Unless the radiating element was decoupled from matching for 100khz and
connected to matching capable of transmit at some other freq? Thence
the need for a tx line in the antenna cable.

I don't claim to know every option available on these things. I have a
Furuno LC-80 Loran c in the basement, it came uninstalled with a boat,
but I never needed to use it nor had it connected for any reason. It
has only 3 pins in the connector, and a big base loading coil.
A relay in there might enable use of the 8 foot glass whip at other
freqs.

Terry K