The poster and commenters do not seem to mind the roll-off above 50MHz.
It can see in video this measuring method is totally wrong if he have tried to show that after mod its BW is 100MHz.
I can take what ever scopes, and what ever signal generator and .... then use this method what guy use in video and all is just garbage what is related to banwidth.
There is two possible reasons who make this video and why result is this related to BW
-- 1. he did not even try measure BW is ok for 100MHz
-- 2. He really do not know anything, not even lowest basic Fundamentals and principles how to measure. (look this totally fun fool connection between these two equipments.)
With this connection, result is of course totally wrong with what ever scope and what ever signal generator.
With acceptable signal connection result is of course totally different (and I believe much of better).
I think this video is not at all made for show accurate result for mod.
But it show simply how to do mod. And for this purpose it is ok.