As the cards are dual tuners I only need to split the arial cable once as each card needs only one arial cable.
keep in mind that each time u split the signal u add approx 3-4dB of noise (and -3dB signal level)! This can reduce performance of the TV-card. When splitting the signal to two cards there is often no problem, but if u need more cards u should add a amplifier close to the antenna/aerial to "mask" this noise addition.
/tompa