“Bitrate” R_bit=SF* BW/2^SF *CR
"BW=125 kHz,SF=7,CR= 4/5
"Bytes to transmit (only data)=12=96 Bits
(96 Bits)/(5468,75 Bits/s)=17,55 ms
Time to transmit the data would be 17,55 ms and the Board is on high power for over 700ms, even I am only sending which these 4 lines:
“Packet transmission time = Packet size / Bit rate”
For LoRaWan Class A, downlinks are only sent after uplinks. After sending, a node need to listen to see if there is a downlink packet sent. This happens during the RX1 or RX2 window (depending on the frequency plan / channel).
So it would make sense to me to wait for the receive window is over before going to sleep…
Okay, got it. Thank you.
Is it possible, that the LoRa module is by standard in the LoRaWAN Class A? So the chip is thinking, that its sending to a network? Cant figure it out why these times are not the same or even in the same area… but the 700ms is to huge!
No, your missunderstanding the difference between what your trying to configure, point to point LoRa, and LoRaWAN.
Tell a LoRa device to send a packet and it does just that, and that only, it sends a packet. When its finished sending the packet it turns the transmitter off. It does not attempt any clever stuff like listening for replies. If you want to listen for a reply (like you might in LoRaWAN) you have to specifically configure the LoRa device to flip to being a receiver.
If you think the LoRa device is transmitting longer than you think it should be, you might want to raise the issue with the author of the library you are using.
As an aside, i notice you are using pins 34 and 35 as RX and TX. Note that those pins are input only. While it works now for an RX only operation, the TX on Pin 35 will never work should you try to transmit out of Serial2.
Thank you again for your explanation. I was just looking for a reason of the behavoir of the board - thats why i made the “default mode suggestion”.
I will try to contact the author of the library I am using with this issue, thats a good idea.