Search RFCafe.com                           
      More Than 17,000 Unique Pages
Please support me by ADVERTISING!
Serving a Pleasant Blend of Yesterday, Today, and Tomorrow™ Please Support My Advertisers!
   Formulas & Data
Electronics | RF
Mathematics
Mechanics | Physics
     AI-Generated
     Technical Data
Pioneers | Society
Companies | Parts
Principles | Assns


 About | Sitemap
Homepage Archive
        Resources
Articles, Forums Calculators, Radar
Magazines, Museum
Radio Service Data
Software, Videos
     Entertainment
Crosswords, Humor Cogitations, Podcast
Quotes, Quizzes
   Parts & Services
1000s of Listings
 Vintage Magazines
Electronics World
Popular Electronics
Radio & TV News
QST | Pop Science
Popular Mechanics
Radio-Craft
Radio-Electronics
Short Wave Craft
Electronics | OFA
Saturday Eve Post

Software: RF Cascade Workbook
RF Stencils Visio | RF Symbols Visio
RF Symbols Office | Cafe Press
Espresso Engineering Workbook

Aegis Power  |  Alliance Test
Centric RF  |  Empower RF
ISOTEC  |  Reactel  |  RFCT
San Fran Circuits

Temwell Filters

LadyBug RF Power Sensors

Please Support RF Cafe by purchasing my  ridiculously low-priced products, all of which I created.

RF Cascade Workbook for Excel

RF & Electronics Symbols for Visio

RF & Electronics Symbols for Office

RF & Electronics Stencils for Visio

RF Workbench

T-Shirts, Mugs, Cups, Ball Caps, Mouse Pads

These Are Available for Free

Espresso Engineering Workbook™

Smith Chart™ for Excel

everythingRF RF & Microwave Parts Database (h1)

Electronic Test Paper
July 1963 Radio-Electronics

July 1963 Radio-Electronics

July 1963 Radio-Electronics Cover - RF Cafe[Table of Contents]

Wax nostalgic about and learn from the history of early electronics. See articles from Radio-Electronics, published 1930-1988. All copyrights hereby acknowledged.

Attempts at making an electronically printed facsimile (fax) of an original document at a location distant from the source have been around for quite a while. As mentioned by Radio-Electronics magazine editor Hugo Gernsback in this article, Samuel Morse had a crude working device for printing messages on paper even before his eponymously named code of dots and dashes became famous in 1837. A couple decades earlier, a fellow named John Redman Coxe, of Philadelphia, Pennsylvania, devised a method of electronically printing images and text on paper using a conductive solution and a direct current pile (aka battery). Dr. Coxe, a physician, is not a well-known figure in the electronics world, but in his day he was a prominent experimenter in the field of electrochemistry. That was the era when people were applying charges to frog legs to get their kicks making them kick ;-)

Electronic Test Paper

Ordinary linotype slug used in the electrical printing experiment - RF Cafe

Ordinary linotype slug used in the electrical printing experiment.

By Hugo Gernsback

Many inventions have a way of becoming forgotten, when later improvements supersede the original.

In American literature, Samuel F. B. Morse is universally acknowledged as the inventor of the telegraph, as of the year 1837. He deserves credit for the idea of tracing on a moving paper tape a zig-zag type of code, for which he was responsible. The telegraphic tracings could be made with an ordinary pencil or pen. The "Morse Code" came many years later.

Several lines printed electrically from linotype slug on the special test paper - RF Cafe

Several lines printed electrically from linotype slug on the special test paper. The two last lines were made with the negative wire touching the test paper.

Much less known is the fact that long before Morse, John Redman Coxe of Philadelphia was probably the first inventor of any electrical telegraph (1810). Coxe's telegraph was a chemical one. Papers which we know today under the name of litmus and other similar test papers, have been around for more than 150 years. Coxe used a wet band of chemical paper which recorded signals in color when a battery was connected to the recording stylus.

A similar chemical telegraph was invented in 1846 by Alexander Bain, a Scottish electrician and inventor.

For many reasons, today we can make good and practical use of chemical test papers, particularly in testing polarity, which otherwise requires instruments such as voltmeters. For a few pennies, experimenters can make an excellent polarity indicator which the present writer used more than 60 years ago and which still works well for anyone who wants to try it.

First you require the type of paper known as Turmeric Test Paper. This can be obtained from large drug stores or directly from the Fisher Scientific Co., which has offices in many large cities.

This paper usually comes in yellow strips about 2 inches long and about 1/4 inch wide. It must first be made conductive by dipping it in an ordinary salt solution. Then place the paper on a metal plate or thick tinfoil and connect one wire - the positive - to the plate. Use a 6- to 9-volt battery. The positive pole makes no impression. The negative wire, however, gives a brilliant red color.

Samples shown in the photographs here show how this is done. The one imprinted Radio-Electronics was made by obtaining a metal linotype slug with the words Radio-Electronics on it, to which was connected the negative pole. It imprinted the entire name excellently, as will be noted. If you want a permanent record, you need about 6 to 9 volts and the contact should last for a few seconds. This will make it indelible. The imprint will vary depending on the voltage used as well as the duration of the contact. Experimenters will find a good use for this Turmeric paper, which is cheap and has many other uses, such as testing chemicals, as well. Thus for instance a solution of ordinary borax stains the yellow paper red.

everythingRF RF & Microwave Parts Database (h1)
Innovative Power Products Passive RF Products - RF Cafe

Exodus Advanced Communications Best in Class RF Amplifier SSPAs

Innovative Power Products Cool Chip Thermal Dissipation - RF Cafe