A new approach to the design of a broadband active loop antenna 50 kHz-30 MHz

The author discusses improvements in the design of active loop receiving antennas. The improvements include segmenting a large diameter single loop into a number of equal smaller loops. This allows the source inductance to be adjusted as required. When this loop array is connected to a common base amplifier a substantial improvement in sensitivity is achieved in the frequency range 3 to 30 MHz. Loop antennas have other attributes. Directivity in the horizontal plane aids rejection of unwanted signals and the absence of a null in the vertical plane makes high angle skywave reception much better than with the vertical monopole. The loop antenna can also be effectively decoupled from local sources of interference which is not possible with monopole antennas and which have the added disadvantage that the feeder forms part of the antenna