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Lora-net / lora_gateway

Driver/HAL to build a gateway using a concentrator board based on Semtech SX1301 multi-channel modem and SX1257/SX1255 RF transceivers.
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Receive uplinks & downlinks #157

Closed MrKoppot closed 2 years ago

MrKoppot commented 4 years ago

Hi All,

Is it possible to receive uplink and downlink packets simultaneously with the SX1301?

I have read "Receive unfiltered LoRa Frames", issue #29 in the lora_gateway git, and "LoRaWAN Gateway as a Repeater" issue 80 in the packet_forwarder git, as well as the SX1301 datasheet.

From reading these, I know it is possible to receive either/or by setting the IQ inversion settings appropriately. My question is: there are two radios used for Rx inside the SX1301, can one be set to listen for uplinks and the other for downlinks? I get the feeling the preamble detection that filters unwanted uplink (or downlink) packets is done with both Rx streams together- with no ability to separate them.

I have tried reading through loragw_reg.h/.c, but there is little to no explanation for what the registers do. Is there a resource that explains the registers anywhere?

Thank you for any help in advance.

Doom4535 commented 4 years ago

@MrKoppot I believe the two radios are used to expand the input frequency range as each of the referenced radios (SX1257) has a bandwidth of 500 KHz and the SX130x needs 1 MHz to scan all eight 125 KHz channels. If you were to configure each with different polarities you would only receive 1/2 the band at best.

With that said, have you made any progress on this and/or found anyone with information on the registers? Semtech doesn't seem to have published hardly anything about these chips, and just says 'go to the HAL' (where the registers have no description other than their names).

smtc-bot commented 2 years ago

Thank you for your inquiry.

Customers are encouraged to submit technical questions via our dedicated support portal at https://semtech.force.com/ldp/ldp_support.

We invite all users to visit the LoRa Developer Portal Forum at https://forum.lora-developers.semtech.com and to join the thriving LoRa development community!