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Crystal Radio

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Agung w

New Member
Hi folks, i try crystal radio by using coil and capacitor i prefer to fm one than am but still wondering about many stations that should be caught by crystal radio not just one channel et cetera.
i just be affecting with condition when there are ordinary variable capacitors then small capacitor in the range about 0-18 pf then the parallel combination with two materials resulting range
about wanted area of fm enveloped et cetera. in another phenomenon i obserb about coils as material scattering on the shop just thinking about what the coils whose length or turn around that
may be as the shame suitable material chosen as parallel capacitor big and small ones et cetera. so the question is about what the area as fm part should be encompassed showing about may the
the practitioner go mislead to be short or to be long because i heard in crystal radio the fm stations can be arranged by using that way than just to go on complex circuit as the amplifier et cetera.
i mean if because the mislead about around those condition or another external effect that arrange about selectivity or sensitivity et cetera. i do that observation as the allocation part of life beside another
needs in the life because be worry about another guys that have similar appetite than whose eagerness to make enslaving behind as if the needs be allocated by another ones should will be more prospherous and complete
than someone else as target et cetera. ok i guess that is enough for my explanation so i keep searching on that information as good life certainly waiting information in crystal radio about the condition
why not be easy to be turning around as choosing capacitor or choosing coils.
 

cowboybob

Well-Known Member
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Welcome to ETO, Agung w.

I'm not exactly clear what you are asking.

But one thing I think I understand is your question concerning a "crystal radio" and its use with FM (Frequency Modulation) signals.

Crystal radios will only work with AM (Amplitude Modulation) signals. They WILL NOT work with FM signals.
 

MikeMl

Well-Known Member
Most Helpful Member
...

Crystal radios will only work with AM (Amplitude Modulation) signals. They WILL NOT work with FM signals.
Practically, yes; In theory, no. If the deviation of the FM signal is wide enough, and the Q of the crystal set's tuned circuit is high enough, "slope detection" (tune to one side or the other of the FM channel) will demodulate FM to create audio.
 

cowboybob

Well-Known Member
Most Helpful Member
Practically, yes; In theory, no. If the deviation of the FM signal is wide enough, and the Q of the crystal set's tuned circuit is high enough, "slope detection" (tune to one side or the other of the FM channel) will demodulate FM to create audio.
True, of course. But wasn't at all sure the OP would be able to appreciate the nuance(s) of that theoretical scenario.
 

Agung w

New Member
i have tried the crystal radio by using in34a diode as demodulator of signal also choose specific copper wire with number of turns i set the variable capacitor whose ordinary pf range with little capacitor pf as series for fixing the gauge of capacitor but will always just catch one signal of stations that is it. so still wondering about perception in signal received if because of mistake of number of coils turns (i think should be correct in the information on the internet about approximation henry value et cetera). actually i still not have the metter of henry (because of the doubtfull about precisely thing as the reason or rarely found on the shop with good price et cetera). another thought if about may be about speaker perception in impedance material. i mean i ever guessed about with high impedance of speaker be like crystal earphone (actually i also not yet got that creature as convincing high impedance written) in the kind plug and play with that thing then give high impact about tunnablelity or good perception et cetera comparing with
ordinary speaker using the transformer as the same handle may be. ok that is folks my complaining about crystal radio to you may be if because there are should be a kind of extention in circuit so tunnable problem happen because of something. bye bye.
 

cowboybob

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Most Helpful Member
If you used wire for you coil (inductor) that is insulated with shellac (not a plastic sheathing), you can also easily "tune" your circuit further by carefully soldering "taps" at various place on the coil. One at a time, try grounding different "taps". That will alter the range of the resonance of you tank circuit.

A crystal earphone is what I used as a kid. Not much volume, to be sure, but I could hear the stations I tuned to.

At what frequencies are the radio stations (AM and FM) in your area transmitting?
 

Agung w

New Member
What the sheating called shellac i am not familiar as i know every copper wire just brown or rather yellow coloring material sometimes must be peeled on end to the end length when be used. i have ever tried to variate the coils but not showing linearity in deviation result of wave even the leakage of the perception always arise frequently et cetera. i also have the eagerness to try the integrated circuits be like tda 7000 but in the turn around the signals little bu little will out of material be like diode with merchandise mark bb.... forget number. so i still be obsessed with a kind of life if the electronics material on the markets are a kind of medicine with rotation of the earth or that is the wrong of concept that electronics stuff should be collected with something perfect then giving the convincing self to arrange or custom something et cetera. actually the hindrance pertaining with dignity if i can easily found the materials then be like plug and play giving spirit to make a kind of collecting of something or even somebody must develop from bottom up then that's capability will bring the components or collection should be correct in the life. ok i guess a kind of that obsession beside human must think about money or allocation of budget to be worry. what do you think ?
 

JimB

Super Moderator
Most Helpful Member
What the sheating called shellac i am not familiar as i know every copper wire just brown or rather yellow coloring material sometimes must be peeled on end to the end length when be used. i have ever tried to variate the coils but not showing linearity in deviation result of wave even the leakage of the perception always arise frequently et cetera. i also have the eagerness to try the integrated circuits be like tda 7000 but in the turn around the signals little bu little will out of material be like diode with merchandise mark bb.... forget number. so i still be obsessed with a kind of life if the electronics material on the markets are a kind of medicine with rotation of the earth or that is the wrong of concept that electronics stuff should be collected with something perfect then giving the convincing self to arrange or custom something et cetera. actually the hindrance pertaining with dignity if i can easily found the materials then be like plug and play giving spirit to make a kind of collecting of something or even somebody must develop from bottom up then that's capability will bring the components or collection should be correct in the life. ok i guess a kind of that obsession beside human must think about money or allocation of budget to be worry.
what do you think ?
I am sorry to have to say this, but, your post makes no sense in English.

JimB
 

audioguru

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FM radios are supposed to ignor the snap, crackle and pop of AM interference. A crystal radio doing slope detection on an FM station will produce all those noises.
The TDA7000 radio IC is obsolete and had VERY poor performance. Newer TDA7088 ICs can scan stations but also have very poor performance. Very cheap radios have them inside.
 

Agung w

New Member
if there are informations about foxhole radio or simple crystal 1n34a diode that can scans many stations in practice be like radio shack. because i am obsessed with something trivial be like gillete or little diode that can do that thanks.
 

atferrari

Well-Known Member
if there are informations about foxhole radio or simple crystal 1n34a diode that can scans many stations in practice be like radio shack. because i am obsessed with something trivial be like gillete or little diode that can do that thanks.
A foxhole radio scanning stations. That is pure nonsense.

Most probably, the only thing a Gillette could do is to cut your hands if you are not careful.
 

Agung w

New Member
i meant if there are the custom techniques about configuration to make deviation of signals to another stations in foxhole radio besides fidelity in a kind of material be like coils gillete or may be variable condensator et cetera. certainly comin from sites that has arrived that achievements.
 

audioguru

Well-Known Member
Most Helpful Member
We speak English on this site. What language are you speaking? Are you using translation software that works poorly?
A crystal radio was used 100 years ago when there were very few radio stations so the poor selectivity did not matter. Today a crystal radio will probably pickup a few radio stations at the same time.
 
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