A Question for Antennas Specialist

got a problem with antennas fixed on my truck

i got this one (x2) fixed on my truck............
http://www.hyperlinktech.com/web/hg2409mgu.php

i saw a thing really weird ... a guy which was wardriving with a truck(im living into one too) and using an antenna really weird, in facts he used his own whole truck, so my questions are.......

1 DO YOU KNOW TUTS FOR USING THE TRUCK AS AN ANTENNA ?

2 IF ITS POSSIBLE, WHAT DO YOU THINK ABOUT POSSIBLE PERFORMANCE FOR THESE SYSTEMS ?

in facts, it's only that i want to test this thing on my own truck but i don't find anything anywhere....

Quote:

---

Originally Posted by shamanvirtuel

got a problem with antennas fixed on my truck

i got this one (x2) fixed on my truck............


i saw a thing really weird ... a guy which was wardriving with a truck(im living into one too) and using an antenna really weird, in facts he used his own whole truck, so my questions are.......

1 DO YOU KNOW TUTS FOR USING THE TRUCK AS AN ANTENNA ?

2 IF ITS POSSIBLE, WHAT DO YOU THINK ABOUT POSSIBLE PERFORMANCE FOR THESE SYSTEMS ?

in facts, it's only that i want to test this thing on my own truck but i don't find anything anywhere....

---

I'm trying to understand what you're asking, I understand you're french, so english might be tough, but here goes.

It would seem you're saying some guy is using the body of his truck as an antenna for wifi? So, basically, he's got a piece of coax attached to the body of his truck and he's picking up signals.

If this is true, then he's also greatly increased the SWR (Standing Wave Ratio) into his card. If he continues to do this, his card will eventually die. As a SWR of 3.0 or greater on any RF transmitter is fatal. There would be no way he could possibly tune the connection to get the SWR within acceptable parameters.

If you're using the antenna in the link, continue to use it, it looked like a decent one.

Sorry my bad english...i promise to learn a little more...

yeah they are fantastics ones i got 2 pieces....one in front and one on rear sides of my truck roof.....

thx for your 2 answers......

i won't do it....better for my cards....

i would maybe buy 2 antennas more, put them in a big square on my truck roof

IS THERE SOME RULES WHEN USING 4 ANTENNAS ? a rule for placing them to obtain maximum receiving capacity ?

Quote:

---

Originally Posted by shamanvirtuel

Sorry my bad english...i promise to learn a little more...

yeah they are fantastics ones i got 2 pieces....one in front and one on rear sides of my truck roof.....

thx for your 2 answers......

i won't do it....better for my cards....

i would maybe buy 2 antennas more, put them in a big square on my truck roof

IS THERE SOME RULES WHEN USING 4 ANTENNAS ? a rule for placing them to obtain maximum receiving capacity ?

---

If you're using 4 Antennae then I would assume you're using 4 cards?

If I recall, when placing multiple antennae of the same band in close proximity they should be at least one wavelength apart, but I might be recalling that incorrectly.

shamanvirtuel,

Something to remember when setting up antennas is the margin of error for 802.11 is very small.

Rough Calculation of Full Wave Length is around:
4.917" @ 2.401GHz Channel 1 Low
4.732" @ 2.495GHz Channel 14 Upper

I agree that using the body of the truck for an antenna would yield poor performance and very high SWR. Bad.

If you spread out the antennas to the four corners of the truck I think you'd be fine.