Default SF and coding rate in LoRa

End Devices (Nodes)
1

Hello Community,

I was wondering what actually happens when I do not use the SF parameter while intilaizing LoRa settings like this

lora = LoRa(mode=LoRa.LORA, region=LoRa.US915, sf=9, coding_rate = LoRa.CODING_4_8, tx_power=20, rx_iq=True)

here I have used SF 9 what if I remove this parameter does it mean that there would be no SF applied ? or will the default of SF 6 be chosen.

What should i do, if i dont want any FEC at all? Do i just remove this parameter as well or by default will some value be applied.

2

What is the application ?

What library ?

What language ?

The LoRa parameters for TTN are normally not an option you would configure at program level, the TTN layer controls them for you.

3

Just to test data rates at different distances. I am using the pycom board for lora and not yet intergrated with TTN. If thats the case will they be still existing at the physical layer by default?

4

oh… I thought he is writing a book :wink:

5

It is a ‘she’ FYI. Also since you assumed i was an author. I am just a student trying to learn most of what I could by figuring out and trying to various experiments myself. So if you can’t encourage then no problem. Good luck buddy !!

1 Like
6

hmmmmmmmmm … no humor sorry :sunglasses:

7

I dont understand the question, will what still be existing at the ‘physical’ layer ?

Please appreciate that whilst you may know what hardware setup and language you are using, it may not be obvious to the rest of the forum.

1 Like
8

This looks like Micropython code, probably for the LoPy or FiPy. As the lora behavior depends on the firmware I think the Pycom forum is a better place to ask for the specifics of their implementation. Especially when using lora (not lorawan) mode which I expect few visitors over here have experience with.

9

Well in most languages, if you do not use (ommit?) a parameter a function is expecting, then you will and should get a program error.

10

I am not sure what you mean by language using? I am using the pycom lora boards and my scripts are written in Micro python.

I am carrying out all my experiments in the US region. To be precise, i am wondering what will be the case when i dont specify any coding rate at all. Will there be no error correction provided? or some level of error correction will always exist ? By physical layer i mean i am just transmitting packets between 2 lopy nodes.

11

what is the relation with TTN network ?

12

just a basic fundamental question which I am unsure about and thought I could get some view on the same.

13

There is no setting to disable the coding rate. You can see the allowed settings for FEC listed in the SX127x datasheet.

As for what happens to your Pycom LoPy when you dont specify the coding rate in a function call and what the defaults may be, is a question you will have to direct to Pycom, they sell and support the LoPy and ought to have detailed knowledge of its operation.

Do appreciate this is a TTN support forum, its unlikely the readers will have a detailed knowledge of the operation of the LoPy firmware for point to point LoRa.

14

absolutely, thats what @kersing mentioned before too.
Therefore I close this thread.