Military Transmitter Model FRT-501 used by RCAF in mid 1950 era used four 4-125 tubes weighs 650 pounds. Used A.M. and C.W. size 60x22x18 inches. Built by Marconi Canada for Canadian Military on DEW or Pinetree Radar installations during Cuban Missle Crisis.contact Jim Loucks VE3BRL E-mail ve3brl@yahoo.ca or call Mississauga 905-279-9574 or Summer Cottage 705-653-1410 Healey Falls