Here is the description of automatic process antenna for UHF (channels 21-60th 470-790 MHz). KND equal to about 8.5.
The antenna design shown in the figure. It contains a symmetrical two-wire distribution line, made of two parallel identical tubes. On each of them in one plane fixed seven polymeration, every subsequent polyfibron directed in the opposite direction as the previous one. In addition to the plane in which are located poluvertsy on each pipe line, parallel, and poluvertsy the same length on different pipes are in the opposite directions.
Coaxial cable with wave resistance of 75 Ohms is held inside one of the pipe line, and the ends of the pipes at the entrance of the feeder are connected by a short metal plate. Where the output cable to give the structure rigidity set dielectric plate. The shielding braid of the cable is soldered directly at the exit of the cable from the tube, and the center conductor is soldered to the blade, which is fixed on the muted end of another pipe. The antenna does not require any adjustment.
According to Radio No. 8, 1990. Nanopool G. External antenna for UHF; Publication: www.cxem.net