| ▲ | mikeweiss 9 hours ago |
| LoRa would go much farther than Wifi on 2.4ghz. Lora uses Chirp Spread Spectrum (CSS) modulation while wifi uses OFDM (Orthogonal Frequency Division Multiplexing). The first being designed for extreme range while the latter for bandwidth. At 2.4ghz you could probably get LoRa connections up to 6 miles with the right antenna height. |
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| ▲ | lormayna 9 hours ago | parent | next [-] |
| 6 miles seems a very optimistic estimation: 2.4Ghz propagation is very reduced by obstacles like buildings or trees and at that frequency the atmospheric water (fog, rain, humidity) have a big impact on propagation. And you need also to consider that 2.4Ghz is a very polluted band, then the noise floor is significatevly higher than in the 865/915 Mhz.
Moreover at 2.4Ghz the Fresnel window is smaller and the risk of multipath fading is higher. |
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| ▲ | K0balt 41 minutes ago | parent | next [-] | | LORA uses a sub noise-floor link budget. It allows some pretty crazy performance, at the expense of massive speed losses. Like 203kbps for LoRa vs 1,376,000kbps for WiFi lol.(max phy speeds, ymmmv). WiFi sensitivity is about -90dB, while LoRa sensitivity is around-150dB…. So that’s about a million times more sensitive. So you need about a million times more signal strength to use low bandwidth WiFi (still impossibly fast by LoRa standards) than to use low bandwidth LoRa. Those are radio specifications. Real links require about 10db more to get any kind of reliability, but the comparison stands. | |
| ▲ | golem14 7 hours ago | parent | prev | next [-] | | The record seems to be 830 miles (with antennas at sea level, no less) https://www.thethingsnetwork.org/article/new-lora-world-reco... But, that's receiving 3 of maybe thousands of packets. There's work on bouncing of LoRA signals off the moon: https://engprojects.tcnj.edu/lora-eme/ Yes, but Joe Shmoe won't see this on their home setup trying to talk to a buddy 2 miles away behind a hill. | |
| ▲ | po1nt 7 hours ago | parent | prev | next [-] | | I did a test with my long range drone on ELRS and managed to get 6km (not miles) so it might be reachable with higher TX elevation. | |
| ▲ | jauntywundrkind 6 hours ago | parent | prev [-] | | I have skepticism too. But also, from a recent LoRa thread, and talking about 900MHz here, but someone said: > Wifi HaLow 802.11ah. LoRa is another level. It works down to -146dBm. 802.11ah dies around -100dBm. https://news.ycombinator.com/item?id=47890598 LoRa looks like someone is dropping a saw wave on the spectrum. It so clearly looks like such a blunt force user of spectrum. Just wild. |
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| ▲ | burnt-resistor 2 hours ago | parent | prev | next [-] |
| When I worked in the Trimble Navigation radio group, 2.4 GHz was tried but its real world range sucked compared to ~900 MHz and CB ~450 MHz bands of existing solutions. It's simply limitations of physics that lower frequencies propagate farther (at lower bandwidth) than higher frequencies. |
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| ▲ | dheera 8 hours ago | parent | prev [-] |
| Just use Unifi Airfiber for 6 miles at gigabit speeds. If you're relying on line of sight then 2.4GHz is nonsense. And if you don't have line of sight then no you're not getting 6 miles |
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