Here in the USA they’re trying to get rid of AM radio. Electric vehicles cause interference which has prompted the manufacturers to stop putting AM radios in electric cars. Now Ford has announced they will stop putting AM radios in ALL their vehicles, because *they know* we really don’t need that anymore... we’re supposed to stream AM stations over our mobile devices. Anyway, I suppose the next step is for AM stations to stop broadcasting because nobody can listen anymore.

yea in the USA digital radio stations exist which has analog and digital

Well... 1- The station is chosen by modifying the position of the coil wire. 2- No FM, only AM 3-Cristal earphones, or any speaker would work, if it don't need a lot of voltage nor current. 4- Every diode would work. The Cat's Whisker, or the Razor Blade, works by making exactly the same job as any diode. Just use it in the correct position.

That's the "fun" of these types of radios. If you can tune it high enough to the FM frequencies you can sort of hear it. The FM messes with the AM detection. I've done this and it works but it's much weaker than AM so it will be very quiet. If you can't find the crystal radio you can use a regular audio amplifier with a speaker. It's "cheating" by using batteries but it's useful for just playing with. I've seen some people use a custom made impedance matching audio transformer. The radio has a very high output impedance. A transformer that can couple the high radio impedance to a low impedance speaker does work. Tuning is done by whatever means you can use. Changing the inductance uses the least amount of parts. Adding capacitors is another way of tuning. If you make the radio so that it's easy to swap in different diodes, then make the radio and start trying different diodes. Some diodes will work better at different frequencies. A small schottky diode might work. I've used a red LED before (only good on really strong stations). The thing to do is play with the parts and see what works and how well they work. This radio is less a science and more an art.

​@@isaacm1929Modern diodes have a higher forward voltage and won't work as a direct substitute in this circuit. I think it might be possible to bias a modern diode using a potato as a battery along with a properly sized resistor. You would still need a crystal ear piece for listening unless you added an amplifier section to this radio circuit. Make that amplifier section potato powered too for real trench war conditions.

​@@therealjammitAM radio is "amplitude modulated" and FM stands for "frequency modulated". It's not as simple as adjusting the coil to a different frequency range.

@@tenlittleindians Yeah. I forgot that. Most diodes today need bias. (But it is still possible to find modern diodes with low forward voltage in some places. ) Thanks for correcting my comment! Also, potatos are a valuable source of food, so, in war, maybe lemon power would be better.

You can find them on eBay.

no, no point,

These radios are getting their voltage directly from the frequency waves hitting the antenna. A hundred years ago they maximized this by increasing the length of this antenna and often ran a long wire out a window to a barn or tree over a hundred feet away. The length of these long wires work best if they are either multiples of or fractions of the wave length of the frequency you are trying to tune in. Those long antennas were insulated from ground at both ends by ceramic insulators about 2" long which I still see for sale in antique shops. Usually they are white or blue with a hole on each end. They had an alligator clip on the wire from the radio to this long antenna so they could disconnect it during storms to prevent lightning strikes from traveling down the antenna and burning their houses down.

you can usually still find suppliers of germanium diodes such as OA91 or equivalents

​@@andygozzo72 The diodes he shows in this video are point contact diodes and each one was hand tuned. They don't make these anywhere anymore as the labor costs to individually tune them would be too high. The modern replacement diodes may be the same materials but they are not point contact and will not give you the same results in a crystal radio.

@@tenlittleindians the OA91 types i mentioned (and OA90) are point contact, and look identical to the ones in the video, get one and look into one with a magnifying glass and you'll see , theres also several earlier OA types with larger glass case

@@andygozzo72 Here's a great breakdown of diodes old and new: kzfaq.info/get/bejne/aN-qpZec3Z63emg.htmlsi=4S9WXoDeDaTCXK_z

He is…

ANY germanium diode should work, to some extent, doesnt have to be russian, a common one was OA91, although no longer made, theres likely still many around