WiFi FAQ

jrtf83 · 07-22-2004, 01:15 PM

Seems we need a WiFi FAQ, I might not be the one to start this but here goes. Firstly:

What's the difference between the different protocalls a/b/g and such?

(From: http://www.webopedia.com/TERM/8/802_11.html)

Quote:

There are several specifications in the 802.11 family:

802.11 -- applies to wireless LANs and provides 1 or 2 Mbps transmission in the 2.4 GHz band using either frequency hopping spread spectrum (FHSS) or direct sequence spread spectrum (DSSS).
802.11a -- an extension to 802.11 that applies to wireless LANs and provides up to 54 Mbps in the 5GHz band. 802.11a uses an orthogonal frequency division multiplexing encoding scheme rather than FHSS or DSSS.
802.11b (also referred to as 802.11 High Rate or Wi-Fi) -- an extension to 802.11 that applies to wireless LANS and provides 11 Mbps transmission (with a fallback to 5.5, 2 and 1 Mbps) in the 2.4 GHz band. 802.11b uses only DSSS. 802.11b was a 1999 ratification to the original 802.11 standard, allowing wireless functionality comparable to Ethernet.
802.11g -- applies to wireless LANs and provides 20+ Mbps in the 2.4 GHz band.

Where can I mount my antenna?

You should really mount your antenna outside your car, metal will block the high frequency WiFi signal pretty easily. Glass will interfere some but not as much as metal.

Can I use my car's AM/FM antenna to recieve wireless?

No, as antennas must be tuned to the proper length depending on the frequency of the signal. Radio signals are a much lower frequency than WiFi and as such require a much longer antenna. Also, WiFi antennas send as well as recieve so they must be powered, powering an AM/FM antenna with your wireless card can fry things so be careful!

What else?

What's the best antenna?
What's the best wireless card?

Tabbe · 07-29-2004, 11:24 AM

Right now the highest speeds available in a wireless network solution is 108mbps. Remember that the speed is the theoreticly max. You will never reach that speed.

For every obstacle in the way, wood, concrete, glass, rain, humidity, will make the signal weaker. Always try to have "eye contact" for the maximum preformance. The standard WiFi products of today usually has a maximum range at 400 yards(although it's possible to extend the range with a different antenna). There are known bridge stations that can establish a stable signal at a distance of 10 miles or more.

There are diffrent types of antennas, they go in to two sections:
Omni directional - antennas that sends the signal in every direction, 360'. these antennas are usually included with the base station, excellent when you want to move around.

directional antennas (don't know the name in english). That only sends in one direction, usually used for connecting another base station or extending the signal in one direction.

Can't think of anything more to add, just ask!

frodobaggins · 07-29-2004, 04:49 PM

I'm going to stick this, keep it clean please.

Chairboy · 07-29-2004, 06:10 PM

A popular use of WiFi in car computer setups is called 'War Driving'. This is a process where you run a program that looks for access points that allow you to access the internet. A typical use of that might be to have a program that periodically grabs a few K worth of data from a traffic site or occasionally uploads your GPS coordinates to a server for tracking.

War Driving, despite the name, is completely legal. Connecting to personal networks to access their internal data, however, is not.

The most popular program for doing this on Windows is called NetStumbler. It is available at http://netstumbler.org/ and supports many popular chipsets. It can also use your GPS to assign a location of each access point found so you can maintain a database. Driving from work to home in Los Angeles, I typically see upwards of a hundred access points, half of them without WEP encryption enabled.

On Linux, popular programs include AirSnort and Kismet, the latter a tool that can also detect people running NetStumbler.

Chairboy · 08-27-2004, 08:42 PM

NetStumbler .4 will actively prevent a computer from going into Hibernation or Standby, so if you're using it in your car you need to exit the program before turning off your car. If you don't, even your Opus will be unable to send it to sleep. An enhancement request has been posted to the Netstumbler.org BBS to make this setting configurable.

samc · 09-06-2004, 09:32 PM

How about a list of good wifi devices? I've tried this microsoft one and it was complete garbage. I locked once ever while wardriving to load up google.com.

I know orinoco silver is a good choice, anything else? I'd prefer something usb.

ppgt94 · 09-06-2004, 11:14 PM

Quote: Originally Posted by samc

I know orinoco silver is a good choice, anything else? I'd prefer something usb.

Orinoco makes a USB version. There is actually a PCMCIA card connected to a USB adapter inside the plastic case. The Orinoco card inside allows you to attatch an external antenna. I'm not sure if they are still made by Orinoco or another company. I got one off ebay a few months ago. Highly recommended.

Picture of the goodies inside:

More Info: http://www.cablemodeminfo.com/quickt...inoco.html-ssi

owenjh · 09-20-2004, 01:36 PM

Please Could We get a description of what is best to look for when buying antenna's / adapters. Explanations of the transmit power (mw, w, Db's)
Also a description of Connections (Pigtails, RP-SMA, SMA, TNC, RP-TNC etc, etc...)

Here is a good FAQ on wireless: http://www.seattlewireless.com/faq.asp

And Here is a list of cards, not sure what all of the data means (Power, which is better w, mW, or dBmhttp://www.seattlewireless.net/index...rs_5f802_5f11b

freestyler · 09-20-2004, 02:06 PM

Quote: Originally Posted by Chairboy

A popular use of WiFi in car computer setups is called 'War Driving'. This is a process where you run a program that looks for access points that allow you to access the internet. A typical use of that might be to have a program that periodically grabs a few K worth of data from a traffic site or occasionally uploads your GPS coordinates to a server for tracking.

albeit somewhat correct that statement isn't 100% correct.

wardriving is "The benign act of locating and logging wireless access points while in motion"

has nothing to do with locating access points for accessing the internet, it's merely a statistical data gathering method.

and your "typical" use is incorrect, it doesn't grab ANY K's of data, it merely notes where a radio beacon is being broadcasted.

nFiniteTuning · 10-26-2004, 05:27 PM

I didn't even know what WiFi was until just now when I searched "Satelite Internet" on google. Could I get a newbie description of this?

I see people saying a 360 range of 10 mile radius? Does this mean I can setup some kind of wireless network device in my car, and have it transfer and recieve network/internet data from my pc which is loged onto the internet? And drive around too?

....I really would love to be able to drive around town and have a connection. The main area I cruise (drive to and from for the hell of it) in my city (albuquerque, nm) is about a 10 mile radius, most likely smaller. From the middle of the city to my home outside the city in the mountains, is 18 miles....soo that leads me to belive that Albuquerque is about 20 miles long and 15 miles wide. And I dont drive to those area's...

Chairboy · 10-26-2004, 05:54 PM

Quote: Originally Posted by freestyler

albeit somewhat correct that statement isn't 100% correct.

wardriving is "The benign act of locating and logging wireless access points while in motion"

has nothing to do with locating access points for accessing the internet, it's merely a statistical data gathering method.

and your "typical" use is incorrect, it doesn't grab ANY K's of data, it merely notes where a radio beacon is being broadcasted.

What's with the lawyerspeak? War driving is finding APs, there's nothing wrong with my description. You sound like you're daintilly trying to avoid the fact that some people who war drive use the connections to connect to the internet.

In regards to marking my description of one typical use as 'incorrect', you're a raving looney. I didn't say 'This is the word of god, all war drivers do this one thing'. I said 'one use is to xxx x xxx'.

Lighten up, Francis.

grepzen · 10-26-2004, 06:13 PM

The two types of antenna are (omni-directional, directional)
HomeBrews will tend to focus on the directional types.
PRO:
<> higher gain/distance for signal, stronger signal for given distance
<> stronger signal can == higher bandwidth
<> W/ a directional (and a known WiFi HOTSPOT), you can keep the ant. inside the car.

CON:
<> Directional ant. make for poor choices when wardriving.
<> If you don't KNOW the location of the wifi ant. you 'could' be close enough to get a signal w/ a omin. but still miss it with the directional.

Extra Reading:
http://www.wi-fi.bz/wifi/how_to_star...sp_802.11.html
BUY a directional ant. :: http://www.ramseyelectronics.com/cgi...ction&key=LPY2
MAKE a directional ant. :: http://www.oreillynet.com/cs/weblog/view/wlg/448
More on homebrew wifi ant. :: http://www.freeantennas.com/.

fuctup · 11-01-2004, 04:56 AM

thought id add a site, http://www.fab-corp.com/ i've bought a few things from them, good stuff. guys that handles there ebay selling is a clown and i dislike him.

nFiniteTuning · 12-08-2004, 01:43 AM

Ok, what would be the best Adaptor? I'm still not hired with this Wireless Internet company yet, but for now I'm using a Linksys Wireless-G USB Adaptor. from one end of my house to another, I'm only getting 1mbps.

You guys said the antena must be mounted outside, well ok....Which Adaptor, prefibly USB, can we use, and hook up an antena to it, so having the adaptor inside wont hurt the signal...

integramodder · 12-22-2004, 12:10 PM

http://www.popsci.com/popsci/how2/ar...714017,00.html

Some great info for a blue tooth adapter from a 15 dollar antenna....

Looks like ill be ordering those. The adapter is avaliable for $43.95 from Dell with a 10% discount ($4.40) and free shipping and no tax in some states, including mine! Comes out to be $39.56.

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