It is a simple project based on a 2 elements Yagi for 20m band. Once I finished the 2 elements Yagi, I find out more unused aluminum tubes and so I added a dipole for 15m and another one for 10m. Also, I had a restriction to only one coaxyal cable and I give a try to open-sleeve feed system. You can find more about open sleeve on ARRL Antenna Book but even more in the book Array of Light written by Tom, N6BT,  the inventor of Force-12s antennas.
Essentially it is as simple as placing another wire in parallel and “close” to another dipole. This allows you to feed the antenna at two different resonant frequencies.  The feedline is attached to the longer dipole only, the second (and/or third) wires or tubes are excited parasitically.

Before going whit hardware I try to simulate a model using MMANA-GAL.Here are the results of my simulation. Each results is compared with the similar measurement taken with my RigExpert AA-54 after the antenna setup. As you can see they are nearly the same!

And here is a picture of the antenna.