The bobtail curtain antenna is a fixed array consisting of three individual quarter- wavelength elements spaced a half-wavelength apart, and fed from the top by ashorting element or wire. The inverted bobtail curtain, or Thorne array, consists of an upside down bobtail curtain as shown in Fig. 12-11. The radiator elements are each a quarter-wavelength long. Their lengths are found from
The lengths of spacing between the elements are exactly twice above the value or
Feed method worked out by the late J. H. Thorne (K4NFU/5), feeds the end elements from the shield of the coaxial cable, and the center element of the array is fed from the center conductor of the coaxial cable. A coaxial impedance-matching section is used between the cable transmitter and the antenna feedpoint.
Johnnie Thorne K4NFU/5 also did a lot of great work in regards to using longwire antennas including his 1250 foot longwire antenna that he had at a farm in South Texas as well as his loop antenna work as well that can be found doing a basic internet search.
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