HORUS 49 – Anstey in (near)-space 2.0 – 30th June

Back in 2016, AREG & Project Horus helped Anstey the Echidna, the Tea Tree Gully Library’s mascot, explore near-space. Anstey didn’t have enough fun on the previous launch, and so on the 30th of June 2018, we will be re-launching Anstey back into near-space on a high-altitude balloon launch!

Anstey in near-space on Horus 39

The launch is currently scheduled for 10AM CST on Saturday the 30th of June, however as usual, weather conditions may cause this to be re-scheduled. The launch will be from the Mt Barker High School Oval, and spectators are welcome. Launch crew should be on-site from approximately 9AM.

Tracking of the flight will be available via the HabHub tracker.

Telemetry Information

The telemetry frequencies for the flight are as follows:

  • RTTY Telemetry – ‘HORUS’ – 434.650 MHz  (100 baud, 425 Hz Shift, 7N2)
  • Wenet Imagery – 441.200 MHz (Wenet 115kbps FSK)
  • Experimental Horus Binary Payload – 434.640 MHz (100 baud 4FSK)

As usual, the RTTY telemetry can be decoded using dl-fldigi. Note: Recent testing of dl-fldigi’s decode performance has found that the auto-configured RTTY receive bandwidth is too narrow, and can detrimentally impact decode performance (by up to 3dB!).

To fix this, open dl-fldigi, and in the Configure menu, select Modems, and then go to the ‘RTTY’ tab. Drag the ‘Receive filter bandwidth’ slider to 200, then click ‘Save’. Note that this setting will be reset whenever you hit the ‘Auto-Configure’ button!

Wenet Imagery

As with most Project Horus launches, this flight will feature live imagery via the Wenet high-speed imagery downlink. Images will be available throughout the flight at this link:


Reception of the Wenet signal requires a RTLSDR and a Linux PC/Laptop. Instructions on how to set up the required software are available here.

Experimental 4FSK Telemetry

This launch will include the use of a re-purposed Vaisala RS41 radiosonde, programmed to transmit a new binary 4FSK telemetry mode, developed by David VK5DGR and Mark VK5QI. This new mode is intended to eventually (read: probably a year away) replace RTTY telemetry on Horus flights. It runs at 100 baud, is approximately 850 Hz in bandwidth, and has an almost 6dB performance improvement over the current RTTY telemetry!

Decoding this telemetry requires installation of a new decoder application (an updated version of FreeDV), and some helper scripts to upload the data to the online tracker. A guide on how to install and operate this new decoder is available here.


More information will be available closer to the flight!

High Altitude Ballooning: Horus 48 – Flight Report

At 10:08AM CDST, on the 11th of March 2018, Horus 48 was launched from Mt Barker.

This planning for this flight started out as an excuse to use up some helium leftover from the previous two launches, and quickly evolved into a mechanism for testing out some new payloads and launch concepts – the main one being the use of the ‘THOR16‘ data mode, which is considerably more robust to interference than RTTY, at the cost of being about 50% slower.

Horus 48 Payloads

Horus 48 Payloads

As we only had a limited amount of leftover helium available (~1.6m^3), the mass of the payloads had to be kept to an absolute minimum. New foam payload boxes were built with this in mind, with the new THOR16 and RTTY payloads weighing in around 70g each. (Thanks to Peter VK5KX for supplying the antenna wire!)

The week prior to the launch, a ‘test and tune day’ was conducted. An example THOR16 signal was broadcast from Mt Lofty summit, with many stations tuning in and decoding telemetry. The responses from this test were promising, with one station reporting he had much more success with THOR with it’s forward-error-correction, as local LIPD noise would disrupt RTTY decoding resulting in invalid telemetry.

Thanks to the following stations who participated – it was great to see so much interest!


Launch Preparation

The launch was quite light-on with helpers – Mark VK5QI and Will VK5AHV performed the launch activities, with help from David VK5DGR, Drew VK5XFG, Rod VK5ZOT and a few others.

The original intention to use a small 100g balloon went out the window the night before the launch, when it was discovered the specified burst diameter for the 100g balloon was not quite as expected – this would have resulted in a ~3km burst altitude! Instead an old 1000g Hwoyee balloon was used. The larger balloon meant all the gas in the cylinder had to be used up, and even this only resulted in an ascent rate of 2.5m/s (we usually aim for 5m/s).

To counter the low ascent rate, which would have resulted in a 4 hour long flight, and a landing well to the east of Bowhill, one of the Horus cutdown payloads was flown, allowing termination of the flight via a command from the ground. This cutdown payload used a newly developed cutdown device (to be kept under wraps for now!), which is intended to replace the nichrome wire string-cutter device previously used – Experiment #2 for this flight!

All up, the payloads combined only weighed ~300g. The smallest parachute we have in stock was used (a 2ft ‘Rocketman’), and was hung off the side of the balloon train instead of in-line with the payloads as we would usually do. This was to try and reduce the tangling of the parachute with the payload string that had been encountered on the last few flights – Experiment #3!

Launch & Chase


Launch was pretty much textbook – some light winds encountered during filling died down for an easy release into the skies. Will and Mark immediately headed off towards the target landing area, while David VK5DGR and co headed off to Mannum for a bakery stop.

At about 10km altitude the cutdown signal was sent to the payload, with the intent of landing the payload to the south-east of Mannum. The new cutdown device worked first-go – a success for Experiment #2! The payloads then quickly descended to a landing on a property just across the river from Port Mannum.

Will and Mark caught sight of the payloads at about 800m altitude, and were able to watch the payloads descending behind a hill, into an empty field. The parachute was clearly doing its job, and was not tangled up or ensnared in the other payloads – another successful experiment!

A quick discussion with the landowners (and their friendly dogs) and permission to enter the field and retrieve the payloads was granted. A short walk and the payloads were in hand!

Flight Statistics

Everything is more interesting with data – so here is the flight’s vital statistics.

Flight Designation:Horus 48 - THOR16 Test Flight
Launch Date:2018-03-10 23:38 UTC
Landing Date:2018-03-11 01:16 UTC
Flight Duration:1 Hour 37 Minutes
Launch Site:-35.07568, 138.85701
Landing Site:-34.93807, 139.31944
Distance Traveled:44 km
Maximum Altitude:10,187 m
Horus 48 Flight Path

Horus 48 Flight Path

New Telemetry System Performance

Even with a 10.2km maximum altitude, many receiver stations around the state were able to decode both the THOR16 and RTTY telemetry:

RTTY Telemetry Scoreboard
CallsignPackets HeardPercentage of Flight HeardPayload Alt at First RX (metres)Payload Alt at Last RX (metres)
THOR Telemetry Scoreboard
CallsignPackets HeardPercentage of Flight HeardPayload Alt at First RX (metres)Payload Alt at Last RX (metres)

The callsign pie chart shows the combined result of both RTTY and THOR telemetry streams – great to see so many contributors this time!

So, was the THOR16 telemetry useful? It’s hard to tell with just one launch. From the chase-car, the following observations were noted:

  • The slow speed of THOR16 (one update every ~20 seconds) makes tracking the flight through critical stages like burst and descent difficult. The chase team ended up switching to the cutdown payload telemetry (updates every 5 seconds) to get more frequent position updates.
  • THOR16 was quite robust to mobile fading, however,
  • … fldigi has no automatic frequency correction for THOR16. While the payload’s transmitter didn’t drift very far, it did drift far enough for the performance of the demodulator to drop, resulting in quite a few lost packets until the issue was noticed.

Since the THOR16 payload is so light (only 65 grams) you can expect to see it on more upcoming flights – please continue to send in reports on how it compares to the RTTY payload!

Thanks again to all listeners who decoded data from the flight, including those who went portable to track the payload down to the ground (VK5KX, VK5ZM & VK5GR).

RTTY as received at VK5KX

THOR16 as received at VK5KX

Addendum: HabHub Tracker Issues

Some listeners noted issues with the Tracker where the payload list on the left side of the webpage did not populate. This is a known bug and is currently being worked on. The bug is related to window sizes, so if you re-size your browser window slightly it should re-draw the web-page, and the payload list should appear.

ADVANCE NOTICE – Horus 48 – Telemetry Test Flight & Test Transmission

On the weekend of the 10-12th of March (exact day TBD), Project Horus will be performing a small (not-so-)high-altitude balloon launch from Mt Barker. The flight will be a short one (~1.5 hrs), with a maximum expected altitude of only 13km. All the payloads have been custom-built to be very lightweight – the total payload mass for this launch is < 300 grams!

The aim of this flight is to evaluate the performance of a new telemetry payload, which uses ‘THOR16‘ modulation. While about half the speed of the current RTTY payload, the THOR modes utilise forward error correction and interleaving. This promises to reduce or remove issues with mobile flutter and multi-path fading that we encounter with RTTY. In short, while we may not be getting telemetry sentences quite as often, we will have a much higher chance of the telemetry that is received being useful to us!

THOR Receiver Tune & Test Day – Sunday 4th March ~10:30AM CDST

To help stations adapt to the new THOR16 signal, this coming Sunday (a week prior to the launch) there will be the opportunity for stations in the Adelaide metropolitan area to set up dl-fldigi as per the linked guide below and have a go receiving a higher-power version of the THOR16 signal. This will be broadcast from Mt Lofty Summit by Mark VK5QI. Mark will be on the VK5RSB 70cm repeater (439.900 -5MHz / 91.5Hz CTCSS) as ‘technical support’, to help assist setting up the software. The signal should be easily receivable from the Adelaide Metro area and some surrounds.

Look for the test signal on 434.640MHz

Horus 48 Launch Campaign – Tentative 10-12th March

For the actual launch the following weekend, the telemetry frequencies for the flight are as follows:

  • RTTY – ‘HORUS’ – 434.650 MHz
  • THOR16 – ‘THORUS’ – 434.640 MHz

Both payloads are running 10mW transmit power, and have essentially identical antennas.

DL-FLDIgi Setup for THOR16

As usual, use dl-fldigi to decode telemetry, but in the case of the THOR16 payload, you will have to manually select the operating mode from the drop-down list as follows:

If you have the capability of running two 70cm receivers, please consider running two instances of dl-fldigi to decode both payloads. This may require either multiple PCs, or multiple sound cards. If you can only run a single receiver, please try and alternate between the different telemetry payloads.

We would very much appreciate reports as to your experiences decoding the different telemetry payloads – please e-mail these through to vk5qi@rfhead.net

Tracking for the launch will be available on the HabHub online tracker. We hope to see you as part of the tracking nets!


73 de Mark VK5QI



Willunga High School Launch – Success!

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On the 7th of December 2017, members of Project Horus participated in the successful launch of the Willunga High School’s 2017 balloon launch. This year Willunga High School was participating in a ‘Balloons Without Borders’ exchange program with the United States ‘Near Space Systems’ – Near-Space Systems would launch Willunga High School’s payload, and the US payload would be launched here in Australia. The US payload contained cameras and various atmospheric sensors.

NearSys BalloonSat Payload

The chase team consisted of Mark Jessop VK5QI, and Matthew Scutter, the developer of SkySight.io, a weather prediction service that Project Horus has made use of many times for launch-day weather predictions. This was Matthew’s first balloon chase, and as is custom, he got thrown straight into the deep end acting as navigator and operator of the chase car software.
Mark describes the launch day as follows:
We launched right ahead of a cold front that was moving in, which threatened to make the flight challenging. During my drive to the launch site I encountered large areas of showers, however the Willunga area stayed clear for quite a while. 
The winds did start to pick up during launch preparations, but were not strong enough to make the launch difficult. We ended up with a total payload mass (combined across the 2x telemetry payloads, 1x Wenet imagery payload, and the BalloonSat) of approximately 1300g.
The flight proceeded pretty much as planned, with an average ascent rate of 5.2m/s. The payload’s ground speed was observed to reach 200kph at some points during the flight. The balloon was cut away at just under the predicted burst altitude of 30km, in an attempt to bring the landing site closer towards the Dukes Highway, a major highway running through the region. The maximum altitude was 29949m. 
The descent rate was faster than expected, around 10m/s on landing. This turned out to be due to one of the payloads tangling with the parachute, causing it to not open completely. This brought the landing location a bit further away from the highway, and made the descent portion of the flight too fast for the our lonesome chase team to get to the landing site in time to watch the landing. 
We arrived about 20 minutes after landing to find the payload in a large, recently cropped field, about 200m from a road. Shortly after we departed, the cold front arrived and the rain started – we had recovered just in time!
All the payloads were recovered in good condition, in spite of the faster-than-expected landing. Constructing the payloads from lightweight expanded polystyrene does have its advantages!
The live Wenet imagery didn’t perform too well, mainly due to lack of receivers. I had a receiver running in my chase car, and Graham VK5EU did a great job of receiving from home.
Thanks also go to VK5HS, VK5APR, and VK5NEX for decoding the RTTY telemetry throughout the flight!
 The flight profile and chase vehicle tracks can be seen here.
The flight statistics are:
Flight Designation:WHS-December 17
Launch Date:07/12/2017 00:11:45 UTC
Landing Date:07/12/2017 02:08:09 UTC (Approx)
Flight Duration:1 Hour 57 Minutes
Launch Site:-35.262946 138.555586
Landing Site:-35.755356 139.736493
Distance Traveled:124.8 km
Maximum Altitude:29,904 m
Thanks to everyone involved in yet another high altitude balloon flight!

SHSSP Horus 41/42 Flights GO for Sunday 22nd

UniSA Flights are GO for Sunday  
Matt and I have just called ‘GO’ for the launches on the weekend. We have enough control variables to play with to be able to make the flights viable with the current predictions. Liftoff will be 10:00am ACDT Sunday from both sites.
Now, onto the current predicted flight paths (with the proviso that things still have a chance of changing a bit between now and then).

McLaren Vale – Horus 41
Ascent Rate: 5m/s
Cutdown at: 32km
Descent Rate: 4m/s
Mt Barker – Horus 42
Ascent Rate: 5m/s
Burst/Cutdown at: 34km
Descent Rate: 4m/s

 How to get involved?
There will be many ways of getting involved in the flight. A live stream of the event will be available (details TBA). You can follow along the university project via their Facebook page as well!
They are also running a competition to name the two balloons. If you’re a primary school or high school student please fill out the form below to submit your idea for a name!  (click here).
Keep visiting our website for ongoing updates for this project!
Details of the payloads and how to track them are available here (click).

Horus 40 Launch imminent – Jan 2nd 2017

Weather conditions are now looking somewhat better for a launch on Monday the 2nd of January. Liftoff is planned for 10.00am ACDT.

Ground wind conditions at Mt Barker should be light, and the current prediction (with some tweaking of launch parameters), has us landing somewhere north-east of Palmer:

Launch Details

The team will be launching from the Mt Barker High School oval. Our NOTAM’d launch time is 10AM ACDT, so we will be on-site from about 8:30-9AM. It is expected that balloon filling will take a bit longer this time, as we really need to get the balloon fill spot-on to achieve the desired flight path. Given this is an AREG test launch, visitors from the Amateur Radio community are welcome!


There will be 5 payload boxes on this flight! (The most in a while)

  • RTTY Telemetry (434.650 MHz 8N1 ASCII 100baud) – The usual RTTY payload as has flown in the past.
  • Flight Control payload (TDMA) – we use this for telecommand to terminate the flight at the right altitude
  • Secondary Test Flight Control Payload (TDMA) – In-air test of new TDMA software updates.
  • Wenet Imagery Payload – 441.200 MHz 115Kbit/s Wideband FSK
  • GoPro HD Hero 3 Video Payload – 25fps 1080p video – to be collected after landing

As usual, you’ll be able to select the flight from a drop-down list in dl-fldigi to decode the RTTY.

Tracking will be available via habhub.org habhublogo

Wenet SSDV imagery will be available via ssdv.habhub.org/VK5QI

Wenet Payload

For those club members involved in the Wenet payload data collection. you *should* be able to decode it using the software stack from last flight, however some Raspberry Pi firmware updates have slightly adjusted what ‘115200 baud’ actually means (115387 -> 115177 baud). Receivers running the old software are going to see a fairly large symbol rate error, and may experience a performance hit because of that. While the old software should work, the best preparation would be to upgrade your software.

As an upgrade, this flight will be sending ‘Full HD’ 1080p images, which should make nice desktop backgrounds! Note that this flight will be sending maybe 2x the number of images as the previous flight, due to some threading improvements made to the software.

As always, the Wenet ground-station software is available on Github at: https://github.com/projecthorus/wenet with an install guide for Ubuntu Linux here. A RTLSDR and a 70cm preamplifier are required for reception.

Launch Site Map

For those who want to see the balloon filled and lift off, here is the venue:



Next Balloon Flight in Planning Stages

The Project Horus team through the Amateur Radio Experimenter’s Group is planning another balloon flight!

Well I’ve got NOTAM’s booked in for the 2nd, 4th, and 6th (Monday, Wednesday and Friday) 10AM, with the plan being to fly on Monday 2nd January. If the predictions are poor for the Monday (which is possible, given what’s coming towards SA weather wise over the next couple of days), then we may have to move to one of the other days, depending on personnel availability.

The flight is intended to have the following onboard:
  • Wenet SSDV payload (new box which I still need to build, new hardware), flying updated software. This will now have live GPS data overlaid on the image, as well as an AREG logo overlay. The images are now also full 1080p, so we’re effectively downlinking desktop backgrounds
  • RTTY Telemetry (the usual, 434.650 MHz)
  • Possibly a GoPro HD video camera We’ll evaluate that one closer to the date, and once I actually have a box made up for it.
Those running Wenet SSDV ground stations will need to update their software before this launch.

High Altitude Balloon Launch WEDNESDAY 27th July with Willunga High School


Andy VK5AKH and Mark VK5QI preping the balloon

Willunga High School undertook a high altitude (well, not so high this time…) balloon launch Wednesday the 27th July, with some tracking support provided by AREG’s Project Horus flight team.

Willunga Balloon Prediction July 2016

WHS Balloon Flightpath Prediction

This flight was organised mostly (gas + balloon + payload + CASA) by a science teacher from the high school, with assistance from myself (telemetry + recovery). The launch being mid-week certainly doesn’t make it easy from our side, so at the moment the tracking crew consists of myself, Gary, and the Adelaide division of IBM Ozlabs (Joel Stanley and Andrew Jeffery).

The flight carryed a GoPro plus the usual tracking & cutdown payloads, beneath a 300g balloon. We expected a burst altitude of around 20km, with a predicted landing zone to the east of Swan Reach:

This was a fairly long distance flight for the predicted altitude, but the predicted flight path holds the promise of some pretty good video of the Adelaide area (assuming the ‘partly cloudy’ prediction happens). The VK5QI chase crew was on the road to Swan Reach roughly 30-45 min prior to the launch time, to get in position to both cutdown (if required) and recover.


During the Chase and recovery

Update: The Flight was a Success!

The flight has been a success and the payload was recovered (albeit a little further away than planned, about 10-15km south of Waikerie). Here was the actual track route from the chase:

Flight Path

Flight Path

The AREG crew helped with filling the balloon as well at the School. Here are their ground crew efforts

The following gives you an idea of some of the frames collected by the camera for the school!

And the following is the recovery action

Thanks to Gary VK5FGRY, Mark VK5QI and Andy VK5AKH for the photos!