Bluetooth Earbud systems take on CW and FT8 Decoding

In this age of miniaturization it is amazing to consider what has been achieved with modern technology. With that thought in mind, a dedicated group of members within AREG has been exploring what could be done using the various models of Bluetooth connected earbud headphones that are currently available. Originally the thought was to see how they could help our fox hunting teams gain an advantage over the VK3 teams at the national championships, but then one of the team members made an amazing discovery. Hidden inside certain manufacturer’s products was a surprising amount of compute power, far more than would ordinarily be needed to convert a simple Bluetooth signal into audio.

On further probing and exploration, the team finally found a way to hack into the EarBud operating system and access the boot loaders. Now these operating systems and compute capabilities were completely unexpected, and so not only was this an eye opener, it was also a game changer as the team pondered just what might be possible! (It also posed the question, what on earth were the manufacturers planning in the future and why such compute capability was even required in these devices, but these are questions for later exploration).

Amateur Radio Applications?

Having opened up the operating system, the team made short work of learning how to load software into the earbuds, and then the creative juices started flowing. One of the early thoughts was whether there might be a way to connect one of the modern Bluetooth capable HF transceivers to these earbud systems. A quick look at the IC-705 from ICOM confirmed that this was simple enough to do.

The trick then was to see what the earbuds could do!

Morse Code – Music to your ears – with Speech Conversion technology!

The first simplest idea was to simply relay CW signals to your ears. The challenge however wasn’t to just relay the raw audio. Given the amount of compute power discovered in these ear buds it became clear much more could be done. The team then built a CW decoder and speech encoding routine that could take a HF signal straight from a Bluetooth transceiver and turn it into synthesized speech. The achieved results were impressive indeed.

CW Input Signal

Earbud Processed CW to Speech

Further work was then undertaken to work on the decoder’s ability to separate out individual signals in a pileup. After some experimental AI routines there was success! Morse Code finally entered the digital age!

Digital Operators delighted by FT8 success

Following on from the CW experiments, the FT8 devotees in the club got together to see if it would be possible to port the WSJT-X FT8 encoder/decoder into the earbuds. After some consternation about running out of memory, the following was achieved! Using additional AI routines to help select which signal to decode, the team was able to convert this:

into this!

Needless to say we believe this is the most unusual compute platform that FT8 has ever been ported to, but the results were simply stunning, with decode rates as good as any of the popular programs currently in use on the PC market today.

SSB Operators were not left out!

Of course AREG is all about equality and accessibility. We do not tolerate discrimination in the group. So, it was important that the SSB voice folk felt they were part of the project too. Of course, then it dawned on us. They were already included, as all we had to do was turn off the decoded software and the pure sound of SSB HF radio could once more be relayed straight to their ears.

How can you get involved?

The system is still in it’s infancy, and so far only a couple of models of Earbuds have been cracked. However as soon as we have stable supplies and have completed licensing the software on git-hub, we will make it available to amateur radio operators to experiment further with!

Next steps are to be able to have the reverse direction function as well, so an operator can simply speak and the earbuds can then turn that into what ever CW or digital modulation system you desire!

Meanwhile, if you would like to know more, please contact us via the project page!

Project Horus High Altitude Balloons: Horus 55 Flight Report

Horus 55 was the culmination of something that had been discussed for many years within the Project Horus team – Live video from a high-altitude balloon. The technical challenges in doing this are many, from designing a transmitter system that provides enough signal without melting in the thin atmosphere at high altitudes, to building a high performance receive system that can capture that signal, and then upload it to the internet for everyone to enjoy. (After all, if it didn’t get live-streamed, did it really happen?)

At 10:30AM on the 7th of March 2021, all of this came to fruition with the first flight of the Project Horus DVB-S payload.

The Payloads: DVB-S Transmitter

The DVB-S payload was the primary experiment on this flight, and had been in development by Mark VK5QI and Peter VK5KX over the last 12 months. The payload utilised a Raspberry Pi Zero W to capture and compress video (using F5OEO‘s DVB-S encoder and natsfr’s LimeSDR Gatewarethis project would not have been possible without their work – thanks!), which was then modulated as a 70cm (445MHz)  DVB-S transmission using a LimeSDR Mini. The signal was amplified to ~800mW using a LDMOS-based power amplifier. The overall power dissipation in the payload was ~6 watts, so a heat-spreading and heat-sinking system was built by Peter, including custom-milled interface plates for the LimeSDR.

Monitoring the temperature of the LDMOS device during testing.

The payload was powered from 8x Energizer Lithium AA primary cells, which are well-regarded for their low-temperature performance.

Much testing and tuning of the payload was performed in the lead-up to the launch, including monitoring of the temperatures within the payload when sitting in full-sun, to ensure it would not reach dangerous temperatures.

Mark VK5QI gave a presentation on the payload at the AREG February meeting, which is available here:

The final DVB-S parameters used on the flight were:

  • Frequency: 445.0 MHz
  • Mode: DVB-S
  • Modulation: QPSK, 1 Msps
  • Forward-Error-Correction: r=1/2
  • Video Resolution: 720 x 404

The Payloads: LoRaWAN Beacon

Horus 55 LoRaWAN PayloadAlso on this flight was an experimental LoRaWAN tracking payload built by Liam VK5LJG. The aim was to transmit position beacons into ‘The Things Network‘ (‘TTN’), which has gateways (receiver stations) in many locations across Australia.

The payload operated on the 915-928 MHz LIPD band, with a transmit power of ~50mW. The hardware was a RAK Wireless RAK5205 board, running custom firmware for the flight. Position updates were only sent every ~3 minutes to comply with TTN fair-usage guidelines.

We expected that this would be received by TTN gateways all around the Adelaide area… it actually performed much better than expected!

The Payloads: Tracking & Flight Management

Reprogrammed RS41

The flight also included the usual complement of telemetry and flight management payloads. Primary telemetry was provided by a reprogrammed RS41, transmitting the ‘Horus Binary‘ 4FSK mode on 434.200 MHz. This was received by a large number of amateur stations running the ‘Horus-GUI’ demodulation software. Tracking of the payload was available on the HabHub tracker online, allowing global access to the position of the balloon throughout the flight.

The separate flight management payload was a LoRa-based payload operating in the 70cm (430.0MHz) amateur band. This payload allows remote termination of the flight if necessary (and it was actually used in anger this flight!).

Flight Preparation & Receiver Testing

VK5APR Receiving DVB-S SignalsOn the weekend prior to the launch, two test-and-tune events were conducted, where receiving stations around the Adelaide area had the opportunity to configure and test the software and hardware necessary to receive the DVB-S signals. Transmissions were conducted from Steve VK5SFA’s QTH on Saturday, and from Black-Top Hill on Sunday. Both sites provided excellent line-of-sight to the Adelaide metropolitan are, enabling eight stations to be able to receive the test  transmissions ready for the live balloon flight the following weekend.

Testing the Ground-Station AntennasFinally, a full systems check was conducted with Peter VK5KX. The test covered all of the equipment which would comprise the primary ground-station for the flight, receiving video from the payload and streaming it live to Youtube. This involved testing of the 2 x 18-element Yagi-Uda array, and all the receiver and streaming software. A big thanks to Hayden VK7HH for helping get the Youtube streaming working via his HamRadioDX channel.


The ground station crew, chase teams, and spectators started to assemble at the Auburn Oval launch site around 9AM, to find that showers had set in.

It was decided to continue on with launch preparations and wait for the showers to pass.

By a bit after 10AM the showers had died away to a light sprinkling, and the balloon filling was started. Around this time the live-stream from the launch site was switched on, with many viewers from around the world tuning in to watch the proceedings.


The balloon used for this flight was a Totex 1000g, and an entire 3.5m^3 cylinder of helium (donated by the University of Adelaide) was used to fill it. Using the fast-fill rig the fill was completed in a few minutes (as opposed to the almost 1 hour of slow-filling that used to be required), and the balloon was tied off ready for launch.

After a final check that all payloads were working as expected, the (short) countdown began, and the balloon and payloads were released!

Ascent & Live Video!

After launch the ground-station system was switched into ‘auto tracking’ mode, and began pointing the high-gain Yagi antennas to follow the balloon and payloads. This ensured the best quality video reception, and it definitely worked!

DVB-S Received by Joe VK5EI after launchViewers at the launch site and all around the world via Youtube were treated to clear visuals relayed from the primary ground station as the balloon ascended up to cloud-base. Reports from other receiving stations around the region started trickling in, with Ian VK5ZD (near Kapunda) and Joe VK5EI (Adelaide) being the first to report in.

As the balloon reached the first cloud layer the views of the surrounding landscape was replaced with grey, and the chase teams took this as a sign that it was time to head off towards the expected landing area. Meanwhile the ground control team of Matt VK5ZM, Pete VK5KX and Grant VK5GR kept watch on the balloon state and the TV signal being relayed to YouTube and being broadcast around the globe.

The ground-station team continue to keep tracking the payload, uploading live video to over 200 viewers on Youtube. A big thanks to Hayden VK7HH for hosting the live stream on his Youtube channel, and helping answer the many questions that were asked by the viewers throughout the flight. Please make sure to Like and Subscribe his Youtube channel!

One of the last shots received before the balloon was cut away so the payloads could land

Chase, Cutdown & Recovery

Chase cars stopped at EudundaThis flight had four chase teams:

  • Mark VK5QI  and Will VK5AHV
  • Darin VK5IX, along with Cameron and Dan
  • Liam VK5LJG
  • Gerard VK5ZQV

All the teams headed off in convoy towards Eudunda as their first stop, where the traditional bakery visit was made mid-flight instead of after recovery.

Receiving DVB-S from Mark's carMark and Will were receiving the video from the DVB-S payload in the car, which worked surprisingly well even with the fairly modest antenna setup on Mark’s car (an upward-fading turnstile).

Tracking the balloon flight-path in the chase car

After a quick lunch, the teams headed south towards the predicted landing area. As the flight processed and the balloon rose past the expected burst altitude of 30km, Mark made the call to terminate the flight to help land the payloads in an easily recoverable area. A few radio commands later, the payloads started falling, with the cut-down event observed via the video link (though the fast tumbling did result in a lot of broken video). The maximum altitude achieved was 32379m above sea level.

The teams headed towards the new predicted landing location, and after a bit of back-and-forth were able to be in position to watch the payloads land under parachute. Unfortunately the payloads were just a bit too far away for the teams to get imagery of the final descent.

After getting permission from the landowners (thanks!), the teams were able to enter the property and drive almost right up to where the payloads had landed.

Landed payloads While a bit bent and dented (and upside-down!), the DVB-S payload continued to transmit video after landing, with the receiver in Mark’s car capturing the team walking up and recovering the payload.

Bent payload

Analysis of log files from the payload showed that overheating was certainly not an issue – instead the heat-spreader plate within the payload reached a chilly -27˚C during the descent phase of the flight!

DVB-S Payload Temperatures

DVB-S Reception Reports

So far the following stations have reported being able to receive video from the DVB-S payload:

  • Bill VK5DSP – Middleton, SA
  • Iain VK5ZD – Kapunda, SA
  • Joe VK5EI – West Lakes, SA
  • Berndt VK5ABN – Nairne, SA
  • Andrew (N0CALL), Pt Noarlunga, SA
  • Steve VK5MSD – Whyalla, SA
  • Roger VK5YYY – Whyalla, SA
  • Gerard VK5ZQV – Mobile, during the chase.

If you received video from this flight, let us know!

The longest distance the payload was received from was by the stations in Whyalla, at almost 190 km range, followed by Bill in Middleton, at 145km range. The payload designers are absolutely ecstatic at how many stations were able to receive video during this flight – hopefully we can repeat this success on more flights in the future!

Horus Binary (4FSK) Telemetry Reception Statistics

With every Project Horus flight we like to thank all the receivers that helped receive telemetry from the flight. All the telemetry you receive and upload to the net helps keep the tracking map up-to-date throughout the flight, and serves as a backup in the case of ground-station or chase-car receiver failure. On this flight telemetry was recorded from as far away as Horsham, though there were reports of telemetry reception in Melbourne – however it appears these stations did not upload their telemetry to the internet.

Horus 55 Callsign Pie

CallsignReceived PacketsPercentage of Flight ReceivedFirst-Received Altitude (m)Last-Received Altitude (m)
VK5LJG (Home)138169.7%29463156

LoRaWAN Experiment Results

As mentioned earlier, the LoRaWAN payload was transmitting telemetry packets to be received by The Things Network gateways. We expected the payload to be received by stations in the general Adelaide area, however it turned out that at the peak of the flight we were received by gateways as far away as Ballarat, Victoria! Full details on what gateways received each packet are available here.

LoRaWAN Coverage

The longest path was 585km, which for a ~50mW transmitter at 923 MHz is quite an achievement! The world record distance for this system is 823km, and we’re interested to see if we can beat this on a future launch!

Flight Track

At the conclusion of the flight we were also able the telemetry into this flight profile, which gives an appreciation of the journey the balloon and the experimental TV transmitter under took.

Conclusion & Future Flights

Horus 55 - Flight Statistics

Flight Designation:Horus 55
Launch Date:2021-03-07 00:02Z
Landing Date:2021-03-07 02:37Z
Flight Duration:~2.5 hours
Launch Site:-34.02932,138.69124
Landing Site:-34.25959,139.11443
Distance Traveled:46 km
Maximum Altitude:32,379 m

With the huge success of this flight, the team plans to follow this up with more video flights in the future. There are many lessons to be learnt from this flight, and many improvements that can be made to both the payload, the ground-station, and the live-streaming systems. Viewers can look forward to higher quality video, more running commentary, and hopefully live video from the chase-cars as they recover the payloads.

The next few months will be getting busy for the Amateur Radio Experimenters Group, with the upcoming Riverland Paddling Marathon taking up a lot of club members time. Expect the next full-scale flight sometime in late June – weather permitting!

AREG Meeting 20th November: FM Broadcast DXing

Often, during the summer months, it is often possible to hear FM broadcast stations from far and wide thanks to the Ionosphere and Troposphere bending signals over the horizon. There are a few tricks to getting the most out of tuning the broadcast band looking for that distant station however.

At the next AREG meeting on Friday the 20th of November, Andy, VK5LA will give a presentation on “DXing” the FM band. He will discuss, what gear is needed, what gear works best and how to identify stations you don’t normally hear and cover topics like locations, antenna polarisation, and explore the RDS station ID feature built in to most modern FM receivers.

Andy will also discuss using the ACMA database to determine if that exotic station you’ve just tuned in to is 70, 700 or 1700 km away and describe the various propagation modes that make this interesting activity possible. Finally he will take a look at how that information can be used to predict openings on the 6 metre (50MHz) band and above.

How can you take part in this meeting?

  • Due to the latest COVID-19 restrictions, the presentation will be via Zoom for members starting by 7.45pm South Australian Summer Time.
  • Visitors will be able to watch the lecture via Hayden VK7HH’s HamRadio DX Channel on YouTube.

We hope to see you there!

For interstate viewers the times are:

  • 8.15pm AEDT (Victoria, New South Wales, Tasmania, Canberra)
  • 7:15pm QST (Brisbane)
  • 6.45pm CST (Darwin)
  • 5:15pm WST (Perth)
  • 09:15 UTC

AREG 2m Fox Hunt Fridays

Have you ever heard of Fox Hunting? Do you remember the days when teams of people chased 2m hidden transmitters all over town? Would you like to join in the fun? The Amateur Radio Experimenters Group is commencing a new series of “Hidden Transmitter hunts” or “Fox hunts” as they are known on the 2m band over the summer daylight savings season this year.

The first event will be held on Friday the 13th of November. This will be a cross-town hunt with a two metre fox being hidden somewhere within the Adelaide metropolitan area. Anyone and everyone is welcome to join in.

The hunt will commence from the car park of the Lockleys Oval, Rutland Avenue Lockleys. Hounds are encouraged to gather at the start from 6.15pm. The fox will begin transmitting at 6.30pm. The fox’s frequency will be announced via the VK5RSB 70cm Summertown repeater on 439.900 MHz just before the hunt begins. Hunters are welcome to liaise via VK5RSB during the event (note that a 91.5 Hz CTCSS tone is required to access the repeater).

This will the first of many monthly fox hunts hosted by AREG over the coming months which will be announced on our website and via our Facebook page as well as the local VK5 WIA news.

So dust off your ARDF gear, we look forward to seeing you there!

AREG to host an Amateur Radio exam session – Saturday Sept 8th

The Amateur Radio Experimenters Group is arranging for a round of Amateur Radio license examinations to be held at the Fulham Community Centre, Phelps Court, Fulham on Saturday 8th September starting at 9.00am.

For those members (and non members) wishing to upgrade their current Standard or Advanced license, or you wish to sit one of these licenses directly (no need to have passed a lower grade – you can directly sit for any license level in Australia)  we need to know by COB Thursday 16th (this week!) so we can arrange for exam papers to be ordered and have them arrive on time.

Foundation License training and exams will also be held. Registrations also need to be completed before Thursday 16th August. Those wishing to sit the foundation license should obtain a copy of the foundation license manual beforehand if they haven’t already done so, and start studying. Come along to the AREG club meeting this Friday (7.45pm) to discuss how to prepare for the exam with the organizers.

Places are limited (unfortunately) for the Foundation license due to the nature of the training so get in quick. If the course fills up, AREG will plan another exam day later in the year.

Costs to sit the exam will be advised later this week (pending the committee meeting). We look forward to seeing new faces join this amazing hobby.

You can email us to register your interest to vk5arg (at)

August Meeting – Using the Bureau of Meteorology Space Weather Site in Amateur Radio

This month AREG is pleased to present a talk by David Neudegg, Space Weather Physicist with the Bureau of Meteorology, on how Amateur Radio operators can use the resources on the BOM Space Weather website to understand HF propagation.

David will walk the audience through each of the resources and will show how the items available represent what people experience when operating on HF.

There will be plenty of opportunities for questions so come along! Everyone, visitors especially, is always welcome.

The club meets at 7.45pm Friday August 17th at the Fulham Community Centre, Phelps Court, Fulham. Help finding us can be obtained on the Adelaide VK5RSB 70cm repeater on 439.900 (-5MHz + 91.5 CTCSS tone).

APRIL FOOLS: AREG Launches new “World Wide Car Parks” awards program!

Are you an Awards chaser?

An urban worker?

Have a young family that takes up all of your waking weekend hours ?

Do you find you just don’t have the time to go bush or climb
those lofty summits to participate in programs like WWFF or SOTA?

Then this new award is for you!

Many amateur operators today live in situations that prevent them accessing the great outdoors either during the week or the weekend. Perhaps your commute is your only radio activity, or maybe you are lucky and you’re “mobile” whilst at work but only have 2m/70cm FM on board. So much of our lives are spent driving to and from car-parks that there has to be another way to have the same amount of fun as the park and summits activator. So, the “Awards Team” at AREG put their thinking caps on and asked themselves – how can we enhance the amateur radio experience for those who find themselves in such circumstances?

Introducing the World Wide Car Parks Award!

The aim is to contact at least 42 points worth of contacts to qualify the car-park for an award. Points are awarded per contact based on a number of factors outlined in the rules below. The more car parks you qualify multiplied by the sum of all contact points accumulated then contribute to your leader-board score. It is as simple as that!

Once you have made and logged the contacts, you can submit them to our new awards site (details below). Once your contacts are confirmed you will automatically be emailed your award.

The Rules


  1. you must be located in a car park when making the contact to qualify for the award. Car park in this definition means a formal area/building set aside for parking cars that is not part of a street or road. (I.e. must be in a parking station – street parking is not accepted). There is an exception however to this rule which is if you are on a designated freeway (where parking is not normally permitted) and are moving at less than 5 kilometres/hour (3.1miles/hour).
  2. a contact must use some form of Amateur Radio somewhere in the process of communicating and include an exchange of call-signs, signal reports and car-park identifiers.
  3. a car park identifier will simply consist of the program prefix for your country, the first 4 letters of your grid square and then the street address of the car park. For example, VKCP-PF95-67FranklinStAdelaide+07. (we thought of serialising each car park like they do in WWFF however there are so many that we felt we would never keep up). The last number is important as it is the level of the car park you are operating from and affects the points awarded.


This is where the challenge lies. How many contacts you need to make to qualify a car park depends on the type of car park you choose and how you make the contact.

4. You get a bonus points for the type of car park and the floor number you operate from. So a contact made from an indoor parking station earns you:

  • Level 5 and above is worth 1 point
  • Level 4 is 2 points
  • Level 3 is 3 points
  • Level 2 is 4 points
  • Level 1 is 5 points (this is the ground floor)
  • 1 level below ground is 10 points
  • 2 levels below ground is 20 points
  • 3 or more levels below ground is 50 points

If you make a contact from an open air ground level car park each contact is only worth 1 point.

Contacts from a freeway moving less than 5km/h (3.1mph) count for 2 points always unless they are in an underground tunnel in which case they are worth 10 points x the length of the tunnel you are travelling through in kilometres.

5. Multipliers are available based on the nature of the contact. Scoring is then calculated based on the number of points total multiplied by the sum of all multipliers.

(a) Simplex contacts are worth 2 multipliers

(b) Use of repeaters, Hotspots, Echo link etc is allowed but do not add any multipliers.

  • in addition, the use of a DMR/Fusion/DSTAR hotspot over cellular provided internet to make the contact will only qualify where the car park in question does not have a cellular in building coverage antenna system inside it.
  • use of EchoLink only qualifies if connected over Cellular Internet and there is no in building cellular antenna system in the car park.

(c) The sum of all DXCC worked per car park can be added as a multiplier. (Note a special talk group on DMR will be established for the awards program plus new Fusion, DSTAR and Echolink conference channels so that the program does not impact day top day repeater operations).

6. Additional multipliers are available for the following activities:

  • Getting Locked in the car park over night – 50 multiplier points
  • Using car park infrastructure as an antenna – 20 multiplier points (Note 1)
  • Operation on MF from an indoor car park – 100 multiplier points (Note 2)
  • Operation on HF and 6m from an indoor car park – 10 multiplier points (Note 3)
  • The following is then a sliding scale as you move up in frequency:
    • 2m = 1 multiplier points
    • 70cm = 3 multipliers points
    • 23cm = 5 multiplier points
    • 13/9 and 6cm = 10 multiplier points
    • 3cm and above = 20 multiplier points
  • Car park to Car park contacts are worth 2 multiplier points

Note 1 – setting off the building fire alarms when transmitting using car park infrastructure will result in a disqualification!
Note 2 – only qualifies if the contact made from levels that are below ground
Note 3 – double points if doing this while driving in the car park and NOT destroying car park lighting infrastructure


7. Special endorsements are available for types of vehicle and transmitted power level as well. These are expected to be sought after additions to your awards certificate.

  • RV and Van category – but only if the applicant has made indoor car park contacts from these vehicles without damaging car park infrastructure. (Indoor Car parks with high clearance are rare hence the value of this endorsement)
  • Motorbike MF category
  • QRP Category – less than 5W
  • Self Powered QRO Category – more than 100W PEP
  • Assisted Power QRO Category – more than 400W PEP – only valid from Tesla charging stations – see notes earlier about the fire systems
  • Hi-Rise Rooftop Parkour assisted Handheld Operation (qualifies for a special Hi-Rise on the Air (HOTA) award endorsement)


To obtain your award, you need to work the required contacts and submit a log to the following web page.

If your log is accepted you will be emailed your certificate of achievement!

All logs must be received before April 1st each year in order to be considered for each year’s Honour roll so get cracking and see how many stations you can work!

Good Luck!


A. AREG is in no way to be held liable for your actions or behavior in a car park. You are expected to follow the rules of the car park operators at all times and always comply with the directions of security staff. If you have the SWAT team called on you for suspicious activities that is your issue.

B.AREG is not liable for any car parking fees you incur in acquiring contacts for this award. All parking costs are your own responsibility.

C. Self spotting is permitted. The committee is considering a bonus points scheme for the number of social media outlets one individual can find to alert people to their presence. There is a special trophy available if you manage to self spot by calling a commercial radio talk-back show and talking about what you are doing provided you get your operating frequency broadcast over the respective AM or FM station concerned.

D. Disputes with award scoring or validity will only be considered by the AREG committee once a year on April 1st before midday. Disputes must be forwarded to the correct galaxy and be filed in the cabinet at the bottom of the broken stairs in the draw above the one marked beware of the leopard in order for them to be considered by the committee. Don’t forget to take a torch as the light is broken.