LoRa transmission from low orbit satellite during The Things Conference

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47

So my setup did not catch anything. I had to step out of the office during the pass of the satellite, you know work…

So I set the LoRa receiver to continuously receive SF12 messages @162MHz. Not taking into account doppler shift or anything. So I might be listening at the wrong frequency… Nothing received during this pass. But that makes sense because I just saw Thomas’ post saying it is transmitting on SF11.

Oh well, will try with a more elaborate setup and the correct SF during the next pass of the satellite… :slight_smile:

48

Just to make sure:

Center frequency: 161.862500Mhz
Bandwidth: 125kHz
Sync word: 0x12
Spreading: SF11
Low Data Rate Optimize: on
Header: on
Coding Rate: 4/8 (this is in the header, no need to configure)
IQ inverted (this is default for rx, don’t change anything)

Good luck tonight!!

Thomas

49

Thanks Thomas,

Yes I set the center frequency to 161.862500MHz too now.

Maybe I have time to quickly put together a cross yagi antenna @ 162MHz for tonight. Don’t know, lets see what bits and pieces I have in the shed for that.

50

Ivo, any luck?

51

Hi Thomas,

Nope. We just had another pass of Norsat 2. I installed ‘gpredict’ and configured ‘Norsat 2’ to actually see when the satellite is passing overhead. But so far my receiver is not picking up the LoRa signal from space.

When will the transmissions stop? As soon as the TTN conference is over? I like the challenge, but my setup needs some more tweaking I am afraid.

Cheers, Ivo

52

It stops tonight 0.00 UTC, so 1.00 Amsterdam time. Even though Stuart has won the prize, still nice to try! (Next pass around 13.35 Amsterdam time.)

@LoRaTracker, congrats on the prize!

2 Likes
53

N2YO is showing passes at 22:41, which will be low in the sky for London/Amsterdam, and 00:17 over Ireland, which is technically tomorrow. Where are you getting 13:35 from?

54

DSC_0182

1 minute!

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55

What did he win? The telex printer used during the conference? :sunglasses:

56

DSC_0183

The previous one was very short…

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57

Telex has captured a few packets just now.

58

It’s mid Atlantic at the moment, about 5 degrees off the horizon. Is that receivable?

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59

Ack. Last pass starts at 23:35:06 CET.

There is a low elevation pass at 22:03 as well (2.3 degrees above the horizon).

60

Unfortunately I did not.

I have a nice node to play with when I get home.

I will post the receiver code at some point, it can be useful to have a simple receiver that can easily configured for different LoRa and frequency settings and can log packets as ASCII and hex to terminal and SD card. The code should run on most Arduino platforms.

We now know that LoRa can be received from low earth orbit with very simple ground based equipment.

And thanks to Thomas for such an interesting challenge.

1 Like
61

Last message was received in Delft last night (1 degree elevation):

TTNSAT-1 2018-02-03 22:47:55.864 goodbye!

It was great, thanks all for your enthusiasm!

3 Likes
62

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

63

BTW, what was satellite’s TX power?

64

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

65

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

image
image2736×1400 366 KB

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:

3 Likes
66

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

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

1 Like