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Whoever authored "AM Loop Antennas" attached to Chuck Olson`s posting
wrote: "A spiral loop is least sensitive to signals received in its plane." Nonsense. Spiral, edgewound, or whatever, any loop antenna which is small in terms of wavelength is sensitive to signals within its plane, and insensitive to signals broadside to its plane. My authority is Kraus` 1950 edition of "Antennas", page 160, Fig. 6-6. The plane wave arriving broadside to the small loop tends to generate currents in the same direction in all sides of the loop. The sides of a turn in the loop are connected in series. So, the currents in opposite sides of the loop tend to add to zero when the wave sweeps the loop from broadside.Time of arrival and phase are the same on both sides of the loop from broadside. Best regards, Richard Harrison, KB5WZI |
#2
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Richard, you are correct - - thanks for spotting that - - the edge-on view
of the loop in red should be in line with the "node" direction rather than in line with the "null" direction. I hadn't looked very carefully at the text since I was more interested in the links section at the end, which I felt might be a good resource for Eric. Chuck W6PKP "Richard Harrison" wrote in message ... Whoever authored "AM Loop Antennas" attached to Chuck Olson`s posting wrote: "A spiral loop is least sensitive to signals received in its plane." Nonsense. Spiral, edgewound, or whatever, any loop antenna which is small in terms of wavelength is sensitive to signals within its plane, and insensitive to signals broadside to its plane. My authority is Kraus` 1950 edition of "Antennas", page 160, Fig. 6-6. The plane wave arriving broadside to the small loop tends to generate currents in the same direction in all sides of the loop. The sides of a turn in the loop are connected in series. So, the currents in opposite sides of the loop tend to add to zero when the wave sweeps the loop from broadside.Time of arrival and phase are the same on both sides of the loop from broadside. Best regards, Richard Harrison, KB5WZI |
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