Devices – M0AWS Amateur Radio

1 October 20264 October 2026

piHPSDR-Improved – Our First Release

piHPSDR-Improved Logo from The Three Amigos Development Team

For some time now Steve (M0XVT), Alan (G1SQB) and I have been working on a version of piHPSDR to use with our Hermes Lite 2, Anan 200D, Adalm Pluto, Pluto+ and LibreSDR transceivers. The biggest problem we’ve had is the constantly changing code on github that often would stop the software from working on one device or more each time we updated and then we’d have to spend hours finding the issue and fixing it.

Eventually we got tired of this and decided to build our own stable version that doesn’t get anything from github and is made up of all the parts necessary to create a version that just works on the devices that we use on a daily basis.

Using piHPSDR on the QO-100 satellite and the HF bands across a number of very different types of hardware is a challenge in itself, especially when the devices use different protocols and only certain library sets work with certain firmware on some devices, the combinations get complicated to say the least.

To differentiate our build of piHPSDR from all the others available on the internet today we decided to call it piHPSDR-Improved.

So what is piHPSDR-Improved?

piHPSDR-Improved is a version of piHPSDR that has the fixes and enhancements in it that we’ve dreamt of having over the last couple of years. Some of the fixes are simple things like being able to detach the toolbar from the main window thus giving more space for the two panadapter/waterfall displays and have all the toolbar buttons on another screen in a floating toolbar. Other enhancements were more involved and addressed some of the most annoying issues like none of the settings for VFOB (RX2) were saved and so, every time you started the program you had to setup the RX2 all over again from scratch. These sound like simple fixes but, believe me, they’re not.

Another thing we wanted to do was make piHPSDR-Improved easy to install. Many Windows users transitioning from Windows to Linux often regret it the moment they have to use the Linux command line to install piHPSDR.

We’ve committed to having GUI installers for all the applications that we develop and release, regardless of how much extra work this entails.

It’s time installing software on Linux desktop PCs was as easy as it has been on Windows PCs for decades.

We’ve taken a modular approach to building piHPSDR-improved. Rather than putting everything into the one application, we’re going to be releasing add on modules that will bring new functionality over time. This way we can build on a structured, stable base keeping everything operational all of the time.

The first module we’re releasing is piSync and we’ve included it in the zip file that you’ll download to install piHPSDR-Improved.

piSync Logo

piSync adds functionality to piHPSDR-Improved that Windows Thetis users have had for a long time, namely the ability to use an online WebSDR along side their own SDR transceiver and have it track the frequency, band and mode automatically. This functionality has proven to be incredibly useful when you are struggling to hear a weak DX or QRP station.

With piSync you can now use an online WebSDR receiver closer to the DX station to aid getting that QSO in the log. It’s like having another receiver in your radio that is located anywhere in the world, for free!

We believe this is a first for the Linux platform and we’re really pleased to be able to share it with the Linux community.

We’ve had great fun with piSync during testing and we think you’re all going to find it extremely useful too.

We’re also planning on adding support for FLRig in the next version of piSync so that you’ll be able to use a WebSDR with any transceiver that is supported by FLRig.

Of course it goes without saying, all of our software is Opensource. When you download and install piHPSDR-Improved or any of the new modules you will get the full source code every time and be free to do whatever you like with it. Every module will also have it’s own GUI installer, no more command line, just double click and go.

Both piHPSDR-Improved and piSync have been tested on RaspberryPi 5/500+, Linuxmint Cinnamon, Kubuntu, Debian 12 (Bookworm) and Debian 13 (Trixie) so, we’re pretty confident it’ll work on most Debian/Ubuntu based Linux distro’s on Intel/AMD PCs and the current versions of the RaspberryPi SBCs.

piHPSDR-Improved, piSync and a WebSDR running on a pi 500+

Inside the zip file you’ll find a file called README.1st, do make sure you read this before installing any of the software as it contains some important information that’ll make installation as easy as possible.

To download both piHPSDR-Improved and piSync in an easy to use zip file, just click the Download button below.

piHPSDR-Improved-v2.42-and-piSync-v0.6 Download

We’ve got lots of ideas for new features, modules and bug fixes (Yes there are still some bugs in there!) which we will be releasing over time. Don’t expect this to happen overnight as Steve still works full time and Alan and I are both enjoying our retirement.

This is just another facet of our hobby and we don’t like to rush things. We do like to use our radios on air, pretty much daily and so we do this software development in between all the other fun things that Amateur Radio has to offer.

To be clear and open we do use Claude Code to help with development. I go through as much of the code as I can without spending days and days just reading code. I am retired after all and have spent enough of my life professionally writing and debugging both my own code and other people’s code. We do a lot of testing on a good number of Linux distros before we even consider releasing the software to the wider world and use it on air as part of the testing process, so we’ve done as much as we can to ensure we’ve not introduced new bugs to the software. Keep in mind we do this as part of our Amateur Radio hobby and so, it needs to be fun and enjoyable.

We hope you enjoy using the software and find it useful. If you’ve got ideas for new things you’d like to see in future versions then please feel free to contact any of us via our contact details on QRZ.

UPDATE: We’ve fixed a little bug in piSync and released an updated version. You can download it from this article.

More soon …

1 September 2026

Building a new Pi Rack

I’m a big fan of the RaspberryPi single board computers (SBCs) and have been using them since the very first model was released. (I still have the first model even now!)

Over the years I have used RaspberryPi computers for all sorts of things. These days I use them for running services on the local LANs here at home along with a number of virtual machines providing services both locally and publicly on the internet. (Yes, you can run virtual machines (VMs) on RaspberryPi computers)

I currently have 4 x RaspberryPi 5 SBCs running 24/7 and have had them stored in a simple rack that I designed when I first got into 3D printing. The rack worked ok but, it was difficult to get access to the Pi’s without removing those around the one I wanted to access. This is a real nuisance when you have services running on them all.

I’ve now had my 3D printer for a while and decided it was time to design a better solution. Before I set about diving into the CAD software I decided to have a look on Makerworld to see if anyone else had already come up with something more suitable.

Trawling through the many offerings from hundreds of 3D designers on the Makerworld website, I found a very nice RaspberryPi Modular Racking System that looked ideal for the job.

Modular RaspberryPi Rack from Makerworld

The nice thing about this design is that each Pi module connects to the other using a simple sliding, locking pin system. This means that over time you can add more and more modules to the rack as your RaspberryPi collection grows. The other nice thing is that each Pi SBC is held on its own removable sled making it possible to remove each Pi with ease and without disturbing any of the others.

I downloaded the design into BambuStudio and went through all the component parts. I was really pleased to see that there were two sizes of module available, a single board Pi only module and a tall module for housing a RaspberryPi with a HAT installed.

Since the 4 x Pi5’s that I am using have either an NVME + 2nd Gigabit Ethernet HAT or a NVME SSD Baseboard installed I will need the taller module for each unit.

To make it easy to identify each SBC in the rack I printed each module in the same colour as the hostname of the Pi, bluepi, redpi, greenpi, orangepi and a spare slot for purplepi when I get it.

My RaspberryPi rack with 4 x Pi5's in place and operational — My RaspberryPi rack with 4 x Pi5’s in place and operational

These 4 little Pi’s work hard and CPU temperatures can exceed 50 degrees Celsius very easily. They all have the Official Pi Cooler with fan installed however, this doesn’t come on until the CPU reaches 50c and so I decided to added some extra cooling in the form of a small USB fan onto the back of each module. This reduces the operating temperature of each Pi down to around 25c under full load.

The purple slot on the end is a spare ready to house another Pi SBC. I’d love another Pi5 16GB model but, at the current ridiculous prices it makes no sense to invest in another and so I will fit my spare Pi4 into the slot for now and find something for it to do.

This has been a fun little project to print and put together and will provide the perfect solution to my Pi management woes.

More soon …

23 August 2026

Building MB7IBW 2m AllStarLink Internet Gateway

I’ve recently built another AllStarLink node to compliment my personal 70cm band SHARI node as I thought since I have a full duplex dual band handheld it would be great to have another node that I could connect to FreeStar or HUBNet at the same time as monitoring the Matrix node.

Rather than build another personal node I decided this time I would build a public node, obtain a callsign from the RSGB and make it available to the HAM’s locally on the 2m band.

This would make it possible for me to monitor both nodes at the same time using my Wouxun KG-UV9K full duplex dual band handheld whilst providing the local HAM community with access to the AllStarLink network.

Initially I thought I may be able to use my old Retevis RT85 handheld and AIOC board for the 2m node but, after a little testing it soon became apparent that it overheats during long overs (which are common on AllStarLink) and so, I needed to find another solution.

Chatting about this in the main Matrix HAM Radio room Steve, M0XVT sent me a message saying he had an old Key KM-4000 converted PMR radio that had been reprogrammed for the 2m band that he was looking to sell and that it might be ideal for the new node. Wasting no time, we came to an agreement and I was soon the proud owner of a converted PMR transceiver.

The KM4000 transceiver has a standard output of 15w, 10w more than I needed for the gateway and so I had to reduce the output. A quick search on the internet and I found the Thames Valley Repeater Group website that had all the information required to turn down the output.

I also had to reprogramme channel 1 to the frequency and CTCSS tone allocated to me by the RSGB so that in the event of a power outage when the radio came back on it automatically jumps to channel 1 which would be correctly setup for operation.

Unfortunately the software for programming the radio is only available for windows and so I had to build a virtual machine running windows 10 to be able to reprogramme the radio.

Once this was done I rewired the AIOC USB audio device to work with the KM4000 radio and built the AllStarLink node on a spare RaspberryPi 4.

For an antenna I made a simple end fed vertical dipole from some RG58 coax and mounted it 8m up on one of my Spiderpoles in the garden. Running a coax feed out to the antenna I did some tests into the Parrot to get the audio levels setup and checked that the DTMF codes were interpreted correctly and that the node switched connections without error.

MB7IBW Internet Gateway hardware at the M0AWS QTH

Once this was done I had a few test conversations with stations on the Matrix node and FreeStar to ensure all was fine and then set the gateway status to “Operational” on the RSGB website.

This worked fine for a while with myself and some local stations using the node regularly but, then the hot weather arrived and things started to overheat. The transceiver was getting incredibly hot in the 30c+ summer temperatures and the power supply was also running extremely hot and so I decided to add some cooling.

Cooling the PSU was simple, it has a perforated top panel to which I strapped a cooling fan. This worked great and brought the temperature of the PSU down considerably.

The radio wasn’t so easy to cool. It has a solid case cover top and bottom and so cooling wasn’t going to be a simple affair.

I decided to remove the covers and drill some holes into them to allow airflow through the unit and strapped a fan to the top cover to pull the hot air out. This worked well however, on both transmit and receive I now had a warbling sound on the audio that was caused by the motor of the fan when powered up.

I found that lifting the fan up away from the case of the radio the warbling audio disappeared and things were back to normal and so, I decided to design a cooling tube to fit to the top of the radio to allow full airflow from the fan but, with the fan raised up away from the radio to resolve the audio problem.

Jumping into my CAD software I quickly designed a cooling tower to fit on the top of the radio that would allow the fan to sit far enough away from the radio so as to not affect the audio whilst at the same time pulling the hot air out of the radio and drawing cooler air in through the bottom of the case.

I sent the design through to my Bambu Lab A1 Combo 3D printer and set the print job running.

The cooler worked great with the radio staying cool to the touch and no longer overheating and reducing O/P power.

It’s amazing how much dust and dirt is in the air from all the farming activities going on at the end of our garden and how much of it is sucked in by the cooling fan. Regular cleaning is a must!

The MB7IBW Internet Gateway has been on air since mid June 2026 and has worked well. It spends most of its time connected to either FreeStar or HUBNet with connections to the Matrix Node when we have our nets.

Details on Frequency, CTCSS etc can be found under the MB7IBW menu above.

Sadly the initial interest from local HAMs has now wained and I am mostly the only user of the gateway. I was hoping more people would use it and bring some life to the 2m band, I guess time will tell.

It’s been a fun project and was interesting to go through the callsign allocation process with the RSGB representative. It was much easier than I thought it would be.

I now have all the parts to build another Internet Gateway for the 4m band. Hopefully that may attract some more interest. It’s certainly worth a try!

More soon …

30 May 20263 June 2026

Node-Red Dashboard for AllStarLink 3 Nodes

I’ve spent some time this afternoon modifying my Node-Red Dashboard for controlling AllStarLink nodes to work with the new AllStarLink version 3.

My original AllStarLink Control Dashboard was designed to work with AllStarLink 2 which I have running on an old RaspberryPi 3b on the 70cm band. The dashboard has worked reliably ever since deployment and is in use daily.

With the release of AllStarLink 3 and all the changes that it entails I’ve had to make a few changes to the dashboard flows in order to make it compatible with AllStarLink 3 nodes.

This entails not only flow changes but also the addition of two new bash scripts that are called by Asterisk to log connect and disconnect messages as they are not logged by default any more. (Seems a bit of a step backwards)

Node-Red AllStarLink Control Dashboard v3.0 for ASL3

The changes also entail disabling the temporary filesystems used by default in the new ASL3 build so that log files etc become persistent.

I’ll spend some time using the new dashboard to ensure it’s working correctly and then will release it into the wild for all those that are brave enough to move over to AllStarLink 3.

More soon …

14 December 202515 December 2025

FreeDV audio routing with PiHPSDR and Hermes Lite 2

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.

So what is FreeDV?

To quote the FreeDV website:

“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:

alsa_input.usb-Griffin_Technology_Inc_iMic_USB_audio_system-00.analog-stereo

This is the microphone connection on the iMic USB device (USB Sound Card 1) and is the analogue transmit audio input to FreeDV.

The Output From Computer to Radio device is set to:

alsa_output.usb-0c76_USB_PnP_Audio_Device-00.analog-stereo

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.

PiHPSDR Transmit Audio Setting

To complete the transmit audio path we next need to look at the PiHPSDR transmit audio setting.

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.

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.

The Input To Computer from Radio device is set to the monitor of the
USB PnP Audio Output Device:

alsa_output_usb_0c76_USB_PnP_Audio_Device-00.analog-stereo.monitor

This effectively routes the digitised audio output from the PiHPSDR receiver to the digitised audio input of FreeDV.

Once again we have to use the monitor of the USB PnP Audio Output device as FreeDV does not recognise the PiHPSDR output as a valid input device.

Next, the Output From Computer To Speaker/Headphones device is set to:

alsa_output.usb-Griffin_Technology_Inc_iMic_USB_audio_system-00.analog-stereo

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.

More soon …

17 April 202517 April 2025

Updates to my install-pihpsdr.sh script

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 …

29 January 202529 January 2025

Breathing new life into a vintage receiver

Sometime back I purchased a RadioBerry HAT for my RaspberryPi 4 single board computer (SBC) to use as an experimental platform to test PiHPSDR software modifications and to test changes to the actual RadioBerry software. With these two projects completed I decided that the receiver on the RadioBerry was so good it would be a shame not to put it to good use.

For many decades I’ve been an avid Short Wave Listener (SWL) but, haven’t had a general coverage receiver for many years. The RadioBerry fills this gap in my radio lineup perfectly but, needs to be put into a suitable cabinet with speakers, display, control knobs and antenna connections.

Rather than just buy another bland square box I decided it would be nice to repurpose an old, vintage radio receiver from a bygone era and bring it into the 21st Century.

1950 Philips valve radio receiver — 1946 Philips valve radio receiver

After much searching on the popular auction sites online I eventually found the perfect old receiver for the project, a vintage Philips 170A-15 valve receiver from 1946.

This lovely old Art Deco looking receiver is made from Bakelite which was an early type of plastic made from phenol-formaldehyde resin, obtained from coal tar and methanol.

The full specification for the receiver can be found on the Radio Museum Website.

Sadly this is a non working example of this lovely old receiver and so I don’t feel so guilty stripping it out and replacing it’s internals with the RadioBerry.

1946 Philips receiver Serial Number plate

1946 Philips receiver Licence Plate — 1946 Philips receiver Serial Number plate

Having the original serial number and Licence plate on the radio is nice, it also makes it easy to search for information about the old receiver.

One nice thing I did discover during the disassembly of the receiver was the signature of the person that put the radio together during manufacture on the inside of the Bakelite cabinet.

Getting the internals out of the cabinet was fun, so many little screws holding the old valve electronics and tuning display in place.

1946 Philips Receiver - Internal View — 1946 Philips Receiver – Internal View

1946 Philips receiver - removing the original control knobs — 1946 Philips Receiver – Internal View

Once the electrical part of the radio was removed I gained access to the old speaker that was fitted to the front panel of the receiver. Unfortunately the speaker cone had a tear in it rendering it useless so I’ll need to get a new speaker(s) for the rebuild.

Once I got the speaker and fittings removed I set about cleaning the cabinet inside and out to remove the 79 years worth of dirt and grime that had collected within. The fascia of the receiver cabinet seems to have lost it’s shine and will need to be polished to get it back to it’s original beauty.

79 years worth of grime and dirt to be removed!

Washing the Bakelite receiver case — 79 years worth of grime and dirt to be removed!

It took 5 lots of fresh water and washing up liquid to get the cabinet clean. The first three lots of water looked like mud in no time at all such was the state of the cabinet.

With the cabinet now cleaned and put to one side to dry thoroughly I have started to search for the best type of polish to use to put the sheen back onto it.

Once I’ve got the cabinet looking good again I’ll start fitting the new internals. I also need to find a source for a new piece of material to cover the speaker hole at the front of the cabinet as the original material is looking somewhat tired.

The old Philips Emblem from 1946 on the receiver case

More soon …

19 January 202511 August 2026

Hermes Lite 2 and Xiegu XPA125B Auto Band Switching

Since I’ve had my Hermes Lite 2 (HL2) and Xiegu XPA125B amplifier combo I’ve had to manually change the band setting on the amp as I never purchased the HL2 I/O board when I initially purchased the kit.

At the time I didn’t think I would need it but, changing band manually on the amp (and sometimes forgetting causing tuning issues) is a nuisance and so I put my hand in my pocket once again and ordered the I/O board for the HL2.

The HL2 I/O board is a small RaspberryPi Pico controlled device that can be used for a multitude of functions depending on the software loaded. Many people are writing their own software for the Pico to do things like control transverters, remote antenna switches, amplifiers and just about anything else you can think of. It’s a really versatile little add on board for the HL2.

The I/O board arrived after about 10 days from Makerfabs, all nicely packaged as always. Unfortunately due to Christmas, New year and other priorities it’s sat in the box since it arrived.

A couple of days ago I finally got round to getting it out of the box and set about configuring it to control the Xiegu amp.

The Xiegu amp needs three connections from the I/O board. They are PTT, Band Switching Voltage and Ground. These are easily accessed from the I/O board via 3 jumper wires to connect to the DB9 connector on the rear of the board.

The other thing that is required is some software for the RaspberryPi Pico to control the whole process. Steve, M0XVT has kindly supplied me with a copy of the software.

Soldering the jumpers from the relevant points on the circuit board to the DB9 connector was pretty straight forward. You can use any of the pins on the DB9 connector that you like as from the factory the DB9 connector isn’t connected to anything. I decided to use pins 2, 6 and 8 and so will refer to those pins from this point forward.

I used a different colour for each of the jumpers so that I knew which jumper was for which connection. The colours used also match the colours of the wire in the old RS232 serial lead that I cannibalized to make the connection between the I/O board and the amp thus making it easy to ensure continuity.

The colours are as follows:

Black Jumper - Ground - Pin 2 on DB9 Connector
White Jumper - PTT - Pin 6 on DB9 Connector
Red Jumper   - Band Control - Pin 8 on DB9 Connector

The I/O board gets its power feed directly from the HL2 main board however, the 3 pins it needs to connect to don’t have any headers in place and so, it’s necessary to solder a short row of 3 header pins onto the HL2 main board.

I found the easiest way to do this was to put the 3 header pins into the correct position and then use the HL2 to N2ADR filter board connector to hold them in place whilst soldering. This worked perfectly and I soon had the header pins soldered onto the main board.

Extra 3 header pins soldered to the main HL2 board

It’s important to note that the 3 extra header pins need to be placed 2 holes away from existing header pins as shown above. Take care to get these pins in the right position so as not to cause any damage to the 3 circuit boards once all are connected and powered up.

Note: The HL2 main board must be removed from the case to solder the extra 3 header pins in place. Take care to ensure the correct fitting of the PA heatsink when when refitting the HL2 main board into the case.

At this point I refitted the N2ADR Filter board back into the HL2 case so that the two sets of header pins aligned correctly ready for the placement of the new I/O board that would connect all 3 circuit boards together.

Preparing the N2ADR Filter board for reconnection

Once the filter board was in place I fitted the new I/O board taking care to ensure all pins aligned with the socket and then gently pushed it home.

Close up of the HL2 I/O board fitted to the main HL2 board and N2ADR Filter board

The close up of the I/O board connector above shows how the extra 3 header pins connect to the last 3 sockets in the I/O board connector. It’s a snug fit with the N2ADR filter board below it.

View of the fitted HL2 I/O board from above

Before the HL2 case can be put back together it’s necessary to load the software onto the RaspberryPi Pico (top left in photo above) that controls the I/O board.

This is accomplished by pressing the tiny button on the Pico whilst connecting a USB lead to the USB socket on the board that had already been plugged into my PC. Once connected the Pico appeared as a USB drive on my Kubuntu Linux desktop. All I then had to do was to copy the software file onto the drive. Once the software file is on the drive the Pico will reboot automatically and the little LED on the board will start to flash to show it has booted successfully. At this point I could safely unplug the USB cable.

The software for the RaspberryPi Pico is available for download below.

main-uf2 Download

The I/O board comes with a new back panel for the HL2 to accommodate the extra connectors on the rear. Refit the top of the HL2 case and then attach the new rear panel using the original 4 counter sunk screws.

Supplied HL2 I/O board replacement rear panel fitted to the HL2 case — Supplied HL2 I/O board replacement rear panel fitted to the case

The final part of this project is to make the lead that will go from the HL2 rear DB9 ACC connector to the Xiegu XPA125B mini din ACC socket.

For this you will need a 6 pin mini din plug (AKA PS2 plug), (these are readily available on Amazon) and an old fashioned DB9 female connector from the days of RS232 serial leads..

The connections are as follows:

DB9 Pin 2 (BLACK) to Mini Din Pin 6 (GND)
DB9 Pin 6 (WHITE) to mini Din Pin 2 (PTT)
DB9 Pin 8 (RED) to Mini Din Pin 3 (Band Switching Voltage)

Below are a couple of screenshots from the Xiegu XPA125B user manual showing the Mini Din pin layout and the data interface connections for the amplifier.

Xiegu XPA125B Amplifier ACC Interface Connections

Xiegu XPA125B Amplifier ACC Connector Pin Information

Before I connected the lead to the two devices, I tested the end-to-end continuity of the lead to ensure all pins were correctly connected and that there were no shorts between any of the pins.

It’s important that the wires are connected to the correct pins on each end of the lead. Failure to ensure correct connection could cause damage to your HL2 and/or amplifier.

Once the lead had been tested, I connected it to both the Hermes Lite 2 and the Xiegu XPA125B amplifier. I also had to switch the amplifier band switching to AUTO.

Now when I change band on my HL2 in the PiHPSDR software the amplifier also changes band at the same time keeping the two devices in sync. No more manual band changing for me!

I hope this article is of use to other Hermes Lite 2 users who have purchased the Xiegu XPA125B but, have yet to setup auto band switching between the two devices.

Thanks to Steve, M0XVT for all the jumper information and the RaspberryPi Pico Software to get this all working.

UPDATE:
The RaspberryPi Pico software originally came from Ramon, KP4RX. More information can found in this Google Groups article where he released the binary into the wild.

A full table of I/O resources available on the HL2 I/O board can be found on the KP4RX Guthub page.

The source code for the main.uf2 file above can be found at KP4RX.com

More soon …

10 December 202413 May 2025

Using the DL1YCF version of PiHPSDR with the RadioBerry

(This information is also for the Hermes Lite 2, Adalm Pluto, Pluto+ and LibreSDR)

During my RadioBerry build I started out using the version of PiHPSDR that was created just for the RadioBerry. The problem with this is that it is hard coded for a very small screen making it hard to use on a big screen since the user cannot resize the window dynamically.

I decided to look for a forked version of the PiHPSDR software that had the ability to change the window size to suit all use cases. During my search I stumbled across the DL1YCF fork of the source code that has some enhancements, one of which is the ability to change the display size.

In no time at all I had the source code downloaded and compiled only to find that it didn’t work with the RadioBerry. After some investigation I found that this was due to the fact that the RadioBerry software has compiled into it code that is used to access the GPIO pins on the RaspberryPi so that it can communicate with the RadioBerry HAT. This is fine except that the DL1YCF version of PiHPSDR also has code in it to use the GPIO pins. This of course causes a conflict and the net result is that nothing works.

Reading through the source code and Makefile I found that all I needed to do was to compile a version of PiHPSDR without GPIO support. This would then remove the conflict and allow the RadioBerry software to operate correctly.

To this end I put together a download/compile/install script for the DL1YCF version of PiHPSDR that will work on a RaspberryPi with a RadioBerry HAT and give the ability to resize the window to fit any size screen.

The script also works on a Linux Desktop PC running Ubuntu/Kubuntu/Linuxmint/Debian operating systems. (It will most likely work on other distro’s too but, these are all I have to hand currently). You can of course also use this software with a Hermes Lite 2 transceiver.

DL1YCF PiHPSDR running on RaspberryPi 4 with RadioBerry HAT on a large monitor

To install this enhanced version of PiHPSDR on your RaspberryPi/Desktop PC with GPIO support disabled, download the installation script below, unzip it and run it in a terminal on your RaspberryPi/Desktop PC in your home directory. (/home/<your-username>).

The script will download the latest source code from the DL1YCF github, disable the GPIO code and then compile and install it to your computer. If installing on a RaspberryPi it will create an icon on the desktop for you to use to start the software.

If installing on a PC then you will need to create your own desktop icon as the one created only works on a RaspberryPi. You can of course just start the software from the command line in a terminal. (My preferred method).

If you have a RaspberryPi 5 then I highly recommend that you run this version of PiHPSDR on it as it has a lot more computing power and handles using dual receive with ease. It will run on a Pi4 but, you will load the CPU more as it’s not as powerful as the later model Pi5.

The script will ask if you want to compile in SOAPYSDR support so that PiHPSDR will work with RTL-SDR, Adalm-Pluto, Pluto+ and LibreSDR. Enter Y to compile in support or N if you don’t need it.

install-pihpsdr-v22-update Download

I hope this proves useful to all the RadioBerry, Hermes Lite 2 and Pluto users out there who want to use PiHPSDR on a big screen.

More soon …

19 November 202429 November 2024

Another new radio!

Many years ago when I lived in France I had a Flex-3000 transceiver, one of the first fully SDR transceivers on the market. It was paired with a proprietary Windows XP application called PowerSDR (now Opensource and called Thetis) and connected via a firewire connection.

17 years later I am once again venturing into the world of SDR transceivers in the form of a Hermes Lite 2. (HL2)

The HL2 hardware is available via the Makerfabs website in kit form. I ordered the HL2 motherboard, the N2ADR Filter Board to ensure a clean signal from the transceiver and the enclosure. Total cost for all the parts and shipping was £288.00 including all taxes.

The kit took about 10 or so days to arrive and was very easy to put together making sure to fit the PA transistor heat sink the right way round so that it doesn’t short out the main board. (There are many videos about this on YouTube)

Once the hardware was put together I needed to install some software to control/drive the HL2. Being a heavy weight Linux user my software choice had to come from the Opensource world.

M0AWS Hermes Lite 2 SDR Trasnceiver and Xiegu XPA125B Amplifier

After much research and chatting with other HAMs on the Matrix who have the HL2 I found that most people use the closed source SDR Console software to control the transceiver. Since this software is for Windows it’s not something I can use as I don’t have any Windows PCs, they’re all Linux only.

To this end I started researching Linux SDR software for the HL2 and decided that PiHPSDR was the one I was going to try first.

PiHPSDR was originally written for the RaspberryPi 3/4/5 single board computers (SBCs) but, I wanted to have a go at compiling it on my Kubunu Linux desktop PC. I found it straight forward to follow the instructions in the pihpsdr-install.pdf file and in no time at all I had the software compiled and running.

PiHPSDT running on Kubuntu Linux 22.04LTS — PiHPSDR running on Kubuntu Linux 22.04LTS

PiHPSDR is infinitely configurable and thus it feels like it has an infinite number of menus and options. Since the HL2 has two separate receivers, it’s possible to listen to two bands at the same time. This is the one feature I really missed more than anything with my FTDX10 so, I’m glad to have dual receive capability back once more!

Going through all the settings I realised that the A and B VFOs have individual settings. Initially I setup the software using just VFO A but, when I switched over to VFO B none of my settings were there. I then had the realisation that the settings apply only to the active VFO. I quickly went through all the settings again for VFO B and all was well.

In no time at all I was on the air with just 5w as my Xiegu amp hadn’t arrived. Not being perturbed I tuned up on the 15m band and started searching for stations. Interestingly it was CQWW SSB weekend and the band was full of contest stations. Working my way along the spectrum I found I was able to work quite a few stations with ease using my vertical and inverted-L antennas.

Contacts of note were VE3KG at 3406 Miles, VE3JM at 3382 Miles, RW9DX at 2380 Miles, KC1XX at 3331 Miles and N1DE at 3600 Miles. I also worked a bunch of European stations and had a great time giving away points with my little QRP rig.

Contests are a good time to try out new radios as all the big stations with good ears are on the bands and make the effort to get us QRP guys in their logs.

I have been extremely impressed with the receivers in the HL2 radio. It handles both strong and weak stations exceptionally well. PiHPSDR really does have brick-wall filtering and I was able to work the weaker stations right next to large contest stations with ease. At no time did the front-end of the receiver get overloaded.

Below is a short video clip of a conversation on the 80m band. The band was quite noisy however, with a reduction of the AGC gain and the 2700Hz filter it’s possible to remove almost all the noise.

Hermes Lite 2 SSB reception on the 80m Band

On CW the radio is a real delight. With the filtering and AGC gain control I am able to use extremely narrow receive filters without any ringing whatsoever. I would say that on CW the HL2 is as good as my FTDX10 when it comes to receiving even the weakest of stations.

I’m sure on paper the FTDX10 receiver has better numbers however, to the ear there really is no discernible difference.

Below is a short video clip of D4DX on CW on the 80m band. The band was noisy but, with the 100Hz filter enabled and clever use of the AGC Gain I was able to remove almost all the noise completely, reducing fatigue on the ears and making reception very easy even though there was some fairly deep QSB at times.

Receiving D4DX on CW on the 80m band using 100Hz filter and reduced AGC gain

A few days later my Xiegu XPA125B amplifier arrived. Unfortunately the amp didn’t come with the normal PTT lead that comes from the factory and is detailed in the user manual. For some bizarre reason this is a chargeable option when you buy the amp from Martin Lynch and Sons even though it is included from the factory.

This meant I had to make a lead which was a problem as I didn’t have one of the mini DIN plugs required for the connection to the amplifier. Jumping onto Amazon I ordered a packet of two and sat back and waited for their arrival.

A couple of days later the DIN plugs arrived and I quickly made up the necessary phono/RCA to mini DIN lead and got the amp operational.

The Xiegu XPA125B isn’t cheap but, it’s a really nice bit of kit. The neat little LCD display keeps you informed of power O/P, I/P and O/P SWR, voltage, current draw, temperature and band selected.

With just 0.7w of input from the HL2 I’m able to get a full 100w O/P from the amp. On the lower bands I have to reduce the O/P from the Hermes Lite 2 even further so that I don’t over drive the amp.

Being an avid Short Wave Listener (SWL) I wanted to see how the HL2 performed when listening to the big AM broadcast stations. To my surprise it makes an excellent SWL receiver with better AM demodulation than many of the more expensive radios. Having the option to select receive filters up to 16Khz wide I found I was able to get the best audio possible from many of the broadcast stations including Radio Caroline on 648Khz. It’s quite an improvement over the 12Khz maximum on the FTDX10.

Listening to AM Broadcast stations

What makes this project even more exciting is that both the hardware and software are from the OpenHardware/OpenSource world. The complete circuit diagram, PCB layout and information is available for all to download, something you don’t often see these days!

PiHPSDR is one of the nicest SDR applications I’ve seen in the Linux world and even comes with a 200 page downloadable user manual. Something you don’t see in many Opensource projects. The source code for the application is downloadable and you are able to make your own changes to it without restriction.

Overall I am really pleased with the Hermes Lite 2 SDR transceiver.
It has two excellent receivers, is infinitely configurable via the PiHPSDR software and performs extremely well under all conditions. Since getting the radio I haven’t even switched on the FTDX10.

More soon …