We expect the local down the block may overload our receiver when he
keys up his kilowatt 40kHz from the frequency we're listening to, but
what are the largest signals received via skip in the HF bands? What
are the chances you'd ever see anything as large, say, as 0dBm into
your receiver via skip? (0dBm = 73dB above s9, given that s9 = 50uV
into 50 ohms.) This could potentially include SW broadcast stations
running fairly high power.

Cheers,
Tom