My father was telling me recently about how he built capacitors from scratch
when he was a boy. He scrounged broken bits of glass and alternated them
with pieces of tinfoil from gum wrappers. Together with some wire leads they
formed a capacitor for use in homebrew crystal radios. He used the large
oatmeal boxes for coil forms, and transducers from old telphone handsets for
the earpiece. A galena crystal and safety pin was used for the detector, but
I don't know where he came upon the galena.

Guy Atkins
Puyallup, WA USA


"Ron Hardin" wrote in message
...
We used to build them with 1N34A diode, capacitor across the headphones,
and a coil wound on a toilet paper tube, with taps on the coil
that you'd clip an allegator clip to, for tuning.

Assemble atop wooden board.

There were some with an actual cat whisker instead of the diode,
but we went the modern way mostly.
SNIP

The modern reproduciton that I have was made by DaMart Company.
I found this web site in Engalnd:
http://www.greatgizmos.co.uk/damert_company_page_1.htm

Rocket Radio (Reference #D4025)
It receives radio signals without using batteries! In the late 1950's,
kids learnt that the magic of radio could be achieved without batteries
through an ingenious gizmo known as the Rocket Radio. Now it's back! By
attaching the antenna/ground wire and tuning the nose cone, a handful
of AM stations can be received and heard through a crystal earphone. An
informative booklet will help curious minds understand the science
behind radio transmissions and crystal diodes. For ages 8 and up.

The show a blue one, but mine is red.
My sister tore mine up back in 1960.
She bought me one in 2001 for my 50th birthday.
My orignal was blue but I didn't complain.
It works pretty well, but I found a site that has some improvements,
but I can't find the $#%^ URL right now. I never got around to
making them, after all why complicate something simple that really
works. When I find the URL I will post it here as a new post.
Terry

Terry
:

"peter berrett" wrote in message
...
No but the radio is very similar

I think I would almost prefer a rocket radio for my son if they are still
available! They look way cool!

cheers Peter

http://cgi.ebay.com/ws/eBayISAPI.dll...482786 4&rd=1

I think you'd be better off getting one commercially first. Then experiment
with it so you can make your own. It's much less frustrating that way.

Purists insist on using a chunk of galena and a "cat's whisker" for the
detector, but you can substitute a plain old 1N34 germanium diode to
accomplish the same thing without all that trouble of having to poke around
to find a "hot spot" on the chunk of galena.

There are different ways to accomplish tuning. You can have a variable
coil, or a variable capacitor. Big variable caps can still be found, though
not new, and they're easier to work with. Smaller variable caps can be
salvaged from junked transistor radios.

It's been said that "A dollar in the antenna is worth ten in the receiver."
That holds true. String up as much long wire as you can for your antenna.
And also make sure you have a good earth ground. That will really help.

After you get all this done, please let us know what you hear!!!!

Matt J. McCullar, KJ5BA
Arlington, TX

-=jd=- wrote:

So out of curiosity, off I went "a-googling". Oddly enough, the first
couple of sources that listed the Rocket Radio for sale were "SOLD-OUT".
Hmm... Perhaps it was a popular item this past Christmas season?

Then, I tried:
http://home.earthlink.net/~wb5rex/xt...newrocket.html

He's got them for $13.95.

I'm sure there are other sites that may have them...

Good Luck with it!

-=jd=-

Here's a froogle search sorted low to high price

http://froogle.google.com/froogle?num=20&hl=en&lr=&c2coff=1&safe=off&tab=wf& scoring=p&q=rocket+radio+crystal&btnG=Search+Froog le

$9.95 (plus shipping) seems typical.

http://www.crystalradio.net/misc/rocket/index.shtml

Good Luck!
Mike
KC6SEG

"peter berrett" wrote in message
u...

Hi all

Cam someone please help me with a query I have about an old crystal set I
used to own.

When I first came to live in Melbourne (1970s) my parents purchased for me
a
small crystal set.at a local, now long gone, toy store. As I recall the
set
was manufactured in England although I may be wrong on this point.

It was housed in a small plastic box (red?) and from memory was about 2
inches long and maybe an inch wide and high.

Inside the box was a small wound coil (about 1/4" diameter) around a thin
cardboard tube. There was a ferrite rod inside this which could be slid
back
and forth within the tube by means of a small rod that stuck out of the
end
of the ferte rod and protruded from the end of the box. This was used for
tuning stations. There was also a piece of wire coming from the box with
an
alligator clip on the end. This was the antenna and by attaching it to a
long piece of wire one could receive stations. There was also another
piece
of twin wire protruduing from the box which went to a crystal earpiece so
that you could listen to stations.

Aside from this I think there were only two other components - a diode and
a
capacitor as I recall which formed the crystal set circuit. Unfortunately
the set is now lost after so many years.

This was my first introduction to radio and despite moving on to bigger
radios and getting my ham license, this example of a crystal set has
always
stuck in my mind as being a particularly simple but efficient example of
electrical engineering. I now have a young son of my own and would like
very
much to buy one of these sets.

Does anyone know who manufactured these sets and whether they are still
available to be purchased?

cheers Peter VK3PB

Ron Hardin wrote:

There were some with an actual cat whisker instead of the diode,
but we went the modern way mostly.

I had a crystal set in the 1960's that used a real galena crystal which
was mounted in a small metal cup. The cup served as one of the
electrical connections for the crystal. The crystal was embedded in some
kind of metal which I assume was poured into the cup in a molten state.
Could it have been lead?


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Matt J. McCullar wrote:
Purists insist on using a chunk of galena and a "cat's whisker" for the
detector, but you can substitute a plain old 1N34 germanium diode to
accomplish the same thing without all that trouble of having to poke around
to find a "hot spot" on the chunk of galena.

In a homebrew crystal radio, I tried a chunk of galena, but it did not
work as well as an iron pyrite ("fool's gold") crystal. For a "cat's
whisker", I used a small gold-plated safety pin.

In my experience, the old high-impedence headphones (which typically have
Bakelite ear pieces and a headband made of spring steel covered with cloth
or leather) work much better than the cheap in-the-ear kind found on
modern crystal radio kits.

As mentioned earlier, http://www.midnightscience.com has some great
crystal radio info.

--Leigh Marrin/KM6JE in Santa Barbara, Calif.

Thanks for the link. The radio will make a great present.

cheers Peter


"-=jd=-" wrote in message
...
On Wed 12 Jan 2005 08:47:21a, "peter berrett"
wrote in message :

No but the radio is very similar

I think I would almost prefer a rocket radio for my son if they are
still
available! They look way cool!

cheers Peter




Hmmm... I've noticed them in Cracker Barrel restaurants recently. I just
checked their website (http://www.crackerbarrel.com) but, they don't list
it online. I want to say they were about $10.00.

So out of curiosity, off I went "a-googling". Oddly enough, the first
couple of sources that listed the Rocket Radio for sale were "SOLD-OUT".
Hmm... Perhaps it was a popular item this past Christmas season?

Then, I tried:
http://home.earthlink.net/~wb5rex/xt...newrocket.html

He's got them for $13.95.

I'm sure there are other sites that may have them...

Good Luck with it!

-=jd=-
--
My Current Disposable Email:

(Remove YOUR HAT to reply directly)

On Thu, 13 Jan 2005 00:21:42 -0500, starman wrote:
I had a crystal set in the 1960's that used a real galena crystal which
was mounted in a small metal cup. The cup served as one of the
electrical connections for the crystal. The crystal was embedded in some
kind of metal which I assume was poured into the cup in a molten state.
Could it have been lead?

You can use solder, but Woods Metal is better as it melts in boiling water
and you can make your mould in wood or plastic. I've just made some crystals
using it for a reproduction 1920s style xtal set.

--
Cheers,
Stan Barr stanb .at. dial .dot. pipex .dot. com
(Remove any digits from the addresses when mailing me.)

The future was never like this!