DX – 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 …

7 September 20268 September 2026

A closer look at my Inverted-L Antenna performance

For some time now I’ve been using an Inverted-L style antenna, albeit not a perfect L but, I have found it to perform extremely well.

When I put the antenna up I was aiming for good NVIS radiation on 80/60/40m for chatting Inter-G and local EU stations <1000 miles from my QTH.

I wasn’t expecting good performance on the higher HF bands as the total length of wire is 37m which is somewhat long for the higher frequency bands however, I’ve found performance around Europe to be very good and extremely good over the north pole to Oceania and the USA.

As you can see from the antenna view above, it’s not a perfect inverted-L by any means however, its shape has actually proven to be advantageous.

Wire 1 is 9m tall, it then goes approximately 10.5m in length up to a peak of 12m above ground in the centre, this is where I have a 12m Spiderpole for support. From there the remaining 17.5m of wire slopes down to 5m above ground and is attached to the back of the house via a large insulator. Total wire length is 37m.

Wire 1 is at the bottom of a South facing garden and direction +X is north.

The antenna is tuned at the bottom of wire 1 using my CG3000 Remote Auto ATU at ground level. There are a number of random length radials hidden in the lawn and around the perimeter of the garden running mainly from South to North. I cannot run any radials to the south (-X) as this is farmland and not owned by me.

The radio I use is a Hermes Lite 2 SDR paired with a Xiegu XPA125B 100w amplifier. I normally only use 80w or less on all bands and so, my results are achievable using any 100w radio.

On the low bands I find it has great NVIS performance with excellent signal reports from all over the UK and out to around 1500 miles into Europe and beyond. This is exactly what I wanted from the antenna and I’ve been very pleased with it’s performance on 80/60/40m.

Looking at the 2D Far Field Plots on the 3 low bands the antenna has a typical NVIS high angle of radiation pattern with some gain.

M0AWS Inverted-L Style Antenna 2D Plot on the 80m Band

On the 80m band maximum radiation is straight up, as expected with a gain of 6.08dBi (3.58dBd). The gain reduces at lower angles however, it still performs well out to around 1500 miles and occasionally even further.

M0AWS Inverted-L Style Antenna 2D Plot on the 60m Band

Once again on the 60m band maximum radiation is pretty much straight up as expected however, I have worked in to Canada many times on 60m with excellent signal reports and so, it also has good DX capability too. With 5.26dBi (2.76dBd) gain it’s not a lossy antenna by any stretch of the imagination.

M0AWS Inverted-L Style Antenna 2D Plot on the 40m Band

On the 40m band things start to change a little with the angle of maximum radiation being at 30 degrees rather than straight up. This gives the antenna “longer legs” on the 40m band making it very easy to work longer distances. It’s still very good for Inter-G but, performance over longer distances is considerably better. With a gain of 3.0dBi (0.5dBd) it’s performance is similar to that of a dipole at a similar height above ground.

Above 7Mhz things start to change considerably. The antenna becomes directional to the North West (NW) and North East (NE) giving excellent DX results over the North Pole into North America and Australia/New Zealand. The antenna does of course also have an element of high angle radiation making it useful into Europe and North Africa on the higher bands.

M0AWS Inverted-L Style Antenna 2D Plot on the 20m Band

On the 20m band the maximum radiation is at 26 degrees with a gain of 5.68dBi (3.18dBd) pointing NW and NE. There is a lower gain lobe to the South West (SW) and South East (SE) giving excellent coverage through Europe and into Africa as can be seen in the 3D Far Field Plot and Azimuth Slice shown below.

M0AWS Inverted-L Style Antenna 3D Plot on the 20m Band

M0AWS Inverted-L Style Antenna 2D Azimuth Slice on the 20m Band

Moving up in frequency to the 17m band the 3D Plot and Azimuth Slice are similar to that on the 20m band but, with a slightly lower angle of maximum radiation and slightly more gain as can been in the 2D elevation plot shown below.

M0AWS Inverted-L Style Antenna 2D Plot on the 17m Band

With a gain of 6.61dbi (4.11dBd) at 22 degrees to the NW and NE and slightly lower gain and higher angle to the SW and SE the antenna has proven to work extremely well on the 17m band. My best DX on 17m so far has been a QSO with Eric, FK8GM in New Caledonia some 10230 miles from my QTH using just 80w of SSB.

The 15m band is a similar story, 7.6dBi (5.1dBd) at just 18 degrees pointing NW and NE. This antenna works extremely well into North America and Oceana (I’ve also worked FK8GM on 15m too). Once again there are lower gain lobes to the SW and SE at a similar angle along with some high angle radiation that aids coverage into Europe. The antenna really is a great all rounder on the 15m band.

M0AWS Inverted-L Style Antenna 2D Plot on the 15m Band

The 12m and 10m bands are a similar story, low angle, high gain lobes to the NW and NE with lower gain coverage to the SW and SE.

M0AWS Inverted-L Style Antenna 2D Plot on the 12m Band

On 12m the antenna has a very respectable gain of 7.66dBi (5.16dBd) at a low 16 degrees pointing NW and NE making it a great DX antenna. Once again, higher angle lower gain lobes to the SW and SE.

Finally on the 10m band the antenna has a gain of 6.96dBi (4.46dBd) at a very low angle of 14 degrees to the NW and NE. If DXing over the pole on the 10m band is your thing then this simple antenna will certainly help you along and maybe even put a smile on your face.

M0AWS Inverted-L Style Antenna 2D Plot on the 10m Band

For such a simple antenna that will fit easily into many typical UK gardens I have been extremely pleased with it’s performance. Whether I’m gassing on the low bands with friends from the Matrix rooms or chasing DX on the higher bands, the antenna has put a smile on my face time and time again.

On receive the antenna is surprisingly quiet, with an S3-4 background noise on the 80/60/40m bands through to less than 1 S point of noise on the higher bands. Picking out the weak DX stations really isn’t a problem.

It just goes to show that you don’t need to spend a fortune on commercial antennas to work the world on the HF bands. With as little as 80w of SSB and a piece of wire connected to a remote ATU you can have just as much fun as the big boys!

More soon …

13 January 202613 January 2026

Using Node-Red to build interactive log maps

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.

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

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 layer menu 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.

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 …

15 January 202415 January 2024

Multi-Band Delta Loop Antenna

This antenna modelling session came about after a conversation with Michael, DK1MI on the Matrix. I believe the antenna design was originally done by Artur, M0PLK with reviews being on EHAM.

The antenna takes the form of a simple inverted triangular loop with a 5.8m flat top and two diagonals each 5.6m long coming down to a point. The antenna is fed in the centre of the flat top with 450 Ohm open ladder line and a 4:1 Balun. This antenna will require an ATU on all bands as the modelling shows a very wide range of impedances at the feed point.

The design seems to suggest using two fixed aluminium tubes with the wire fed up through them for the two diagonal elements of the antenna however, it would probably be easier to use a pair of collapsable fibre glass poles (Not Carbon fibre) with the wire attached via some clips or tape.

I decided to model the antenna with the top horizontal wire 10m above ground putting the point of the triangle 5.2m above ground. I felt this was an achievable height for most HAMs. Lowering the antenna will raise the resultant angle of maximum radiation on all bands.

Looking at the 2D Far Field Plots (2DFFP) the antenna radiates through the loop as expected with a higher radiation angle on the lowest band and the lowest radiation angle on the highest band. The antenna is of course bi-directional and so could be rotated just 180 degrees to obtain global coverage.

On the 30m band the antenna has a very high angle of maximum radiation making it ideal for short distances. There is a little gain to be had at 25 degrees however, this is nowhere near the maximum but, will possibly aid working longer distances. A maximum gain of 5.31dBi is obtained at 72 Degrees on the 30m band.

Multi-Band Delta Loop Antenna 30m 2D Far Field Plot

On the 20m band the 2DFFP is fairly similar to that of the 30m band but, with 5.57dBi gain at a lower angle of 34 Degrees. This will provide excellent results on medium distance contacts and reasonable results on the long haul.

Multi-Band Delta Loop Antenna 20m 2D Far Field Plot

Once above 14Mhz things start to get more interesting. From the 17m band upwards the radiation pattern changes quite drastically and starts to provide some excellent gain at relatively low angles. This will improve the antenna’s DX performance considerably on the higher bands.

Looking at the 17m band the angle of maximum radiation is now down to 26 degrees with a gain of 7.64dBi. At 12 degrees there is a gain of 4.59dBi. This radiation pattern will make this antenna ideal for the medium to long haul contact with very little interference from NVIS signals.

Multi-Band Delta Loop Antenna 17m 2D Far Field Plot

The 15m band follows the trend with the angle of max radiation now down to 22 degrees with a max gain of 8.54dBi. Even at 10 degrees there is a gain of 5.34dBi which will be very welcome for DXing. There is slightly more near vertical incident skywave (NVIS) radiation on the 15m band and so the antenna should provide short, medium and long haul contacts with the latter being favoured.

Multi-Band Delta Loop Antenna 15m 2D Far Field Plot

Moving up to the 12m band the angle of maximum radiation now comes down to 18 degrees with a gain of 8.61dBi. There is also 5dBi of gain to be had at 8 degrees which is ideal for DXing. Unfortunately there is slightly more NVIS radiation on the 12m band than there is on the 15m band. I’m sure with a little change in height this could be reduced such that the antenna provides only low angle radiation.

Multi-Band Delta Loop Antenna 12m 2D Far Field Plot

Finally we reach the 10m band, this is where the antenna has the lowest angle of maximum radiation. With 8.56dBi gain at 16 Degrees, 5.59dBi at 8 degrees and a much reduced NVIS radiation. This antenna should be excellent for the long haul on 28-29Mhz. (It would also make an excellent 11m/CB antenna).

Multi-Band Delta Loop Antenna 10m 2D Far Field Plot

It’s interesting to note the similarities between this multi-band delta loop design and my Bi-Directional Slot Fed Antenna design. They both exhibit very similar radiation patterns and gain figures with the Slot Fed Antenna providing slightly more gain and an even lower angle of maximum radiation on the supported bands.

Overall this easy to construct multi-band delta loop antenna would be ideal for the HAM that just wants a single antenna for 30m and upwards or is looking to go portable. The only disadvantage is that a good Remote Auto ATU is required to provide matching of the antenna to the 50 ohm coax at the feed point. Something like the LDG RT100 would be an ideal ATU choice for this application and would remove the losses caused by having a high SWR on the coax feed to the antenna.

Using an ATU in the radio in the shack isn’t going to provide the same results as the coax cable from the antenna to the shack will become part of the antenna and will be detrimental to the antenna performance. It will also create high losses on the coax feed to the antenna due to high SWR being present over the length of the coaxial feed.

26 October 202327 October 2023

13m Multiband Vertical Antenna – 18 Month Summary

Following on from the article I wrote about the performance of my multi band vertical antenna I’ve now put together a table showing it’s performance on each band as experienced over a period of 18 months.

It’s interesting to note the antenna wavelength measurements on each band as 13m (43FT) seems to be an almost perfect length for a simple multi band vertical HF antenna with excellent DX capabilities.

M0AWS 13m (43FT) Multiband Vertical HF Antenna Info (Click to Enlarge)

Looking at the information you can see that performance on the 160m band is poor. This is to be expected as the antenna is far too short for a band with such a long wavelength. I knew this would be the case from the outset and never planned to use this antenna on the 160m band. I’ve included the data here just for completeness. If you’re looking for a reasonable 160m band antenna that can fit into an average UK garden then take a look at my Inverted-L antenna article.

Performance on the 80m band is surprisingly good considering the antenna is only 1/6th of a wavelength long. With contacts into Indonesia achieved using relatively low power levels this antenna surprised me with its performance on the 80m band. A 1/4 wavelength antenna would of course perform better but, like all multi band vertical antennas for the HF bands there is always a compromise.

On the 60m band the antenna is pretty much a 1/4 wave vertical, it works great on this band and I’ve had a lot of fun chasing DX in the winter months. With the longest contact being into Brazil at 6144 miles this antenna performs extremely well for such a simple design.

On the 40m band performance is better still. With the antenna being just over a 1/4 wavelength long the point of max current is above ground level making this a very good DX antenna. With multiple contacts into Australia at distances over 10,000 miles this antenna is the ideal 40m band DX chaser for small gardens.

Moving up onto the 30m band this antenna now begins to really shine. Being a half wave long on 30m the point of max current is half way up the wire lowering the angle of radiation considerably. This results in excellent global coverage with contacts into Australia being a breeze. With the longest distance achieved being 11,776 miles into New Zealand this really is the goto antenna for fans of the 30m band with small gardens. This antenna easily out performs my 30m band Delta Loop design whilst giving better global coverage.

On the 20m band this antenna performs very well indeed. Considering it’s 3/5th of a wavelength long which is a strange length to have, it’s no slouch. Global coverage is excellent and working into Australia is relatively easy. I’ve yet to work into New Zealand on the 20m band using this antenna but, that’s mainly due to me not being on air at the right times. Best distance worked so far on this band is 10,656 miles.

On the 17m band the antenna is 3/4 wavelength long. This is a very useful length and easy to tune as it presents pretty much 50 ohm impedance at the feed point. Performance is simply stunning on 17m, if you can hear the DX you can work them. I am amazed at how well this antenna works on this band. It seems to have a low angle of max radiation making it excellent for chasing DX stations. Giving me my first contacts into Alaska and New Zealand this is my goto antenna for the 17m band.

On the 15m band this antenna is 7/8th of a wavelength long. Performance doesn’t feel as good as it does on 17m but, with the longest distance achieved being 8023 miles there’s really no reason to doubt it. With only 87 contacts being made on this band due to the fact that I always get trapped chasing DX on the 17m band and never make it any further up the bands, I’m sure this antenna will perform extremely well long term on 21Mhz. I just need to make more effort to get on this band.

The 12m band is one of the bands I didn’t expect this antenna to perform well on.
Being 1 and 1/8th wavelengths long it’s not a length that you would normally consider using for an antenna however, performance is excellent. This is most likely due to the point of max current being a fair way up the wire resulting in a low angle of maximum radiation. DXing is great fun with this antenna on the 12m band and it’s surprised me time and time again at how easily I’ve been able to work DX stations. With the best distance worked so far being into the Falkland Islands at 7973 miles, this antenna has huge potential on this band. Like the 15m band, I need to make an effort to spend more time on the 12m band and see how far I can push this antenna.

Finally we reach the dizzy heights of 28Mhz on the 10m band where the antenna is 1 and 1/4 wavelengths long. Again this is a useful length as it presents almost 50 ohm impedance at the feed point. DX performance on the 10m band is good. It’s probably very good however, like the 15m and 12m bands, I rarely make it up onto the 10m band and so I’ve not really given the antenna the time to prove itself at 28Mhz. My best distance worked so far on this band is 4872 Miles into the USA but, I’m sure I could easily do better if I committed more time to it.

I’ve pretty much covered all the good points of this simple multi band antenna so, now let’s look at the not so good points.

If you’re in the UK and are looking to work other UK stations then this antenna isn’t for you. Like all vertical antennas there isn’t much in the way of NVIS radiation and so you’ll find UK stations just won’t hear you. You’ll also often find you won’t hear UK stations at all due to the null at the top of the antenna that attenuates signals arriving from high/very high angles. For me this is fine as I wanted an antenna that was focused on DXing as much as possible.

From 10Mhz upwards the antenna also isn’t that good for working stations in nearby Europe. Most of the time you will only hear European stations that are more than 1000 – 1500 miles away, anything closer just doesn’t appear in the receiver. On the 15m and 12m bands often you will never hear European stations at all, only DX stations. This does of course reduce the QRM from UK/EU stations considerably making it easier to work those weak/QRP DX stations.

So as you can see, 13m (43FT) of vertical wire is probably one of the best lengths you can possibly use for a multi band vertical HF antenna especially if like me, you have a small garden to squeeze your antennas into. I don’t like to say it but, this could be the magical length we’re all looking for when making a multi band HF vertical antenna.

Tuning of the 13m (43FT) vertical antenna is achieved using my CG3000 remote auto ATU. I initially started off using my home-brew Pi-Network ATU but, changed over to the CG3000 so that in the winter months I don’t have to run out into the rain and wind to change bands. It’s important to note that the ATU must be at the base of the wire and not in the radio shack. It’s also important to note that I have 4 x 20m long radials connected to the CG3000 along with an earth spike at the base of the wire. This combination of ground and tuner works incredibly well with the ATU tuning on each band with ease in less than 3 seconds. I’ve also not had any issues with the CG3000 attempting to retune whilst in the middle of a QSO, once it’s initially tuned it doesn’t retune again until I either change band or make a large change in frequency.

The achieved SWR on all bands is <1.5:1 except for 160m where it is 1.8:1.

More soon …

7 October 20238 October 2023

Modelling my Inverted-L Antenna

Since I put together my Inverted-L antenna and Pi-Network ATU I’ve been having a lot of fun on the low bands.

Getting back onto 160m has been most enjoyable and I’ve now had over 100 ‘Top Band’ contacts with distances covered as far as 3453 Miles into Sosnovoborsk Asiatic Russia.

I must admit I am amazed at the distances achieved on the 160m band as the antenna isn’t very high above ground level when compared to a single wave length on 160m.

The Inverted-L antenna at the M0AWS QTH was designed purely around the size of the back garden. Using a couple of 10m Spiderpoles the vertical section of the antenna is 10m tall and the horizontal section is 28m long. Naturally the antenna resonates around 2.53Mhz but, can be tuned to resonate anywhere on any band using the Pi-Network ATU I built that is situated at the base of the vertical section of the antenna.

Looking at the far field plots for the antenna on each band we see that as we move higher in frequency the radiation pattern becomes more complex and the radiation angle gets lower, exactly what we would expect from such an antenna. The antenna runs pretty much North/South in the garden ( X axis on the diagram above) and so we would expect the antenna to radiate East/West (Y axis on the diagram above) however, this isn’t always the case.

M0AWS Inverted-L Antenna 160m 3D Far Field Plot

M0AWS Inverted-L Antenna 160m 2D Far Field Plot — M0AWS Inverted-L Antenna 160m 3D Far Field Plot

(Click Far Field Plots for full screen view)

On 160m the antenna favours the South (-X Axis) and presents some usable high angle gain although, from using the antenna you would never know this to be the case as it seems to have pretty good all round coverage. With the best distance of 3453 Miles being covered to the East into Asiatic Russia the antenna performs well even though the far field plot is slightly biased to the South.

M0AWS Inverted-L Antenna 80m 3D Far Field Plot

M0AWS Inverted-L Antenna 80m 2D Far Field Plot — M0AWS Inverted-L Antenna 80m 3D Far Field Plot

On the 80m band the Inverted-L antenna becomes a cloud warmer and exhibits very high angle radiation. On 80m the antenna is ideal for NVIS Inter-G propagation and is great for rag chewing with other UK/Near EU stations.

M0AWS Inverted-L Antenna 60m 3D Far Field Plot

M0AWS Inverted-L Antenna 60m 2D Far Field Plot — M0AWS Inverted-L Antenna 60m 3D Far Field Plot

Looking at the far field plots for the 60m band once again the antenna provides lots of high angle gain however, there is also some very useable lower angle gain that has proven to be excellent for working long hauls into North America and east into Central Asia. On the 60m band during the day the antenna is excellent for Inter-G chatting, using just 20w-40w I can very easily chat with other UK HAMs even when the band is noisy.

M0AWS Inverted-L Antenna 40m 3D Far Field Plot

M0AWS Inverted-L Antenna 40m 2D Far Field Plot — M0AWS Inverted-L Antenna 40m 3D Far Field Plot

Moving on up to the 40m band we find the far field plot starts to get a little more complex. Looking at the 3D plot you’d think that the antenna favoured the South (-X Axis) however, in reality it favours the NorthWest with both some high and low angle gain. This antenna has proven to be excellent for DXing into North America on 40m but, has also been great for DXing into South America getting great signal reports from stations in Panama at a distance of 5415 Miles. During the day NVIS propagation is excellent and I find I can chat with other UK and near EU stations with ease using just 25w.

M0AWS Inverted-L Antenna 60m/40m Global Coverage

Above is a screen shot from PSKReporter showing stations that have heard me on the 40m and 60m bands. As you can see, global coverage is excellent with stations as far as Australia and New Zealand hearing me on the 40m band and stations on the West Coast USA hearing me on the 60m band. I was also pleased to see I was heard in Africa on both bands, a region of the world I would like to get more contacts from.

M0AWS Inverted-L Antenna 30m 3D Far Field Plot

M0AWS Inverted-L Antenna 30m 2D Far Field Plot — M0AWS Inverted-L Antenna 30m 3D Far Field Plot

On the 30m band the Inverted-L antenna starts to exhibit two lobes with gain to the NorthEast and NorthWest. This makes the antenna ideal for working into the USA and Australia/New Zealand over the North Pole. Working US stations is a breeze with relatively low power and I almost got a contact with New Zealand during the evening greyline but, unfortunately the DX station dropped out before I managed to get my signal report back to him. As time goes on I’m sure the antenna will more than prove itself on the 30m band.

So far I’ve not ventured above the 30m band with the Inverted-L antenna as I’ve really been enjoying access to Inter-G chats on 80m, 40m and 60m and chasing DX on 160m, 60m, 40m and 30m. I need to venture up onto the higher bands before the long winter nights settle in and the higher HF bands close for the winter season.

Looking at the far field plots on the higher HF bands the antenna has huge potential as it provides some nice low angle radiation in useful directions.

M0AWS Inverted-L Antenna 20m 3D Far Field Plot

M0AWS Inverted-L Antenna 20m 2D Far Field Plot — M0AWS Inverted-L Antenna 20m 3D Far Field Plot

On the 20m band the far field plot starts to get much more complex with lobes at many different angles. The main gain lobe is to the NorthEast towards the USA and is at a fairly low angle and so this antenna should be great for working stateside on the 20m band. There are also lobes to the NorthEast and so hopefully working VK/ZL over the pole should also be possible. As I said above I’ve not yet used the antenna above the 30m band and so at this time cannot confirm performance but, it looks promising.

M0AWS Inverted-L Antenna 17m 3D Far Field Plot

M0AWS Inverted-L Antenna 17m 2D Far Field Plot — M0AWS Inverted-L Antenna 17m 3D Far Field Plot

The 17m band also looks promising with a similar far field plot as the 20m band but, with lower angle of maximum radiation and more gain. It will be very interesting to test this antenna on 17m especially since the noise level is below S0 and I can very easily hear the weakest of stations on this band.

M0AWS Inverted-L Antenna 15m 3D Far Field Plot

M0AWS Inverted-L Antenna 15m 2D Far Field Plot — M0AWS Inverted-L Antenna 15m 3D Far Field Plot

Once again the 15m band looks very similar to the 17m band, low angle radiation but, with a slightly more complex far field plot.

M0AWS Inverted-L Antenna 12m 3D Far Field Plot

M0AWS Inverted-L Antenna 12m 2D Far Field Plot — M0AWS Inverted-L Antenna 12m 3D Far Field Plot

The 12m band far field plots continue the theme with the angle of maximum radiation slightly lower than on the 15m band and slightly more gain. This antenna should be great for chasing the DX on the very quiet 12m band.

M0AWS Inverted-L Antenna 10m 3D Far Field Plot

M0AWS Inverted-L Antenna 10m 2D Far Field Plot — M0AWS Inverted-L Antenna 10m 3D Far Field Plot

Finally the 10m band is very similar to the 12m band in that the far field plots show low angle gain albeit with an even more complex radiation pattern.

I originally put this antenna up so that I could work Inter-G on the low bands but, it has proven to be a much more worthy antenna than I originally thought it would be. I need to spend more time with this antenna on the bands above 30m to really see how it performs on the higher HF bands but, so far I’m really pleased with it’s overall performance on all the bands tested to date.

I can highly recommend using FT8 to test new antennas. With PSKReporter and my own NodeRed World Map WSJT-X interface I can see realtime the antenna performance on each band. FT8 is an extremely useful tool when it comes to testing antennas to see if they perform as per the modelling and can often provide some performance surprises!

More soon …

26 September 202323 February 2025

20m Band Delta Loop Antenna

I’ve had this antenna model for ages now but, never got round to putting it onto the website until Alex, GM5ALX was talking about making one the other day whilst chatting on the QO-100 satellite.

The 20m band delta loop follows exactly the same design principles as all the other delta loop designs I’ve already put on the website. They are designed such that they present a 50 ohm impedance at the feed point and thus have no requirement for complex impedance matching circuits/transformers.

M0AWS 20m Band Delta Loop Antenna - Antenna View — M0AWS 20m Band Delta Loop Antenna – Antenna View

The dimensions for the antenna are as follows:

Wire 1 – Horizontal exactly 1m above the ground for its entire 10.2m length.
Wires 2 & 3 are exactly 6.18m long each with the top being 4.5m above the ground.

M0AWS 20m Band Delta Loop Antenna - 3D Far Field Plot — M0AWS 20m Band Delta Loop Antenna – 3D Far Field Plot

The 3D far field plot shows a typical delta loop radiation pattern with the maximum radiation through the loop and a deep null in the centre.

M0AWS 20m Band Delta Loop Antenna - 2D Far Field Plot — M0AWS 20m Band Delta Loop Antenna – 2D Far Field Plot

The 2D elevation plot shows that the antenna will give a maximum gain of -0.79dBi at 30 degrees when used over average/poor soil types. If like me you use your Delta Loop antennas on the beach then the antenna will present considerably more gain as it will benefit from the salt water reflection.

If you want to lower the angle of maximum radiation and increase the gain over average ground just raise the antenna up so that the top is around 7m above ground. This will give a much lower angle of radiation and improve the gain figure by 2-3dBi. Don’t forget that if you raise the antenna the point of resonance will also rise in frequency and so you may need to shorten the wires a little to get the point of resonance back to where you want it.

The SWR plot shows that the antenna will have a fairly wide bandwidth and match to 50 ohm coax extremely well. The antenna is designed to be fed in one of the lower corners via a 1:1 balun for best results.

M0AWS 20m Band Delta Loop Antenna - SWR Curve — M0AWS 20m Band Delta Loop Antenna – SWR Curve

Summary:

Total Wire Length: 22.56m
Horizontal Wire Length: 10.2m @ 1m above ground
Diagonal Wire Lengths: 6.18m
Wire Dia: 2.5mm
Height at Centre: 4.5m
Feed Type: 1:1 Balun in bottom corner (Can use coax if necessary)
Impedance: 50 Ohm
SWR: <1.5:1 at resonance

6 September 20236 October 2023

Getting back onto 160m “Top Band”

Since setting up the new HAM station here in the UK the one band I’ve not yet got back onto is 160m, one of my most favourite bands in the HF spectrum and one that I was addicted to when I live in France (F5VKM).

Having such a small garden here in the UK there is no way I can get any type of guyed vertical for 160m erected and so I needed to come up with some sort of compromise antenna for the band.

Only being interested in the FT4/8 and CW sections of the 160m band I calculated that I could get an inverted-L antenna up that would be reasonably close to resonant. It would require some additional inductance to get the electrical length required and some impedance matching to provide a 50 Ohm impedance to the transceiver.

Measuring the garden I found I could get a 28m horizontal section in place and a 10m vertical section using one of my 10m spiderpoles. This would give me a total of 38m of wire that would get me fairly close to the quarter wave length.

For impedance matching I decided to make a Pi-Network ATU. I’ve made these in the past and found them to be excellent at matching a very wide range of impedances to 50 Ohm.

Since I still had the components of the Pi-Network ATU that I built when I lived in France I decided to reuse them as it saved a lot of work. The inductor was made from some copper tubing I had left over after doing all the plumbing in the house in France and so it got repurposed and formed into a very large inductor. The 2 x capacitors I also built many years ago and fortunately I’d kept locked away as they are very expensive to purchase today and a lot of work to make.

Getting the Inverted-L antenna up was easy enough and I soon had it connected to the Pi-Network ATU. I ran a few radials out around the garden to give it something to tune against and wound a 1:1 choke balun at the end of the coax run to stop any common mode currents that may have appeared on the coax braid.

Connecting my JNCRadio VNA I found that the Inverted-L was naturally resonant at 2.53Mhz, not too far off the 1.84Mhz that I needed. Adding a little extra inductance and capacitance via the ATU I soon had the antenna resonant where I wanted it at the bottom of the 160m band.

With the SWR being <1.5:1 across the CW and FT8 section of the band I was ready to get on 160m for the first time in a long.

Since it’s still summer in the UK I wasn’t expecting to find the band in very good shape but, was pleasantly surprised. Switching the radio on before full sunset I was hearing stations all around Europe with ease. In no time at all I was working stations and getting good reports using just 22w of FT8. FT8 is such a good mode for testing new antennas.

As the sky got darker the distance achieved got greater and over time I was able to work into Russia with the longest distance recorded being 2445 Miles, R9LE in Tyumen Asiatic Russia.

In no time at all I’d worked 32 stations taking my total 160m QSOs from 16 to 48. I can’t wait for the long, dark winter nights to see how well this antenna really performs.

M0AWS Map showing stations worked on 160m using Inverted L Antenna

The map above shows the locations of the stations worked on the first evening using the 160m Inverted-L antenna. As the year moves on and we slowly progress into winter it will be fun to start chasing the DX again on the 160m band..

UPDATE 6th October 2023.
Been using the antenna for some time now with over 100 contacts on 160m. Best 160m DX so far is RV0AR in Sosnovoborsk Asiatic Russia, 3453 Miles using just 22w. Pretty impressive for such a low antenna on Top Band.

More soon …

23 June 202329 June 2023

QO-100 Satellite Update

I’ve been active on QO-100 for a few days now and I have to admit that I’m really pleased with the way the ground station is performing. I’m getting a good strong, quality signal into the satellite along with excellent audio reports from my Icom IC-705 and the standard fist mic.

I’m very pleased with the performance of the NooElec v5 SDR receiver that I’m now using in place of the Funcube Dongle Pro+ SDR receiver. Being able to see the entire bandwidth of the satellite transponder on the waterfall in the GQRX SDR software is a huge plus too.

M0AWS QO-100 Satellite Log map showing contacts as of 23/06/23

As can be seen on the map of contacts above, I’ve worked some interesting stations on some of the small islands in the Atlantic and Indian Oceans. The signals from these stations are incredibly strong on the satellite and an easy armchair copy.

DX of note are ZD7GWM on St. Helena Island in the South Atlantic Ocean, PP2RON and PY2WDX in Brazil, 8Q7QC on Naifaru Island in the Maldives, VU2DPN in Chennai India, 5H3SE/P in Tanzania Africa and 3B8BBI/P in Mauritius.

There are many EU stations on the satellite too and quite a few regular nets of German and French stations. I’ve not plucked up the courage to call into the nets yet, perhaps in the future.

There are a lot of very experienced satellite operators on QO-100 with a wealth of information to share. I’ve learnt a lot just from chatting with people with some conversations lasting well over 30mins, a rarity on the HAM bands today.

We also had our first Matrix QO-100 Net this week, an enjoyable hour of chat about all things radio and more. We have a growing community of Amateur Radio enthusiasts from around the world on the Matrix Chat Network with a broad spectrum of interests. If you fancy joining a dynamic community of radio enthusiasts then just click the link to download a chat client and join group.

More soon …