Herman Affel

Herman A. Affel (1893-1972) was an American electrical engineer and inventor, noted for coinventing the coaxial cable carrier system for multiple high speed long distance data transmissions. The cable can carry different signals at different frequencies, so a single cable can simultaneously carry multiple telephone conversations with little signal loss or interference. Today coaxial cable is used to carry television, telephony and data signals.

Arthur Kennelly and Affel (then a research assistant at MIT) wrote a 1916 paper on the measurement of skin-effect resistance of conductors at radio frequencies. The research was funded by AT&T's Bell Telephone Laboratories. As a variable frequency source, Kennelly and Affel employed a 2 kW Alexanderson radio alternator which could generate frequencies up to 100 kHz at a rotor speed of 20000 rpm. From MIT he went to work at Bell Laboratories. Among other projects he worked with Lloyd Espenschied on the characteristics of coaxial cable. Espenschied and Affel jointly applied for a patent on a wideband coaxial cable system of transmission, filed in 1929 and granted in 1934. The invention was disclosed in a prize-winning paper published in AIEE's Electrical Engineering in October 1934.

During his career at Bell Labs, Affel worked on combining coaxial cable with microwave relays. He co-authored or authored around 40 patents for electronic devices, including advanced transmitters and innovative antennas.

In 2006 Affel was inducted into the National Inventors Hall of Fame.

US Patents

*US Patent|1511013 "Equalization of Carrier Transmissions," 1924, Herman A. Affel
*US Patent|1835031 "Concentric Conducting System", 1929, Lloyd Espenschied and Herman A. Affel

External links

* [http://ieee.cincinnati.fuse.net/reiman/04_2002.htm Kennelly and Affels 1916 paper]
* [http://www.ieee.org/web/aboutus/history_center/biography/espenschied.html Epenschied's biography at IEEE]