I'm surprised at the depth of the dips in the FDTD plots,
is the amplitude scale correct?

The FDTD results are consistent with my complete inability to
detect anything of the 2970 Hz signal here, whereas 5170 Hz
is quite easy to receive.

It also suggests it would still not work at 2570 Hz but we
should get a result at 4390 Hz.

Currently, still nothing from Stefan's 2970 carrier in 48 hours,
5.8uHz bandwidth down to 0.01 fT.  Not the slightest hint of
signal.

Stefan, maybe you want to try a higher frequency?  4390 not
so good here but the range 4370 to 4380 is ok, 4378 looks
best of all.

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Paul Nicholson
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