Foxhole Radio detector variant

[vu2nan]

Please do check this out.

http://tinyurl.com/cccnh6d

Many thanks.

73,

Nandu.




--
vu2nan

[philo]

On 5/18/2013 4:29 AM, vu2nan wrote:
> Please do check this out.
>
> http://tinyurl.com/cccnh6d
>
> Many thanks.
>
> 73,
>
> Nandu.
>
>
>
>

I recall, as a kid building a crystal set with my father.
we used a razor blade and a piece of pencil graphite, but never got it
to work.

Later, with a "crystal diode"...it worked.


That was in 1957 and I still have the roll of wire were used to wind the
coil

[Michael Black]

I guess my childhood was more upscale. I remember having a tiny box that
was a crystal radio, complete with tuning dial. Maybe three inches long,
two inches wide? SOmething like that. It was a commercial product. I
have no idea if it was given to me, or I kind of used it because my father
had it. I can't even remember if it worked, I vague remember something
about clipping it to some metal frame, it had an alligator clip or two.
That had to be the early sixties.

Then in the early seventies, I had one of those plastic crystal radios, a
famous brand that doens't come to mind right now. A plastic case with a
slider for tuning, it had a piece of plastic in a circule, kid of like an
antenna, and I think the whole thing was blue. Only one earphoe, but soe
metal to hold it onto your head. That worked, though I can't remember the
antenna, and I seem to recall multiple stations at the same time, so not
much selectivity. I can't remember if that was a kit or not.

Michael VE2BVW

[philo]

On 06/15/2013 06:41 PM, Michael Black wrote:


<snip>

>> That was in 1957 and I still have the roll of wire were used to wind
>> the coil
>>
> I guess my childhood was more upscale. I remember having a tiny box
> that was a crystal radio, complete with tuning dial. Maybe three inches
> long, two inches wide? SOmething like that. It was a commercial
> product. I have no idea if it was given to me, or I kind of used it
> because my father had it. I can't even remember if it worked, I vague
> remember something about clipping it to some metal frame, it had an
> alligator clip or two.
> That had to be the early sixties.
>
> Then in the early seventies, I had one of those plastic crystal radios,
> a famous brand that doens't come to mind right now. A plastic case with
> a slider for tuning, it had a piece of plastic in a circule, kid of like
> an antenna, and I think the whole thing was blue. Only one earphoe, but
> soe metal to hold it onto your head. That worked, though I can't
> remember the antenna, and I seem to recall multiple stations at the same
> time, so not much selectivity. I can't remember if that was a kit or not.
>
> Michael VE2BVW
>
>

Yep.When I was a tad older I got, as a gift, one of those plastic
crystal radio kits, it was yellow.

The kid next door had one but his was "louder" than mine.

We experimented by swapping them and determining that it was not the
antenna, then we exchanged diodes and it turned out his diode was more
sensitive than mine.

A few years later I put one one stage transistor amplifier in it
and one of my friends wanted it so badly that I ended up swapping him
the radio for a huge box of parts.

[coffelt2]

"philo " <ph...@privacy.net> wrote in message
news:kpk9ro$7sn$1...@dont-email.me...

> On 06/15/2013 06:41 PM, Michael Black wrote:
>
>
> <snip>
>>> That was in 1957 and I still have the roll of wire were used to wind
>>> the coil
>>>

<snipped to bits>

> We experimented by swapping them and determining that it was not the
> antenna, then we exchanged diodes and it turned out his diode was more
> sensitive than mine.
>
> A few years later I put one one stage transistor amplifier in it
> and one of my friends wanted it so badly that I ended up swapping him the
> radio for a huge box of parts.

My "foxhole" radio never did perform, but our nearest 500 watt station
was 30 miles away.
The "Technical experts" writing of the day explained that the sensitive spot
on the blue blade
was the fine line where the blue coating met the sharpened edge, where there
was no blue.
Some think that since the bare sharpened edge tended to rust, there could
have been a
crude junction of sort where the beginning of rust interacted chemically
with something in the
blue substance. Wada U think?
Later in life, maybe 1958 or so, Tucson Radio Supply had CK722's for
less than $15. I
sprung for one, and tried the "Foxhole" thing again. Hey, it received
several stations, one on
top of the other. You could see several AM towers nearby. Discovered that
you didn't need
any razor blade at all. Just touching two slightly corroded copper wires
together did the same
thing. All H*** broke loose when the price of surplus 1N23's got less than
$2. Then selectivity
became an issue.

Old Chief Lynn, W7LTQ since 1948 (CW every month or so)

[Geoffrey S. Mendelson]

coffelt2 wrote:
>
> My "foxhole" radio never did perform, but our nearest 500 watt station
> was 30 miles away.
> The "Technical experts" writing of the day explained that the sensitive spot
> on the blue blade
> was the fine line where the blue coating met the sharpened edge, where there
> was no blue.
> Some think that since the bare sharpened edge tended to rust, there could
> have been a
> crude junction of sort where the beginning of rust interacted chemically
> with something in the
> blue substance. Wada U think?

It may also have been impurities in the blade that caused it to work.

While cleaning out things, I found some FAN brand blued steel blades,
purchased by a late friend in the 1970's.

Maybe someday I will find someone local to me (Jerusalem) that wants
to try them. :-)

73,

Geoff.


--
Geoffrey S. Mendelson, N3OWJ/4X1GM/KBUH7245/KBUW5379
It's Spring here in Jerusalem!!!

[Michael Black]

On Mon, 17 Jun 2013, Geoffrey S. Mendelson wrote:

> coffelt2 wrote:
>>
>> My "foxhole" radio never did perform, but our nearest 500 watt station
>> was 30 miles away.
>> The "Technical experts" writing of the day explained that the sensitive spot
>> on the blue blade
>> was the fine line where the blue coating met the sharpened edge, where there
>> was no blue.
>> Some think that since the bare sharpened edge tended to rust, there could
>> have been a
>> crude junction of sort where the beginning of rust interacted chemically
>> with something in the
>> blue substance. Wada U think?
>
> It may also have been impurities in the blade that caused it to work.
>
> While cleaning out things, I found some FAN brand blued steel blades,
> purchased by a late friend in the 1970's.
>
> Maybe someday I will find someone local to me (Jerusalem) that wants
> to try them. :-)
>

I suspect there are still plenty of those Blue Blade razors at the back of
medecine closets. Just pushed back as new things come in. Or maybe the
time is passed, the blades have finally been tossed out "nobody will ever
use these".

Kind of like old radios, a period when they are common but nobody wants
them, then later they are desired, but attrition has reduced the numbers.

Michael VE2BVW

[Jim Mueller]

Some medicine cabinets have a slot in the back for disposing of used
razor blades. If yours does, you could pull the cabinet and see if a
previous owner of the house left you a supply inside the wall!

--
Jim Mueller wron...@nospam.com

To get my real email address, replace wrongname with dadoheadman.
Then replace nospam with fastmail. Lastly, replace com with us.