How does the end node know the direction of the gateway, so that they can reflect builidng or diffraction big obstacles the right way to come to the gateway?
Hi, if I just have a transmitter and receiver without using gateway, can I calculate the free space loss using the distance between transmitter and receiver? because you mentioned in the video that D represent the distance between the end node and the gateway.
Hi Sir, I'm using a SX1276-915 LoRa module with maximum tx power of 20dB and minimum sensitivity of -148dB (7.8 Khz bw). Calculating the D value on the presented equation with f = 915, and L = -168 dB (20 - (-148)) gives me a value of 6548 km, which is pretty high. Even if i use a loss (L) of 148dB (sensitivity) it yields a distance of 654 km. The manufacturer claims only 4 to 8 km. Am i doing something wrong?
Pedro, you can not use this equation to calculate D. Use this equation to calculate the free space loss. See: www.mobilefish.com/download/lora/lora_part8.pdf page 4, for a better understanding of TX power, path loss and receiver sensitivity.
Your sensor can transmit over a distance of 4 to 8 km ONLY when: 1) Your sensor has a direct line of sight with the gateway 2) Your sensor has a "good" antenna (preferably outdoors and VSWR < 2)
@@Mobilefish Thank's for your answers. Is there any equation which can be used to calculate D? It would be interesting to know how the manufacturers specifies the maximum range.
To be honest, I do not think the manufacturer knows the actual maximum range. The manufacturer just specified this range. There is probably an equation to calculate this, but it theoretical. You will never reach this distance! As I said it depends on the line-of-sight, the antennas used and other factors. If you read this article: www.thethingsnetwork.org/article/lorawan-distance-world-record a distance of 766 km could be reached, but they had "perfect" line-of-sight AND they were using a directional antenna. I have build this simple end node: www.mobilefish.com/developer/lorawan/lorawan_quickguide_build_lora_node_rfm95_arduino_pro_mini.html and I was able to reach a distance of 14 km BUT ONLY IF CERTAIN CONDITIONS WERE MET: 1) good line-of-sight (few obstacles, just trees) 2) end node (altitude = 11m) and gateway (altitude=40m), think Fresnel zone! 3) nice weather 4) end device had a directional antenna But when using a simple omnidirectional antenna (and in all weather conditions) I could only reach gateways 2 km away. By the way in both cases, the gateway antenna was outdoors and my end device antenna was indoors (this is not good)! If you look at my example the distance depends largely on other factors than the end device it self.
😍 amazing tutorials, thanks for sharing knowledge.
Thanks very much for the wonderful explanation.
Thanks mate, you're gonna help me pass my exam!
Thanks, sir for helping in an easy way .....
Pine trees are really bad at specific UHF frequencies because of the length of their needles.
How does the end node know the direction of the gateway, so that they can reflect builidng or diffraction big obstacles the right way to come to the gateway?
The end node does not know anything, it emits in all directions. Look up "omni-directional antenna"
Hi, if I just have a transmitter and receiver without using gateway, can I calculate the free space loss using the distance between transmitter and receiver? because you mentioned in the video that D represent the distance between the end node and the gateway.
best
Hi Sir, I'm using a SX1276-915 LoRa module with maximum tx power of 20dB and minimum sensitivity of -148dB (7.8 Khz bw). Calculating the D value on the presented equation with f = 915, and L = -168 dB (20 - (-148)) gives me a value of 6548 km, which is pretty high. Even if i use a loss (L) of 148dB (sensitivity) it yields a distance of 654 km. The manufacturer claims only 4 to 8 km. Am i doing something wrong?
Pedro, you can not use this equation to calculate D. Use this equation to calculate the free space loss.
See: www.mobilefish.com/download/lora/lora_part8.pdf page 4, for a better understanding of TX power, path loss and receiver sensitivity.
Your sensor can transmit over a distance of 4 to 8 km ONLY when:
1) Your sensor has a direct line of sight with the gateway
2) Your sensor has a
"good" antenna (preferably outdoors and VSWR < 2)
The gateway antenna must be outdoors and must also have a good antenna (omidirectional, VSWR
@@Mobilefish Thank's for your answers. Is there any equation which can be used to calculate D? It would be interesting to know how the manufacturers specifies the maximum range.
To be honest, I do not think the manufacturer knows the actual maximum range.
The manufacturer just specified this range.
There is probably an equation to calculate this, but it theoretical.
You will never reach this distance!
As I said it depends on the line-of-sight, the antennas used and other factors.
If you read this article:
www.thethingsnetwork.org/article/lorawan-distance-world-record
a distance of 766 km could be reached, but they had "perfect" line-of-sight AND they were using a directional antenna.
I have build this simple end node:
www.mobilefish.com/developer/lorawan/lorawan_quickguide_build_lora_node_rfm95_arduino_pro_mini.html
and I was able to reach a distance of 14 km BUT ONLY IF CERTAIN CONDITIONS WERE MET:
1) good line-of-sight (few obstacles, just trees)
2) end node (altitude = 11m) and gateway (altitude=40m), think Fresnel zone!
3) nice weather
4) end device had a directional antenna
But when using a simple omnidirectional antenna (and in all weather conditions) I could only reach gateways 2 km away.
By the way in both cases, the gateway antenna was outdoors and my end device antenna was indoors (this is not good)!
If you look at my example the distance depends largely on other factors than the end device it self.
Thank u Sir, ur channel are really helpfull
A tutorial on Link Budget in communication.
Link budget will be my next tutorial
@@Mobilefish w're waiting for this tutorial ^^