The Collaborative International Dictionary of English v.0.48:

Radioconductor \Ra`di*o*con*duc"tor\
   (r[=a]`d[i^]*[-o]*k[o^]n*d[u^]k"t[~e]r), n. (Elec.)
   A substance or device that has its conductivity altered in
   some way by electric waves, as a coherer.
   [Webster 1913 Suppl.]