Mhz Ground Plane Antenna Close Up
Removing the radials from the base of the N Type chassis socket and soldering them to the outer of the N Type plug at the same level as the feed point for the radiating element I found that an almost perfect SWR can be achieved very easily.
M0AWS 868Mhz Antenna with radials soldered to the N Type Plug
It seemed weird to me that such a small change could have such a big effect on the obtainable SWR for the antenna but, as can be seen in the image below with the radials soldered to the N Type plug and bent downwards I immediately got an SWR of 1.07:1 and a much wider SWR curve.
M0AWS 868Mhz Antenna SWR curve with radials soldered to N Type plug.
By making my own antennas I’m learning a lot about antenna design for the 800-900Mhz frequency range. Minor changes seem to have a much bigger impact than they do at much lower frequencies.
This is a question I get asked regularly via email and so I decided to post this article so that I can refer to it in future emails.
Callum of DXCommander fame has just published a great video explaining the difference between dBi and dBd that is well worth watching if you don’t understand the difference between the two.
In my quest to improve my Meshtastic signal range using home-brew antennas I’ve finally put together a neat little ground plane vertical antenna for the 868Mhz ISM band.
The design follows the normal ground plane simplicity using 4 radials and a vertical radiating element albeit on a tiny scale. The radiating element is 82mm long and the radials are each 92mm long.
M0AWS 868Mhz Ground Plane Vertical Antenna
Initially I modelled the antenna at a height of 3m above the ground with the radials tilted downwards at 45 degrees. I took this approach as this is how I have built ground plane verticals for the 70cm band in the past and so I thought I’d try the same approach on the 868Mhz ISM band. (I later found this to be detrimental to tuning!)
The 3D far field plot for the antenna shows it has a very nice, relatively high gain lobe at just 2 degrees elevation with a number of lower gain lobes higher up.
M0AWS 868Mhz Ground Plane Vertical Antenna 3D Far Field Plot
Looking at the 2D far field plot you can get a better understanding of the radiation pattern and gain figures at various angles. At 2 degrees there is 6.7dBi gain with the next major lobe being at 8 degrees with 4.36dBi gain, far more than I imagined I’d see for such a simple antenna.
M0AWS 868Mhz Ground Plane Vertical Antenna 2D Far Field Plot
Putting the antenna together was easy enough with particular attention being paid to the measurements of both the radials and radiating element. I soldered some lugs to the ends of the 2.5mm diameter solid core wire radials to enable easy attachment to the N Type chassis socket that I decided to use as the base for the antenna. This worked out well and provided a good solid mechanical and electrical connection for the 4 radials.
For the radiating element I used an N Type plug with the vertical 2.5mm solid core wire element soldered to the inner centre pin of the male connector. I also slid a small piece of insulation down the wire to stop it from shorting against the metal outer of the plug and then pushed in a tight rubber plug to stop water ingress.
M0AWS 868Mhz Ground Plane Antenna Close Up
Connecting my VNA I found the antenna was mostly resonant at 790Mhz with an SWR of 2.5:1. I knew this would be the case and that the wires would need a little trimming.
Trimming the wires a couple of times in 1mm nibbles I got the point of resonance up to 868Mhz but, the antenna was still exhibiting a lot of reactance that was keeping the SWR above 2:1. Trimming the radials reduced this slightly but, I could not get an SWR much lower than 1.95:1.
Scratching my head I decided to try moving the radials back up so that they were horizontal rather than at 45 degrees downwards, this had the immediate effect of the SWR dropping to 1.1:1.
M0AWS A rather fuzzy photo of the 868Mhz SWR curve for the GP Antenna
The SWR stays below 1.2:1 from 868Mhz to 871Mhz which is plenty wide enough for the Meshtastic devices. Why there is so much reactance when the radials are bent down at 45 degrees I am not sure, but it was easy enough to resolve.
M0AWS 868Mhz Ground Plane Antenna
The finished antenna is tiny but, seems to work well. Signals from my other nodes are up by 6-9dB according to the SNR reports in the Meshtastic app. I now need to make a couple more of these for my other nodes and then hope to hear some other nodes locally once they appear on air.
Remodelling the antenna in EzNEC with the radials as shown above the gain at 2 degrees is now 5.5dBi, down 1.2dBi but, the overall radiation pattern is identical to the original.
Total cost of the build is about £1 and an hour of my time tinkering with it, bargain!
M0AWS-4 Meshtastic Node 868Mhz Antenna Deployment
More soon …
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