The RFchoke is described in the Popular Electronics article for those who want to wind it.
射频抗流圈为那些转动它的人在流行的电子学文章中被描述。
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A diode or a 27mH rfchoke going to ground provides the dc return so the detector will work. The rfchoke does a better job, but they aren't always available. So the diode will work ok.