On 03/03/17 10:24, NY wrote:
Try telling the 2.4 GHz point to point links that are here that. One
is 6 km the other only 4 km. Another site has around 20 km and 15 km.
Rain, hill fog, snow or all three didn't stop 'em working.

Do they use 2.4 GHz? I'd assumed/read somewhere that they didn't use a
resonant frequency of water for that very reason, and that 2.4 was only
available because no-one (eg military, broadcast) could use it for
anything else long-distance. On the other hand, with a dish aerial to
concentrate the available power into a narrower beam, maybe water
attenuation can be overcome sufficiently to transfer a usable signal at
20 km range.
2.4 is not used much for point to point. It is used for 'village wifi'
and can get a km or two with the right antennae, BUT it does tend to
stop working in rain

2.4Ghz is probably good for rain radar tho.

Point to point is at a lot of other frequencies.

Rain and microwaves is a very interesting subject. generally te higher
the frequency the worse the effect BUT there are as has been pointed
out, deep and narrow notches in longer wavelengths like 2.4Ghz.

Which is why 2.4Ghz is left for 'amateurs' use. In practice that means
microwaves, wifi, model radio control, some local telemetry and a few
other short distance uses.

Tony Sayer will be along with chapter and verse on what is used
professionally.

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a matter of elementary environmental protection, or a search for
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