The only way I can image something like that can happen is with an
extremely high impedance device coupled DC (or very low freq. AC) and a
transient spike in the power line, rather than field at 60 Hz.
It's hard anyway to imagine a front end design that uses something like
a FET with 10 MOhm gate impedance and coupled to the antenna input with
only a capacitor and without any kind of filter. Such a front end will
respond to transients beeing only limited by the coax line capacitance
(small if the line is short), will behave like a broad band amplifier
(similar to those used in the so called "active antennas") and its IMD
products could be really very high.
For transient protection and a *primitive* high pass filtering, a few
uH inductor inside the rig (i.e. a VK200), just across the antenna
terminals/connector, will solve this problem and will be transparent to
VHF/UHF, rx and tx.
73,
Mauri I4JMY
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