Hi Gleff, the extender antenna is 1.3 metres long but from what i remember it doesn`t need a power supply. The gain of the antenna is in the design of the antenna itself - not a preamp. Preamps are normally an addition and are for the required frequency although there are some broadband devices that can be used. I did check on e-bay here for the extender and sure enough, you can shove it on a pole without problems and the hardware for mounting appears to come with it. As for premaps, i would recommend using a mains powered voltage supply primarily because even if the device has low consumption, you`d be suprised how often a battery change is required. Hope this has been of some help, Bi now, Roger