You wanna write a book about it? I'm learning new stuff, and there's experience in your words which speaks volumes.
On Tue, 9 Jul 2002 08:52:57 -0500 "David A. Bandel" <[EMAIL PROTECTED]> wrote: > On Tue, 9 Jul 2002 08:54:57 -0400 (EDT) > begin Net Llama! <[EMAIL PROTECTED]> spewed forth: > > > On Mon, 8 Jul 2002, David A. Bandel wrote: > > > On Mon, 08 Jul 2002 20:12:14 -0700 > > > begin "Net Llama!" <[EMAIL PROTECTED]> spewed forth: > > > > > > > i guess i'm showing my ignorance. so a base-station/access-point > > > > is basically an embedded device that doesn't need an OS based > > > > driver to work? > > > > > > > > i guess i need "wireless for dumbies", cause i don't fully > > > > understand how it all comes together. > > > > > > > > > > commercial "access points" cannot be used as anything but that, they > > > can't be used as Master or Repeater stations. It has to do with > > > proprietary code in the cards, and the big boys don't want anyone to > > > muck with their gravy trains. > > > > > > In a linux box, however, a wireless card in ad-hoc mode is basically > > > an ethernet card. You do need to understand radio signals and how > > > they work, fresnell zones, and more, but that's not hard either. > > > > > > Tell me what you need, I'll give you more than you've ever wanted to > > > know. > > > > OK, what i attempted to diagram in my previous email was, that i'm > > getting DSL activated this Friday at home. My grand plan (excluding > > the WiFi > > stuff) is to run a Freesco box box that has 2 NICs, one plugged > > directly into the DSL router that the DSL provider gives me, and then > > the other plugged into a 10 port hub (yes, i know switches are better, > > but this is all i have on hand, and all i can afford right now). I've > > got 2 linux boxes that my wife & I use, plus 2 laptops (also linux). > > everything is a static (10.x.x.x) IP, and will have the Freesco box as > > its gateway to the internet. > > > > Now my vision for wireless is to get 1 or 2 wireless cards for the > > laptops, and a base-station/access-point. Plug the access-point into > > the hub, point it to the Freesco box as the gateway (as i'm already > > doing), and then get the laptops online anywhere in my house. > > > > So, is this possible, or am i completely misunderstanding what > > wireless can do for me? > > My suggestion for you is the following: > forget the access point, it's an unnecessary expense. > In one system that's always on (I suppose, but don't know, that it could > be the freesco box), put a PCI-PCMCIA bridge card (I recommend one with > the Ricoh chipset) and a wireless card. Spend the money you saved on > the access point to buy something like the Orinoco Extender antenna > (works with Orinoco/Agere cards, whatever card you use you'll need a > compatible connector for the card). Place the extender antenna at > approx eye-level(when you're standing). > Install WIFI cards in your laptops. Depending on your distance from the > desktop, and the geography of your house, you may need small antennas > for the laptops. The WIFI network will, of course, be a different > network than your desktops, so make sure your routing is correct if you > need to talk to your desktops. > > On WIFI cards, antennas, and wireless: > Most current WIFI cards are 50mW in power with no antenna. An antenna > effectively increases the power for both sending and receiving. > Outdoors, you can easily go 1/2 mile without antennas. Newer cars w/ > 100mW and even 200mW can go to almost a mile. An antenna extends the > sensitivity and range. > Wireless is LOS (line of site). It will pass through glass, but not > solid objects. It will work in your house because for the most part > you'll be inside the "ground plane" (fresnell zone). An antenna, > particularly one place up high, increases the ground plane (which size > is based on antenna height and output power). So while the signal can't > see through walls, it can travel around them if the walls are within the > ground plane. With overlapping ground planes, you'll always have > connectivity despite the LOS limitations. > > On amplifiers: > Some folks (often HAM operators) think amps will increase distance > through increased power. While this is true, you run the risk of > overmodulating stations closer in. WIFI works on SNR (signal to noise > ratio). Amps boost both, signal and noise. They do little to change > the SNR very much. > Imagine you get 50 e-mails a day, 10 of which are important. Your SNR > is > -.20. This is good (actual WIFI calcs are much more complicated, with > 93/93 being perfect). You can effectively process 100 e-mails per day, > but no more (limitation on your time). Suddenly, you find yourself > getting 500 messages per day, of which 100 are important. While the SNR > is the same, you'll probably never see any of the 100 important messages > because you're drowning in the 400 spams. Same principal applies to > amp'd signals. > > What haven't I covered? Lots. How antennas (typically 3dbi to 24dbi) > boost effective power (power is measured at the antenna). Signal > polarity(must say a word or two here). > > Signal polarity: If you use something like the Orinoco range extender > antennas, you'll see that they are similar to an omni. That is, they > have a radiation pattern, 360 degrees around, but probably vertically > about 22 degrees (except within the ground plane). However, you'll find > that if you have two spaced out beyond the ground plane and you rotate > one, even though they are "pointed" at each other (signal-wise, > meanining they are perpendicular one to the other physically), the > signal will decay and perhaps even disappear. > Note: You can effectively do "df" on a signal in the distance by > reorienting the antennas to find the lull, do this from different > places, and you can triangulate lines of bearing to get a df (direction > finding) on the remote site. > > The above is probably more than you wanted to know, but should give you > good background to get you started. > > Ciao, > > David A. Bandel > -- > Focus on the dream, not the competition. > -- Nemesis Racing Team motto > _______________________________________________ > Linux-users mailing list - > http://linux-sxs.org/mailman/listinfo/linux-users > Subscribe/Unsubscribe info, Archives,and Digests are located at the > above URL. _______________________________________________ Linux-users mailing list - http://linux-sxs.org/mailman/listinfo/linux-users Subscribe/Unsubscribe info, Archives,and Digests are located at the above URL.
