[geeks] Ultra-Portable UNIX

Patrick Giagnocavo patrick at zill.net
Sun Mar 5 15:42:51 CST 2006


On Sun, 2006-03-05 at 15:48, Geoffrey S. Mendelson wrote:
> On Sun, Mar 05, 2006 at 03:21:44PM -0500, Patrick Giagnocavo wrote:
> > You have to stay within the total EIRP and may home-build and use up to
> > 5 antennas of any design.  In this case total EIRP would be higher
> > because it is a point to point link and not point to multipoint.  
> 
> Total EIRP is based upon transmitter power plus (or minus) antenna gain.
> If you have an antenna that is radiates 100% of of the output power,
> which is quite easy to do at 2.4gHz, but has no gain, and then narrow

There are two rules:  one for point to point, another for point to
multipoint.  Total allowed EIRP is different between the two. 

There is also the home-built exception, provided you stay within the
rules for total EIRP.

Note that many of the current consumer grade, and the early pro-grade,
wireless chips have a small amount of transmitter power, e.g. the
Lucent/Orinoco Silver and Gold PCMCIA cards have 30mW transmitter
power.  This was due to difficulties in increasing the power without
increasing the noise as well.  

Not sure what the Linksys WRT54xx units put out, but there are at least
5 different variations of those.

Later or more expensive cards will use the new radios that will put out
100mW or more.  ISTR a chipset that could do 250mW but am not sure.

I think that what you are saying is more along the lines of "many uses
of a dish will put you over the allowed total EIRP" . 


--Patrick



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