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gotthardp / lorawan-server

Compact server for private LoRaWAN networks
https://gotthardp.github.io/lorawan-server
MIT License
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Tx power jumping #99

Closed Kralg closed 7 years ago

Kralg commented 7 years ago

Hello,

I have noticed that if I switch between 20 and 19dBm TX power, actually power jumps much more than that. Is there a way to make set 18-19dBm? I guess this is related to LUT in global_conf.json

gotthardp commented 7 years ago

You mean uplink or downlink power? For uplink it is not possible to set any other value than those in the web-admin list.

Kralg commented 7 years ago

Well I mean the ones that are in web-admin TX Power(dBm) I can see that I can increment the power by 1dBm. I connect Gateway output to frequency analyzer (no antenna) and I can see that actual power at 19dBm is much less and at 20dBm it jumps to somewhere closer to 20dBm.

gotthardp commented 7 years ago

The TX power you set corresponds to the power sent by LoRa chip. The attenuation depends on the HW design of the signal path between the LoRa chip and your measuring equipment. Apparently the attenuation is not linear, but this is nothing related to the server.

Kralg commented 7 years ago

So you think the power settings are not related to lut in global_conf.json? I thought that webserver sends command to packet forwarder which then looks for configurations in global_conf.json and choose corresponding ones. If there is none exactly matching then it (probably) takes the closest ones. I was looking on ttn webpage and I found some similar discussions just without clear explanation on how to create intermediate power settings lut, because luts are just for some of the power settings but not for all settings with 1dBm increment.

gotthardp commented 7 years ago

To be honest, I was not aware of the tx_lut_xx configuration. :) For downlinks the server sends directly the TX power in dBm. I don't know what the lut is good for.

gotthardp commented 7 years ago

Did you manage to solve this somehow? May I close this issue?