When version of Vegas? If you have VP15, you have the additional choice of MAGIX AVC, which includes an updated MainConcept codec, presumably with higher quality per bit, as well as QSV & NVENC encode modes.
"The ITU-T H.264 standard and the ISO/IEC MPEG-4 AVC standard (formally, ISO/IEC 14496-10 – MPEG-4 Part 10, Advanced Video Coding) are jointly maintained so that they have identical technical content."
A little off topic but still related to TV. If you haven't already is to record colour bars and tone in the beginning of your 30 minute segment for at least a minute. The engineer at the TV station can see via the waveform monitor if their system is lined up before viewing your segment.