RADIO / CRYSTAL SET ...Increase & Economize!!

I always go to build the radios before careful consideration to technical principles of radio. Am I wrong?

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Crystal SetProjects of eternal crystal radio sets

Fox hole Radio FigureConpanionAre you understanding?
This is a Radio, called
Fox hole Radio
(POW Radio at home).

Fox hole Radio TopView

But, we do not use a razor blade & a pencil lead because that is too experimental and modern earphones are not fond of components like that.

Fox hole Radio schematicCircuit
L = Coil.
wound 0.5mm copper wire 180 turn on your Toilet paper core roll with mounted 3mm * 3mm square lumber to establish points of contact for slider. (figure below)
VC = Variable Capacitor(Condenser)
about 100 - 200pF.
D = Detecter. 1N-60?(or similar)
(You can use a razor blade and a pencil read, but I am afraid that you lose the sensitivity.)

We provided a few taps on the tuning coil because to take Antenna-matching for an improvement of selectivity (in your room)!
R = Resistance,C = Capacitor are had added to output side to soften the rough sounds, for your ears.

TunerSliding Tuner(Swing tuner)
Project with Primitive Parts
Bend 3mm diameter Copper bar to make a right angle.
Put it into 3mm inside diameter Copper pipe without soldering as free-rotation.
Put the component on a particular insulator ( plastic bar ) which has been driven into the base. Bind tightly a wire that is connected to other parts on the Copper pipe without soldering.

Variable CapacitorVariable Capacitor(Condenser)
Project with Primitive Parts 2nd
(↑meaningless 2nd)
put 3 Metal(Aluminum) plates in pile. Isolate them each other.(e.g. packing-tape?)
Approx. max.100 - 200pF
But, we used one above is some metal fittings to fix boards of furnitures.
this one is NOT high-precision!!! this is been using as a supplementary instrument.

8th radio with VC for fine-tuningVariable Capacitor

And... what is this an art craft?

This one is a VC for fine-tuning. This is bigger than above-mentioned one for to be serious tuning. Approx. max.150pF rather-precision....
This VC is been setting on 8th radio practically to take tuning radio waves.

More sets I've built
7th Crystal set 7th fox hole
7th schematic
8th Crystal set 8th cosmic force
8th schematic
We regret to inform you that, 9th set is .....

9th ........
9th schematic
Mystery crytal set 9.5th(an Extra) Mystery set
9.5th schematic
10th Crystal set 10th Variometer
10th schematic
11th Crystal set 11th Orthodoxy (simple)
11th schematic

sniffThere is not "4th".
Because number of 4 brings Unhappy in Japan. (And, 9 too!)
In that case, "1st" was reformed as "4th", however I didn't count it.
9th set was made a mistake as I expected unfortunately.
And, why does the blue-headed girl is there always?
"万年" means "10,000 years".... eternal, OH!!!

The ionoshere8th set is able to receive weak waves come from far away(DX), about 500mile over.
but some strong waves that come from neiboring countries, always disturb weak DX waves I desire to listen indeed.

Put up a great antenna as possible.
We are using one : Horizontal 12m, height 5m, East-West azimuth in the air.
It is not enough to use receiving DX. It depends upon the ionosphere, as always.

trap filter
Some struggling case.

dual earphones Antenna matching
to take measures against the problems on the economical way.

Mystery Crystal set project

from Australia that had been published by Proton on "The Sunday Mail" in 1932. I have found a funny circuit like this on the way of several researches of handmade Crystal sets. W, What's this???
winding bifilar coilGround(Earth) has been pulled out from a strange point you can not understand.
(See the schematic figure above)

How to take winding Bifilar coil
Mystery Crystal set / winding bifilar coil
Are You trying to squelch us!?
and, in a delicate selectivity ....(however, there are solutions to the problem)

If your Mystery Crystal set you built produces strange bad voices and sounds (under using a crystal or ceramic earpiece), fit a 100 kilo Ohm(approx.) resistor (brown-black-yellow) across the output terminals.
But if you use high impedance headset(headphones) to listen, the 100k resistor is unnecessary.

Mystery Extra Coupler
Mystery Crystal set extra CouplerAn example of an improvement of the selectivity.
Mystery Crystal set extra Coupler
We tried several experiment to improve the selectivity, so we have got to this way that is easy to try for you. Add red letter division!
But, it has a delicate effect.... I am a little afraid of these affairs.
Better than nothing. We evaluate this extra-coil so.

Variometer crystal radio set project

Variometer crystal radio setHIGHER PERFORMANCE!!

But, this one is hard to be built, for you.
A small coil is rotated in a large coil!
The complex system drives you crazy!
Even if it is very interesting one as a radio that you can build.
But, You'll be fascinated by this set surely because it shows principles of ancient(primitive) radio age!
Awesome!Oh! I have been fascinated already!!!
Japanese people make anythings from wood, always.

Method of the hanging inner coil (Variometer)← This is a figure of
"Method of the hanging inner coil".
They are built out of thin square lumber all.
Oh! Inner coil is wound on a paper core, A mistake!
The inner coil is simply hung in the air outer coil, for easy build up.
#24 magnet wires are pulling down the inner coil easily, with the light tension.
If they are distorted when you manipulate them, an effect for tuning is small, I think so.
Because the analog system is random.

Halfway through Variometer coilsWhere do you get 8cm(approx. 3" ) diameter paper(cardboard) core out of?
But, perhaps you know it. And you have ever seen solution to the problem.
That is a core of packing tapes. You can find that kind of thing anywhere. in your place of work, in your school....
(Yesterday I have found it on stairs of an apartment building I don't live in!)

widening narrow one <<<< A way of widening the narrow paper core you have found.
You can thrust a shaft to rotate inner coil to tune through the gap you opened to widen the narrow one.
You should make high performance manufactured goods out of cheap materials.
(on second thought, they are all trashy ..... forget it.)

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