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Re: [LUG] wireless musings



Okay,
This are a little hazy on what eirp is actually allowed these days.
I've actaully spoke to one installation company that told me the limit is now 
250mW in the UK - I always believed it was 100mW.

I know in the US, that the rules change slightly when you're talking about a 
point ot point link. Once you add an Ae, you're supposed to lower the 
trasmitter power output by 1dB for each 2dB of Ae gain.
I don't know if the UK also have that sort of ruling.

Jon

On Friday 25 Jul 2003 11:37 pm, Paul Weaver wrote:
> On Saturday 26 July 2003 01:20, you wrote:
> > So a directional aerial won't actually boost your transmit power, if you
> > are to stay within the law, but will allow you a stronger receive signal,
> > yeah?
>
> No. As wifi is a two-way signal, a decent antenna will boost your signal
> 20+dB. Thats a 100-fold increase on the original signal.
>
> You transmit at 100mW, you lose some in the cable to the ariel, the air
> between ariels, and the cable from the Rx ariel. You gain because of
> ampliefiers and ariels. Typically you transmit at 10dB and receive at
> -80dB. The total loss, of cable and air combined with the total gain of
> amps and ariels, must be less then that 90dB difference.
>
> > I've seen some impressive statistics quoted using normal equipment
> > strapped to an old satellite dish, I might try that some day... although
> > I think it's still pretty much "line of sight". :-(
>
> 2.4GHz cant go through objects, so while LOS is possible, using multipath,
> its not really probable. With full LOS you should push 10 miles by only
> breaching the 100mw "by a little bit".
>
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