Browse Prior Art Database

Comments, Queries, and Debate: German Ferrite Cores from World War II

IP.com Disclosure Number: IPCOM000129749D
Original Publication Date: 1992-Sep-30
Included in the Prior Art Database: 2005-Oct-07
Document File: 2 page(s) / 16K

Publishing Venue

Software Patent Institute

Related People

Robert Donald Carter: AUTHOR [+2]

Abstract

At the suggestion of the Computer Museum, Boston, we are publishing excerpts from two letters sent by retired RCAF Wing Commander R.D. Carter to the museum, giving his recollections of circumstances surrounding the acquisition by the RAF of some ferrite cores during World War II. We would be interested in hearing from readers who can confirm, or add to, the facts and dates recounted here.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 52% of the total text.

Page 1 of 2

THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

Copyright ©; 1992 by the American Federation of Information Processing Societies, Inc. Used with permission.

Comments, Queries, and Debate: German Ferrite Cores from World War II

Robert Donald Carter

505 Beatrice Street Venice, FL 34285 USA

At the suggestion of the Computer Museum, Boston, we are publishing excerpts from two letters sent by retired RCAF Wing Commander R.D. Carter to the museum, giving his recollections of circumstances surrounding the acquisition by the RAF of some ferrite cores during World War II. We would be interested in hearing from readers who can confirm, or add to, the facts and dates recounted here.

May 1, 1986 ...enclosed are the details of the ferro core used by Germany in WW II to produce a compact and high-gain airborne direction finder antenna. The Royal Air Force (RAF) sent a few samples of this material to the Royal Canadian Air Force (RCAF) HO for analysis. It was obvious that the material was formed of iron particles of a dust-like consistency, and the first electrical tests showed high resistance between the particles, excellent transformer core properties at RF frequencies, plus a curious rectangular hysteresis loop. The value of this last characteristic was not recognized for some time.

Fellow telecom officers Bob Woodhead, Jack McCalla, and I had a keen interest in matrix memories. Our tasks in the RCAF had allowed us to collect many of the highlights of computer development, including Eckert's work on the ENIAC. One of his problems was the result of no data storage -- to change an equation, a board had to be rewired. A programmable memory would form a vital component in a computer.

Our first experiments were with old-fashioned germanium detector crystals fitted with a grid tickler in addition to the cat-whisker, which looked promising but rather unreliable, even when the sensitive loci were gold-plated in the crystal lab. Next we used miniature VR92s that were used in the Chain Home (CH) and Chain Home Low (CHL) Radar designed by Sir Watson-Watt, which were so effective in the Battle of Britain. These reduced the size of a 10 x 10 matrix substantially; however, they still used considerable power. The next step was to use small neons, but their triggering voltages were gross; they had to be match-selected and then completely light-shielded, otherwise their triggering point would be altered.

One evening both Bob and I separately arrived at the possibilities offered by the peculiar hysteresis loop of the ferro-particulate cores. Before the night was over, we had proved that...