[MLB-WIRELESS] (WAS: New submission up at Inquiry) Link Length Limitations and Power Requirements

[Ben Ryan]

>> Now let's do some quick math...  an eighth of legal would be 
>> 0.5watts EIRP.
--snip--
>> Who's got the crack-pipe, and can I have some?

Tony:
> Park on a couple of hills and it should be quite possible. :)  Running 30 mW
> with "full legal antenna gain" it should be possible to make almost 100km
> (albeit most likely at 1 or 2 Mbps and with no real fade margin).  at 1/8
> power, the possible distance reduces by a factor of approx 2.8 (i.e. 2x
> square root of 2).

Something for all to keep in mind.. IIRC, there are limitations in the timing
specifications of 802.11b which, when adhered to in radio/DSP design, impose an
arbitrary length limitation on a link. Spose due to propagation delay, the times
eventually wind out past the frame timing windows (like 10BaseX segment length.. once
the frame arrives at a remote node at a time PAST the interframe gap any TX will
end up as a collision {runt, giant, etc}).

Since the IEEE have locked up the free-to-world version of 802.x Technical
Standard (spare $900 anyone?) I can't look at the exact limitations.
Anyone have more info on this?


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