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I've thought about trying to do long reach WISP stuff in the 900 MHz band for similar reasons - its too hard/expensive to get affordable licensed spectrum. I'd
by Aloha 11y ago
I've thought about trying to do long reach WISP stuff in the 900 MHz band for similar reasons - its too hard/expensive to get affordable licensed spectrum. I'd like to see more unlicensed spectrum out there to make this easier, ideally lower than 2.4 GHz
- Gibbon1 11y agoThe 900MHz band is great if you can use it, since for the same power 900MHz goes substantially farther than 2.4 or worse 5GHz. The old inverse square law is 'in a vacuum' Once you your signal is going through air, drywall, masonry, or my favorite steel re-enforced concrete, you're looking at exponents of 2.5 (just air) to 3.5 or worse. This only get more sad the high frequency you go.
- jdiez17 11y agoWhen you start lowering the frequency and going further, you can have a path loss exponent of up to 4, so you have to be wary of reflections from the atmosphere. [1] Radio engineering is really interesting. [1] https://en.wikipedia.org/wiki/Path_loss#Loss_exponent https://en.wikipedia.org/wiki/Path_loss#Loss_exponent
- Aloha 11y agomultipath is a pain in the ass - so are atmospheric inversions (which effects much higher frequencies).