Nope, the antenna is BALanced and the coax is UNbalanced. Thats why you need a balun (a balanced to unbalanced transformer).Without using balun, can I just directly connect a 75 ohm coax to the feedpoints (antenna terminals)?
Oh, so its an optical illusion, heh.It appears in the picture that the elements don't correspond to the NEC file, but it's because half of the elements are closer to the camera. When viewing the antenna from the top, you could see that the elements form an 'arrow' shape.
Yeah, heres something on that.Another reason for using 300ohms is that the characteristic impedance of a tuned folded dipole is 300 ohms. At one time, almost all TV antennas were folded dipoles so it became a de facto standard.
http://www.qsl.net/co8tw/openline.htmWhich Impedance and Why
Constructing an open wire transmission line is a balance of two factors: the optimal impedance for the line and the ease of construction. Let's spend a moment on the first of these factors.
Besides being cheaper to manufacture, TV-type transmission line uses a 300-Ohm impedance for convenience. Remember that the 300-Ohm figure is "nominal," meaning it is an approximation and may vary by 10% to 20%, depending upon the quality control of the manufacturing process. Its convenience stems from the emerging television industry in the post-WWII era. Folded dipole elements provided a rough match for the line, and TV sets were engineered to have 300-Ohm inputs. Outside of this industry, the line was used for its price and handiness, with little regard to matching. Amateurs used an antenna tuner (ATU) to compensate for reactance at the shack end of the line and to change the impedance to the emerging 50-Ohm coaxial cable standard. However, except for some briefly available transmitting versions of the line, the typical 300-Ohm line available today is composed of thin wires closely space (under 3/8").