Raspberry gateway with 2 sx1278

[zaiplanet]

Hi sir!
I running this project on raspberry 3B+ gateway with 1 sx1278 and 2 node also use sx1278.
But while 2 node transmit same time to gateway, gw only received 1 packet from 1 node.
Can we set one more sx1278 on second spi on raspberry, sir?
Sorry about my english

[CongducPham]

It is theoretically possible but managing both radio modules is very tricky. In your scenario, you may have packet collision. You may need to implement simple listen-before-mechanism with random back-off procedure to limit packet collision.

regards,

[zaiplanet]

Ok sir. Thank u sir

[zaiplanet]

How i can enable LBT at nodes with sx1278, sir?

[CongducPham]

You have to implement it yourself using LoRa's CAD mechanism. You can have a look at our modified SX12XX lib and look at the CarrierSense function:

LowCostLoRaGw/Arduino/libraries/SX12XX/src/SX127XLT.cpp

Line 6224 in 9f930cd

void SX127XLT::CarrierSense(uint8_t cs, bool extendedIFS, bool onlyOnce) {

[zaiplanet]

Thank you very much, sir
I'll check it 👍

[zaiplanet]

hi sir,
gateway can send request then node reply?

[CongducPham]

That can be done through a downlink message from the gateway, then the node would decide to send something following the reception of the downlink. regards,