Horus 52 – SHSSP 2019 Flight Report

This year AREG was once again involved with the International Space University’s Southern Hemisphere Space Studies Program (SHSSP), hosted by the University of South Australia. As with previous years, AREG performed a high-altitude balloon launch, carrying a SHSSP-developed payload. AREG members also worked with the project participants, running tutorials on various aspects of the launch.

The planned launch date was the 2nd of February, but had to be delayed a week due to poor flight-path predictions. In the lead-up to the new launch date (9th of February) predictions were looking good, however as the date got closer the prediction moved further and further north with a predicted landing to the west of Morgan. To make things even more interesting, the chance of showers at the launch site increased from 10%, to 30%, then to 70% over the final 3 days before the launch, along with predictions of 30kph winds.

Still, launch planning continued, and on the morning of Saturday the 9th of February the Project Horus launch crew and the SHSSP participants assembled at the Mt Barker High School oval for one of our most challenging launches to date!



After finding a filling location mostly out of the wind, the launch crew were able to get the balloon filled quickly and get the payloads laid out ready for launch. SHSSP participants assembled and tested their payload, before sealing it up ready for the launch.

Just as the planned launch time of 11AM approached, the launch director was informed by Air Traffic Control that a 10 minute launch hold was required. This couldn’t have come at a worse time, as the wind started to immediately pick up. The balloon wranglers had a very challenging time stopping the balloon from blowing around in the wind, with the latex envelope coming dangerously close to bursting many times.

Finally the launch was given the all-clear from ATC, and the payloads were released during in a short lull in the wind, using the classic ‘running launch’ method. Unlike a previous launch in high winds, the payloads easily cleared the trees and were on their way to the stratosphere.

A big thanks to all the launch crew for helping out – it was great to see many members at the launch site, and it certainly made this challenging launch a lot easier!

The Chase!

The chase teams for this flight consisted of Mark’s team (Mark VK5QI, Andy VK5AKH and Will VK5AHV), and Liam VK5LJG flying solo. As the flight path was predicted to be a long one (landing near Morgan!), the teams set of immediately after launch, leaving pack-up to the rest of the ground crew (thanks guys!).

Meanwhile tracking stations across the state began collecting telemetry. Michael VK5ZEA in Port Lincoln had his station in full swing:

While the AREG ground station deployed and manned by Peter VK5KX collected as much of the telemetry as possible from the multiple transmitters on this flight.

As for the chase and recovery teams, they steadily drove north through Palmer and Sedan heading for an expected landing near Morgan. The teams were caught by surprise by the balloon’s early burst at 25km altitude (the expected burst was 35km), which shifted the resulting landing prediction very close to the River Murray north-west of Waikerie.

Mark’s team immediately diverted through Blanchetown and headed towards landing area, and were able to track the payloads down to 62m altitude from the highway. A route to the landing site (in a vineyard at Qualco) was determined, and the team continued on. Unfortunately Liam VK5LJG had a vehicle fault, and had to stop at the Blanchetown roadhouse to await repairs.

Horus 52 Flight Path

While Mark’s team was approaching Waikerie, Steve VK5ST also made an appearance – he had been waiting near Morgan for the balloon to land, and had made his way to the landing area. After a brief discussion with the Vineyard manager the teams were able to drive right to the payloads, which had landed across four rows of ripe grapevines.

The SHSSP payload, suspended between grapevines.

Mark’s team then headed on to Waikerie for a much needed Bakery visit!

Tracking & Telemetry

As usual, we had a good showing of Amateur Radio operators from around the state receiving telemetry from the balloon. It was good to see a few new callsigns tracking telemetry (Hi Liam!) as well as our regulars.

The flight had the usual RTTY and 4FSK payloads, the telemetry statistics of which are shown below:

RTTY Payload

CallsignReceived PacketsPercentage of Flight ReceivedFirst-Received Altitude (m)Last-Received Altitude (m)

4FSK (Binary) Payload

CallsignReceived PacketsPercentage of Flight ReceivedFirst-Received Altitude (m)Last-Received Altitude (m)

Thanks to all who participated!

Wenet Imagery Payloads

This flight featured two Wenet imagery payloads – one with a downward-facing camera, and one outward-facing (for nice horizon photos). For the most part, these were identical to the Wenet payloads flown in previous Horus launches. The downward-facing payload was also configured to to receive telemetry from a SHSSP-designed payload and relay it to the ground via the Wenet FSK downlink.

Even though it was quite cloudy, the two payloads were able to capture excellent imagery throughout the flight.

Thanks to the following receiving stations who contributed to the Wenet reception effort:

Downward Facing Imagery

This slideshow requires JavaScript.

CallsignPackets ReceivedTotal Data Received (MiB)
VK5QI (Mobile)338708.27

Outward Facing Imagery

This slideshow requires JavaScript.

CallsignPackets ReceivedTotal Data Received (MiB)
VK5QI (Mobile)9776223.87

SHSSP Payload – Radiation Monitoring

This year, the SHSSP decided to develop a payload to measure ionising radiation throughout the balloon flight. The majority of ionising radiation observed in the troposphere and stratosphere are a result of cosmic rays interacting with particles of air, producing showers of secondary particles which can be observed using radiation sensors.

Two radiation sensor types were used: a geiger-muller tube, and a PIN-diode-based sensor. Radiation detection events were logged by a Raspberry Pi Zero W, and relayed to the downward-facing Wenet payload for transmission to the ground throughout the flight.

From the flight data, Bill Cowley (VK5DSP) was able to create plots of radiation count vs altitude:

These plots show the ‘Regener-Pfotzer Maximum’ at ~18km altitude the characteristic peak in the distribution of charged particles in the atmosphere. Above this point the radiation intensity drops due to there being less atmosphere for cosmic ray interactions to occur; below it, the intensity drops due to secondary particles being blocked by denser atmosphere.  A full writeup of the payload and results are over on Bill Cowley’s blog.


With the usual excellent imagery from the Wenet payloads, and the good data from the SHSSP payload, this flight can definitely be considered a success – even with the early burst. Thanks again to all who participated, and we look forward to more Project Horus flights in the future!

Horus 52 - Flight Statistics

Flight Designation:Horus 52 - SHSSP 2019
Launch Date:2019-02-09 00:40 UTC
Landing Date:2019-02-09 02:38 UTC
Flight Duration:1 Hour 58 Minutes
Launch Site:-35.07668,138.85643
Landing Site:34.12273,139.871
Distance Traveled:140 km
Maximum Altitude:25,497 m

Horus 52 / SHSSP 2019 – Frequency & Tracking Data

Horus 52 – Saturday 9th February 11.00am Liftoff!

AREG is pleased to once again be involved with the International Space University’s Southern Hemisphere Space Studies Program hosted by the University of South Australia. This year one balloon is being launched from Mt Barker High School as part of the program. All amateurs across the state are invited to participate in the flight through collecting the RTTY telemetry. All you need is an SSB receiver on 70cm, and an interface to your computer. The rest is software!

You can find out more about the software you need to track the balloon via our software tracking page

Telemetry Payloads

As always, we’ll be flying the usual assortment of telemetry payloads, including:

  • Our usual 100 baud 7N2 RTTY telemetry on 434.650 MHz USB. This can be decoded using dl-fldigi, with a reception guide available hereNOTE: There is a known issue with dl-fldigi where it does not upload any received telemetry until about 10 minutes after the software is started. Any telemetry received in this time period will be queued and uploaded after the startup period has completed (i.e. no telemetry will be lost).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!
  • 4FSK Telemetry decoder

    The new 4FSK Binary telemetry will be transmitting on 434.640 MHz USB. This uses a separate decoder, with setup instructions for this available here. We would love reports of how the 4FSK signal compares to standard RTTY!


Wenet Imagery Payloads

This flight will feature two ‘Wenet’ high-speed imagery payloads, as have been flown on many previous Horus launches. The centre frequencies for the transmissions are:

  • 441.200 MHz – Nadir-pointing (Downward) Imagery
  • 443.500 MHz – Horizon-pointing Imagery

These will be downlinking HD pictures throughout the flight, which will be available 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.

Note that users running an ‘older’ version (Circa mid-2018) of the Wenet receiver software will need to apply a -220kHz offset to the above frequencies in their setup_rx.sh file (i.e. 440980000 or 443280000) – or just leave them at their defaults, which should already be correct.. Those running the latest version can just define the centre frequency as-is. Older versions of the Wenet software will show a lot of ‘Unknown Packet Type’ messages due to some new telemetry formats we are trialling on this flight.

Online Tracking

Tracking of the flight will be available on the HabHub Tracker, available at this link. (Note that other balloon launches will also be visible on this page, including the Bureau of Meteorology launches from Adelaide Airport).
Follow the #SHSSP hashtag on Twitter for updates from the launch and chase teams on the launch day.

Flight Prediction

The following will give you an idea of the expected flight track for Saturday. It is going to be a LONG chase this time! See you all on Saturday!

Project Horus – Telemetry Test Flight #2 (Horus 51) Flight Report

Today’s telemetry test flight (now designated as Horus 51) was performed with (mostly) good results! This launch was an experiment to investigate solutions to the ‘Horus Binary’ payload PLL-loss-of-lock issue that has been observed on previous launches. Three payloads were launched, with variations on insulation and transmit power, all using reprogrammed Vaisala RS41 radiosonde PCBs. As a result, there was a lot of telemetry to receive on this flight!

Getting ready to launch the payloads

The launch was a fairly relaxed affair, with only a small launch crew on-site. Launch occurred right on time at 11AM. It was quickly discovered that a bit too much helium was used (dodgy gas flow-rate meter!), and so the ascent rate was higher than expected resulting in the small balloon used bursting at 16.2km altitude.

Horus 51 Flight Path

As the pre-launch flight path prediction had the landing area somewhere south-west of Loxton, none of the launch crew attempted to chase this launch. Instead, Ivan (VK5HS) from the Riverland Radio Club lead a small team (Ivan, David and Peter) out from Renmark to recover the payload. As it turns out, the higher ascent rate and lower burst altitude resulted in the landing location being further away from Loxton than expected, but the Riverland boys were able to track payloads down to the ground and easily recover them not long after landing.

David (left) and Peter (right) with the recovered payloads.

Many thanks to Ivan & Co for making the effort to get out and chase, it is much appreciated!

Horus 51 - Flight Statistics

Flight Designation:Horus 51 - Telemetry Test Flight #2
Launch Date:2018-11-25 00:30 UTC
Landing Date:2018-11-25 01:40 UTC
Flight Duration:1 Hour 10 Minutes
Launch Site:-35.07568, 138.85701
Landing Site:-34.68642,139.92380
Distance Traveled:106 km
Maximum Altitude:16,201 m

Telemetry Statistics

Thanks to all who participated in the launch by receiving telemetry from one (or more!) of the three payloads. Statistics on how much telemetry was contributed by each receiver callsign is below:

Horus 51 - HORUSBINARY (434.640 MHz) Receiver Statistics

CallsignReceived PacketsPercentage of Flight ReceivedFirst-Received Altitude (m)Last-Received Altitude (m)

Horus 51 - HORUSBINARY2 (434.650 MHz) Receiver Statistics

CallsignReceived PacketsPercentage of Flight ReceivedFirst-Received Altitude (m)Last-Received Altitude (m)

Horus 51 - 4FSKTEST (434.660 MHz) Receiver Statistics

CallsignReceived PacketsPercentage of Flight ReceivedFirst-Received Altitude (m)Last-Received Altitude (m)

Please make sure you follow the configuration instructions when using the Horus Binary decoder, to avoid the ‘YOUR_CALL_HERE’ entries seen in the above tables!

Payload Testing Results

Previous Horus launches have seen the repurposed Vaisala RS41 payloads lose PLL-lock mid-flight, with the transmit frequency drifting up the 70cm band as temperature decreases. Testing on the ground indicated this may be due to the Radio IC (a Silicon Laboratories Si4032 FSK transmitter) failing with the low temperatures experienced during flight. The fact that the the RS41 sondes do not usually fail during their intended application pointed at the lower transmit power (25mW vs 50mW) used on Horus flights being a possible factor.

On previous flights the following results were seen:

  • Horus 49 (Anstey 2.0) – RS41 Foam Only, 25mW – No issues Encountered.
  • Telemetry Test Flight #1 – RS41 Foam Only, 25mw – Failed on Ascent at 9km altitude, recovered on descent at 1km altitude.
  • Horus 50 – Stock RS41, 25mW – Failed on descent for ~6 minutes between 13km and 9km altitude.

With 2 failures and one success, it was decided that more data needed to be gathered.

Foam-Only (Left), ‘Stock’ RS41 (Middle), Custom Enclosure (Right)

On this launch, two payloads were operated at 50mW transmit power, one with a ‘stock’ enclosure (‘HORUSBINARY’) and one with only the inner foam insulation (‘HORUSBINARY2’). Using only the inner foam insulation provides a significant weight reduction, cutting the payload weight almost in half (~120g to ~60g).

A third payload (‘4FSKTEST’), using a custom-built foam enclosure was also tested, transmitting at 25mW. This had a similar overall weight (66g) to the foam-only RS41 enclosure, and re-flew the RS41 board that failed on Horus 50.

A bug in the firmware, discovered after the Horus 50 flight, was also fixed for this launch. This fix allowed gathering of measurements from a temperature sensor on the silicon die of the radio transmitter IC – unfortunately the temperature measurements captured on previous launches are invalidated as a result of this bug.

Horus 51 Payload Temperatures

Sadly, the foam-only payload (‘HORUSBINARY2’) was observed to fail at 14.3km altitude during ascent, and recover at 4.8km on descent, failing with a radio IC temperature of 0 ˚C.

Failure of the HORUSBINARY2 payload, as observed by Joe VK5EI

Both the stock RS41 and custom enclosure payload remained operational throughout the flight. The overall higher temperatures reported by the Stock RS41 payload may be a result of a bias in the temperature sensor, or may be a result of the better insulation – Further investigation will be performed once the payloads make their way back to Adelaide.

Curiously, the two other payloads reported radio IC temperatures lower than the failure point of the foam-only payload (0˚C), indicating that perhaps it is not the radio IC at fault, but another component on the PCB. Further investigation will be performed on RS41 PCBs using selective cooling of components, prior to the next Horus launch sometime in January 2019.

However, based on the results from this flight, it appears that the safest option for the moment is the Stock RS41 enclosure, transmitting at 50mW. As always, Horus flights use  redundant telemetry transmitters, so that a failure of a single transmitter does not compromise our ability to track and recover!

Project Horus – Telemetry Test Flight #2 – Sunday 25th November 11AM CDST

UPDATE: Predictions look good, so this flight will be going ahead as planned. The launch team will not be chasing this flight – others are welcome to chase/recover the payloads if they wish.

Current planned flight parameters (for prediction purposes) are a 4m/s ascent rate, 20km burst altitude, and a ~7m/s descent rate.


On Sunday, the 25th of November, Project Horus will be performing a small balloon launch from Mt Barker High School Oval, at approximately 11AM CDST. Live flight tracking will be available on the HabHub online tracker as usual. A guide on how to decode the new Horus binary telemetry mode is available here.

This launch is another test flight of the new ‘Horus Binary’ telemetry payload, which uses a new modulation mode developed by David Rowe VK5DGR and Mark Jessop VK5QI with 6dB better performance than the usual RTTY telemetry. This telemetry mode has been flown on a few recent Project Horus flights, with mixed success – The modem has performed flawlessly, the payloads themselves not so much! These flights have flown reprogrammed Vaisala RS41 radiosondes, which while working perfectly on Bureau of Meteorology launches, have proven troublesome on Horus launches!

Drifty Horus Binary Payload – Hopefully not on this this flight!

The last telemetry test flight suffered a loss of PLL lock on ascent, believed to be due to temperature issues, causing the payload to drift right up the 70cm band. On Horus 50, a similar fault occurred on descent, though the payload recovered within a few minutes. Further investigations confirmed a temperature issue, likely due to the lower transmit powers used on Horus flights (25mW) compared with the stock transmit power of 50mW.

This flight aims to test a few different variations on the payload flown on Horus 50, to determine if transmitting at a higher power keeps the payload alive. A few different modifications to the payload insulation will also be tested.

Currently we plan to fly 3 telemetry payloads (all on USB, +/- temperature drift):

  • 434.640 MHz – Callsign ‘HORUSBINARY’ – Unmodified RS41, 50mW TX power.
  • 434.650 MHz – Callsign ‘HORUSBINARY2’ – RS41 without outer plastic shell, 50mW TX power. Prioritise reception of this payload.
  • 434.660 MHz – Callsign ‘4FSKTEST’ – RS41 PCB in custom enclosure, 25mW TX power.

The Horus Binary uploader script will automatically determine the payload callsign as long as you are running a recent version. Please make sure you have updated to the latest version (2018-11-15) of the Horus Binary uploader before this flight, otherwise the HORUSBINARY2 payload will not be recognised, and data for the other payloads may be corrupted. Those who were set up for Horus 50 can simply download the latest payload ID list, and place it in their horusbinary directory.

Launch will be from the usual Mt Barker High School Oval site, and launch teams will be on-site around 10:15AM, for a 11AM launch. All are welcome!

AREG’s 20th Anniversary Event – Horus 50 Balloon Launch – 4th November 2018

2018 marks 20 years since the Amateur Radio Experimenters Group was formed. To celebrate this milestone, the club is planning to fly a special Amateur Radio focused high altitude balloon in what will be the 50th Project Horus Mission.

The Project Horus team itself is also celebrating 8 years in the air! Project Horus was founded by Terry Baume and continues to perform regular high-altitude balloon launches from locations around South Australia under the auspices of the Amateur Radio Experimenters Group.

When will this be happening? Currently it is planned to fly on Sunday the 4th of November (weather permitting). Liftoff is planned for 10AM ACDT. We are going for altitude so coverage will hopefully extend as far as Melbourne at the peak of the flight.

The goal is to engage with amateur radio in as many ways as possible. We want you to talk through the balloon, see the world from the balloon’s perspective and know where the balloon is during the flight! How can you do all this you might ask? The Project Horus team have specifically tailored this flight to include:

  • a 2m (down) / 70cm (up) Cross-band FM repeater. Amateurs within the repeater footprint will be able to make live QSOs with the club station VK5ARG and each other via the FM repeater using relatively modest stations.
  • a 2m SSTV beacon transmitting images from the balloon live during the flight. You will be able to see the world from the balloon’s perspective using a 2m receiver and simple software (you can even use an app on your phone).
  • Track the balloon via a 2m APRS beacon during the flight!

The launch site will be the usual Mt Barker High School Oval. Launch crews should be on-site around 8:30-9AM. If you haven’t attended one of our launches before, this is a great opportunity to come along and see what’s involved first-hand!

As usual, there’s always the chance the weather for the planned launch date may not be suitable, so a backup launch date of Sunday the 18th of November has been tentatively penciled in (the 11th being the AHARS buy & sell weekend).

Cross-band FM Repeater

Likely suspects operating the cross-band repeater on Horus 23

The cross-band repeater will be using the following frequencies:

  • Uplink: 438.900 MHz, with a 123 Hz CTCSS tone required for activation.
  • Downlink: 147.500 MHz  (~1.4W output power).

To transmit to the balloon at the maximum range of 700km (once the balloon reaches >30km) you will need approximately 10-30W and an 10dBi gain antenna and a clear takeoff towards the balloon. Those stations closer to the launch site will be able to get away with much less.

PLEASE MAKE SURE YOU can hear the repeater before transmitting
and remember to make sure you SET YOUR CTCSS TO 123Hz
or you will not access the repeater.

As with previous flights, the repeater will be run as a controlled net. Listen for VK5ARG acting as net control and please follow their instructions so that as many people as possible can share the repeater.

FM-SSTV Imagery Payload

Instead of the usual Wenet imagery payload this launch will have a new SSTV transmitter operating on 145.100 MHz FM. It will run approximately 250mW transmit power. The transmitter will have 30 second gaps between image transmissions to avoid overheating the transmitter.

Scottie 2 SSTV Imagery Example

The payload will be transmitting images using the Scottie 2 SSTV mode throughout the flight, and can be decoded using any SSTV software capable of decoding this mode (pretty much all of them!). This is a mode that typically is used on HF but is equally adapted to VHF FM work. (Note it is not the same as the PD120 transmissions from ISS).

Examples of suitable software you can use to decode the SSTV pictures include:

Any FM receiver (including handhelds) should be capable of receiving this payload, though as with the cross-band repeater, a Yagi antenna may be necessary for reliable reception at the edges of the transmitter footprint.

If you do receive images, please post them to Social Media and on Twitter include the #horus50 hashtag so everyone can see them!

Telemetry Payloads

As always, we’ll be flying the usual assortment of telemetry payloads, including:

  • Our usual 100 baud 7N2 RTTY telemetry on 434.650 MHz USB. This can be decoded using dl-fldigi, with a reception guide available hereNOTE: There is a known issue with dl-fldigi where it does not upload any received telemetry until about 10 minutes after the software is started. Any telemetry received in this time period will be queued and uploaded after the startup period has completed (i.e. no telemetry will be lost).
  • 4FSK Telemetry decoder

    The new 4FSK Binary telemetry will be transmitting on 434.640 MHz USB. This uses a separate decoder, with setup instructions for this available here. (Previous listeners note that there have been updates to the software – please re-download the latest version!). We would love reports of how the 4FSK signal compares to standard RTTY!

  • If weight permits, there will be an APRS beacon operating on 145.175 MHz with the callsign VK5ARG-12. This will be received automatically by the APRS network.
Tracking of the flight will be available on the HabHub Tracker, available at this link. (Note that other balloon launches will also be visible on this page, including the Bureau of Meteorology launches from Adelaide Airport).
Follow the #horus50 hashtag on Twitter for updates from the launch and chase teams on the launch day.
Stay tuned for updates closer to the launch date…
Mark VK5QI

Horus Telemetry Test Flight 29th July 2018 – Flight Report

With all the successful flights that Project Horus has had recently, I guess it’s about time we had one that didn’t quite go to plan…

Windy conditions at the launch site made filling difficult

First up – the weather. If this was a full-size Project Horus launch, we would have likely cancelled and re-scheduled the flight. However, since this was just a small test flight with a disposable payload, we decided to have a go.

Thankfully we didn’t experience the forecast showers, however 30-40kph winds at the launch site made filling an exciting experience, with the balloon blown all over the place. Mark VK5QI, Will VK5AHV, Chris VK5FR and Matt VK5HZ were the launch crew for the morning. Graham VK5GH also made an appearance. Just as we were starting to tie off the balloon a wind gust came up and tore the balloon off the fillter… goodbye balloon! (Memories of Horus 8, though this time without the garage to stop the balloon flying away).

Bye bye balloon… (Photo courtesy Matt VK5HZ)

There was just enough gas left in the cylinder to fill a small ‘backup’ balloon (a 100g Hwoyee) and get enough lift to get the payload in the air.

The achieved ascent rate after launch was ~3m/s, a bit lower than the planned 5m/s, however with the switch to a smaller balloon, this actually resulted in a fairly similar flight path to what was originally planned.

The first part of the flight went pretty normally. Many receiving stations came online to decode the new 4FSK Horus Binary mode, including a few new callsigns. Will VK5AHV and Mark VK5QI headed off towards Bear Rock to track the payload as long as possible, while Marcus VK5WTF was already stationed up on Accomodation Hill to do the same. Ivan VK5HS and Peter VK5PE were already out in the expected landing area (South of Loxton), recovering the morning’s Bureau of Meteorology radiosonde launch.

Faulty payload!

At just about 9km altitude… something went wrong in the payload. The signal became very wide, and then immediately started drifting up the band. The current theory is that the payload flew through a cloud on ascent, and a combination of condensation within the payload and extreme cold caused some problem with the radio IC. UPDATE: Testing has confirmed that the issue was related to insufficient insulation around the radio IC. Better sealing around the payload edges solves the issue, and hopefully this won’t occur on future flights.

The transmitted signal continued to drift up through the 70cm band, topping out at about 436.4 MHz before descending back down again. At some point (estimated to be about 21km altitude) the balloon burst, sending the payload quickly back towards the ground.

As we watched the signal drifting back down the band, we wondered – what will happen when it gets back to the original frequency – 434.640 MHz? Sure enough, as the frequency drifted closer towards 434.640 MHz, the drift rate sped up, and it almost ‘snapped’ back into place – and the 4FSK started up again! (Later analysis of the telemetry showed that the GPS & micro-controller continued operating while the radio went walkabout.)

Quickly we rushed to get the decoder up and running again, to find the payload was at ~1km altitude and dropping fast. From Bear Rock we were able to decode the payload down to ~300m (at a distance of 140km, not bad!). Peter VK5PE’s home station in Renmark was able to track it down a bit further, to ~220m.

Ivan and Pete turned around (they were halfway back to Renmark) and were able to recover the payload not far from the last reported position.

Peter VK5PE with the payload in hand!

Even with the issues this flight, we still met the primary goal of getting stations decoding the new Horus Binary telemetry mode. Stations seen to upload telemetry included:


Thanks to all for your participation! We will be evaluating the received data and working out better ways of weatherproofing the modified RS41 payloads to avoid the issues encountered on this flight. Expect to see the Horus Binary telemetry on future flights!

Horus Telemetry Test Launch – Sunday 29th July 11AM CST

UPDATE: Unfortunately the payload failed at approximately 9km altitude. It recovered on descent just prior to landing, and we were able to get a landing location. Ivan VK5HS and Peter VK5PE were able to recover the payload from the middle of a large field south of Loxton.

Thanks to all that decoded the initial part of the flight. If you could please e-mail your log files through as mentioned below that would be appreciated.

This coming Sunday, the 29th of July, Project Horus will be performing a small balloon launch from Mt Barker High School Oval, at approximately 11AM CST. Live flight tracking will be available on the HabHub online tracker as usual.

This launch is another test flight of the new ‘Horus Binary’ telemetry payload, which uses a new modulation mode developed by David Rowe VK5DGR and Mark Jessop VK5QI with 6dB better performance than the usual RTTY telemetry. The first flight of this new payload was on the Horus 49 (Anstey 2.0) flight, where it performed well!

A modified Vaisala RS41, which transmits the new Horus Binary telemetry

The aim of this flight is to provide another opportunity for listeners to attempt decoding of this mode. Like the RTTY telemetry, the Horus Binary telemetry can be received using a 70cm Single-Sideband receiver. Telemetry will be on 434.640 MHz USB (+/- temperature drift). This will be the only payload on this flight, and we are not intending on recovering the payload (though others are welcome to go after it!).

Decoding of the the new mode is not supported in dl-fldigi, and hence new software must be installed – a guide on how to install and run the required Horus Binary decoder software is available here.  (A note to those listeners that decoded the binary payload on Horus 49: a few new features have been added to the Habitat uploader utility – please update to the latest version!)

To help debug some issues that were encountered on the last flight, it would be appreciated if all listeners e-mailed the ‘telemetry.log’ and ‘horusb_debug.log’ log files (created by the horusbinary uploader) through to Mark VK5QI (vk5qi@rfhead.net) at the conclusion of the flight.


Horus 49 – Anstey in Space v2.0 – Success!

On Sunday the 8th July, the Tea Tree Gully Library’s echidna mascot, Anstey, rose into the sky to an altitude of 36,374 metres under a High-Altitude Balloon. This was Anstey’s second flight into the stratosphere, and Project Horus’s 49th balloon launch.

Originally planned for the 30th of June, Horus 49 had to be delayed a week due to very poor weather conditions. Even still, this flight was a a long one for the chase teams! Fortunately we had the assistance of a team from the Riverland Radio Club who mobilized from their home base (much closer to the LZ) and who then played a big part in tracking and retrieving Anstey at the end of his flight. You can read about their adventure on the RRC Blog.

Launch Activities

As usual, the launch was from the Mt Barker High School oval – thanks must go to the school for allow us to use their oval for so many launches! A good number of AREG club members came along to help out with the launch. Also present at the launch were members of Anstey’s Space Club, there to watch the launch and see Anstey off into the stratosphere!

Filling the balloon.

Payloads were laid out, turned on and tested, and the balloon was filled with somewhat more gas than usual. The flight path predictions had a possible risk of landing close to Loxton, so additional gas was used to give a higher ascent rate (as it turned out, a *very* high ascent rate). Wind gusts made filling the balloon a bit of a challenge, but there were no lack of hands to help keep things from getting out of control.

At just after 10AM, the wind died down and we had a perfect launch!

Launch of Horus 49

The Flight

On board Anstey had two cameras recording things. The first was a GoPro miniature video camera! The second was a still camera that was sending photos live to ground as the flight progressed.

Chase & Recovery

Right after the launch, Mark VK5QI and Will VK5AHV quickly headed off towards the expected landing area to the South-West of Loxton – a long drive away! Marcus VK5WTF and partner were also following not far behind.

The ascent rate ended up being much higher than intended – ascent rates as high as 9m/s were observed at some points in the flight, resulting in a shorter than expected flight. Even still, the Hwoyee 1600g balloon used made it to a very respectable 36374 metres altitude before bursting.

With the original flight path prediction due to land near Loxton, it was looking pretty unlikely that the chase teams departing from Mt Barker would make it there before landing. Luckily, a group of Riverland Radio Club members were on the case! Ivan VK5HS, Peter VK5PE, Danny VK5DW and Andy VK5LA also headed out to chase, starting from the Loxton area. Rob VK5TRM was also out for the chase. Ivan & co had been practicing by hunting the Bureau of Meteorology radiosondes, so were well experienced in chasing balloons – so much so that they were able to get into position to watch the balloon land in an area of scrubland near the locality of Mantung (40km SW of Loxton).

Mark and Will were not far behind, arriving at the landing site a few minutes later. A short walk later and Anstey was sighted… about 8 metres up a gum tree!

With some persuasion from a SpiderBeam pole, Anstey was recovered. Many thanks to all those who came along for the chase!

Horus 49 Recovery Team

Live Wenet Imagery

Throughout the flight Anstey was imaged via a version of Project Horus’s ‘Wenet’ imagery payload, which transmits images down to the ground via a 115kbps 70cm transmitter. As expected the images of Anstey were amazing, and were viewable live via HabHub’s SSDV webpage.

This live imagery is only possible through volunteers running ground-stations. Thanks go to VK5APR, VK5EU, and VK5KX who ran stationary receivers. Mark VK5QI was also running a mobile Wenet receiver in his chase car.

CallsignPackets ReceivedTotal Data Received (MB)
VK5QI (Mobile)21801253.23

Telemetry – RTTY & Horus Binary

As with all previous Project Hours flights, a RTTY payload was flown. Many listeners contributed to tracking this payload:

CallsignPackets HeardPercentage of Flight HeardPayload Alt at First RX (metres)Payload Alt at Last RX (metres)

New to this flight was an experimental ‘Horus Binary’ payload, which was transmitting a MFSK telemetry mode developed by David Rowe VK5DGR and Mark Jessop VK5QI. This new mode has significant performance advantages over RTTY, and will hopefully become the new default telemetry system for Project Horus flights. David VK5DGR also has an overview of the payload and how it performed on the flight on his blog. Many stations were able to run the new decoding software and track the flight using this mode:

CallsignPackets HeardPercentage of Flight HeardPayload Alt at First RX (metres)Payload Alt at Last RX (metres)
VK5AKH/KX/ZM (Portable)151182.4%6970101
VK5QI (Mobile)156085.1%34364
VK5WTF (Mobile)103956.7%2776139

The new mode provides position updates twice as fast as the 100 baud RTTY payload, and with 6dB better decoding performance (meaning double the range!). The update rate may have been too fast it seems – while about 2600 packets were transmitted during the flight (confirmed as received on VK5QI’s mobile station), only ~1800 of these made it into the Habitat tracking database! This is likely a result of upload timeouts – some changes will be made to the software prior to the next Horus Binary flight so this issue can be further debugged. Still, the new mode performed incredibly well in the chase cars, providing  rapid and regular updates to the chase car mapping systems.

Thanks again to all who helped track the flight using both Wenet, RTTY, and the new modem. Expect the Horus Binary mode to make appearances on more flights in the future!

Upcoming Launches

To give more listeners an opportunity to decode the new Horus Binary mode (and to use up some leftover gas from Horus 49!), a small balloon launch will take place sometime in Late July. This will be a ‘small’ balloon launch (as per the CASR Part 101.E definition), flying a re-purposed RS41 radiosonde clocking in at just over 40 grams. A new version of the Horus Binary decoder will be released prior to this launch to allow better analysis of the upload issue encountered on Horus 49.

Also coming up is the 20th anniversary of AREG – as part of the celebrations, we will be performing Project Horus’s 50th launch! On this flight we expect to fly:

  • A 2m/70cm Cross-Band repeater, similar to what was flown at the WIA AGM launch.
  • A SSTV transmitter, sending images in the PD120 SSTV mode.
  • An APRS beacon (depending on weight budget)

.. along with the usual telemetry and cutdown payloads. Stay tuned!