The RCA Selectron -- Charactron Tube Development --

The RCA Selectron -- Charactron Tube Development

These excerpts and documents are reproductions of material not readily available from libraries in electronic form, and span the history from the origins at Consoldated Vultee Aircraft Corporation through the final commercial products from Datagraphix Corporation.

Although the character stencil beam tubes had been explored at other organizations for purposes other than human readable displays Joseph McNaney Working for Convair was the first to reduce to practice both the CRT and supporting electronics. Like devices from Bell Telephone Laboratories, McNaney's first work was for converting alphanumeric data encoded as holes on punched paper tape in a digitally encoded format to human readable characters printed on photographic film. The first disclosure was in June 1940 as a US patent application which was granted in 1942 as US2275017. This patent teaches a way to transform a sequence of data punched onto a paper tape into a sequence of single characters appearing in the center of a CRT face which then exposed photographic film. This device anticipated the single character Indicoder of sixteen years later.

US Patent 2275017 Signalling System

By 1952 McNaney's designs had progressed to where multiple characters forming a message could be displayed on a CRT face as shown in US2735956.pdf. At this early stage the character selection was performed with conventional electrostatic deflection places while the deflection of the character to the desired location on the screen was performed by a rather unconventional set of deflection coils:

US Patent US2735956 Cathode Ray Apparatus

Photo courtesy Glenn Robbins
Note that the actual cathode ray tube was produced by Vacuum Tube Products Company of Carlsbad, California, with the assistance and expertise of VTP founder and chief engineer Harold W. Ulmer. Convair did not yet have the facilities nor expertise for electron tube design and realization. Before founding VTP Ulmer worked for Raytheon Mfg. Company and ITT Corporation.

Earliest trade magazine mention of the Charactron

Copyright 1949 Caldwell-Clements, Inc
All Rights Reserved
Archived copy courtesy AmericanRadioHistory.com

Earliest trade magazine photograph of Joseph McNaney

Copyright 1949 Caldwell-Clements, Inc
All Rights Reserved
Archived copy courtesy AmericanRadioHistory.com

Additional coverage of Charactron introductory press release

Copyright 1949 McGraw-Hill Publishing Company
All Rights Reserved

Photo of Convair's McNaney with VTP's Ulmer
This link takes you to John Atwood's One-Electron pages which include many documents and history about Harold Ulmer and Vacuum Tube Products Co.
This link takes you away from rcaselectron.com

Photo copyright 1952 VTP Co.
All Rights Reserved

In March of 1952 McNaney presented a paper on the Charactron at the annual convention of the Institute of Radio Engineers in New York City.

The below photograph may be of the Convair exhibit which would have been at the convention.

Convair Charactron exhibit

Photograph courtesy of and used with permission of Glenn Robbins.

In July of 1952 Convair, as Consolidated Vultee now called itself, advertized for engineers on the project.

Convair employment ad

Copyright 1952 McGraw-Hill Publishing Company
All Rights Reserved

1953 group photos at Convair site at Lindbergh Field in San Diego, California

Convair group photo with a 19" and 5" Charactron

Photograph courtesy of and used with permission of Glenn Robbins.

Convair group photo

Photograph courtesy of and used with permission of Glenn Robbins.

Convair employee newspaper

Copyright General Dynamics Corporation. Convair Division. Used by permission.
Convairiety, Volume 7, Number 16, Wednesday, August 11, 1954, periodical, August 11, 1954; Fort Worth, Texas.
(https://texashistory.unt.edu/ark:/67531/metapth777361/: accessed July 3, 2020)
University of North Texas Libraries, The Portal to Texas History, https://texashistory.unt.edu;
crediting Lockheed Martin Aeronautics Company, Fort Worth.
(Whew!)

By this time the contract with IBM for the AN/FSQ-7 (SAGE) displays was in full force.
Convair worked with IBM, MIT, and several other firms -- and competitors -- to deliver
military project quality Charactron tubes in production quantities.

Massachusetts Institute of Technology -- Project Whirlwind
Development of the Charactron and Typotron