They were equipped with early versions of
ASV radars, which included a thicket of Yagi aerials protruding from the
nose and the wings, four stickle-back mast antennae sticking upward from
the ventral fuselage, and a set of towel-rail type antennae attached to
the sides of the rear fuselage. The aircraft looked not unlike a flying
porcupine. For attacks on surfaced U-boats, Liberator Is were fitted
with a pack for four forward-firing 20-mm Hispano cannon underneath the
forward fuselage. These modifications were carried out by Heston
Aircraft Ltd. The normal operating crew was seven."

Thanks for trying there Anonylous but this does not describe the
aircraft that I posted. The mystery antenna that I posted has NOT been
seen in any Commonwealth aircraft. And does seem to be unique to the
PTO (I thought I found one in service over Italy recently but I made a
mistake.)

Here is a picture of the aircraft that you suggested. Note the YAGI on
the nose and wings and the further set of antenna on the fuselage
sides.

FWIW re the Mystery Antenna I am lately torn between thinking it is
either an ELINT receiver suite, or a self-protection jammer
installation.

This sort of mystery really bothers me.

Waldo.