What does this mean?

[perfectbite]

RonH. It did occur to me that common plate glass would have to be so heavily doped that it would be useless as window glass. Light wouldn't make it through. I did think that perhaps there was a specially made plate glass of this type that would be made in a sheet and then broken and the shards sold to those interested in uncovering its properties.<p>I remember coming across a wooden boxed crystal radio (head set and all) from the 1920s in my pre-teens and being cautioned, quite offhandedly by my parents, (it was old technology to them and not worth a second look) not to mess with the cat's whisker. Turning the knobs or changing the orientation of the crystal in its little clamp was OK, it was made to do that, but not to touch anything else. There wasn't much else to touch.

[Will]

David (Of Camberley) See my post re Tom Lehrer on the Joules thread

[jwax]

RonH- You are correct, that is what Dean meant for the glass plate- it is not a resonator by any means.
Maybe on another planet......
John

[Edd]

Definitely, the glass reference, was to the working surface upon which the grind was to be performed. A non contaminating flat blank of ¼ in sheet plate, none of the commom wavy window glass variety, or, I have also used clear surface side pieces of ¼ in plate glass mirrors. Also the use of cerium oxide was superior….used by lens makers, amateur telescope makers and even rock hounds in their final polish stages.
Also this was for the old pressure style holders with its bare quartz xtal blank being accessible by disassembly. None of the plated mounts enclosed within hemetically sealed cases of the current H , U and F series xtal housings. If you overshot the freq a bit , a minute degree of correction could be enacted by increasing of the xtals mass. Others used pencil graphite, I was more successful in accuracy/ retention by the select size marking of an X on the xtals X-Y axis with wire solder. Incrementally and symmetrically increasing its size to trim in.
<<I remember coming across a wooden boxed crystal radio (head set and all) from the 1920s in my pre-teens and being cautioned, quite offhandedly by my parents, (it was old technology to them and not worth a second look)
[[[ not to mess with the cat's whisker.]]]
Turning the knobs or changing the orientation of the crystal in its little clamp was OK, it was made to do that, but not to touch anything else. There wasn't much else to touch. >>
Wonder if its still in the family. those Hi-Z magnetic headphones are getting very hard to find, I had to manufacture the last one I needed. It really was quite superior also with newer magnetics being used as well as a mylar diaphragm being used in place of the thin sheet steel being used on old design.
Repositioning of that phosphor bronze springs tip on the detector for a sensitive spot was a constant recurrence, particularly, if the unit was subject to vibrations or inadvertent stretching of the headphones leads to their limit and upsetting the unit. Sometimes it would result in quite a loss of reception time, chopping out some informative news conversation until another detector hot spot could be re found.
73's de Edd
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:p<p>[ October 22, 2004: Message edited by: Edd Whatley ]</p>

[perfectbite]

It's long gone Double D. That was over half a century ago. In looking back I think my mother had a golden ear and that radio set probably just put her teeth on edge. She would hear pops and clicks and hisses that no-one else heard. She was probably glad to get shut of it.<p>It's long gone along with the pianola and the 78 RPM wind up gramaphone with the big horn. I remember buying the small tin boxes of gramaphone needles and having to run to the store to get them before it closed because company was coming and we were out of good needles.<p>My parents were both from large working class families and I think they would pool their resources and buy the latest gizmo. So when they said "We've got one of those." They meant 'held in common'. My aunts had a portable radio in the 50s. Movable was more like it. The batteries weighed a ton. Two of them would carry it between them.