Could the transmission line you ordered for your new DTV transmitting antenna be obsolete in a few years? That's a possibility if an industry effort to standardize EIA rigid line sizes succeeds.
While it may orphan some products, the long term benefit of not needing to worry about inner conductor dimensions and flange construction when connecting line from different manufacturers is obvious. Read more about this in
TV Technology's sister publication,
Radio World, in an article by Randy Stine:
Rigid Coax to Get Size Makeover—Manufacturers Hope to Address 'Fit-up'.