HD-SDI Cable Length
The limiting factor in cable length has less to do with the DVMHD-Pro output, but more related to the display device (or cable equalizer) at the receive end. Assuming a high-quality input circuit, the maximum cable length recommended is 100m of Belden 8281 or 140m of Belden 1694.
It's important to remember to use a coax cable designed to carry SMPTE-292M signals. Belden 8281, Belden 1694, Gepco VSD2001, or equivalent should be used with high-quality BNC connectors.
In any case, you should never use more cable length than is absolutely necessary.