O RLY?
1992-ish RSGB 432MHz FM contest, located Cyrn-y-Brain GW/NW-043 with a Tonna 21 ele horizontal and Tonna 19 ele vertical with remote switching between antennas and switchable masthead “hot-as-hell” GasFET preamp at about 15m.
FT736 with squelch adjusted so it was just flickering between open and closed. Being FM contest, normal search pattern was to leave vertical selected. Station called in from Birmingham way and squelch flicker rate changed so it was open more of the time. That was the only indication there may be a signal. Preamp off and flicker return to usual pattern, preamp on and squelch more open than closed. Tweak rotator but still no discernable signal other than flicker of squelch.
Flip to horizontal and there was an audible click as the FT736 S-meter hit the end stop and other station continued calling us. Other station had a single long horizontal Yagi running c. 25W up moderately high and could not hear us when we were on vertical but a local told him our QRG and he could hear others work us and called us blind-ish. He was S9++++ with the correct polarisation. Looked like the path and it was LOS so with both antennas well clear of of the ground there were few reflections so essentially no workable vertical component to signals.
Maybe our vertical system was pants… well if we didn’t win the contest we were top 3 so probably quite good.
Such path losses can occur in reality. For stations located in a built up area, there is normally sufficient local scatter from nearby roofs etc. that you don’t see the extreme so often.