Rectangular Short-Wave Frame Aerials for Reception and Transmission

Previous work on the optimum dimensions of tuned rectangular frame aerials for the reception of short waves has been continued, and the theory has been extended to include an additional condition, the fulfillment of which results in a large frame current. The analogous problem of the optimum dimensions of a tuned rectangular transmitting frame actuated by a local oscillator has also been investigated, and the critical dimensions for maximum frame current have been deduced from the theory, and tested experimentally. The critical dimensions of the frame for maximum radiation in a given direction are not necessarily the same as those for maximum frame current. From the theory developed it is concluded that, for maximum radiation perpendicular to the sides and in the plane of the frame, the height and width of the frame should be 0.40λ and 1.0λ, respectively, and for no other dimensions (less than one wavelength) will the radiation be as great for the same applied electromotive force.