Looks perfect.
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The poor SND might be a problem of a noisy environment. The antenna actually receives, what's in the air.
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The AAA-1C allows switching between magnetic loop mode and electric dipole mode. Have you tried this und what is the result?
What about your power supply, is it a quiet linear regulated supply or a (noisy) switched supply?
Take care of possible noise ingress via unwanted ground loops.
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regards, Fred
