LoRa transmission from low orbit satellite during The Things Conference

TTN Announcements
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Thanks for the challenge Thomas,

I attempted to receive the messages from space. Unfortunately I received nothing with my setup. Probably my antenna setup was too simple. I colocated an aircraft antenna (120 - 140MHz) with the TTN node on the balcony. So wrong frequency and probably also wrong polarization. I did not have time to create a more sophisticated setup. You know… busy busy,…, but it was fun to try! :smile:

It would be difficult to come up with a matching challenge for a next TTN event.

Cheers, Ivo

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BTW, what was satellite’s TX power?

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BTW for those of us not at the Conf what was the ‘secret message’? (Just curious!)

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The message is in the video, but the code is masked there:

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The xxxxxx showed some numerical code during Thomas’ presentation, either accidentally or on purpose, at which point the challenge kind of ended :slight_smile:

Hopefully next year Thomas’ / http://www.lacuna.space/get-involved/ has launched at least one satellite with the LoRa stuff. No pressure, @telkamp :wink:

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26dBm into an approx 6dBm gain antenna I believe.

Anyway just off to the Flying Dutchman near Amsterdam Central station for a ‘few’ beers.

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Well done! I couldn’t find the story behind it… Did this satellite use some sort of software-LoRa on an already present radio transmitter?

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At the beginning of this thread:

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It was an interesting experiment. I tried to receive it a couple of times with an RFM96W/433 module (from London) but no luck. I didn’t really expect it to work but wanted to try anyway :slight_smile:

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A major achievement, congratulations.

I noted on Saturday that reception started just as soon as TTNSAT appeared above the horizon, it looks like at a distance of 2760km or so.

What was the SNR reported at this time ?

You could then estimate what maximum data rate you could get, above the 293bps that TTNSAT was sending.

Do you know the gain of the antenna on the TTN building roof ?

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I was trying to capture the 162 MHz signal from home (Zürich) with an SDR, but my line-of-sight and antenna were sub-optimal. Bart Root (https://twitter.com/Bart_Root/status/958985584130879488) kindly gave me a copy of his SDR recording, in the form of an IQ file, which I have been trying to replay on a LimeSDR transmit channel on 868MHz and decode using a LoPy running a LMIC-based LoRa listener, but with no luck…

I would like to find out what in that chain I did not have working properly. Now that the competition is over, would you mind sharing (part of) the IQ file that the satellite was loaded with, so that LoRa & SDR enthusiasts can try completing the challenge?

Congratulation for a great challenge!

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LoRaTracker, can you elaborate on how you configure an SX127x to have it let CRC-check-failing packets be read from the FIFO? Thanks!

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Just read the FIFO as normal, though be aware the packet length may be wrong.

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The receiver code I used is here, its called ‘LoRa_Receiver_Logger’’

You can choose the frequency and LoRa settings and log ASCII or HEX packets to serial monitor or SD card.

You can have raw packet data or add SNR and RSSI to the output. Should work on most Arduino platforms including the humble Pro Mini.

Looking at adding a display option; for cross platform use I have an I2C connected display backpack PCB that allows a range of displays, ILI9341 etc, to be connected via a very low memory driver.

See the document ‘How to Use the Test Programs.doc’ for more details.

If you want to do clever stuff with the received packet, its transferred on receipt from the LoRa FIFO into a buffer, so you can do stuff with it if you so desire.

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Starman_view

And for the 2019 edition of The Things Conference the TTN team will make sure the conference date aligns with an earth flyby of Starman sending out transmissions down to earth from aboard his Tesla Roadster using LoRa… :sunglasses: