[GLLUG] Mobile phone antenna / booster

[James Courtier-Dutton]

On 11 September 2013 05:40, Christopher Hunter <cehunter at gb-x.org> wrote:

> Try that by all means, but if the signal is marginal (less than all bars
> lit) bear in mind that a wet roof (very common in the UK) is very
> absorbent to RF.  You may lose your already poor signal each time it
> rains!
>

Rain fade does not really affect 3G bands (2.1 GHz and 0.9 GHz). It affects
microwave bands more (11+ GHz), e.g. Satellite TV.
UK Freeview terrestrial TV is even lower (0.6 GHz to 0.8 Ghz) so rain also
does not affect UK TV much.

Explained here:
"According to the CWNA Study
Guide<http://tcs.uwstout.edu/wireless_docs/docs/CWNA_Study_Guide.pdf>,
2.4 GHz signals may be attenuated by up to 0.05 dB/km by torrential rain or
0.02 dB/km by thick fog. 5 GHz signals may be attenuated by up to 0.5 dB/km
by torrential rain or 0.07 dB/km by thick fog. Rain can also reduce signal
strength through water accumulation on other objects (trees, leaves,
absorbent walls) which serves to increase their attenuation."

See the difference between 2.4 and 5 GHz. 10 times more dB loss.
A loss of 0.05 dB/km by torrential rain is not much at all.
If you start losing 3 dB or more, it becomes important to consider.

James
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