high gain antenna recommendations ?

[jvtsd142]

Currently using a http://amzn.to/f8c1Zw 5 dbi omni antenna, direct connected on the receiver and clipped on the dash Hoping to upgrade, and eventually move it outside the vehicle.

Wondering what folks are using for higher gain antennas, and magnetic mounts as well. Naturally, I'm trying to mag mount a 2.4 ghz antenna of some sort, not to transmit at all, but to receive via kismet.

Also, any short-run wire suggestions welcome, as needed.

Eventually, I'd love to come up with a good way to mutiplex receiving off a single good antenna to multiple receivers, to set up what seems a popular solution : 4 receivers, running on channels 1, 6, and 11, and the 4th scanning the remaining (somewhat less common) channels. There has to be some sort of small amplifier made to allow this sort of thing, no ? Picture for rough idea of what I'm saying / this isn't for wifi : http://www.dsvideo.tv/images/products/1536-01.jpg

Actually, the mad scientist part of the brain would love to go further, but we'll see