Continued The antenna looks like that. All wires are Copper, 2mm in diameter. Transmission line characteristic impedance is 450 ohms. Both lines are 2.5 m long in the NEC model but when building this antenna one must multiply this value by the VF (Velocity Factor) of the transmission line used. VF usually equals 0.9-0.91 for a 450 ohm window line. So, in the real world implementation, each TL should be 2.25 +/-0.05 m long. The feed point will be a little closer to the driven element than shown in the picture above. The main feed point is on the boom, the split feed points are 1.87 m above and below the boom. The antenna impedance is approx. 450 ohm. So, you will need a 9:1 balun to feed it. A 3-core Guanella balun seems to be the best choice. The distance between the driven element and the reflector is 3.2 m. The table below presents dimensions of the loops. The SWR, gain and F/B ratio plots of the 5-band SPF Cubical Quad are shown below. To be continued.