Art wrote:
"I have an on order a tilting system for my antenna to probe the
polarisation of incoming signals for maximum audio clarity and gain."

That may be interesting but do you ever recall cross polarization of an
incoming ionosphere reflected signal being unreadable because
polarization was wrong?

So many different and quickly changing path variations exist in the
ionosphere that the best antenna to use is based on probability.

E.A. Laporte says on page 215 of "Radio Antenna Engineering":

"To make best use of this effect (randomness of ionospheric waves) it is
desirable to employ complimentary antennas for transmitting and
receiving."

Most commercial HF circuits I`ve experienced and seen use horizontal
polarization. It is because much severe man made interference arriving
at a receiving antenna is vertically polarized.

Best regards, Richard Harrison, KB5WZI