CUSF Launch

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William Yu

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Mar 16, 2024, 8:50:14 PMMar 16
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Hi all,

Apologies for the short notice but CUSF are doing a launch from Churchill today (Sunday, 17th March)! Expected release time is 12 noon with either a Hwoyee 200 / 350 depending on the wind. 

Transmission will be LoRa mode 1 on 434.425 MHz, callsign LONGAN and Horus on the backup - 434.600MHz,  Horus Binary 4FSK V2 on 434.600 Mhz - callsign WS-RS1 (this is a reprogrammed Radiosonde RS41). Very thankful to anyone who can help track!
 
This is actually a memorial launch for Stuart Constable (M0CHW) alongside Jonathan Constable (M5FUN). We're very honoured that Jonathan has decided to work with us and are keen to make it a successful day tomorrow :) 

Will

Cambridge University Spaceflight

Owen Allpress

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Mar 17, 2024, 5:48:40 AMMar 17
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Just seen this, I've prev never looked at or interacted with this group, so please excuse my ignorance. I have a radiosonde lora unit flashed with that Italian firmware i can decode sondes but i pressume i cant use this with Lora Mode 1. im limited in time this morning to try to find out, (I have kids). 

be interested to see if i can track this while out and about later.

O

Mark Jessop

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Mar 17, 2024, 6:18:17 AMMar 17
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A ttgo unit running MySondyGo (or rdz_ttgo_sonde) will not track this flight.
While the radio modem on the ttgo units (a lora module) is capable of receiving the telemetry, the software is not.

Typical receivers for LoRa amateur balloon flights use a shield on a Raspberry Pi.

73
Mark VK5QI

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Owen Allpress

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Mar 17, 2024, 6:34:15 AMMar 17
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Kevin Walton

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Mar 17, 2024, 6:48:45 AMMar 17
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An esp32 lora hab mode reciever option (ttgo etc) that might be interesting thanks to Roel:

https://github.com/RoelKroes/TBTracker-RX

Cheers
Kev
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Sent from my Android device. Please excuse my brevity.

Ross G6GVI

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Mar 17, 2024, 7:32:54 AMMar 17
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If you have a suitable TTGO board, try Dave Akerman's program: https://github.com/daveake/LoraBluetooth
Then you can connect the receiver via USB (or Bluetooth) to a PC running his HAB Base program. 
My friend Jack G8HIK has used this setup very successfully to track many LoRa flights over recent years.


On Sunday 17 March 2024 at 10:48:45 UTC Kevin Walton wrote:
An esp32 lora hab mode reciever option (ttgo etc) .

Andrew Mulholland

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Mar 17, 2024, 8:29:25 AMMar 17
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Just an update, slight delay in the launch, looking like should have it up hopefully in the next 30 mins.
One other adjustment, switched to a backup radiosonde, so the radiosonde callsign is now

FHS-RS1 - Horus Binary 4FSK V2 on 434.600 Mhz

Andrew Mulholland

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Mar 17, 2024, 9:15:34 AMMar 17
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After a delay from ATC, we're now clear to launch so balloon is being filled currently.

Sasha Tim

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Mar 17, 2024, 11:07:25 AMMar 17
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Looks like LONGAN lost GPS lock

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William Yu

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Mar 17, 2024, 11:12:53 AMMar 17
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Definitely looks it - hope it picks up again below 17.3

Thankfully just got the pop - cross-checking our predictions, looks like it will be super close to sea!

Will

From: uk...@googlegroups.com <uk...@googlegroups.com> on behalf of Sasha Tim <sasha...@gmail.com>
Sent: Sunday, March 17, 2024 3:07 PM
To: uk...@googlegroups.com <uk...@googlegroups.com>
Subject: Re: [UKHAS] Re: CUSF Launch
 

Steve

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Mar 17, 2024, 2:42:47 PMMar 17
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Nice to meet you all today - quite like old times.


Any consensus on LONGAN ? - looks like GPS stopped working at 17,300m on the way up - but kept on transmitting the position over and over - then GPS started working again once it landed.


GPS pack up in the cold?

   

    Steve G8KHW

Matt Taylor

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Mar 17, 2024, 5:29:06 PMMar 17
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I was wondering if this was related to the 18KM limit if not using airborne flight mode? Cold GPS module a more likely reason than bugs in battle-hardened firmware though :-) 

Congratulations on the successful flight! I followed the backup tracker to the ground and could see you'd parked up on the other side of the A12 from the payload. Were you able to recover everything successfully?

- Matt (M0XIN)

Steve

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Mar 17, 2024, 5:44:13 PMMar 17
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I guess it could be the 18Km CoCom limit - but it had been spitting out positions every 100+ meters of so - so I would have expected a few more above 17,300m before stopping.

I saw a herd ;-) of CUSF guys crossing the road just were I parked my car - across the road to a footpath.  By the time I got up the footpath the guys were already pulling the payload out of a tree - very easy find and recovery - everything recovered OK I believe.

    Steve G8KHW

Mark Jessop

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Mar 17, 2024, 11:03:52 PMMar 17
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Good thing that backup tracker was on there! 
Here's the grafana plots from the backup tracker: https://grafana.v2.sondehub.org/d/HJgOZLq7k/basic?var-Payload=FHS-RS1&from=1710683142627&to=1710690216888&orgId=1

Taking a look at the raw data from the LONGAN payload, I can see:

At launch:
$$LONGAN,226,13:46:18,52.21316,0.10008,00017,6,0.0,15.4,0.0,0,0.0,0.00,0.00000,0.00000,0.0,0,0.00000,0.00000*BD60

Then nearer where it lost lock
$$LONGAN,573,14:44:07,52.28231,0.93296,16492,4,0.0,-41.2,0.0,0,0.0,0.00,0.00000,0.00000,0.0,0,0.00000,0.00000*D650

.. then at 17300m we see:
$$LONGAN,595,14:47:47,52.27818,0.96125,17300,0,0.0,-42.1,0.0,0,0.0,0.00,0.00000,0.00000,0.0,0,0.00000,0.00000*6D78

After landing:
$$LONGAN,5,15:44:25,52.20227,1.47811,00008,6,0.0,5.1,0.0,0,0.0,0.00,0.00000,0.00000,0.0,0,0.00000,0.00000*84AE

I've highlighted what I *think* is meant to be the number of satellites used in the GNSS fix. It seems pretty low in general, but that it goes to 0 at 17300 exactly does make me wonder a bit... I'm curious what that tracker was running.

73
Mark VK5QI

Mark Goergen

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Mar 18, 2024, 3:44:11 AMMar 18
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This looks like a frozen GPS receiver to me. I had very similar problems before.

Mark G

Matt Taylor

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Mar 18, 2024, 6:03:06 AMMar 18
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I'd be interested to know which GPS module was used, with or without a TCXO, etc.

I also couldn't receive any packets from LONGAN. Admittedly I was the furthest north of UK receivers and not using a yagi, but I have received other payloads at that distance/altitude in the past. It looks like a few of our European friends did well on that front, though.

- Matt (M0XIN)

David Brooke

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Mar 18, 2024, 6:56:03 AMMar 18
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On Mon, Mar 18, 2024 at 10:02:52AM +0000, Matt Taylor wrote:
>
> I also couldn't receive any packets from LONGAN. Admittedly I was the
> furthest north of UK receivers and not using a yagi, but I have received

I received fewer packets from LONGAN than I would have expected, though
I didn't actually check if the frequency was otherwise quiet.

David G6GZH

Ross G6GVI

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Mar 18, 2024, 8:21:58 AMMar 18
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Here in Bolton, Jack G8HIK and I were monitoring the flight on both modes. Neither of us received anything at all on LoRa (whilst we each got hundreds of 4FSK decodes). We have both had a lot of success receiiving LoRa flights in previous years, over similar distances. Jack also has an SDR display and he couldn't see any trace of the LoRa signal there, nor did it show on the web SDR at Nantwich: http://hackgreensdr.org:8902/
Hence we were also wondering if the LoRa transmitter was running very low power, or if its antenna had been damaged on launch?

Andrew Mulholland

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Mar 18, 2024, 8:28:21 AMMar 18
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Thanks all for the help with the tracking. Beyond the LONGAN issues and the camera onboard it seems getting knocked right before the flight, so stopped recording, the flight was actually very successful. It landed in a tree (with the main payload within arms reach). 
The flight computer is a custom one built by CUSF based on a Pi Pico. Will can correct me if I'm wrong, but I believe the GPS chip is the uBLOX MAX-M8Q (same one used by the modules from Uputronics). In terms of temperature, the LONGAN flight computer wasn't insulated (being simply in a 3D printed case to keep the payload small and light). The only temperature sensor in use would have been on the Radiosonde CPU, which was insulated in foam and reported around -18c at the time of the cutout, meaning LONGAN was likely quite a bit colder at the time.

This isn't the first time that that setup/code has experienced exactly the same issue. I think it may be time to go back to the drawing board on it...
For anyone curious, I believe the code flown was very similar to this code - https://github.com/westminster-school-balloons/Pico-flight-tracker

Will might be able to share some pictures of the payload if he's got any? It was a intentionally a very small / lightweight payload.

Matt Taylor

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Mar 18, 2024, 7:32:47 PMMar 18
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That's a real shame about the camera getting bumped :-(

I had a quick peek at the code, and flight mode is being set to airborne <1g above 100M. The M8Q has a TCXO too, so typically pretty resilient to sub-zero temps. If this is a recurring issue and you figure out the cause, I'd love to know :-) 

- Matt (M0XIN)

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