Do some want to signal no catch on a dropped foul fly ball?

I do, if it's obviously foul and it's a close catch/no catch. Usually happens when F2 goes to the screen or dives toward a fence.

Wouldn't just a foul signal suffice? Nobody going anywhere on a "dropped" foul ball regardless.

My thoughts exactly. In fact, this is one of the few instances where a verbal FOUL call is actually helpful.

It's just the way I was trained, & I don't really see a problem with the "no catch" signal. Remember, this would be on a ball that's in obviously foul territory -- the kind where you'd give no signal if someone weren't trying to make a play on it.

CT1, I am not ganging up here but, I believe that is the point being made here,obviously foul territory. Its either caught or a dead ball. If its a dead ball, it just doesn't matter what happens next.

The "correct" call is "FOUL BALL" or "FOUL". Kills the play clearly and concisely.

A "no catch" signal is really meant for fair balls where play is continuing and a loud call by an umpire would be disruptive.