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Fast Long Range Radio

This is information about a communication time test with an oscilloscope to measure and show how fast our long-range LoRa technology works.

Below is a picture of the data communication time.

The Green pulses were inbound 16 bytes of data on a UART into Radio #1 at 38400bps.

The Yellow pulses are the outbound 16 bytes of data on a UART in Radio #2 that received the over-the-air message from #1.

So from the time the first message was sent into the radio it fully came out of the other radio in 40mS. 

This is Raveon’s RV-M50 ISM band transceiver that uses LoRa technology.

This message passed along over the M50 radio modes was doen with them in the spreading factor of 7. With LoRa technology, there are many spreading factor options to utilize. Following is a list of over-the-air data rates for LoRa data radio modems.

In Raveon Radios, Channel data rate varies by spreading factor, spreading factor can be set with ATSF <val>, where <val> is set according to the table below:  

ATSF Setting Bit Rate for 500kHz Channels Duration for 20 Data Bytes Dur. 100 Bytes
Typical Packet FEC=0(4/4) FEC=1(4/5) FEC=4(4/8) FEC=1(4/5)
7 21.87 kbps 20mS 25mS 30mS 52mS
8 12.50 kbps 44mS 44mS 56mS 92mS
9 7.03 kbps 64mS 78mS 100mS 160mS
10 3.90 kbps 125mS 144mS 184mS 310mS
11 2.14 kbps 240mS 265mS 340mS 580mS
12 1.17 kbps 480mS 520mS 680mS
(Don’t Use)
1020mS (do not use)

For packets greater than 10-20 bytes, we recommend not to use Forward Error Correction FEC 4(4/8) with the Spreading Factor ATSF of 12, because packets are too long for the system. 

The fast efficient over-the-air protocol is ideal for sending data between RTUs and between Master Controllers and RTUs. This RV-M50 radio modem can send information between two devices 20-50 times per second, and even get responses back in 40mS, so a round-trip inquiry can take place in 80mS out and back.

Filed under: Data Radio Technology, Over-the-air protocol, SCADA and Telemetry, Testing | Posted on January 21st, 2020 by John Sonnenberg

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