Launch Allert: Urgent tracking help needed for a HAB balloon on Sat 6/6/26 between 11 AM – 1.30 PM

[Ayse Koklu]

Hi all, 

Would anyone be free and interested to help us with tracking and locating our HAB to  sondehub.org?

We have got a custom made gps with strong signal, operating on 434 MHz and we need someone to track it. We are trying to work out dlfl digi software, but it is exceeding our expertise at the moment. So, would anyone either be kind enough to jump on a call urgently to help us work it out, or be kind and passionate enough to do this using a SDR software of their choice?

Please feel free to message/call to discuss if asier: 0787 6052734.

Look forward to hearing from you.

Best wishes,

Ayşe

[Mark Jessop]

You need to provide a lot more information than this.

What modulation, what callsign, etc?

The community has pretty much entirely moved on from RTTY (I'm kind of assuming this given the mention of dl-fldigi), and support for uploading RTTY to Sondehub is very limited. 

Maybe someone in the UK / Europe can get you a Horus Binary tracker before then, since that's much better supported, and *far* more robust than ye olde RTTY.

73

 Mark VK5QI

--
You received this message because you are subscribed to the Google Groups "UKHAS" group.
To unsubscribe from this group and stop receiving emails from it, send an email to ukhas+un...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/ukhas/bd30459f-9c5f-4b98-aeab-2ad4586eeeeen%40googlegroups.com.

[Ayse Koklu]

Hi Mark,

I am working on gathering the information. I will confirm whether the callsign is MOD1 or MOD2.. I will let you know about the modulation and we are working with 434,651,010 Htz.  What else would you be needing? We are %50 there, but need guidance using the software.

Thanks,

Ayşe

[Ben Z en de rest]

The modulation type is still unknown to the listeners. So the frequency is now known, but what kind of receiver program is needed is unknown.

That, and if you need receivers to recover your sonde it's necessary to know about the launch location, balloon size, ascent rate, parachute size 

And it would be very helpful if you can receive your own tracker in a mobile setup (sdr device, laptop, mobile antenna) to make hunting your tracker possible.

Good luck,

Ben

Op zo 24 mei 2026 om 18:20 schreef Ayse Koklu <kokl...@gmail.com>:

To view this discussion visit https://groups.google.com/d/msgid/ukhas/caad1d10-ae7c-4374-b817-534881b255d3n%40googlegroups.com.

[Ayse Koklu]

Thank you for your helpful reply Ben.I appreciate this. 

We now have 

the modulation:  2-FSK (RTTY) .  Baud Rate: 50 Baud.  Character Format: 7-bit ASCII.  Stop Bits: 2 Stop Bits.  Callsign: MOD1.  Checksum: CRC16-XMODEM

call sign: MOD01 

and the frequency is:  434,651,010 Htz

@Mark, this also replies to your email (if you are still following the thread).

We have a recovery team and a car with our tracker in a mobile set up:) 

And yes, I am waiting for my camera to arrive early this week, so I was going to calculate and provide the estimate ascent rate by Friday 29 May (8 days before the launch) will provide together with launch location, balloon size and parachute size.  Hope 8 days notice for this information is workable?

Thank you once again,

Ayşe

[Mark Jessop]

If you're a week away from launch and haven't got reliable decoding working yet, this is sounding highly risky. 

RTTY trackers (sending UKHAS string format) can currently only be decoded by:

- dl-fldigi, which uploads to Sondehub using Daveake's HAB-base software. I'm not even sure where to point to for guides anymore...

- Horus-GUI *may* decode and upload to sondehub, but it is very picky about what has to be transmitted.

Can you provide an audio recording of the transmitted signal? 

Is there anyone in the Europe/UK that can flash up a RS41 with RS41ng and get it to Ayse before their launch? Having something that's known-reliable on the flight would be a lot safer...

73

Mark VK5QI

To view this discussion visit https://groups.google.com/d/msgid/ukhas/2d2bb971-226c-4ba8-afdd-f53603c06ed2n%40googlegroups.com.

[Mark Jessop]

For others benefit, I also received the below information via another path.

A little odd that they say frequency of 434.650 MHz, and the photo shows a NTX2 setup for 434.075 MHz. Also, being an OG NTX2, that means it'll be drifty. Welcome back to 2009 I guess :-/

73

Mark VK5QI

Details:

the modulation: 2-FSK (RTTY). Baud Rate: 50 Baud. Character Format: 7-bit ASCII. Stop Bits: 2 Stop Bits. Callsign: MOD01. Checksum: CRC16-XMODEM

the call sign: MOD01

the frequency is: 434,651,010 Htz

I am waiting for the camera to arrive early this week and I will calculate and provide the estimate ascent rate by Friday 29 May (8 days before the launch). I will provide this  together with launch location, balloon size and parachute size.

_

Radiometrix NTX2-434.075-10 25Khz NNFM UHF

[Ayse Koklu]

Hi Mark,

Thank you for your your thoughts.

In case there was a confusion, the launch is on Saturday 6 June, just under 2 weeks.

I am sorry that the initial frequency was misleading; I got it from the screenshot shared with me from the previous successful launch.  I updated my notes with  434.075 MHz. I am attaching all of the details once again below.

Today we are doing another test, building on from the guidance here:  https://ukhas.org.uk/doku.php?id=guides:tracking_guide. We are also in touch with the engineer who built our custom tracker to help our Tech team steering  the SDR settings.

VBL

- modulation:  2-FSK (RTTY) .  Baud Rate: 50 Baud.  Character Format: 7-bit ASCII.  Stop Bits: 2 Stop Bits.  Callsign: MOD02.  Checksum: CRC16-XMODEM

- call sign: MOD02 

- the frequency is:  434.075 MHz

I will see if we can record the transmitted audio signal.

A

[Mark Jessop]

That tracking guide is *horribly* out of date (as is a lot of stuff on that wiki).

Habhub does not exist anymore, nor does the Habhub parser for the UKHAS-compliant (hopefully) strings that tracker is transmitting.

You *might* be able to decode your payload using Horus-GUI (https://github.com/projecthorus/horus-gui/releases ) set into RTTY 7N2 mode and the right baud rate selected, but it will be very dependent on what's transmitted. 

Also, with that ye olde NTX2, your signal is going to drift around the band. We used to deal with that back in the early 2010s, but we've all moved on from those problems now..

Dave's HAB-Base software should be able to receive data from dl-fldigi too: https://www.daveakerman.com/?p=2994

Anyway, hopefully someone else in the UK can help out with a more reliable tracker than this...

73

Mark VK5QI

To view this discussion visit https://groups.google.com/d/msgid/ukhas/6c5f4db7-f46c-4e45-8812-d98bba163f36n%40googlegroups.com.

[Ayse Koklu]

Hi Mark,

Thank you — this is very helpful, and I take your warnings seriously.

When you emailed, we had also just figrued Habhub was down as we were not getting any dropdowns under flight, so we will no longer pursue that route. 

Given your concerns about the NTX2 drift and the limited current support for RTTY, I agree that flying a known-reliable backup tracker would be much safer.

Could I ask whether anyone in the UK has an RS41 with RS41ng, a Horus Binary tracker, or another reliable HAB tracker that we could borrow or buy in time for Saturday 6 June? We are based in London and can arrange collection/postage tomorrow morning first thing.

Thanks,

Ayşe

Thanks again,

Ayşe

 Ayşe Köklü
+44 (0)787 605 2734
www.aysekoklu.info

On 25 May 2026, at 12:08, Mark Jessop <lennieth...@gmail.com> wrote:

That tracking guide is *horribly* out of date (as is a lot of stuff on that wiki).

Habhub does not exist anymore, nor does the Habhub parser for the UKHAS-compliant (hopefully) strings that tracker is transmitting.

You *might* be able to decode your payload using Horus-GUI (https://github.com/projecthorus/horus-gui/releases ) set into RTTY 7N2 mode and the right baud rate selected, but it will be very dependent on what's transmitted. 

Also, with that ye olde NTX2, your signal is going to drift around the band. We used to deal with that back in the early 2010s, but we've all moved on from those problems now..

Dave's HAB-Base software should be able to receive data from dl-fldigi too: https://www.daveakerman.com/?p=2994

Anyway, hopefully someone else in the UK can help out with a more reliable tracker than this...

73

Mark VK5QI

On Mon, May 25, 2026 at 7:36 PM Ayse Koklu <kokl...@gmail.com> wrote:

Hi Mark,

Thank you for your your thoughts.

In case there was a confusion, the launch is on Saturday 6 June, just under 2 weeks.

I am sorry that the initial frequency was misleading; I got it from the screenshot shared with me from the previous successful launch.  I updated my notes with  434.075 MHz. I am attaching all of the details once again below.

Today we are doing another test, building on from the guidance here:  https://ukhas.org.uk/doku.php?id=guides:tracking_guide. We are also in touch with the engineer who built our custom tracker to help our Tech team steering  the SDR settings.

VBL

<Screenshot 2026-05-25 at 10.58.52.png>

- modulation:  2-FSK (RTTY) .  Baud Rate: 50 Baud.  Character Format: 7-bit ASCII.  Stop Bits: 2 Stop Bits.  Callsign: MOD02.  Checksum: CRC16-XMODEM

- call sign: MOD02 

- the frequency is:  434.075 MHz

<Screenshot 2026-05-25 at 10.58.52.png>

-- 
You received this message because you are subscribed to a topic in the Google Groups "UKHAS" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/ukhas/vjCOASqHQNY/unsubscribe.
To unsubscribe from this group and all its topics, send an email to ukhas+un...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/ukhas/CABD2Lt0M2CUNHcvJaMDZom1Jofd3Yg_hOpL%2BC4-uoFF1woKoPw%40mail.gmail.com.

[Nick McCloud]

On Monday, 25 May 2026 at 13:45:46 UTC+1 Ayse Koklu wrote:

Could I ask whether anyone in the UK has an RS41 with RS41ng, a Horus Binary tracker, or another reliable HAB tracker that we could borrow or buy in time for Saturday 6 June? We are based in London and can arrange collection/postage tomorrow morning first thing.

Yes, there is a possibility of helping out with a tracker, I've got several of different sizes but I'd need a bit more clarity because I've a fair amount on at present so squeezing provisioning a tracker will be a challenge.  

Has anyone in your project ever launched a HAB before? This isn't a show stopper, but it does let us know how much prior experience you have.

 

On Mon, May 25, 2026 at 4:33 AM Ayse Koklu wrote:

And yes, I am waiting for my camera to arrive early this week, so I was going to calculate and provide the estimate ascent rate by Friday 29 May (8 days before the launch) will provide together with launch location, balloon size and parachute size.  Hope 8 days notice for this information is workable?

As much of the text above, not knowing your location, balloon & parachute size is a bit of a concern. Do you have some balloons & parachutes on order to arrive soon?

Most importantly have you applied for permission to launch from the CAA? (Which absolutely requires you to know the launch location).

Many of us are happy to facilitate, but answering questions about three months back would have been good!

Nick

[Ayse Koklu]

Hi Nick/All,

I know we are in communications, so this message is more for the community to be aware and on the loop.

Basically yesterday, we managed to get the custom tracker to work (screenshot attached here)

, however so that the HAB community is on board and can track, I decided to go with the tracker which community can receive basic telemetry easily for tracking with RTL–SDR & HorusGUI. On this note, if anyone is reading this message and is planning to track the flight on the date, I would appreciate their contact and support.

I have CAA permission for Sat 6 June starting at 11 AM for several hours, as informed by them. I am expecting to receive the details of the appropriate CAA exemption/authorisation in the coming days.

I will be uploading the predictions and the details next week too. 

Thank you Nick once again for your support.

Warmly,

Ayşe