On Thu, 29 May 2003, Chaves, Jan Amcil wrote:
..
> A friend and I are coming up with specs for a really long 802.11b link (some
> 20km, maybe more, over open ocean).  The idea is to minimize transmission

You cannot do that with cheap AP's due to the low receive sensitivity. For 
example Linksys AP's only have -80dBm sensitivity at the receiver @ 1Mbps.

Contrast this with -91dBm for the Aironet 340 and -94dBm for the Aironet 
350 (both by Cisco).

We have a 10km overwater link between Cebu and Mactan. As you well know, 
path loss overwater is tremendous. We could only get 2Mbps over that link 
using Cisco 21dBi solid parabolics. Adding an amplifier to one end 
(increased transmit power to 500mW and receive gain by 12dB) increased 
speed to 5.5Mbps.

So for a 20km link overwater, forget about cheap AP's. Use the best ones 
you can get. And, on top of that, get yourself some amplifiers. We use 
antennas and amplifiers from Hyperlink (www.hyperlinktech.com) -- Cisco 
antennas cost too much.

BTW we *do* have NTC licensing for the link I mentioned. Don't think you 
can get away with it unless you are on very good terms with the local NTC.


---
Orlando Andico <[EMAIL PROTECTED]>
Mosaic Communications, Inc.

--
Philippine Linux Users' Group (PLUG) Mailing List
[EMAIL PROTECTED] (#PLUG @ irc.free.net.ph)
Official Website: http://plug.linux.org.ph
Searchable Archives: http://marc.free.net.ph
.
To leave, go to http://lists.q-linux.com/mailman/listinfo/plug
.
Are you a Linux newbie? To join the newbie list, go to
http://lists.q-linux.com/mailman/listinfo/ph-linux-newbie

Reply via email to