Since the launch and unsuccessful recovery of Ozhab1, I’ve always planned to reattempt another launch. However time and more important tasks seem to get in the way. However 2018 brings on many new challenges., so why not throw the construction of Ozhab2 into the mix. Though I still hope Ozhab1 will be found (slim chance), I’ve certainly learnt a lot and had a lot of fun building, launching and tracking it.
Construction of Ozhab2 has now commenced with the 2m – VHF APRS module arriving a week ago. The module is the same Radiometrix HX-1 used in my previous launch and I was very happy with it.
For Ozhab2, I’m not trying to reinvent the wheel, so will base my tracker off the Trackunio project code for Arduino. I won’t be using the Trackunio Shield as that wouldn’t be as much fun,
APRS looks to be transmitting already, but I haven’t tested a decode yet. A little more to go yet.
Here’s the video of OZHAB01 being launched from Barmedman NSW as well as other data I have collated so far
Unfortunately I have not yet recovered the payload of OZHAB01 so I am unable to provide any of the on board collected data. However I do have some flight data that was collected via APRS and the RTTY transmitter which gives a good indication of the flight progress.
The APRS was being received by digipeaters around 1000m and continued to have contact until it burst about 31000m. APRS Google Earth KML OZHAB01
The RTTY was decoded on my laptop as I chased the balloon and followed the same path as the APRS. I did loose signal a few times as it was climbing to its burst altitude. RAW KML of RTTY Flight for Google Earth
Pre fill of balloon
OZHAB01 in flight
Post Flight thoughts for next time
Ensure I pack a highly directional antenna to locate the payload.
Something with variable attenuation would be great.
Use a weight instead of digital scales to determine correct lift and helium dosage.
The digital scales were difficult to read as the wind blew the balloon around, which lead to less helium in the balloon and a slower ascent.
Cut balloon away when approaching max altitude to ensure a cleaner descent.
As I haven’t recovered payload yet, I don’t know how much balloon was intact and this could have impeded the parachute
Don’t forget the tarp next time.
Blankets worked , but were too small
Improve my APRS decode.
APRS was decoding sporadically.
I didn’t have an app installed that would upload the APRS data to the web
After a long wait, the day has finally come where I hope to have a successful launch of my first ever Arduino based High Altitude Balloon project.
My launch approval has been granted through CASA and my NOTAM has been issued for Wednesday morning 9am / Tue 10pm UTC.
The approval process was a lot easier than I had expected. I ensured that I provided all the information required from the regulations for a light balloon and the rest was easy.
I’m currently camped out at the launch site in Barmedman NSW where it must be at least 30 degrees C, so its going to be a hot night. Not going to make sleep easy when I’m rattling all the things of forgotten to bring through my head.
The predicted flight looks straight forward and as long the transmitters hold out, I should get some good results.
I’ll have a APRS tx on 145.175 , and RTTY on 433Mhz.
As long as I have mobile reception I should be able to upload to https://tracker.habhub.org/ or http://aprs.fi
I’ve reached a point where I am now securing the payload to the tie lines running up towards the chute and balloon. I want to have as much of the securing done prior to the launch day so I save time and potential last minute problems.
I have seen some launches where the balloon is tied in line at the top of the chute as well as others where it is tied below. My initial though is that the payload is going to weight as much as the balloon itself. If upon bursting the remnants weigh the same or maybe slightly more, then the payload, its possible that the balloon will pull the chute upside down preventing it from opening.
I have placed a mini carabiner similar to that used to hold your keys onto the line running to the chute. I’m hoping that when the balloon bursts it will fall causing the carabiner to slide down towards the payload leaving the chute clear to open. I just need to ensure that the chute doesn’t tangle with the balloon line.
Both methods seem to have been successful for other people’s launches but I feel that the 2nd method will allow for a better chance of recovery.
The lines around the payload are taking shape with some test lines taped to the sides. I still need to load the items into the payload and balance out and finally secure with more tape.
I will be placing the trackers in a separate box, so need to ensure that the antenna doesn’t become tangled or interfered with.
I am also trialing some fishing swivels that have a hook clip at one end. They seem to allow the rope to fit onto the swivel and are smaller then the small carabiners.
I have had to use two of these specific types as the clipped end connects nicely to the rope whilst the eyelet on the swivel would require thinner rope.
I am still working on the balancing of the payload but the below shots give you an indication of what it looks like so far.
My Totex – Kaymont 1500g balloon has arrived, so its getting closer to having the critical parts needed for launch.
I decided upon the Totex balloon after reading reports of other balloon launches having success with them but also because there are limited sources for weather style balloons down under. The 1500g should be suitable for my payload which is already at 1.2 Kg’s and hopefully reach a good altitude.