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sandeepmistry / arduino-LoRa

An Arduino library for sending and receiving data using LoRa radios.
MIT License
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Transmission takes more than a second #274

Closed cpsinghopl closed 5 years ago

cpsinghopl commented 5 years ago

Hello,

I checked using oscilloscope, the LoRa module SX1276 takes more than one second to transmit data.

i.e. after following statement is executed (top go to transmit mode), it takes around 100mA for more than second which in my opinion is too much.

writeRegister(REG_OP_MODE, MODE_LONG_RANGE_MODE | MODE_TX);

Any idea how to reduce it? with this timings, it is too inefficient to run on battery

PS: Following configuration is used: LoRa.begin(868E6); LoRa.setSpreadingFactor(12); LoRa.setCodingRate4(8); LoRa.setSyncWord(0x13); LoRa.setPreambleLength(8); LoRa.setTxPower(40); LoRa.setSignalBandwidth(125E3); LoRa.enableCrc();

Regards

torntrousers commented 5 years ago

The time a transmission takes depends on the spreading factor, bandwidth and coding rate. Its not super speedy and with high spreading factors and low bandwidths it can take several seconds. All you can do is send less data or use a lower spreading factor / higher bandwidth.

cpsinghopl commented 5 years ago

oh yes, thats what I found now.. on increasing bandwidth from 250 to 500, tx time just halved! Thanks a lot for your response.

cpsinghopl commented 5 years ago

But with higher bandwidths, range will be decreased?

IoTThinks commented 5 years ago

LoRa.setTxPower(40); Tx power can be so high? Or you are using another more powerful chip than Ra01, 02 and RFM95?

IoTThinks commented 5 years ago

But with higher bandwidths, range will be decreased?

Higher bandwidth leads to less sensitivity on antenna. Hence will decrease range.