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How are frequencies for different ITU regions handled when the satellite is in orbit?

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  • #16
    No it does not help, because of 2 reasons:
    1. any band that could be used by the 3U could instead be used directly by the sprites. So if the 3U can use 10%, so could each sprite.
    2. TTN's fair use policy allows a maximum of 30 seconds of TX time per device per 24 hours. So if the 3U starts using 10% duty cycle the allotment will be over just 5 minutes after midnight. After those 5 minutes, the 3U would have to be silent for 1435 minues.

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    • #17
      Ladies and gents,

      I see. I didn't describe my idea well enough.
      1. Let's for the moment assume, we decide to communicate directly from the sprites to ground gateways.
      2. We know, that the communication distance is very limited (max. 800 km). That means, we will only be able to "see" the ground gateways right under our position.
      3. The only thing we need to do is:
        1. Start the measuring cycle.
        2. Listen to 868 Mhz. No traffic on this frequency means switch to 915 MHz send data via 915 MHz.
        3. If there is traffic on 868 MHz, send data on 868 MHz.

      I'm not really an expert on LoRaWan technology. I just started to learn. But, in other RF technologies, this is exactly what they do to find a free communication frequency/slot.

      Nice side effect could be, that if we know through what gateway the data was send, we more or less know the position of the sprite.

      Please correct me, if I'm wrong!

      Gerd

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      • #18
        In the US, the 868 band is used for other stuff. So if the sprites listen, they will still hear something. LoRa signals from the ground will likely be too weak to be decoded, so the sprites will probably not be able to differentiate if they hear LoRa messages or something else.
        same thing for 915 in EU.
        and we would be ignoring all other regions (China, Australia, Japan, Malaysia, Singapore, Indonesia, Brunei, Cambodia, Hong Kong, Laos, Taiwan, Thailand, Vietnam and more)

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        • #19
          Not sure if being able to communicate in a subband will make a difference. However, we can make the 3U act as a repeater for the sprites so that the TTN Gateway 'sees' a sprite transmission rather than a 3U transmitting 200 pieces of sprite data at a time.

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          • #20
            Have you gotten the required licenses to use the ISM band from space? (As it is internationally designated for on Earth use only unless you request permission) Who ever handles the twitter account seems to think you don't have to follow the rules put out by the ITU.

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            • #21
              Originally posted by Spacecased View Post

              Does the ability to transfer in different sub-bands help this situation? I'm new to this so this might be a dumb question. Is there a reason it couldn't communicate in the g3 subband and take advantage of a 10% duty cycle?
              Looks like a good suggestion and I can't see any reason why not. For reference, here's the TTN Duty Cycle reference: https://www.thethingsnetwork.org/doc...uty-cycle.html

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              • #22
                Originally posted by Admin View Post

                Looks like a good suggestion and I can't see any reason why not. For reference, here's the TTN Duty Cycle reference: https://www.thethingsnetwork.org/doc...uty-cycle.html
                The page you linked says
                in a sub-band with 8 channels and a duty cycle of 1%, each channel has a duty cycle of 1/8% (that’s 0.125%).
                So no, sub-bands will not help.

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                • #23
                  Originally posted by mfalkvidd View Post

                  The page you linked says


                  So no, sub-bands will not help.
                  How about this sub-band reference with a 10% duty cycle: "g3 (869.4 – 869.65 MHz): 10%"?

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                  • #24
                    Originally posted by Admin View Post

                    How about this sub-band reference with a 10% duty cycle: "g3 (869.4 – 869.65 MHz): 10%"?

                    TTN's fair use policy allows a maximum of 30 seconds of TX time per device per 24 hours. So if the 3U starts using 10% duty cycle the allotment will be over just 5 minutes after midnight. After those 5 minutes, the 3U would have to be silent for 1435 minutes (23h55m).

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                    • #25
                      Was my concerns just ignored?

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