That‘s hard to say, because it very much depends on the peripherals used and the quality of the interface installed. The question is comparable to one you would ask the filling station attendant: If I fill 10 liters of gasoline into my car, how far can I drive? The answer to the question would depend on the type of vehicle, and the same it true for HD-SDI cables. Here too, the hardware data must be considered and used to calculate the transmission length. An SDI-cable should be capable of transmitting 270 Mbit/sec., the HDTV-cable is designed to transmit within a range of 1.5 Gbit, thus providing the resolution required for the PAL 625-line format. The range of the HD-SDI depends on the bitrate used (compressed or not compressed). At 1.485 Gb/s (not compressed), the damping value is drawn on at half the bit rate (720 MHz) and the cable length possible at a damping value of 20 dB or 30 dB is considered relevant parameter.