Transponder intall in an LS-4

My partner and I are thinking about installing a transponder
in our LS-4. If anyone has done this in an LS-4, can
you send either a textual description or pictures of
the antenna installation?

We cannot use our tail battery (because of a repair),
and I wonder if we can put the antenna in that compartment.
I assume the encoder will fit somewhere behind the
instruments?

Thanks
Dan
N2YA, '45'