Greetings,

I'm currently listening to WHRI on 15665 kHz here in Luxembourg at
10:30pm local (2030 UTC). The signal is fairly good, subject to fading
and atmospheric noise, but very audible (SINPO 45433)

Applying basic HF propagation rules, 15 MHz would be a bad choice for
night-time DXing, wouldn't it? In fact, the predicted MUF is 10 MHz at
this time, the day/night line runs almost exactly at mid-point between
the TX site and my location; and yet I'm able to get an audible signal
over 6500km (4288 miles) at 10:30pm local, on 15 MHz.

I might add that I'm unable to hear any other DX signals above 12 MHz
and have never before been able to pick up anything particularly
interesting on the higher end of the SW spectrum at night. Equipment in
use here is a JRC NRD-345 receiver and a 15 feet "long"wire (RF-Systems
EMF). Should I consider this a lucky catch or am I just missing
something regarding HF propagation?

regards, Manuel