All of our products rated to IP56 and are constructed from fully enclosed and watertight components. Self amalgamating tape may be used as an extra seal around your coaxial plug at the feedpoint.
The screw terminals are stainless steel but it may still be advisable to dip them in grease to protect them from severe elements.
For the HW-40HP you will not need an ATU to operate on the 40, 20, 10 and 6m bands and for the HW-20HP for the 20,15, 12, 11, 10 and 6m bands. On other bands an ATU will be required. The Magitenna will tune from 80m - 6m (including 60m) via an ATU. An ATU is necessary when using any of the LW (Long Wire) range of aerials.
No, not at all. fit them up at whatever height suits you best. We don't all have massive towers and if you wish, you may run them along the top of your garden fence. Just remember, if they are close to the ground or other objects, there may be some capacitive effects but this should not affect the performance too much.
A common misconception is that an aerial needs to be completely flat. They can be mounted as an inverted Vee, an inverted L, a sloper, dog legged or in just about any configuration to fit them into the space you have available.