Steve (M0XVT), Alan (G1SQB) and I are pleased to announce piSync v0.9, bringing synchronised WebSDR access to Linux users running piHPSDR-Improved and now, a much wider range of transceivers through FLRig.
Windows users have enjoyed this kind of functionality through applications such as CatSync for some time. To the best of our knowledge, piSync may be the first Linux application to offer an equivalent solution for both piHPSDR-Improved and the huge range of transceivers supported by FLRig.
piSync v0.9 with FLRig support
Bringing New Life to Existing Radios
The addition of FLRig support is a significant step forward. piSync can follow your radio’s frequency, operating mode, active VFO and PTT status, allowing a compatible WebSDR receiver to follow you around the bands.
Whether you’re using a modern SDR or a conventional transceiver, piSync opens up new possibilities for exploring propagation and comparing signals received at different locations around the world — without replacing your existing radio.
What’s New in v0.9?
This release also introduces several improvements:
Persistent WebSDR list: Your receiver URLs are now saved on your PC and restored after restarting piSync, rather than being stored in your web browser.
WebSDR map: A new launcher button provides quick access to the WebSDR World Map.
piSync v0.9 – Synchronising WebSDR’s to your Radio.
Easy Installation for Linux Users
Getting started with piSync is easier than ever, thanks to its new GUI installer. Designed to simplify installation and setup, it makes piSync more accessible to everyone, including amateur radio operators making the move from Windows to Linux.
Alongside the GUI installer developed for piHPSDR-Improved, this is another step towards making Linux a practical and welcoming platform for amateur radio enthusiasts.
piSync GUI Installer – One Double Click and it’s ready to use.
We’ve Kicked the Tyres, So You Can Hit the Airwaves!
piSync has been tested on Raspberry Pi, Kubuntu (KDE Plasma), Linux Mint (Cinnamon), Debian 13 (Trixie) and Ubuntu. While we can’t test every Linux distribution, it should work on most Debian and Ubuntu based systems. We’ve done the testing so you can spend less time setting up and more time enjoying your radio!
Get piSync
If you’re a Linux-based amateur radio operator, whether using piHPSDR-Improved or a transceiver supported by FLRig, piSync is worth a look.
Synchronised WebSDR access, on Linux, using the radio you already own.
It’s been a busy week of software bug fixes and enhancements on piHPSDR-Improved and piSync.
piSync v0.9 is currently in test after we added the support for FLRig. This extends the support for many transceivers new and old along side piHPSDR-Improved and makes it useful to HAMs who aren’t using SDR’s.
piSync v0.9 with FLRig support in test
piHPSDR-Improved has also had a lot of work done to it this week with a splurge of bug fixes and enhancements being made. We decided to bring the release forward as we can then concentrate on writing the new modules to bring even more functionality to the SDR solution.
piHPSDR-Improved v2.45 in Test
We’ve put some effort into tidying up the user interface in piHPSDR-Improved along with the new, second S Meter for VFOB. This is a really nice enhancement we’ve been wanting to do for some time but, haven’t had the time to devote to it until now.
piHPSDR-Improved v2.45 in test with Horizontally stacked RX
The floating toolbar has also had some upgrades and is not only looking good but, we’ve added new functionality to it as well.
piHPSDR-Improved v2.45 Floating Toolbar in Test
We’re hoping to release both of these updated software packages very soon once we’ve completed all our testing and are happy that’s it ready for release.
The articles I write for the blog are mostly technical but, I thought it was about time that I wrote this article as it’s been buzzing around inside my head for some time now.
So, what are the 5 things that I have found revolutionary in my shack that have brought new, exciting ideas and projects to life making amateur radio more enjoyable.
1: A RaspberryPi Single Board Computer
RaspberryPi 5 Single Board Computer
Ever since the first RaspberryPi Single Board Computer (SBC) was released I’ve been a huge fan. This little credit card sized number cruncher has been the base for so many projects, it has to be the first on my list.
The RaspberryPi SBC has been through a few iterations since its initial conception and is now powerful enough to take on most tasks that any radio HAM is going to throw at it.
So, what have I done with them?
Well I’ve used them to run Node-Red services for my many web app dashboards that control things like my QO-100 Satellite Ground Station, UPS power monitoring, Internet speed graphs, server and virtual machine monitoring, AllStarLink nodes, hosting websites, building an SDR shortwave receiver, running HAM Clock / Open HAM Clock, developing my own software, hosting virtual machines and a whole host of other fun and interesting things. I’m even writing this article using my RaspberryPi 500+ computer that is my daily desktop PC.
There are an endless number of things you can do with a RaspberryPi to bring new life and functionality to your radio hobby.
Want to get into Amateur TV? Want to decode digital modes real time? Want to track aircraft in the sky real time on a virtual radar screen? Want to search the shortwave bands for stations of interest? Want to host your own blog and website?
All these things and a lot more are easily within reach with a RaspberryPi.
The RaspberryPi is only limited by your imagination, the more imaginative you are the more your number crunching little friend will do.
2: A 3D Printer
Bambu Lab A1 Combo 3D Printer
Every HAM should have a 3D printer. These manufacturing marvels bring a new level of quality, design and simplicity to your HAM radio projects. I’ve found it incredibly useful since venturing into the rabbit hole that is 3D printing. When I think back to the weeks and months of my life I’ve spent making cabinets and boxes out of sheet metal, aluminium or wood for the numerous projects I’ve built over the years, a 3D printer would had made my life so much easier. 3D printing has revolutionised the making of things for the Amateur Radio home brewer.
There’s a multitude of useful things on websites like Printables, Thingiverse , Makerworld and others where you can just download the files and print high quality designs for all those things you’ve wanted to do but, don’t have the time or inclination to craft by hand.
The real satisfaction with 3D printing comes from designing your own things and making them. My first project was to design and print a fan cooling system for my Xiegu XPA125B amplifier.
From the factory the amp is passively cooled and doesn’t take long for the heat-sink to become saturated resulting in a high operating temperature. I was never happy with this and so was determined to resolve the problem.
Getting to grips with TinkerCAD was a bit of a vertical learning curve but, after a few mistakes and design mishaps I soon had it under my belt and pressed on with designing the cooler unit.
Designing the Xiegu XPA125b cooling system using tinkerCAD.
It’s not until you start designing and manufacturing things that you suddenly realise how much effort goes into them but, I persevered and over the period of about a week or so I had a perfectly fitting, operational cooling system that kept the amp super cool regardless of how long I waffled on for on the HF bands.
Once you’ve got your first design made you suddenly find yourself wanting to improve it and add things. In my case this was adding a Hermes Lite 2 holder to the top of the amp cooler and then a top shelf to hold my cross needle SWR and power meter.
Since then I’ve progressed massively with my designs and have even designed and printed things for other HAMs and family members, it’s totally addictive!
I can highly recommend the Bambu Lab A1 Combo (As shown above). It’s a quality piece of equipment that has operated faultlessly since purchase. Right now it’s printing a case for my RaspberryPi 4, just one of the many projects I’ve used it for since becoming a happy owner.
RaspberryPi 4 case from printables.com
Go on, release your inner creativity and treat yourself to a 3D printer, you won’t regret it and it’ll help you bring to life all of those radio projects you’ve dreamt of doing but, never got round to starting.
3: An AllStarLink Node
M0AW AllStarLink Node 61928 sitting on the equipment rack
Many people say that using VOIP over the internet isn’t real radio, I know because I used to be one of those people however, it has become an invaluable resource for keeping in touch with people all over the world.
Being part of an online HAM Radio Community it’s important that as a group we are able to talk to each other regardless of where we live, what bands we have access to and whether there is any propagation.
The AllStarLink (ASL) network gives global FM quality audio no matter where you are in the world. We use it daily for our breakfast net, general chatter throughout the day and even hold a weekly Matrix ASL Net on a Thursday evening.
Using our VHF/UHF handhelds (Real Radios!) and an easy to make AllStarLink Node we’re able to join in with the conversation regardless of propagation, licence type or distance, it really is great for bringing people together.
With devices like the SHARI and AIOC board now being readily available for minimal cost it really is very easy to get onto the AllStarLink network and talk to people even if you live in an antenna restricted location.
Why be alone when you can use the Matrix ASL node ( 642332 ) and join in the conversation.
4: Node-Red
M0AWS – Updated NodeRed QO-100 Dashboard with PTT button
Node-Red is a low-code programming tool for event-driven applications.
Node-RED’s goal is to enable anyone to build applications that collect, transform and visualise their data; building flows that can automate their world. Its low-code nature makes it accessible to users of any background, whether for home automation, industrial control systems or anything in between.
I’ve been using Node-Red for a number of years now and have developed a suite of web app’s that control and monitor just about every aspect of my Amateur Radio hobby and IT infrastructure.
Node-Red forms an integral part of my QO-100 Satellite Ground Station providing control of both the uplink and down link radios whilst synchronising the VFO’s, controlling filter selection and more, all from one simple to use interface using nothing more than a web browser.
It doesn’t stop there, my AllStarLink (ASL) nodes are also managed through a user friendly Node-Red Dashboard that removes all the need for technical know how and makes ASL node management as simple as clicking on a button to connect or disconnect to the many global networks.
Much of this functionality is achieved without writing a single line of code. If you can use a mouse, drag and drop objects on the screen you can develop Node-Red web app’s, it really is that easy.
M0AWS Interactive Log Flow
It doesn’t end there, Node-Red is great for presenting data in easy to digest formats.
Whether it be HAM Radio Log data presented on an interactive world map or monitoring of your server, RaspberryPi, virtual machine or UPS using gauges and graphs, this can all be achieved easily with nothing more than a mouse. There’s no need to spend hours writing thousands of lines of code, just drag and drop a few nodes onto the screen and join them up. You’ll be amazed how easy it is.
I believe every Amateur Radio enthusiast should have Node-Red available in their radio shack. It’s easy to install on your RaspberryPi 4 or 5, Linux or Windows PC and Apple Mac with the same great functionality available on all platforms.
Once you’ve developed your first web app you’ll suddenly find a million more ideas will come into your head and before you know it, you’ll be where I am today with Node-Red at the centre of your radio hobby.
5: A Hermes Lite 2 HF SDR Transceiver
For years I used black box HF radios from the big 3 manufacturers along with the odd radio from the smaller enterprises like TenTec but, they all had their foibles and there was often nothing I could do about it.
My last acquisition from the big 3 was a Yaesu FTDX10, a competent hybrid SDR radio with a good receiver however, the menu system is terrible, the button layout not much better and the user experience not as good as it could be. Of course the software is closed source so there is nothing you can do about it. The radio did its job but, it wasn’t fun to use, it wasn’t what I really wanted and it didn’t put a smile on my face.
I looked at moving to software defined radios (SDR) but, with prices in the many thousands of pounds bracket and the software being closed source I came to the conclusion that they wouldn’t give me what I really wanted either.
So what was it that I was searching for?
Thinking long and hard about it I came to the conclusion that what I really wanted was a radio that gave me the same satisfaction that OpenSource software has given me for decades, namely an HF radio that I have complete control over, from the hardware through to the software and everything in between.
I wanted something that I could tailor to my exact needs. Something that was built using open hardware and open software, something where if I wasn’t happy with it I could change it, improve it and do the things I wanted with it.
At this point my search for the ideal radio headed in a completely different direction.
Xiegu XPA125b Cooler with Hermes Lite 2 cradle – front view
The Hermes Lite 2 SDR HF Transceiver (HL2) has been around for a number of years. I was first introduced to it by Michael, DK1MI and then Roger, G8VLR via the Matrix. Both Michael and Roger use the HL2 on a regular basis and have often waxed lyrical about how good it is.
Being designed by radio amateurs for radio amateurs it’s based on an open architecture from the ground up. Being an OpenSource junky this really appealed to me and as I looked deeper into it from both a hardware and software point of view I soon realised that it had the potential to be exactly what I was looking for.
It wasn’t long before I found myself on the Makerfabs website placing an order for the HL2 mainboard, filter board, I/O board and case. A couple of weeks later it arrived and I dived head first into the SDR rabbit hole.
2 years later and the HL2 has become my main HF radio in the shack. Partnered with a Xiegu XPA125B amplifier and PiHPSDR software running on my Kubuntu Linux PC it is everything I have been looking for in an HF radio.
I’ve made modifications to the software to suit my operating style and needs with the user interface being exactly how I want it, no unnecessary buttons or knobs, just the controls that I use on a daily basis cleanly placed in a logical, easy to use layout, the way I want it.
My understanding of software defined radio and how it works has improved a hundred fold. Having access to the software and being able to go through the code and understand the architecture has been an interesting journey and one that has enhanced my radio enjoyment considerably. I now have a smile on my face every time I go on air.
Do I miss the FTDX10?
No, not in the slightest!
So, those are the 5 things that I feel have revolutionised my radio amateur hobby and made it a more enjoyable experience. I’m sure over time I will add to this list as I venture down future rabbit holes in our wonderful radio hobby.
I’m sure there are many radio amateurs around the world today who have an old handheld radio sat on the shelf that works perfectly but, has been replaced by a new, shiny, all singing, all dancing model that gets used on a daily basis. I for one have fallen into this trap with the recent purchase of a very nice Wouxun KG-UV9K full duplex 2m and 70cm handheld.
On my shelf there is a cheap Retevis RT85 that gave sterling service for a number of years and even today is ready to continue that service, if only I had a need?
Well now I do!
Currently I have an AllStarLink node running on a RaspberryPi 3b connected to a SHARI device that operates on the 70cm band. This node works great and gives me the ability to chat with people all over the world from my trusty handheld. It does of course also give me access to the weekly Matrix AllStarLink Net that happens on our Matrix node ( 642332 ) every Thursday evening at 20:00 UK time, a great way of bringing the Matrix HAM Radio community together regardless of propagation.
For some time I’ve been wanting to bring another AllStarLink node online so that I can have a connection to HUBNET/FreeNet whilst keeping my current node connected to the Matrix node for our regular daily chats. Since my new Wouxun handheld is a full duplex unit it makes sense to bring a new node up on the 2m band as I can then monitor both at the same time easily. I do have a spare SHARI node however, it’s a UHF only unit and I don’t want another node on the 70cm band. This is where the old Retevis RT85 comes in to play.
The AIOC board really is tiny but, beautifully put together. The four large solder pads on the top and more on the underside are positioned such that the TRS plug solder lugs line up perfectly for soldering. Attempting to do this by hand would be impossible as it’s critical that the spacing between the two connectors matches that of the spacing of the sockets on the radio.
AIOC Solder Jig.
Searching online I found a very handy soldering jig on Github that enables you to hold both the TRS connectors and AIOC board in the perfect position for soldering.
Downloading the .STL file I quickly printed off a solder jig on my Bambu Lab A1 Combo 3D printer and fitted the components into place ready for soldering.
Fitting TRS connectors into the AIOC solder jigFitting AIOC board into the solder jig.
Everything fitted rather snugly into the jig and I soon had the board and connectors soldered together. Test fitting to my Retevis RT85 I found the TRS plugs lined up perfectly and it slid into the sockets with ease.
I then thought about designing a case for the AIOC board so that the bare circuit was nicely protected but, quickly searched online and found that NA6D has already designed a case and made the .STL available publicly for download on Printable.com. I quickly grabbed a copy of the file and punted it off to my 3D printer to get to work on.
3D print NA6D AIOC case.
Once the print was complete I fitted the AIOC board and snapped it together ready for testing.
Fitting the AIOC into the 3D printed case.AIOC case with 2 x TRS connectors in place.AIOC case USB-C view
Now that the AIOC was production ready I moved on to getting the latest version of AllStarLink onto my RaspberryPi 4 that I had taken out of my RadioBerry based shortwave receiver that I am going to upgrade to a Hermes Lite 2 in a later project. The RaspberryPi 4 is perfect for AllStarLink 3, a 64bit app and operating system.
Using the RaspberryPi Imager I pulled the image down onto an SD card and slipped it into my Pi4. ( Instructions on how to do this are on the AllStarLink website here )
Booting the Pi4 for the first time I found that it went through a number of reboot and configuration cycles before it was ready for use.
AIOC connected to the Retevis RT85.AIOC connected to the Retevis RT85.
Once ready I went through all the normal configuration of the Pi4 namely, static IP assignment, timezone config, security, port forwarding etc etc.
Having configured an AllStarLink node for myself and only just a few days ago for another HAM I was pretty familiar with the setup. Wanting to make sure there were no “gotcha’s” I also watched a couple of KM9G’s videos on Youtube to make sure I wasn’t missing anything.
Using the asl-menu command line app as user root I set about configuring Asterisk to work with the AIOC board. Much to my frustration I could not get Asterisk to recognise the AIOC board as an available sound device. I checked and double checked all the settings ensuring that I had selected “AIOC” in the available devices menu but found that Asterisk constantly errored saying it could not find the selected audio device. This went on for a whole day without success and so, I decided to put it to one side and come back to it later, a method I found that often worked.
A couple of days later I revisited the problem and had decided to take a different approach. Rather than continue going through the asl-menu app I decided to drop down to a lower level and go through the asterisk config files in the /etc/asterisk directory.
It wasn’t long before I found a file called res_usbradio.conf. Inside this file was the config for the AIOC board however, it was all commented out which meant it was disabled.
I’m guessing here but, I imagine this is what should get enabled when selecting AIOC in the available devices menu in the asl-menu command line app but, for some reason it doesn’t happen.
[general]
;usb_devices = 1209:7388 ;comma delimited list of usb
;descriptors to allow.
;format vvvv:pppp in hexadecimal
;vvvv=vendor id, pppp=product id
;
;1209:7388 = AIOC (all in one cable)
Above is the disabled configuration which is easily edited to enable the AIOC device as shown below.
[general]
usb_devices = 1209:7388 ;comma delimited list of usb
;descriptors to allow.
;format vvvv:pppp in hexadecimal
;vvvv=vendor id, pppp=product id
;
1209:7388 = AIOC (all in one cable)
Once the updated file had been saved and I restarted Asterisk using systemctl the AIOC burst into life and Asterisk recognised it immediately. The Retevis RT85 switched between TX and RX and I was ready to check out the audio.
Setting the volume levels for both RX and TX via the command line tuning app I connected the node to my already existing node. Sure enough the two nodes connected without error and I was able to send and receive audio between them via the AllStarLink net.
Connecting the new node to the parrot I checked the audio levels to ensure it sounded ok and then connected it to the Matrix node where I had a brief chat with Ben, M8TKK.
All that is left to do now is to 3D print a case for the Pi4 so that it isn’t left naked and at risk of being shorted out on conductive surfaces and it’ll be ready for service.
I also plan to build another AllStarLink node using a 4m band handheld and another AIOC board and then will apply for MB7Ixx callsigns for the two new nodes. This will hopefully help to bring some life to the 2m/4m bands locally and introduce HAM’s both to the weekly Matrix Net and HUBNet/FreeStar via AllStarLink.
Following on from my previous article on using Node-Red to build interactive log maps I’ve now reworked the flow to make it more efficient with less Javascript.
The original flow had a function that handled the issue of FT4 contacts being recorded in two different ways depending on which app you use for your FT4/8 operations.
<mode:4>MFSK <submode:3>FT4
or
<mode:8>MFSK FT4
The code I wrote to handle this wasn’t particularly elegant and so I decided to remove the code entirely and just use a simple change node.
M0AWS New node to handle FT4 more efficiently
This is the great thing about Node-Red, there’s always more than one way to do something.
With this fix in place and the old code stripped out of the format generic payload function, the new flow is much tidier and easier to comprehend.
M0AWs Updated ADI Log Map flow
With testing complete and the two maps now live on my website the flow is finally ready for release into the wild.
If you fancy presenting your ADIF logs in a more visual, interactive format then just download the flow below and import it into your Node-Red flow editor.
Don’t forget that you will need to change the path to the log files in the file read nodes to suit your setup and change the location data in the My QTH trigger to match your callsign and location. Other than this the flow should just work.
I’ve not been on the radio much over the last few weeks as I’ve had my head down other radio related rabbit holes.
One of the rabbit holes is a Node-Red project to make my online logs a little more interactive. For sometime now my logs have been displayed on my website as nicely formatted, searchable HTML pages however, they don’t really allow the viewer (myself included) to see the global coverage of all the contacts so, I decided to write a Node-Red flow that would do just that.
M0AWS Interactive Log Flow
The flow itself isn’t too complicated and basically consists of reading in the individual ADIF formatted log files, processing the data and then sending the data in the correct format to the map node for display.
I’ve had to write a few functions to handle the processing of the ADIF formatted data but, these aren’t particularly complex and are fairly easy to understand even if like me, you’re not a Javascript programmer.
The flow is working perfectly however, I’m in the process of reworking the format generic payload function to reduce the amount of code and make it more efficient.
M0AWS SSB / CW / FreeDV Interactive Log World Map
M0AWS Interactive Log Map Layers Menu
The flow generates two maps, one for voice / CW /Satellite contacts and the other for WSJT-X FT4/8 contacts. Every pin on the map is colour coded by band with satellite contacts being denoted by a satellite icon.
Each pin / icon on the map is clickable and reveals the data of the QSO being displayed.
In the top right-hand corner of the map there is a drop down layermenu that allows the viewer to filter by band thus reducing the number of icons on the screen at any one time.
Seeing the data presented on a map really brings my logs alive. An example of this is that I had no idea I’d worked so many stations in India on the QO-100 Satellite.
The small icons in the pins show a microphone for SSB/FM/FreeDV contacts and a downwards pointing triangle in a box for CW contacts. Sadly I couldn’t find a Morse key icon in the collection available.
M0AWS filtered view of QO-100 Satellite contacts
I only use FT4/8 for testing new antenna designs however, it’s interesting to see the global coverage accomplished with this weak signal mode.
M0AWS WSJT-X FT4/8 Interactive Log World Map
Once I’ve finished rewriting the format generic payload function I will make the flow available for download here so that others can also create an interactive view of their radio logs.
If you want to have a look at the maps and try them out for yourself, they are available under the Logs menu above.
This Node-Red instance is running in a virtual machine (VM) on a 16GB RAM RaspberryPi 5 that is also running a number of other VMs at the same time so, it’s safe to say it’s not heavy on CPU and will run on the older Pi4 as well.
I’ve recently been trying out the FreeDV RADEv1 digital voice mode on the HF bands with great success. The audio quality is astounding when compared to the normal analog SSB mode. Using only 20w I’ve been surprised how successful I’ve been talking to stations in the UK and Europe as can be seen in my FreeDV Log.
FreeDV has been around for quite a few years with development being funded by an ARDC grant and financial sponsorship from the Software Freedom Conservancy.
“FreeDV is a suite of digital voice modes for HF radio. Our flagship mode is the Radio Autoencoder (RADE). You can run RADE using a free GUI application for Windows, Linux and macOS that allows any SSB radio to be used for high quality digital voice.“
And the most important part:
“All software is open source, released under the (a) GNU Lesser Public License version 2.1 (GUI and legacy FreeDV modes) and two-clause BSD license (RADE).“
FreeDV running under KDE-Plasma on Kubuntu PC
Looking at the digital voice (DV) community in the HAM Radio world, it’s stuffed full with proprietary DV modes from small software houses and black box transceiver manufacturers with no real OpenSource alternatives, until now.
Installing FreeDV is pretty simple regardless of which operating system (O/S) you use. Being a Linux user I grabbed the AppImage from the website and set about reading up on how it works and how it is configured.
I decided to take the two sound card approach since I have 2 USB sound cards connected to my shack Kubuntu Linux PC.
Configuring the audio routing isn’t straight forward as both the receive and transmit audio to/from the radio needs to be routed via the FreeDV app. To make this even more complicated I am using my Hermes Lite 2 SDR transceiver and PiHPSDR software, a complete OpenSource/OpenHardware Amateur Radio Station.
M0AWS FreeDV and PiHPSDR Audio Routing Diagram
Trying to clearly describe the audio routing using words alone would be impossible and very confusing so, I put together the diagram above.
Using two USB sound cards I’ve configured the system such that USB Sound Card 1 (an old Griffin iMic USB sound device) handles just the audio from/to the headphones and microphone. All the audio at this point in the system is analogue.
The second USB sound card, a cheap Plug and Play (PNP) USB audio device from Amazon, handles all the digitised signals from/to FreeDV and PiHPSDR.
Taking this 2 sound card approach keeps confusion to a minimum and separates the analogue and digital components of the audio routing.
So, how does this translate to the FreeDV and PiHPSDR audio settings?
Transmit Audio Chain
FreeDV Transmit Audio Settings
Starting at the beginning of the transmit audio chain, let’s look at the transmit audio settings in FreeDV.
Looking at the FreeDV Transmit audio settings screenshot below we can see that the Input From Microphone to Computer device is set to:
This is the digitised audio output from FreeDV (via USB Sound Card 2) to PiHPSDR and is used as the transmit audio that is sent to the Hermes Lite 2 transceiver.
FreeDV Transmit Audio Settings
PiHPSDR Transmit Audio Setting
To complete the transmit audio path we next need to look at the PiHPSDR transmit audio setting.
PiHPSDR Transmit Audio Settings
As can be seen in the screenshot above, the Local Microphone device in PiHPSDR is set to the Monitor of USB PnP Audio Device Analogue Stereo.
This effectively routes the digitised output audio from FreeDV (Output From Computer to Radio device) to the Input audio of PiHPSDR.
The reason for using the Monitor audio feed is because FreeDV does not recognise the Mic Input in PiHPSDR as a valid output device for FreeDV to use, hence we just need to monitor the FreeDV output device and use it as our input audio device in PiHPSDR.
This completes the transmit audio chain.
Receive Audio Chain
PiHPSDR Receive Audio Setting
Starting at the beginning of the receive audio chain we first look at the PiHPSDR receive audio setting.
PiHPSDR Receive Audio Setting
In the screenshot above we can see that the receive audio output from PiHPSDR is set to USB PnP Audio Device Analogue Stereo (USB Sound Card2). This is the DX station’s digitised audio as received by the Hermes Lite 2.
FreeDV Receive Audio Settings
Next let’s look at the receive audio setting in FreeDV.
FreeDV Receive Audio Settings
The Input To Computer from Radio device is set to the monitor of the USB PnP Audio Output Device:
This is the analogue audio output on the iMic USB Sound card (Sound Card 1) that routes the analogue audio to the headphones and completes the receive audio chain.
Summary
The audio routing required by FreeDV can appear very daunting when first attempting to configure it on the Linux platform but, hopefully the diagram and screenshots above will help in understanding the complete end-to-end audio chain that is required to make this mode work.
PiHPSDR can of course be replaced by your black box radio CODEC entries that will appear in the device lists shown above if you have your radio connected via USB. The config is basically the same but, just uses a different device instead of USB sound card 2 shown in the diagram above.
I hope this article is useful to those wanting to try FreeDV on the Linux platform and I look forward to hearing you on RADEv1.
For sometime I’ve been using PiHPSDR software to drive my Hermes Lite 2 (HL2) SDR transceiver. It’s a great piece of OpenSource software for SDR transceivers and has the best documentation that I have ever seen from an OpenSource project.
I must admit, I’ve had to make a few changes to get the software how I like it but, that’s the great thing about OpenSource software, you get the source code and can do what you like to it.
Following in this thread I recently decided to give DeskHPSDR a try. DeskHPSDR is a fork of the original PiHPSDR but, with some changes mainly aimed at larger display computers.
After compiling DeskHPSDR on my Kubuntu Linux PC in the radio shack, I found there were a few issues, mainly the colours were hard on the eyes and band/channel markers wrong/missing on a few of bands.
DeskHPSDR default colour scheme on Kubuntu 22.04LTS (KDE-Plasma)
I decided to dive in and take a look at the source code and try and sort out the colour issues as blue writing on dark buttons made them almost impossible to read under a KDE-Plasma desktop.
Delving through the appearance.c and css.c files I found that there were many changes required to get the end result I wanted. The biggest pain is that you have to recompile the source code after each change to see if the code change had worked, this results in many recompiles, a tedious task.
After spending many hours making changes I decided to email Heiko, DL1BZ who is the developer of DeskHPSDR. Over a number of emails we discussed getting the colour management code changed such that it was read in at start time from a separate css file rather than having to be compiled into the main program.
After a few emails back and forth, Heiko changed the code so that a separate CSS file could be read in at start up instead of the hard coded CSS in the C code files, this worked great and made it much easier to make colour changes without constant compilations of the code.
Next I needed to edit the bands.c file to change some of the band edge markers to show the UK band plan as, by default they are incorrect even though I have the region set to UK.
Editing the appearance.c file once more I was able to change the colour of the rather bright green panadapter signal display to a much more pleasing blue fading to red as the signal gets stronger.
One thing I really like about PiHPSDR was the channel markers on the 60m band. Anyone that uses the 60m band will know that the UK allocation is split into 11 different channels separated by spaces used by the primary user of the band. The channel markers make it just that bit easier to ensure you don’t stray out of the allocated channels however, this code had been removed from DeskHPSDR as Heiko didn’t consider it necessary.
Once again I pinged an email over to Heiko explaining how useful it is to UK HAMs and he very kindly put the code back into DeskHPSDR so that the 60m channels are once more clearly visible on the panadapter.
DeskHPSDR modified colour scheme on Kubuntu 22.04LTS (KDE-Plasma)
Feeling happy with the new colour configuration I decided to test it out on Linuxmint Cinnamon. Sadly the scheme that looked so nice under Kubuntu 22.04LTS didn’t look the same under Linuxmint and so I had to set about coming up with a version of the CSS file for this platform too.
After quite a few hours tinkering with CSS code I found it to be impossible to get the colour scheme on Linuxmint Cinnamon Edition identical to that I’d created under Kubuntu KDE-Plasma so, I settled for a look that was as close as possible.
DeskHPSDR on Linuxmint Cinnamon Edition with colour modifications.
Chatting with Steve, M0XVT we thought it would be a good idea to test it on his Kubuntu Linux and Linuxmint PCs. He is using a later version of Kubuntu than I am (24.04LTS) and so, it would be a good test to see if the colour scheme looked the same.
Sadly it turns out that for some bizarre reason the colours come out different in the later version of Kubuntu. This is a real nuisance as it means we’d need a separate colour scheme defining for each version of the O/S. Perhaps using CSS isn’t the best way to define a colour scheme in applications.
For some very strange reason the colours were also rendered differently on his Linuxmint PC even though he was using the same version of the O/S as I am.
DeskHPSDR running on Kubuntu 24.04LTS with colour scheme not rendering correctly
Another issue was found whilst testing on Steve’s computers which seems to be caused by the fact he uses an Anan 200D SDR.
Looking at the documentation on github in theory DeskHPSDR should support the Anan range of SDR transceivers however, we found that it’s impossible to select the sample rate as the drop down selection list is completely missing from the Radio menu with the radio defaulting to its lowest sample rate of 48k resulting in not being able to see the full spectrum of frequency ranges on the bands.
DeskHPSDR Sample Rate drop down missing when using an Anan SDR
The other thing to note is that the Remote Server functionality has also been removed from the code by Heiko as he feels it’s not necessary. This may be a deal breaker for some and so they may choose not to use DeskHPSDR and to continue using PiHPSDR instead.
I will at some point make the O/S specific CSS files and source code available for download for those that want to use DeskHPSDR with my colour scheme changes.
I’m not sure at the moment whether I will continue using DeskHPSDR or go back to PiHPSDR, time will tell.
Back in January 2025 I wrote an article about a little RadioBerry Project I’d started that was based around a very old Philips 170A-15 receiver from 1946.
The idea of the project was to build a nice shortwave receiver for the radio shack based around the RadioBerry HAT on a RaspberryPi 4 housed in a vintage receiver cabinet.
The project has taken longer than I imagined due to getting side-tracked by other projects that I already had ongoing.
With the original internals removed there’s plenty of room inside for the RadioBerry, RaspberryPi 4 and the small 15w audio amplifier. The audio is delivered via a pair of Celestion speakers that I had that were originally part of an old surround sound TV system.
Power distribution is achieved very simply using a multi-plug adapter that also has USB A connections in it. The whole thing is then powered via one 240v mains cable.
The screen fits over the original opening for the glass tuning display and is held in place by two mounting screws on the rear of the LCD panel.
I purchased some new speaker grill cloth from Amazon and remade the speaker grill front with cut outs for the speakers. It looks really tidy and matches the rest of the bakelite cabinet nicely.
1946 Philips 170A-15 Shortwave Receiver RadioBerry HAT on RaspberryPi 4
To finish the project off I need to purchase 3 rotary encoders so that I can have a VFO knob and two more knobs for other things (to be determined). The Volume control is already in place with the original knob fitted to it. It will be nice to complete the 4 knob line up.
I had to make a couple of fittings top and bottom to hold the original rear panel in place but, it worked out just fine and I only had to fit an SO239 antenna connector and ethernet RJ45 port so that it can be connected to my local LAN.
Receiving radio Caroline on 648Khz
The audio quality from the little RadioBerry and 15w amp is pretty good. With the speakers hidden nicely behind the refurbished speaker grill the project looks quite tidy!
It also makes a great receiver for the HAM bands with it’s coverage of 100Khz to 30Mhz.
The DL1YCF Enhanced fork of PiHPSDR works really well on the touchscreen and provides a modern control interface to the RadioBerry HAT.
Listening to the 20m HAM Band
I’ll drop a final article once I have purchased the 3 rotary encoders to fill the 3 remaining holes in the front of the cabinet.
Over the last few weeks I’ve been working on my install-pihpsdr script to build a version of the DL1YCF PiHPSDR fork that will work with the Adalm Pluo, Pluto+ and LibreSDR transceivers.
Since I don’t own any of these devices, Steve M0XVT has loaned me his Adalm Pluto and LibreSDR devices to test with.
Initially neither of the devices would work with the PiHPSDR build that my script was creating. After some investigation I found this was due to the fact that the developer build script was only building the SOAPYSDR library, it wasn’t building the modules for each device type.
This was easily fixed by adding some extra code that would build the necessary SOAPYSDR modules so that the devices were discovered on the local LAN.
Since I had the devices to hand I took the opportunity to test the updated build script on a number of Linux Distro’s that I have to hand.
PiHPSDR running on Linuxmint 22.1 Cinnamon Edition using the LibreSDR transceiver
I tested the updated build script on Kubuntu 22.04LTS, Linuxmint 22.1 Cinnamon Edition and RaspberryPi 4/5 running the latest RaspberryPi OS 64bit version.
These all worked great with the transceivers and will now make a great platform for QO-100 stations that use either the Adalm Pluto, Pluto+ or LibreSDR devices.
Of course this build of PiHPSDR will also work with the Hermes Lite 2 and RadioBerry devices that I use most of the time in my own radio shack.
The updated PiHPSDR install script can be downloaded from my original blog article on the subject that is located here: https://m0aws.co.uk/?p=3686
The updated build script will most likely work on most Debian based Linux distro’s and build a working version of PiHPSDR. If you find a distro where you have problems please email me and let me know the details and I’ll happily look at the issue and try to resolve it.
Thanks to Steve for the loan of his precious SDR transceivers, I had a lot of fun with them!
More soon …
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