Distance 9dbi omni + 12dbi directional

For 2.4 Ghz, if I have a 9dbi omni directional on my building's roof and a
12dbi directional on a mobile unit (vehicle roof, top of a van - or
something similar that I can park the vehicle and point its antenna at my
building roof from remote locations with line of sight), how far away might
I be able to roam and still acheive a good connection? (Assume all
atmospheric conditions are reasonable and line of sight can be maintained).

And, if there is a mathmatical formual for figuring this sort of thing out,
could someone point me to a link where I might see some examples?

Thanks!

"i'm_tired" <(E-Mail Removed)> wrote in message
news:Q_Zeb.391531$(E-Mail Removed). net...
> For 2.4 Ghz, if I have a 9dbi omni directional on my building's roof and a
> 12dbi directional on a mobile unit (vehicle roof, top of a van - or
> something similar that I can park the vehicle and point its antenna at my
> building roof from remote locations with line of sight), how far away
might
> I be able to roam and still acheive a good connection? (Assume all
> atmospheric conditions are reasonable and line of sight can be
maintained).
>
> And, if there is a mathmatical formual for figuring this sort of thing
out,
> could someone point me to a link where I might see some examples?
>
> Thanks!
>
I haven't tried this, but it came up in Google and looks interesting:
http://www.radiolan.com/Calc.html

If you read over this entire page, you'll find some very useful tools --
maybe just what you're looking for!
http://www.swisswireless.org/wlan_calc_en.html

Also here is a very good wireless link analysis tool:
http://my.athenet.net/~multiplx/cgi-...eless.main.cgi