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Re: which one is faster?



On 08/10/2012 12:52 AM, Kelly Clowers wrote:
On Thu, Aug 9, 2012 at 9:00 AM, lina<lina.lastname@gmail.com>  wrote:
On 9 Aug, 2012, at 23:05, Chris Bannister<cbannister@slingshot.co.nz>  wrote:

On Wed, Aug 08, 2012 at 09:00:18PM +0800, lina wrote:
I don't know the reliable of the connection between the two servers, I
guess it's okay.

But from my side, the wireless is not stable.
I don't know how to let it stable. I mean, not login every 10~15 minutes.
(btw, Is big wind affects the wireless signal, kinda of silly to ask,
I prefer the fresh air outside, so move laptop outside)
Wind won't affect the signal, but if you are outside you may be in a
spot where the signal is weak. Can you see what the signal strength is?
Wind won't affect the signal?!
Thanks.
Nope. The air itself absorbs some of the electromagnetic spectrum
(which is why gamma ray and x ray telescopes are *all* in space).
Movement of the air does not really affect it much though. Density
changes in the air (from pressure or thermal differences) can affect
EM radiation, which is one reason the big optical telescopes have
computer controlled micro-adjustments or are in space (Hubble).

However, that is visible light, which has a much shorter wavelength
than radio. Being longer, radio is much less affected by density
differences, and on the scale of wifi it is not worth thinking about.
And wind is basically a non-effect even for light (unless it carries
dust or snow or something, but that is a different matter). I will
say that in a heavy Montana blizzard, satellite TV signal can fade.
But that comes down to the amount of water (frozen) in the air,
as water tends to be a pretty good absorber of EM radiation in
general.

Cheers,
Kelly Clowers


All of that is quite correct, but it neglects one parameter: if the
RF connection depends on directional antennas, which it will
for any reasonable distance--say 1/2 mile or more--then wind may
become a significant effect if it causes the antennas to jiggle, or
to point off-target sometimes.

--doug, WA2SAY, retired RF engineer

--
Blessed are the peacekeepers...for they shall be shot at from both sides. --A.M. Greeley


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