LAUNCH ANNOUNCEMENT - 3RD JULY 2024

[Mark Harper]

Hi All

The team from hi-impact based on the Wirral, have another HAB Launch
planned - Our first launch of 2024!

This time working along side staff and pupils from Monks Coppenhall
School, near Crewe, we will launch at 11am, on the 3rd July 2024, from
our usual location in Cilcewydd, near Welshpool.
This launch will be running with a HABduino,
Frequency is: 434.650MHz (USB)
Transmitting: 50 Baud RTTY (450Hz Shift)
Running with standard: 8 Bits, No Stop, 1 Parity (8N1)
Callsign: MONKS_HAB

73..Mark

[Ross G6GVI]

Currently tracking with 7-bit 50 baud, 490Hz shift.

There's a lot of wobble on the frequency - probably wind-shear?

[Mark Harper]

Hi Ross

Apols for the late reply!

It has been behaving a bit weirdly since it took a bath in a golf course lake, on it's previous flight...It did spend about a week on a windowsill in the office drying out, but it does seem to not be at it's best. I noticed during testing, that while sat on a windowsill, with the window slightly open, that the breeze was causing it to drift a fair bit (more than I'd experienced previously) so maybe the TCXO isn't working as well as it should - so maybe it was wind-shear.

I need to get into LoRA and similar tech a bit more - I'll see how it goes on a future flight..but we may have to retire it...We've still got PITS somewhere though!

Did anyone ever hear if Ofcom have approved Packet on HABs?...I still think 9600bps Packet would be brilliant for HAB use

My mistake on the data format, I should have corrected that!

Thanks again for being one of regulars, Ross!

73..Mark

[Ross G6GVI]

Hi Mark, so did you actually manage to retrieve this latest flight? The last positions uploaded to the SondeHub showed it still at more than 2km up, but were you receiving it closer to the ground from your chase car?

I don't think that you should blame your TCXO: it wasn't the drift which was unusual, but the rapid frequency-jitter. Now comparing the Grafana plots of calculated speed against reported altitude (see below) shows that it was moving really fast (and maybe spinning like a top?) at about 10km up, but things did get a lot calmer above about 16km:

And I remember Jack G8HIK observing that the frequency got more stable near the top of its trajectory.

Perhaps the wider bandwidth of the LoRa signals would be less susceptible to this frequency-jitter, but I wonder if anyone has done a LoRa flight at such speeds?

Ross.

[Mark Harper]

Hi Ross

Yes..We retrieved the flight! - Landed in Moreton-In-Marsh, in a field right by a road, so a lot easier than having to fish it out of a lake! (There's a vid at: https://www.youtube.com/watch?v=SsYG5LgE4EE)

It topped out at 26,500m - I'd have to look through the logs to see when I lost it - I actually stay on site, until the craft is down - It's easier, I then communicate via Whatsapp, and the occasional phone call - But I also enjoy watching for when others are receiving it, as I'm only running a fairly basic setup (what I can throw into the back of a Fiesta) so once everyone else can see it, I don't need to worry if I lose signal -  It's great when it's picked up overseas - France and the Netherlands are usually the main ones, I think on the stats, the French station received more packets than me, this time.

Frequency jitter - Interesting..I'd never considered that, maybe I need to do a bit deeper analysis of that side of things.  Usually though I download everything and let someone else look at it, as they then put the videos together and also use some f the data in the school presentation.

We did have AmbaSat on one of our flights, and the coverage etc was actually quite good, but I wasn't monitoring that, and they were using the Things network, so I've got no data as regards signal quality, unfortunately!

73..Mark

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