JFET matcher using an OpAmp
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On the off chance there is interest in matching JFETs for a clone of the Wellbrook loop antenna, I've posted a PDF of a simple and effective unit.
Layout isn't critical, I constructed mine on vero-breadboard with 0.1" centers and used point to point wiring and mounted it ~1/8" above an unetched PCB for a ground plane.
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Note 1: I did not design the unit, I built one late last night and tested a bunch of 2N3819.
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A lifetime ago, 1975, I was given several hundred prime TI 2N3819s. Sadly the 2N3918 isn't the most useful JFET but it was nice to test 50 and find 3 that matched extremely closely.
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YMWV
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Note 2: The 2n3819s aren't for sale.
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The file name is
JFET-matcher-rullywow.com-Build-Doc-v1.01.pdf
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It can be found in the files section.
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