@foone @philpem Yeah, I think RF is a bit overkill for videotape in most cases. The only exception I can think of are the EIAJ PCM formats, as they stored the data starting around line 10 in the VBI.
There are methods for “copying” other VBI data into the ‘visible raster’ so that it can be digitized (i.e. Nielsen’s SID in the U.S.), but the equipment is made only by one company, requires a dealer, etc etc.*
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* The backplane on mine died a few months ago … replacement is difficult.