Located where the transponder antenna would go in the floor of the airplane, under the pilot's seat. Updrilled with a unibit.
The wire from the ELT to the remote behind the passenger's head, is just a straight-through telphone wire. I pathed it to go along with the magnetometer wires and so wire-tied all the wires together for a neat installation.
I'm out of useful things to do until I can move the plane into the garage to do fuel and engine work.
Hole drilled for transponder antenna
Gray telephone wire secured from ELT to ETL remote.