Mystery Antenna on B-24. - Mystery antenna.jpg (0/1)

I have come across a bit of a mystery that I am hoping that someone
could help solve.

I am including a picture of a B-24 that has an odd (partial Yagi)
antenna just below the flight deck that I cannot ID. I have seen them
on the occasional B-24, only, serving in both the ETO and the Pacific.
Only seen them on US operated planes, never Commonwealth aircraft.
Seen the antenna on 'ordinary' B-24's and also they are included on
some of the Ferret conversions.

A fellow researcher suggested that it is associated with an early war
IFF unit. pre IFF Mark III, but I don't think so. Another suggestion
was that is was somehow associated with an ASV radar set - but again I
do not think that this can be so for various reasons.

Does anyone know what this is?

Waldo.