Much has lately been published about magnetic antennas.Their performance on the air often belies their low theoretical efficiency [though, with a loop circumference approaching λ/A and good construction, the efficiency-to-size ratio is not all that bad - G4LQI]. There remains the narrow bandwidth, which often requires elaborate tuning provisions. Frits thought that two loops in parallel might bring relief and tried it on 145MHz, a size very convenient for experimenting. The one shape that worked was the figure-8 shown in Fig 1, with a preset capacitor resonating the double loop and mechanically separating the two conductors at the cross-over.
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