Bertram studied at Graz University of Technology in Graz, Austria.
In 1972 Bertram worked in Muller's Inc. in Stroudsburg, Pennsylvania, United States. From 1972 to 1977 he worked as an electrician in Siemens AG, Erlangen in Germany during the summer breaks.In 1978 he became research assistant of Graz University of Technology. He worked there for two years.
From 1980 to 1983 he worked as a research associate in Joanneum Research in Graz, Austria. In 1983 he became a member of technical staff at Intelsat in Washington DC, United States. In 1988 he became Head of Propagation Section of the European Space Agency in Noordwijk, The Netherlands. In 2007 he became Head of the Electromagnetics and Space Environment Division of the European Space Agency.
In 2008 Bertram was elected Chairman of the ITU-R Study Group. Since 2014 he works as a Senior Advisor at the SpaceTec Partners SPRL. In 2016 he was elected President of the Austrian Institute of Navigation.
Bertram married to Elfriede Klein on June 14, 1980. Children: Barbara, Thomas.