Yokohama Floater Launch - Sunday 20th - LoRa, RTTY & Horus FSK4

[Kev Walton]

Hi All

I am  hoping to do a launch on Sunday (20th, tomorrow) morning, before 9am GMT from Northamptonshire, UK of a Yokohama Balloon, carrying a custom built 'Single AA' tracker based originally on the TBTracker code base, but heavily expanded and modified.

Looking to A) test my ability to get a Yokohama to float, and B) the custom tracker being able to be decoded across RTTY, LoRa and Horus FSK4.  Flight path is predicted to take it across Holland, Germany & maybe Poland - but with the weather systems all over the place at the moment, who knows! :)

The tracker is based on the ATmega1284 running at 1.8432Mhz, Ublox GPS and DRF1278 radio module, all with a 1.8v VCC.  About 25g with 1 x AA.

Yokohama is 48.6g and was pre stretched at 0.22PSI up to about 99" circumference and filled to 6g of free lift.

Transmission details:

RTTY - KW-BCK1 - 50 Baud, 8n2, 610Hz shift, 434.113Mhz, 1 short sentence repeated 3 times every once every 2 minutes
    RX Frequency for me was about 434.084Mhz

LoRa - KW-BCK2 - Mode 5, 433.650Mhz, 1 sentence repeated 3 times every once every 2 minutes
    Field String of 0123456AI9, RX frequency for me of 433.653

Horus FSK4 - G7PMO-V2 - 50 Baud, 244Hz shift, 434.340Mhz, 1 binary packet repeated 3 times every once every 2 minutes
    RX frequency for me was about 434.312Mhz

Listeners, reports and feedback highly appretiated.

Thanks very much

Kev

P.S. Tx Aerial will be replaced with a monopole and ground plane before flight :)

[Mark Jessop]

For those listening for the 4FSK transmissions using Horus-GUI, you will probably need to deselect the "Enable Mast Estim." (Enable Mask Estimator) option if it is selected.

This will let it handle the different frequency shift used by this payload.

Re-transmitting the same packet multiple times probably isn't the best idea, but I don't think it will cause too many issues.

73

Mark

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[stephenb...@gmail.com]

Where are you doing the launch from?  I live in Wellingborough, and know of two good launch sites nearby, if you don't need to let the CAA know.

[Kev Walton]

Thanks Mark.

When I say the 'same packet', thats not quite true - the sentance counter is incremented, and the CRC recreated, just the GPS isnt re-read as it is powered off (apart from backup power) at that point.

"Enable Mast Estim." wise, I have been leaving it on but setting the "Tone Spacing (Hz)" setting to 244.  The 244 (rather than 270) is due to the SX1278 Frequency synthesizer step of 61Hz as I understand it.

Cheers

Kev

[Kevin Walton]

Thanks Stephen, launching from my loft window hopefully :) I did a couple from there during lockdown and they seemed to go OK. No permission needed, just a pico less than 2m.

FYI I do have annual CAA (and landowner) permission for a field just N of the A14 near Market Harborough if you need it - just need NOTAM's doing.

Cheers
Kev

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Sent from my Android device. Please excuse my brevity.

[stephen billings]

OK, I'll watch it on the tracker.  

I've launched a  4 wheelie bin bag long, solar balloon from Santa Pod.  A few years ago. (One of the sites I was on about.)

It had my email address on it, and I had a reply from just south of Birmingham.

Hope the fight goes well.

Stephen.

To view this discussion on the web visit https://groups.google.com/d/msgid/ukhas/C449B3B2-94D2-4D3F-9A82-D1173AECAE2D%40unseen.org.

[Kev Walton]

Hi All

A quick note to say thanks for all the listeners and the help on Sunday!  

Not a total success, a mistake on the board meant the payload was very difficult to hear, but the persistence and great rx setups of a few of you rescued me.  The Yoko did float, at just above 10km, which is pretty good considering the 28g payload.  The 1 x AA did last for 14 hours despite being at -55 deg C after dark and transmitting both RTTY, 4FSK and LoRa into a near short ;)  

Thanks to Mike / Mark for finding the issue.  

Thanks to Ben for rounding up listeners in the right places.

A call out to the main receivers G8KNN, G8FJG, F5APQ, Ben, PA3DJR and DK6OV at the end

And a special thankyou to all those providing the backends, infrastructure and receiver code that allows us to do this, past and future.

https://grafana.v2.sondehub.org/d/HJgOZLq7k/basic?var-Payload=KW-BCK2&from=1668927600000&to=1668985200000&orgId=1

https://grafana.v2.sondehub.org/d/HJgOZLq7k/basic?var-Payload=G7PMO-V2&from=1668927600000&to=1668985200000&orgId=1

Cheers

Kevin