antenna design & usage

04-07-2002

A question for all those 'wardrivers' out there....

Which simple (and cheaper) antenna(s) do you use to get the best signal?

I've stumbled w/ an Orinoco silver w/ no antenna and had decent results, but picked up considerably more the good ol' pringles can. I plan on trying the coffee can design next to see what kinda results I can get. Any suggestions or input?

Is it possible to use, oh, say, a radio shack standard magmount scanner antenna as an omnidirectional? It's supposed to go up to 1.3 ghz, but what kinda reception can one expect on 2.4ghz? I've found the pl259 -> N Male adapter @ radshack and was just curious. Even though the antenna is not 'tuned' for 2.4ghz. I would get the fab-corp 9" magmount, but they seem to be outta stock and for that much money for an antenna & a hobby is a bit steep although I'll prolly get one anywho.

I have notices while driving that I get significantly better results when the antenna is OUTSIDE the vehicle due to all the interfernce from within.

Anyway, any comment &/or feedback is always welcome. Happy driving

04-07-2002

This has been discussed a lot. For omni directionals, search these forums for the following topics:
"antenna", "antennas" (sic), "antennae", "Antenna Specialists", "Fab-corp"

The last two are dealers. One of the people at Fab-corp is on these forums sometimes (Borg Man) and offers a discount to others on these forums. The people who have about one of the Fab-corp models rave about it.

A car body, because it contains a lot of metal will block an RF (radio frequency) signal. (A pretty obvious statement, when you think about it.) The "pringles can" and "coffee can" tend to be very directional. If you point them outside the car, say to the left, you might very easily miss an AP on your right. To wardrive well, you really need an external omni. BTW, don't point a directional at body parts (especially your eyes), or have a body part with about 20cm of the radiating (open) end of the directional. A directional antenna concentrates the radio energy. This stuff is low power, but it is still microwaves.

Cheers,
Thorn

04-08-2002

an Orinoco "popsicle" stick antenna. White 6inch tall plastic thing. I've slapped a strong magnet to the bottom and it works well. since I'm simply stumbling and not trying to access an AP from a distance an Omni makes the most sense - no reason to skew my data to the direction the antenna is pointing.

Good tip on th eOmni's though. I'd not considered it but yeah I gues pointing it at yourself wouldn't be too smart. I've yet to build one or have reason to but I appreciate the warning!

04-08-2002

BLKMGK

how'd you get that thing on the roof? my cable is way too short!!!!!!!! i'd have to mount my libretto to the headliner (somehow) in order for mine to get enough distance to get to the roof!

04-09-2002

I am in Alphaetta, GA... near atlanta and I am wondering if anyone knows where I can pickup a mobile magmount 2.4ghz antenna...

anyone? drop me a line?

04-09-2002

you can pick up an omindirection 5dbi magmount from www.fab-corp.com .. good prices (netstumbler discounts) and great products. Havent had or heard a complaint yet. They're located in the Tampa, FL area and it's about 10$ for fedex 2 day shipping (at least to here)

04-09-2002

I received mine on Monday and it is awesome! I get almost twice the AP's than I did before! Dude its so worth it.

04-10-2002

Hi,

Were using http://www.frars.org.uk/cgi-bin/render.pl?pageid=1103 . They have a 2 stage LNA built in and give a gain of around 20Db. Used with Kismet they are untold.

btw, they are receive only - transmitting up them would prolly make the second stage mmic fail. Maybe a couple of pin diodes across the RF out could protect the MMIC? I'll try.

Regards,

mr_wlan

04-11-2002

Cable on mine is fairly long. I just stick it out a window and don't try to center it on the roof unless we put it out the SUV's sunroof :-)

As for a receive only antenna - I'm pretty darned sure that 'stumbler transmits. Might be interesting to use with Kismet or WalensomethingIcan'tpromounce or perhaps a dedicated sniffer but sure as heck I'd get stupid and blow it up :-(

04-07-2002	#1 (permalink)
Posts: n/a	antenna design & usage A question for all those 'wardrivers' out there.... Which simple (and cheaper) antenna(s) do you use to get the best signal? I've stumbled w/ an Orinoco silver w/ no antenna and had decent results, but picked up considerably more the good ol' pringles can. I plan on trying the coffee can design next to see what kinda results I can get. Any suggestions or input? Is it possible to use, oh, say, a radio shack standard magmount scanner antenna as an omnidirectional? It's supposed to go up to 1.3 ghz, but what kinda reception can one expect on 2.4ghz? I've found the pl259 -> N Male adapter @ radshack and was just curious. Even though the antenna is not 'tuned' for 2.4ghz. I would get the fab-corp 9" magmount, but they seem to be outta stock and for that much money for an antenna & a hobby is a bit steep although I'll prolly get one anywho. I have notices while driving that I get significantly better results when the antenna is OUTSIDE the vehicle due to all the interfernce from within. Anyway, any comment &/or feedback is always welcome. Happy driving

04-08-2002	#3 (permalink)
Posts: n/a	I use... an Orinoco "popsicle" stick antenna. White 6inch tall plastic thing. I've slapped a strong magnet to the bottom and it works well. since I'm simply stumbling and not trying to access an AP from a distance an Omni makes the most sense - no reason to skew my data to the direction the antenna is pointing. Good tip on th eOmni's though. I'd not considered it but yeah I gues pointing it at yourself wouldn't be too smart. I've yet to build one or have reason to but I appreciate the warning!

04-08-2002	#4 (permalink)
Posts: n/a	Orinoco "popsicle" stick antenna BLKMGK how'd you get that thing on the roof? my cable is way too short!!!!!!!! i'd have to mount my libretto to the headliner (somehow) in order for mine to get enough distance to get to the roof!

04-09-2002	#5 (permalink)
Posts: n/a	Any 2.4g Ant Dealers near Atlanta,GA?? I am in Alphaetta, GA... near atlanta and I am wondering if anyone knows where I can pickup a mobile magmount 2.4ghz antenna... anyone? drop me a line?

04-10-2002	#8 (permalink)
Posts: n/a	active receive antenna's for wlan Hi, Were using http://www.frars.org.uk/cgi-bin/render.pl?pageid=1103 . They have a 2 stage LNA built in and give a gain of around 20Db. Used with Kismet they are untold. btw, they are receive only - transmitting up them would prolly make the second stage mmic fail. Maybe a couple of pin diodes across the RF out could protect the MMIC? I'll try. Regards, mr_wlan

04-07-2002	#2 (permalink)
Posts: n/a	This has been discussed a lot. For omni directionals, search these forums for the following topics: "antenna", "antennas" (sic), "antennae", "Antenna Specialists", "Fab-corp" The last two are dealers. One of the people at Fab-corp is on these forums sometimes (Borg Man) and offers a discount to others on these forums. The people who have about one of the Fab-corp models rave about it. A car body, because it contains a lot of metal will block an RF (radio frequency) signal. (A pretty obvious statement, when you think about it.) The "pringles can" and "coffee can" tend to be very directional. If you point them outside the car, say to the left, you might very easily miss an AP on your right. To wardrive well, you really need an external omni. BTW, don't point a directional at body parts (especially your eyes), or have a body part with about 20cm of the radiating (open) end of the directional. A directional antenna concentrates the radio energy. This stuff is low power, but it is still microwaves. Cheers, Thorn

04-09-2002	#6 (permalink)
Posts: n/a	you can pick up an omindirection 5dbi magmount from www.fab-corp.com .. good prices (netstumbler discounts) and great products. Havent had or heard a complaint yet. They're located in the Tampa, FL area and it's about 10$ for fedex 2 day shipping (at least to here)

04-09-2002	#7 (permalink)
Posts: n/a	I received mine on Monday and it is awesome! I get almost twice the AP's than I did before! Dude its so worth it.

04-11-2002	#9 (permalink)
Posts: n/a	Cable on mine is fairly long. I just stick it out a window and don't try to center it on the roof unless we put it out the SUV's sunroof :-) As for a receive only antenna - I'm pretty darned sure that 'stumbler transmits. Might be interesting to use with Kismet or WalensomethingIcan'tpromounce or perhaps a dedicated sniffer but sure as heck I'd get stupid and blow it up :-(

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