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--- lora_rf [2023/11/20 13:24] – [Data Rate] river
+++ lora_rf [2024/07/31 14:45] (current) – river
@@ Line 1: / Line 1: @@
-====== LoRa: RF Paramaters, Power, Regulations ======
+====== LoRa: RF Parameters, Power, Regulations ======
-===== Paramaters =====
+===== Parameters =====
 ==== Spreading factor (SF)====
@@ Line 50: / Line 50: @@
 Further limits on usage in relation to LoRa one may see are probably just rules of The Things Network.
-The Things Network uses channels defined by LoRaWAN people, with max 16dBm (40mW) eirp. Most of the frequencies I see in the linked ofcom document though are max 25mW or 10mW erp. (40mW eirp is around 25mW erp though, maybe that is it.)
+The Things Network uses channels defined by LoRaWAN people, with max 16dBm (40mW) eirp. Most of the frequencies I see in the linked Ofcom document though are max 25mW or 10mW erp. (40mW eirp is around 25mW erp though, maybe that is it.)
 ===== 433 MHz UK / EU =====
@@ Line 71: / Line 71: @@
 ===== LoRa WAN =====
-LoRa WAN is a network built ontop of LoRa. The standard does not apply to general LoRa use, but maybe of interest to see what frequencies, bandwidth, etc. they use.
+LoRa WAN is a network built on top of LoRa. The standard does not apply to general LoRa use, but maybe of interest to see what frequencies, bandwidth, etc. they use.
 [[https://lora-alliance.org/wp-content/uploads/2020/11/lorawan_regional_parameters_v1.0.3reva_0.pdf]]
@@ Line 79: / Line 79: @@
 [[https://unsigned.io/website/loramon/|LoRaMon]] - LoRa packet sniffer using RNode code on LILYGO boards.
-===== Experimental Data =====
-During a test with Heltec Wireless Tracker, I received on the edge of the usable range:
-RSSI: -123dBm, SNR:-17.3dB
-SNR(dB) = sig(dB) - noise(dB)
+===== Bibliography =====
--noise = SNR - sig
-noise = sig - SNR
-noise = -123dBm + 17.3dB = -105.7dBm
-Meshtastic was on the default LongFast setting, which uses:
+[[https://arxiv.org/pdf/1607.08011.pdf|Understanding the Limits of LoRaWAN]]
-TX power 27dBm (500mW).
-SF 11
-Link budget (from meshtastic docs): 148.5dB
-"The link budget used by these calculations assumes a transmit power of 17dBm and an antenna with 0dB gain"
-SF 11 requires -17.5dB SNR, so SNR was just acceptable by spec.
-In a later test, with VeryLongSlow, lowest RSSI seen with connection was -124dB and -6.0dB SNR, so not better.
+[[https://www.etsi.org/deliver/etsi_en/300200_300299/30022001/03.01.01_60/en_30022001v030101p.pdf|ETSI Short Range Devices, Technical characteristics and methods of measurement]] (e.g. how to measure duty cycle)