Variable inductor crystal set drives a speaker 

Sure, you can order whatever you want from Amazon or eBay. I really like the idea of being able to build a receiver with whatever is lying around, which I think is the point of this video.

@@johnwest7993 I commented for those just starting out and thus may not know about high impedance earphones.

Excuse the ignorance. Question, why does the transformer help the signal be Heard on a speaker rather than high impedance headphones? Because it steps up the current but I don't understand how it lowers impedance as well? Thank you in advance. I'm trying to build one and wow so much to take in!

@@brandonlaragirl Roughly Z = V / I Where Z=impedance, V=Voltage, I=Current A transformer with a 2:1 turns ratio will have 1/2 the voltage on the secondary. If you draw current from the secondary, only half as much is need on the primary. Thus going primary to secondary, voltage is divided by two while current is doubled Z(secondary+) = (1/2V)/(2*I) Thus Z(secondary) is 4 times lower

@@kensmith5694 awesome, thank you!

I think the biggest improvements you'll get are if you can optimise the tapping point of the diode and coupling from the antenna. Kits often have a compromise position that isn't best for your circumstances.

X-rays are fun to play with if you know exactly what you're doing. if you do not they're dangerous as hell and you should not be toyed with.

He is going to built something to suck all the power from the radio transmitter to light his house lol.

I think a version with fewer turns would be fine for an antenna tuner. Variometers were widely used last century. I agree that mechanical complexity probably made manufacturers stop using them but not an issue for hobbyists, especially with 3D printing making custom parts easier to make.

About 30m of wire, maximum height 11m up but most lower.

That should be OK. But if possible I'd use thicker wire eg from an old power extension cable.

@@vk3ye I do have a 10 to 470pf varible cap

I have had good luck using a single strand of cat wire. 24 gauge. I always wind 57 turns on a 3.25" diameter PVC pipe. You can use different diameters by consulting "Professor Coyle" online. The described coil uses 49 feet of wire. 24 gauge cat wire gives you about 27 turns per inch.

Higher capacitance with a given inductance allows tuning in of LOWER frequencies.

@@vk3ye awesome, thank you. Gonna work on building an amp today. Got a 386 and a transformer. Question! Is it better to use AC or DC current to power the amp.

About 20-30 m would do it.

@@vk3ye Thank you.

@@vk3yeI am more interested in utilizing H-field instead of noisy E-field. So I designed earlier a magnetic loop antenna on an X frame of wood. Each corner was 24 inches away from its nearest corners. I used audio speaker wire with 11 turns and a gang variable capacitor of 365pF in parallel to this loop antenna. There was 2mm gap between each turn of the loop antenna to cater for stray capacitance. One day the back of my hand touched the metallic plates of the gang cap and I felt induction and shock. So I used my gauss meter to check and it was detecting the induction. I have an idea to design crystal radio and place it near the same loop antenna instead of connecting a 20m long ant wire. At the output side I am intending to use ultra low power buck boost converter like LT3108 with a step up transformer to harvest maximum energy out of it. Of course I'll use good earthing. If you kindly give your comment or any guideline on this idea. I shall be grateful.

Nonsense.

Yeah, I can tell you left the knowledge behind you

I had two E.T.s tell me I couldn't hear what I was listening to.

A high degree of knowkedge / education doesn't always equal wisdom.

Nonsense.

@@vk3ye i agree

Anyone who ever messed with crystal radios knows it works without any power. It's amazing when you make one yourself

@@vk3yeI just love it when someins is shown something that's working and they deny it works. lol