What decides the LoRa frequency?

Using Arduino Programming Questions
1

Hi all,

I have used LoRa a bit and am wondering what decides the frequency of the LoRa transciever (868mhz, 915mhz)? I know that the antenna is different and you say what frequency you want to use in the code, so does that mean you can change your antenna and code and it will be a different frequency?

I am asking this because lots of hardware with LoRa does not specify it's frequency!

Thanks,

Zeb

2

The standard UHF LoRa devices from Semtech cover the frequency band 137Mhz to 1020Mhz. The operating frequecy is determined by register settings.

Manufactures of modules then add the necessary antenna matching and filtering components to make a module.

These modules, because of the matching and filtering components are then limited to use in a particular band, 434Mhz, 868Mhz, 915Mhz etc.

So no, changing the registers and antenna will not allow you to swap bands, if it was possible why would they sell banded modules in the first place as there would be no need for them.

3

Hi srnet,

Thanks very much for your help that is good to know!

I am looking at this PLC here (with the LoRa feature)

It says:
Module Type RLYR894 | RLYR406 (Order depending on regional regulations)

Those seem to be quite weird frequencies, right?

Thanks,

Zeb

4

ZebH:
Those seem to be quite weird frequencies, right?

No idea, what are weird frequencies ?

Perhaps quote them here so that people dont have to hunt around for what you mean ..............

5

ZebH:
It says:
Module Type RLYR894 | RLYR406 (Order depending on regional regulations)

Different regions have different radio frequency assignments. Check your local regulating authority to find out what bands you are allowed to use for LoRa in your region.

LoRa uses license-free sub-gigahertz radio frequency bands like 433 MHz, 868 MHz (Europe), 915 MHz (Australia and North America) and 923 MHz (Asia).

https://lora-alliance.org/sites/default/files/2018-05/lorawan1.0.1final_05apr2016_1099_1.pdf

  • US 902-928MHz ISM Band
  • China 779-787MHz ISM Band
  • EU 433MHz ISM Band
  • Australia 915-928MHz ISM Band
  • CN 470-510MHz Band