High Efficiency Linear Amplification via Parametric Synthesis

One of the two linear transponders on board AMSAT OSCAR-7 was the first to use the HELAPS modulation method developed by the founder of AMSAT-DL, Dr. Karl Meinzer. It serves to increase the efficiency by a parametric decomposition of the transmitted signal and the voltage-controlled modulation by a switching regulator. This so-called Mode B transponder, which gave radio amateurs worldwide access to the satellite frequencies at 435 and 145 MHz, was built by Karl Meinzer, DJ4ZC and the late AMSAT-DL co-founder Werner Haas, ex-DJ5KQ.

The following PDF documents provide further insight into AMSAT’s HELAPS technology.

Karl Meinzer (DJ4ZC): “Lineare Nachrichtensatellitentransponder durch nichtlineare Signalzerlegung”, Inaugural dissertation for the award of a doctorate from the Physics Department of the Philipps University of Marburg/Lahn, 1973

A Linear Transponder for AMATEUR RADIO Satellites by Dr. K. Meinzer, DJ4ZC