Datarate and duty cycle calculation

[Michael]

While experimenting with the mDot and Conduit, my mDot started outputting an error like
“Data exceeds datarate max payload”

I understand there’s a somewhat complicated relationship between the length of the message and the number of times it’s allowed to be sent in a given time period, etc.

I also just discovered the so-called “LoRa Calculator” (or LoRa Modem Calculator)
http://semtech.com/apps/filedown/down.php?file=SX1272LoRaCalculatorSetup1%271.zip
but I haven’t figure out how to use it or if it will even help me. It asks for things like “BW” (I know what that is but have never set it) and “Coding rate” (what is this and how is it set?) and “Programmed preamble” (what is this?).

Can anyone point me to any online resources that have an explanation of these settings and how I can calculate my max throughput, etc.?

Thanks.
Mike

• This topic was modified 8 years ago by Michael.
• This topic was modified 8 years ago by Michael.

[Jason Reiss]

Max payloads for each datarate can be found here as well as SF and BW settings for each.
http://www.multitech.net/developer/software/lora/introduction-to-lora/

Coding rate will be 4/5 for LoRaWAN and programmed preamble is 8 symbols.

There is a “built-in preamble” of 4.25 symbols that the “Programmed preamble” excludes.

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