Antonio wrote:

Combining the two antennas using identical pieces of coax, you would
obtain a system polarized on a 45-deg slanted plane, that would not help
in receiving randomly polarized signals (signals that are orthogonal, or
nearly so, to the antenna polarization plane would be strongly
attenuated). You should instead aim at obtaining a circular polarization
which causes a steady 3 dB loss independently of the signal polarization
plane.

To do that you must introduce an extra 90-degree phase shift by adding a
quarter-wavelength 50-ohm section to one of the two indentical-length
75-ohm coax pieces.


Instead of this, why not use identical feedline lengths into a Tee and
position one cross polarised antenna 0.25WL in front of the other, to obtain
the 90-deg phase shift?

David, VK3BDK