Oops! I responded too quickly to this message! You were responding to Casey Halverson's posting, not mine.
Apologies, Greg On Fri, 2003-07-25 at 08:40, Greg DesBrisay wrote: > > > Jim, > > I specifically said this was a non-802.11a system. > The power was higher than 200 mW. > > Greg > > > > On Fri, 2003-07-25 at 00:14, Jim Thompson wrote: > > > > For F in MHz and D in miles, free space path loss = 36.6 + 20 * log(D) + 20 * > > log(F) > > > > for 2.4GHz and 10 miles, the free space path loss is 124dB. > > > > lets assume a 23dBm transmitter, -89dBm rx sensitivity @ 11Mbps and > > FER of 0.08, and 24dBi of gain at each end of the link. > > > > 23dBm + 24dBi + 24dBi + 89dBm = 160dBm of available link budget, less > > the 124dB of "free space" path loss, less the "about 30dBm of > > attenuation", and you're at 6dB of link margin, before you count other > > losses (connectors, coax, antenna pointing errors, etc, etc.) > > > > Those 200mW cards only have a -92 or -93 dBm rx sensitivity @ 1Mbps, > > so you're at perhaps 10dB of link margin before losses. > > > > If you established a link in these conditions, it couldn't have been > > solid, and there is no way you had "plenty of signal left over to make > > a link with a reasonable fade margin". > > > > Perhaps your 2 miles of trees/urban clutter/housing had < 30dB of > > attenuation? > > > > Jim > > > > Casey Halverson writes: > > > "NLOS" (i really hate that acronym) can be done with 802.11b gear, but its > > > mainly a hit or miss. > > > > > > For example, I had about a 10 mile path, 2 miles of which were solid tree/urban > > > clutter/housing/etc. all of that garbage caused about 30dB of attenuation, but > > > I had plenty of signal left over to make a link with a reasonable fade margin. > > > This is a story of a link that probably shouldnt have even worked that did. > > > > > > Next example, on a 2 mile shot, i cannot get through 30-50 feet of my apt with > > > 24dBi parabolics and 200mW radios. Here is a sad story of not being able to > > > make it through obstructions, no matter how little or insignificant i thought > > > they were. > > > > > > It all depends on the materials in the path. Since we do not all possess > > > magical powers to determine path content, its hit and miss. > > > > > > We could paper link this path to death, or you could find someone with some gear > > > and try it yourself. Two 24dBi parabolics and a pair of 200mW radios are your > > > best shot if you want to use 802.11b. > > > > > > > > > > > > -----Original Message----- > > > From: George [mailto:[EMAIL PROTECTED] > > > Sent: Thursday, July 24, 2003 11:16 AM > > > To: 802.11B NEWS GROUP > > > Subject: [BAWUG] 802.11b Long Range non line of sight > > > Importance: High > > > > > > > > > Hi guys, > > > > > > I was wondering if anyone had came across with an 802.11b equipment that > > > doesnt need clear line of sight. > > > I am tasked of bridging a link for a10mile remote site. But Line Of sight > > > is not very clear. Can anyone please > > > suggest what can i possibly do to accomplish this. > > > > > > thanks in advance > > > > > > George > > > -- > > > general wireless list, a bawug thing <http://www.bawug.org/> > > > [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless > > > > > > > -- > > "Speed, it seems to me, provides the one genuinely modern pleasure." > > -- Aldous Huxley (1894 - 1963) > > > > -- > > general wireless list, a bawug thing <http://www.bawug.org/> > > [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless > > > -- > general wireless list, a bawug thing <http://www.bawug.org/> > [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless -- general wireless list, a bawug thing <http://www.bawug.org/> [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless
