I built one of these when I was 12 years old.....I wound wire on a toilet paper tube for days with wax paper in between the coils....It didn't work....So, I did it again winding onto a paper towel tube and keeping the wire at a single thickness....It worked! I learned to improve the audio output with a bigger coil. Everything was going fine until I "invented" a better antenna and was installing it in our attic. I accidentally stepped between the rafters and feel halfway through my parents bedroom ceiling.......My fledgling radio career very nearly came to a end..... Hey Dad....THIS is a VERY GOOD project to share with your kids.... KF7ZSA
Nice job. My grandfather built one of these with me as a child. 30 years later, I still love electronics. Everyone should build at least 1 crystal radio from scratch.
Yes, but only if you can put up a long wire antenna and a proper grounding. I just built a crystal set and I can hear some stations at night, BBC, some russians, Romania... The nearest MW stations are abt 1000 miles away from me.
Isse behtar kisi ne bhi radio project ko nahi banaya ...sab koi ya toh resister ya fir capasiter use karke hi bataye hai aur uska karan bhi kabhi nhi btaya...aapka project lajawab hai sir hatss off
The Old Gillires Blades in 1940's was made of different metal in 1945. My Grandfather was in WW2 as a Batann Death Marcher & POW. He Build me one in 1956 it had to be Gillettes "BLUE" COLOUR. The NEW pincels also are not GRAPHITE in USA. Gotta get ATIST PINCIL. I have a set of Watercolours and they won't work.Oh I seen HOW you MAKED a BLUE BLADE...Oy Vey! How syupid are I am?Nu? But the Foxhole Radio in the POW Camp was DETECTED DRIVEN. No Ciols, because (As Grandfather explain) ONLY ONE STATION IN ROAD JAIL where he at was.
Into the 2 minutes mark, your background voice, and your cellphone emissions are bleeding upon the ground which emitting data transmission over your speaker of the cellphone.
The detector is metal-oxide-carbon. There is a physics effect that says that an electron can go some distance into an insulator like metal oxide. This distance is tiny and depends on what the electron starts out in. You can think of it as depending on the speed of the electrons in the material. The "speed" is very different for carbon and iron. Thus electrons can make it right through the oxide on only one direction.
Finally! Someone gets it. These are TUNNEL DIODES but *not* semiconductors. They are MIM tunneling diodes which stands for Metal-Insulator-Metal. The Work Function of the two metals (or carbon must be different because electrons move in both directions and one direction must exceed the other for useful detection to result. @@kensmith5694
The only catch to this is that you need a very high impedance earpiece or headphones, otherwise you will hear nothing, I built many crystal sets as a kid and used a crystal earpiece.... I went on to become a chartered radio consultant
I built ine using a 1n34 diode and i can use magnetic stereo hedphones just fine. It sounds like pocket radio on comfortable low volume. I get am 650 and one Mexican station depending on the chosen coil tap.
You Tube this Engine er did not understand the how make radio my request this engi ner take help from so lding iron than he will Successful.You Tube Yrs every program goi ng very wel.Thanks.
Yes but u need to have a really big antenna and be close to the staation for it to work. Otherwise youll only hear a whisper if it works. Instead get the thing that beeps in a microwave or similar piezo type speaker. I use regular hedphones and get decent volume on mine. If u have them give it a try and see if it works for you
yes fox hole catches AM signals. Usually AM's radio signal strength will not be good if it crosses 250-300 km. but if the radio brodcaster amplify enough its quite possible,
@@huseyinuguralacatli5064 That would be EXTREMELY rare. You would need an excellent antenna, a diode, probably a 5 stage radio, even then it would be highly unlikely. You might be able to hear Shortwave 5000 km away, with all that I said above. A foxhole radio like this with a good antenna and ground, tuned with a capacitor instead of inductance could hear an AM (MW) station 500km away at the right time of the year and the right time of the day. I've done it.
Hi sir! can i use copper wire for everything, or should it be covered enameled? what kind of pencil did you use sir, graphite or lead? please reply, it would greatly help, thank you in advance :)
किन तारों को तुमने स्पीकर से जोड़ा है, बताया नहीं । रेडियो सेट को इधर से उधर बार बार इतना हिलाते रहते हो इस कारण दिखाई नहीं देता है कौन तार किस चीज़ से जुड़ा है ।
Speaker doesn't amplify the signal!!! Does anybody know how the frequency domain response of an LC circuit ? And y the inductor doesnt allow sudden changes in the current flowin through? "Jw" ??
Good job! Your fox-hole radio worked better than mine. The signals I got using the razor blade was so weak. I could hardly hear anything. I'll keep trying. PEACE !
I would stay up late at night and tune into Ira Blue at the Hungry Eye (50,000 watts) in San Francisco from my childhood home in Coquille Oregon......55 years ago.........................gently, gently, ever so gently probing that razor blade with my pencil lead secured to a bent safety pin and my ears stinging from the plastic headset.... Sometimes, rarely but sometimes...I could hear foreign language radio......Where is this from, I would wonder.......... KF7ZSA
Joanna Siddika, remove bit of pencil's wooden body until u see graphite inside. Then wind wire ending around pencil and tighten it. Make sure wire ending is in contact with graphite.