The Inverted L for 40m/80m is shown below. It is essentially one half of a W3DZZ dipole fed against ground using one 7.1 MHz trap. The 40m / 80m Inverted L has the advantage of providing both horizontal and vertical components. It's a very compact antenna and is simple to construct. It is most efficient, of course, on 80 metres and 40 metres, but can also be used, with an a.t.u., on 20m, 15m and 10m. While Inverted L's might make good TX aerials, like ground mounted vertical aerials they can be quite noisy on RX.
Find out how to make one here: http://www.users.icscotland.net/~len.paget/5%20band%20Inverted%20L.pdf
Adding 160m / Top Band to an Inverted L
The 160 metre Top Band can be added to this aerial by connecting a 3.5 MHz trap at the end of the 80 metre wire (where to monofilament joins the 6.55m section of wire below) with another length of wire on the other side, increasing the overall length of the antenna.
Find out how to do it here: http://www.users.icscotland.net/~len.paget/Inverted%20L%20adding%20top%20band.pdf
Adding Top Band to an Inverted L by Len Paget GM0ONX (Practical Wireless magazine)