3 ms·
To someone that understands this, I'm curious: is line of sight, especially this far, impacted by something like a bird flying in the middle?
by aledalgrande 5y ago
To someone that understands this, I'm curious: is line of sight, especially this far, impacted by something like a bird flying in the middle?
- marcodiego 5y agoBy line of sight, I think it means that it must be held in a tall enough mast not to be impacted by curvature of the earth. IIRC curvature of the earth limits line of sight to around 35km at 1.7m of height.
- Reventlov 5y agoThis might interest you: https://en.wikipedia.org/wiki/Fresnel_zone https://en.wikipedia.org/wiki/Fresnel_zone
- topspin 5y agoNot unless the bird is very close to the antennas at either end. This is a neat exercise in antenna design. They've built high gain directional antennas and minimized transmission line losses. The 15 dBi antennas aren't even that remarkable; you can buy 30+ dBi wifi antennas. My first 'better than dial-up' internet connection was a 2.4 GHz wifi service across 7 miles. On my end was a roof mounted aluminum parabolic grid antenna. It worked rather well and sometimes I wish I still had it.
- creeble 5y agoMine too! Though mine was the other way ‘round: I had a frac T1 line (256kbps iirc) and shared it with two other locations via a central omni antenna. Breezecom radios that I think were frequency-hopping (pre-spread-spectrum).
- ajsnigrutin 5y agoNope, not really. Very simplified, the signal is carried within a "fresnell zone", which s basically a 3d ellipse, that is relatively wide in the middle, and you'd have to cover a lot of that area, to block the signal... definitely more than a bird can do. https://en.wikipedia.org/wiki/Fresnel_zone#Clearance_calculation https://en.wikipedia.org/wiki/Fresnel_zone#Clearance_calcula... ...unless the bird is standing infront of the transmitter/receiver.. then yes.