Help with understanding Uplink down link channels and Radios

[88bit]

Hi I have a Laird RG191 and trying to configure it to be used in Australia. I’m using my own Lora server.

There are a couple of things I’m really struggle to get my head around.

1 . In my Radio configuration section are the following parameter for AU 915

"radio_0": {
"freq": 917200000
},
"radio_1": {
"freq": 917900000
},

I have the settings from a forum post and they work but im not sure if it is right? and why it is right. Looking at the AU 915 Frequency plan I can’t make heads and tails of it. Maybe someone can point me in the right direction. Please

This is the AU_915 frequency plan

[BoRRoZ]

• Laird RG191 working in Australia
• https://github.com/TheThingsNetwork/gateway-conf/blob/master/AU-global_conf.json

[cslorabox]

@88bit

"radio_0": {
"freq": 917200000
},
"radio_1": {
"freq": 917900000
},

These are the frequencies for the physical IF’s of each of the SX1257 chips that feed into the SX1301.

The SX1301 then has four digital demodulators configured around each IF with slight frequency offsets, you will see those listed as in the global_conf.json. In the file the given “if” is a relative offset of the digital demodulator from the physical signal feeding it, so if you add that offset to the corresponding radio frequency from the first part, you will find the actual channel frequency matching the bandplan document.