[Boatanchors] Coke as a detector - was: Foxhole Radios

[Barry L. Ornitz]

Mick Harley wrote:

> I have a book called "Crystal Receiving Sets and How to Make 
> Them" published in England around the early 1920's by 
> "Amateur Wireless Handbooks".
>     This book has a very informative chapter on the crystals 
> used in the construction of crystal sets and lists the 
> following as being able to be used as detectors when 
> building crystal sets.
>      Silicon, Galena & Special Galena , Bornite , 
> Radiocite , Carborundum (3 kinds), Copper Pyrites, Zincite , 
> Tellurium , Lybdenite, Iron Pyrites , Molybdenite and 
> Permanite. I like many others on this list made crystal sets
> for my first venture into "Radio". One of the most popular 
> items on display in "The Wireless  Shack" is the humble 
> crystal set. And yes the most unusual Crystal set on display 
> is the Razor Blade detector type.
> 73's Michael Harley,
> Curator "The Wireless Shack" Caboolture Historical Village,
> Brisbane Australia.

In case we have some more crystal set builders pout there, I 
submit the following additions.  [I know we have a few crystal 
aficionados out there like youngster Ken Hickman, N5CM!]

The basic list of minerals was found in one of my handbooks.  
I looked up the chemical structure for each and included it, 
noting which metals are involved.  The reader should note some 
commonality to the chemical structures.  Some of these 
compounds, in far more purified form, are once again being 
explored for new semiconductor uses.  Silicon carbide, which I 
mentioned yesterday, is used in some blue light emitting 
diodes.  Selenium, of course, was once used extensively for 
rectifiers, as was copper sulfide.

For those wishing to experiment, I wonder if anyone has tried 
heavily tarnished silver as a detector, or a copper wire 
heated to redness and dipped into sulfur.  I know this second 
one can work as I made copper sulfide rectfiers from pennies 
years ago (when a penny was solid copper, not copper clad zinc).

Feel free to pass this table on to other crystal set 
experimenters.  But please include the copyright notices.  I 
think the table will be approximately formatted if a fixed 
width font is used.

        73,  Dr. Barry L. Ornitz     ornitz@tricon.net

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


                         Table of Radio Detector Materials
                         ---------------------------------

from:  Wheery, R. T., "American Mineralogist", 10, Part 2, 
       Page 28, 1925

quoted in:  Lange, Norbert A., "Handbook of Chemistry", 6 ed., 
       Handbook Publishers, Inc., Sandusky, Ohio, 1946

added notes:  Barry L. Ornitz, PhD   copyright 1992       
       all rights reserved
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
       Good Detectors                Added Notes

                   Chemical Structure           Metals    
Pyrite, impure       FeS2            Fools Gold, iron ore
Tennanite       Cu2S 2ZnS 2As2S3     copper, zinc, arsenic
Enargite          3Cu2S As2S3        copper, arsenic
Galena, impure        PbS            lead

             Fair Detectors

Graphite               C        pencil lead, forms thin sheets
Octahedrite           TiO2           titanium
Brookite              TiO2           titanium
Molybdenite           MoS2           molybdenum
Pyrolusite            MnO2           manganese
Lollingite            FeAs2          iron, arsenic
Hematite              Fe2O3          iron
Taenite             4Fe Ni           iron, nickel
Chalcopyrite         CuFeS2          copper, iron
Tetrahedrite   3Cu2S Sb2S3 +/-Fe,Zn  copper, antimony 
Linneite             CoS Co2S2       cobalt
Glaucodite      mixed silicates of Al,Ca,Fe,K,Mg
Rammelsbargite        NiAs2          nickel, arsenic
Chalconite            Cu2S           copper
Beegerite         6PbS Bi2S3         lead, bismuth
Berzelianite          Cu2Se          copper, selenium
Famatinite         Cu3SbS4           copper, antimony
Stromeyerite       Ag2S Cu2S         silver, copper
Aguilarite         Ag2S Ag2Se        silver, selenium
Naumannite        (Ag2Pb)Se          silver, lead, selenium
Hessite               Ag2Te          silver, tellurium
Sylvanite          (Ag,Au)Te2        silver, gold, tellurium
Calaverite            AuTe2          gold, tellurium
Zincite                ZnO           zinc
Tiemannite            HgSe           mercury, selenium
Coloradorite          HgTe           mercury, tellurium
Clausthalite          PbSe           lead, selenium
Chiviatite       2PbS 3Bi2S6         lead, bismuth
Guitermanite     3PbS As2S3          lead, arsenic

Sulfur, Selenium and Tellurium all fall in Column VIa of the 
atomic table.  Metal compounds of these elements are often 
semiconductors.  Oxygen is also in this column but the metal 
oxides are usually insulators (but not all).  Phosphorus, 
arsenic, antimony and bismuth are in Column Va in the atomic 
table.  Many of their compounds are semiconductors.