Two signals polarization on same RF channel; how does it work ?

[Externet]

Hello.
Long ago, I read about a single RF channel transmitting two 'modulations' each on a vertically polarized and a horizontally polarized antennas; being received by corresponding antennas yielding each its signal. Perhaps on left and right hand circular polarization antenna pairs too.
It is strictly about discriminating RX polarizations ? How does it work ?

 

[G4BCH]

It is strictly about discriminating RX polarizations ?

Yes. Transmit a signal from a vertically polarised antenna and receive it on a vertically polarised antenna and transmit a transmit and receive another signal with horizontally polarised antennas. You could also use right and left hand circular polarised> the signals will isolated from each other by may be 20dB or so because of the polarisation difference. The local TV station here transmits the same signal on horizontal and vertical antennas in different directions to reduce. co channel interference.