On Thu, 26 May 2011 02:08:04 BST, Brandon Butterworth said:
One _cannot_ do this with 'modern' digital TV trasmission, because the _end-to-end_ technolgy does not support it.
Apologies for disagreeing, but this is exactly what the modern technology does.
Digital TV (ATSC in your case, DVB-T & DVB-S in our case) has a multiplex of a number of independent data streams that can be data, video or audio. That is carried end to end.
When Stargate stuck (say) 10% more data into TBS's analog signal by stashing it in retrace and blanking intervals and the like, TBS's bandwidth requirement went up zero. Zip. Zilch. How much does your bandwidth usage on your new miracle boxes go up if you stick another 10% data stream in there? Probably a measurable amount more than zero.