On Wed, 14 Jan 2004, David Rhodes wrote: > Tim - I thought this thread sounded familiar..
I was sort of wondering when people would just get over it and realize that "journalists" are prone to hyperbole. > I also seem to remember a > discussion on whether or not to add the gains of the two yagis together in > passive mode - in reference to the effective +36db of the two yagis. > Correct? Of course reductions here would just further prove the point.. > > D. > > > >From a previous mail of almost two years ago. :-) > > > > From: Tim Pozar <[EMAIL PROTECTED]> > > To: Walter Bruce <[EMAIL PROTECTED]> > > Cc: Tom Farrow <[EMAIL PROTECTED]>, [EMAIL PROTECTED], > > [EMAIL PROTECTED], [EMAIL PROTECTED] > > Subject: Re: [BAWUG] Re: Passive repeater net gain > > Message-ID: <[EMAIL PROTECTED]> > > References: <[EMAIL PROTECTED]> > > <[EMAIL PROTECTED]> > > <[EMAIL PROTECTED]> > > In-Reply-To: <[EMAIL PROTECTED]>; > > from [EMAIL PROTECTED] on Tue, Feb 12, 2002 at 01:23:21PM -0800 > > Date: Tue Feb 12 14:08:01 2002 > > X-Original-Date: Tue, 12 Feb 2002 14:07:48 -0800 > > > > On Tue, Feb 12, 2002 at 01:23:21PM -0800, Walter Bruce wrote: > > > So, why did it work for Cringely? > > > > Hmm... Let's calculate it... > > > > He states in the article that he is using a WAP11 at his > > house running at 100mW (too bad as a WAP11 splatters all up > > and down the band in this mode and he is likely violating the > > FCC's spectrum > > requirements) into a 21dBi dish. The mountain top is 1.5 > > miles away. He is using some sort of yagis on the mountain > > top. The second path is 5 miles. He doesn't state the gain > > of the yagis or what the antenna is at the ISP. But we can > > make some assumptions... > > > > Ignoring cable/connector losses at his home he is doing 41dBm > > EIRP out of his antenna (20dBm + 21dBi). The free space loss > > at 1.5 miles is about 108 dB. Lets assume his yagis are 18dBi > > and there is no loss on the cable connecting them together. > > The 5 mile path will have a free space loss about 118dB and > > we will assume he has a 24dBi gain antenna on the roof of the > > ISP. Lets add this up... > > > > 41 dBm EIRP (20dBm + 21dBi) at his house. > > - 108 dB Free space loss - first link > > + 18 dBi antenna gain on the mountain. > > + 18 dBi antenna gain on the mountain. > > - 118 dB Free space loss - second link. > > + 24 dBi antenna gain at ISP. > > ========= > > - 125 dBm > > > > Most cards will start to work about -90dBm so this is 35dB > > below his receiver threshold. Unless my assumptions or > > interpretation of his paths are are wrong, it doesn't look > > like the numbers hold up his claim. > > > > -- > > 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 > -- -------------------------------------------------------------------------- Joel Jaeggli Unix Consulting [EMAIL PROTECTED] GPG Key Fingerprint: 5C6E 0104 BAF0 40B0 5BD3 C38B F000 35AB B67F 56B2 -- general wireless list, a bawug thing <http://www.bawug.org/> [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless
