When the war came, Bombardier was contacted by the military as his newest model, the B7, was capable of moving troops and cargo over ice, sand, and swamps. He produced several hundred of these machines as his part in the war effort, never collecting any royalties from the sales ("Joseph Armand Bombardier"). Another Canadian inventor that developed inventions prior to WWII but partook in the effort was that of Reginald Fessenden. Known as the "Father of Radio", this scientist from Quebec created the basic concepts of Radar and Radio Sonar (Clarkson Secondary). Sonar, which was further developed during the war, gave the Canadian convoys transporting aid and supplies to Britain an edge in regard to defending themselves against German U-boats. The technology consisted of sending short bursts of sound to calculate the distance from a ship to the nearest underwater object, and this was proven useful over and over again as it kept the convoys aware as to the location of the powerful submarines controlling the battle of the Atlantic Ocean (Hacker). In addition to radar and sonar, Fessenden is credited with being the first to transmit continual sound waves wirelessly. This advancement played a great role, as it paved the way for the portable two-way radios known as walkie-talkies, and the "wirephoto", an invention by scientist and special agent Sir William Stephenson, known as "Intrepid" throughout his undercover missions in WWII. This device was put to use throughout the war to send letters, notes, and drawings to and from military personnel. Already, after looking at only these select few out of the many inventions prior to WWII it is easy to see how Canada was contributing its great minds to the war even before it began. In 1939, however, Canada answered the call of war, and mobilized yet more scientists to apply their knowledge towards military solutions for the problems arising in Europe.