Asimov wrote:


TW If you're using germanium diodes get some spares -- I've found them
TW very susceptible to lightning strikes, at least in the circuit that my
TW son and I built.


Why bother? Get a solar cell and power a radio with it. There is
more than 900watts/metre^2 free energy right outside the window.
(mumbling something about "idiots"...)

A*s*i*m*o*v

... Hey everbody, I am crushing your head! Crushing it! Crushing it!

How does using a solar cell prevent a detector diode from getting zapped?

73,
An idiot

On 07/04/2005 8:50 AM, Al wrote:
In article ,
wrote:


We dropped molten solder in a pile of sulpher in a bottle cap.
On 5 Apr 2005 20:45:34 -0500, wrote:


When I was in high school (many MANY years ago), a classmate of mine
"grew" his own crystal by melting (IIRC) lead and sulfur together.
It was an ugly-looking mess, but it worked.


You were making "galena" which is PbS, Lead Sulfide. I used one for my
first crystal radio in the 50's. Had to find a sensitive spot. You might
be able to find some in a hobby shop (If you can find one.) that deals
with minerals.

You might also try a "blue blade" razor blade. The GIs used them in WWII
for making foxhole radios. The bluing produced a chemical (unknown to
me) that rectified the signal.

For this purpose, almost any anodized metal should suffice. The "Blue
Blades" were, AFAIK, simply anodized and polished high-carbon steel.
The aonodized surface would be covered with fine steel-oxide crystals.
I wonder if anodized aluminium would work? I'm theorizing here that we
want some sort of crystal to interact with a base conductor.

This kind of thing is still done for some special "blue" hack- and
reciprocating saw blades. I think there are even circular saw blades
that are anodized in a similar way. These would be expensive and hard
to come by. I'm sure people will pay to get them rebuilt rather than
toss them out, and I have no idea how an average tinkerer might easily
cut pieces of a think saw blade up!

However, if you can find a hacksaw blade treated in the same manner,
this give supplies for a number of experiments.

"Asimov" wrote in message
...
Why bother? Get a solar cell and power a radio with it. There is
more than 900watts/metre^2 free energy right outside the window.
(mumbling something about "idiots"...)

Yeah, too bad it tends to be go away at night! :-) (And if you were just
going to store it anyway, why not start with batteries in the first place?)

"Bill M" bravely wrote to "All" (07 Apr 05 10:43:57)
--- on the heady topic of " Crystal radio"

BM From: Bill M
BM Xref: aeinews rec.radio.amateur.homebrew:9179

TW If you're using germanium diodes get some spares -- I've found them
TW very susceptible to lightning strikes, at least in the circuit that my
TW son and I built.


Why bother? Get a solar cell and power a radio with it. There is
more than 900watts/metre^2 free energy right outside the window.

BM How does using a solar cell prevent a detector diode from getting
BM zapped?

By mounting the detector diode under the solar cell of course! That
wasn't my point however. What I really meant to get at is that high
impedance headphones (25K ohms) are hard to find these days as are
germanium anything. The better alternative is perhaps the Schottky
small signal diodes and a crystal earphone (which are also rare). On
the other hand if one powers a small transistor radio from a solar
cell charging a battery then it results in something practical.
Perhaps it isn't as educational as winding your own coil on a
cardboard tube of Quaker Oats and finding a Galena out in the
old quarry but there is nothing wrong with not re-inventing the wheel.
Do we really need to re-invent it to learn how to be a car mechanic?
We would have to be idiots if that was the case.

A*s*i*m*o*v

.... We're young, rich, and full of sugar, what do we do?

Asimov wrote:
"Tim Wescott" bravely wrote to "All" (05 Apr 05 09:26:07)
--- on the heady topic of " Crystal radio"

TW From: Tim Wescott
TW Xref: aeinews rec.radio.amateur.homebrew:9149

TW KA6PNL wrote:

Hi I have a friend that son wants to build a crystal radio. I seam to
remember that we grew our own crystal back in the early 60 any help?? Also
where can I find a 1n34 quick have 2 weeks for his science fair.


TW A silicon diode will work, it won't be as sensitive but you can get
TW one at the local Radio Shack (they carry germanium diodes off and on,
TW so they may have some).

TW If you're using germanium diodes get some spares -- I've found them
TW very susceptible to lightning strikes, at least in the circuit that my
TW son and I built.


Why bother? Get a solar cell and power a radio with it. There is
more than 900watts/metre^2 free energy right outside the window.
(mumbling something about "idiots"...)

'cause crystal radios are more fun, and when your 10-year-old puts one
together he or she can understand each and every part in it (those
charge regulator IC's are kinda hard to grok when you're not firm on how
a diode works).

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Tim Wescott wrote:


charge regulator IC's are kinda hard to grok when you're not firm on how
a diode works).


Help out an oldster. What the heck does "grok" mean?

-Bill

On Sat, 09 Apr 2005 00:35:11 -0400, Bill M
wrote:

Tim Wescott wrote:

charge regulator IC's are kinda hard to grok when you're not firm on how
a diode works).


Help out an oldster. What the heck does "grok" mean?

-Bill

A word from Robert Heinlein's 1961 novel "Stranger in a Strange Land".
Rough meaning is to understand thoroughly and profoundly.

"As one character from Heinlein's novel says:

'Grok' means to understand so thoroughly that the observer becomes
a part of the observed - to merge, blend, intermarry, lose identity in
group experience. It means almost everything that we mean by religion,
philosophy, and science - and it means as little to us (because we are
from Earth) as color means to a blind man. "

From:
http://whatis.techtarget.com/definition/0,,sid9_gci212216,00.html

Happy trails,
Gary (net.yogi.bear)
--
At the 51st percentile of ursine intelligence

Gary D. Schwartz, Needham, MA, USA
Please reply to: garyDOTschwartzATpoboxDOTcom

Gary S. wrote:

On Sat, 09 Apr 2005 00:35:11 -0400, Bill M
wrote:


Tim Wescott wrote:


charge regulator IC's are kinda hard to grok when you're not firm on how
a diode works).


Help out an oldster. What the heck does "grok" mean?

-Bill


A word from Robert Heinlein's 1961 novel "Stranger in a Strange Land".
Rough meaning is to understand thoroughly and profoundly.

"As one character from Heinlein's novel says:

'Grok' means to understand so thoroughly that the observer becomes
a part of the observed - to merge, blend, intermarry, lose identity in
group experience. It means almost everything that we mean by religion,
philosophy, and science - and it means as little to us (because we are
from Earth) as color means to a blind man. "

From:
http://whatis.techtarget.com/definition/0,,sid9_gci212216,00.html

Happy trails,
Gary (net.yogi.bear)


Well THAT explains it!

Thanks,

-Bill M

Bill M wrote:
Gary S. wrote:

On Sat, 09 Apr 2005 00:35:11 -0400, Bill M
wrote:


Tim Wescott wrote:


charge regulator IC's are kinda hard to grok when you're not firm on
how a diode works).


Help out an oldster. What the heck does "grok" mean?

-Bill



A word from Robert Heinlein's 1961 novel "Stranger in a Strange Land".
Rough meaning is to understand thoroughly and profoundly.

"As one character from Heinlein's novel says:

'Grok' means to understand so thoroughly that the observer becomes
a part of the observed - to merge, blend, intermarry, lose identity in
group experience. It means almost everything that we mean by religion,
philosophy, and science - and it means as little to us (because we are
from Earth) as color means to a blind man. "

From:
http://whatis.techtarget.com/definition/0,,sid9_gci212216,00.html

Happy trails,
Gary (net.yogi.bear)



Well THAT explains it!

And now you grok!

- Mike KB3EIA -