Project Horus High altitude balloon project


A successful weekend of launches

We're happy to report that both launches this weekend (Horus 26 & 27) were a success.

Many thanks to everybody who turned out at the WIA AGM to hear our talk and witness the launches, and an extra thanks to everybody who helped make this weekend possible.

Keep an eye on the blog over the coming days for full details of the launches including photos & videos of the day.

Filed under: Launch 7 Comments

WIA Launch Frequencies

Tomorrow the 27th of May we will be launching two balloons from Mildura, Victoria.

Data from the telemetry payloads can be demodulated using the dl-fldigi software, available by clicking the tracking link above.

All those wishing to track should take note of the following frequencies:

Horus 26 - WIA Repeater Launch - 0800 AEST

  • Telemetry: 434.075MHz USB 300baud RTTY 7N1 (Select "HORUS" from dl-fldigi's dropdown list.
  • APRS: 145.175MHz AFSK using callsign VK5ARG-11
  • Cross-band Repeater:
  • Uplink 438.900MHz FM 123Hz CTCSS. Please use the CTCSS tone, or else you will only be causing interference to other repeater users.
  • Downlink: 147.500MHz FM.

The repeater will have net control run by VK3WIA.

Horus 27 - Imaging Payload - 0900 AEST

  • Telemetry: 434.650MHz USB 300baud RTTY 7N1 (Select "DARKSIDE" from list)
  • APRS: 145.175MHz AFSK using callsign VK5ARG-12

Between-car comms frequencies

We will primarily be using the airborne repeater for comms, and as such, the following callsigns should be given priority on the repeater:

  • VK5ZM
  • VK5GR
  • VK5QI
  • VK5VZI

For close range comms we will be using 146.550MHz FM simplex.

Long-range HF comms frequencies are 3640KHz LSB and 7070KHz LSB.

Filed under: Launch No Comments

The WIA Annual General Meeting Voice Repeater Flight This Sunday

Several months ago, the Project Horus group was invited to participate in the Wireless Institute of Australia's Annual General Meeting and Technical Symposium presentations, being held in Mildura, Victoria over the weekend of Friday May 25th to Sunday May 27th. The group happily accepted, and is now in the final stages of preparation for what will be a very busy weekend for us.

Firstly, the Project Horus group will be giving a technical presentation on Saturday afternoon as part of the AGM technical sessions. During our 40 minute presentation we will be giving an introduction to the project and highlighting some of the amateur radio aspects of the project's operations. You can find out more about the Technical Symposium and other AGM activities on the WIA's website:

The main event for us, however, begins on Sunday with the launch campaign planned from Mildura.

Flight #1 - HORUS 26 - Amateur Radio Repeater - Sunday May 27th

The first balloon that will be launched at the convention is going to carry aloft the flying cross-band FM voice repeater. This repeater will be accessible at apogee from nearly 2,000,000 sq km of SE Australia and is expected to cover Sydney, Melbourne, Canberra and Adelaide simultaneously.

Expected radio footprint at apogee.

Horus 26 should lift off at approximately 8am AEST Sunday May 27th. (2200 UTC May 26th).

The window for contacts covering that footprint will only be ~30-60 minutes at apogee which should be reached at approximately the 90-120 minute mark in the flight. In all, 2,000,000 sqkm of SE Australia will be able to see the balloon repeater as the footprint will extend to approximately a 1600km diameter.

The FM cross band voice repeater frequencies on the balloon for this flight are:

  • 438.900 MHz Uplink with 123Hz CTCSS (FM)
  • 147.500 MHz Downlink (FM)
PLEASE REMEMBER TO TURN ON YOUR CTCSS tone - otherwise you will only cause interference to others accessing the system.

Net control will be a joint effort between our usual net controller in Adelaide (VK5GH) and a local net control operator based out of Mildura (to cover the flight until it can be heard in Adelaide).В Contacts will be logged and QSL cards will be provided for all contacts via the HORUS balloon repeater.

Horus 26 Telemetry Sources

In addition to the voice repeater, amateurs will be able to follow the flight via the APRS network on 145.175MHz. VK5ARG-11 will be beaconing the balloons position throughout the flight via a “WIDE2-1” beacon path. This will enable it to be picked up by iGATE systems across SE Australia and then be relayed to the Internet. Amateurs will be able to watch the balloons progress via popular APRS sites such as

To provide the ground crews with some systems redundancy, the standard RTTY 300 baud telemetry payload will also be flying. This beacon can be received and decoded with the DL-FLDIGI software. You can find out more about how to decode this beacon here:

This 300baud RTTY telemetry beacon will fly on 434.075MHz ± 5kHz USB (the beacon drifts as the payload gets cold – it can reach below -50dec C during the flight in the payloads). This flight will identify on the air as HORUS.

The project group is very keen for amateurs within the footprint to also attempt to receive this beacon, as the data collected is (when you enable the Internet option in the software) also uploaded to the website. There it is aggregated and used to help predict the landing zone of the balloon during flight. As such, it is a valuable resource for the chase teams, and is a great way for the amateur radio community to get involved in the engineering side of the flight.

Flight #2 – HORUS 27 – Imaging Payload

The Project Horus group has carried a number of imaging payloads aloft over its more than 2 year history. We have had one of these payloads waiting for the right weather conditions for some time now. The legendary sunny weather of Mildura and reduced risks of landing in the ocean has given the team the inspiration to attempt to fly this imaging payload as well this weekend. As a result, Horus 27 is also planned to fly THIS SUNDAY.

Horus 27 will also carry an APRS and RTTY telemetry system.

APRS will operate as VK5ARG-12 on 145.175MHz operating in the same way as VK5ARG-11.

The 300 Baud RTTY will operate on 434.650 MHz ± 5kHz USB. HORUS 27’s RTTY telemetry will identify as DARKSIDE to separate the telemetry streams when they are uploaded to .

The Horus 27 flight is currently planned to lift off at ~0900Hrs Sunday 27th May (2300 UTC May 26th).

Amateurs are invited to also track HORUS 27 and provide their received telemetry feed via the Internet to the SpaceNear website. The project team would really appreciate seeing telemetry from both balloons (which will both be in the air simultaneously) being captured by amateurs from around SE Australia as it all helps capture as much data as possible about the progress of the flight.

For confirmation of launch of each balloon, the team will post announcements to the VKLOGGER DX Cluster as well as progress updates via Twitter (look for hash tag #projecthorus).

We look forward to seeing amateurs from across the region get involved in tracking and communicating via this unique experimental system!

Best Regards,
The Project Horus Balloon Team

Filed under: Launch 4 Comments