Crystal radio technology has been around for many years. This “bottle radio” take on a crystal radio requires no power source, operates on the power from radio waves, and receives signal from a long wire antenna. As radio stations slowly move away from the AM band, the “window of opportunity” to experience this remarkable technology is dwindling. On that note, the closer you are to an AM station or transmitter, the more likely you are to hear distinct radio waves with this project.
The “crystal” in question is contained inside a germanium diode, and is used to rectify the radio signal so that our ears can hear it. Since this project has no power source, the signal can be quite weak – crystal earphones are a fun way to hear low-amp signal (due to their sensitivity), or, alternatively, you could hook up a 9V mini-amplifier.
For more information on this battery-less technology check out this Wikipedia article.
David makes very good points – you’ll need to use some judgement when selecting your coat hangers – mine were bare metal but I’ve seen the enameled ones. I remember being apprehensive about sanding the coil surface, but it turns out to be easier than it looks. Using a substantial gauge wire and sandpaper 150 grit+ has minimal risk, I’ve made dozens of coils over the years without too many issues.
can you give us a tutorial about that.?
Hi Brian,
The diode between E/D is a germanium diode – you can see it being installed in the video, here: http://youtu.be/9VqVaFMQd2o?t=5m34s
The diode rectifies the incoming signal, essentially turning the alternating signal into a direct signal, so yes it is necessary! Note that silicon diodes won’t work in place of the NTE109, but other germanium diodes can be used depending on your incoming signal. Feel free to experiment!
Hi Ebel,
Did you make your tube coil radio yet?
cheers, Nick
I cannot access the RF amplifer circuit to built this project. I clicked on “here” and it would not open. Why? You need to fix the link.
I would also like to know how to build the RF amplifier, the link doesn’t work for me either. Please Help!
Does the color of the type effect performance? I am using the green color after the red got extremely tangled and construction is still underway, Thanks.
You can build a simple amp with a darlington transistor, two 150k resistors. Go to Techlib, here is the link: http://www.techlib.com/electronics/audioamps.html#class-a
Hi !Could anyone help me.I try to do this radio but it doesn’t work.
I think it’s antenna’s problem but the radio didn’t say how to do it.
i need help in doesnt work. i did everuthing as the video said, but still didnt work pleasee help
I used a 28 awg cable could that be?
help
binary options
Very good post. I am facing a few of these issues as well..
binary options
This post is truly inspiring. I like your post and everything you share with us is current and very informative, I want to bookmark the page so I can return here from you that you have done a fantastic job..
Im making this at the moment, one question.
How many twists with magnet wire do you need around the bottle?
Answer a.s.a.p. please.
Use all the wire on the spool – the kind they recommend. Fill the whole space of the fat end of the bottle.
http://www.amazon.com/b?_encoding=UTF8&site-redirect=&node=468642&tag=tabbooingcom-20&linkCode=ur2&camp=1789&creative=9325
Does this radio have FM and AM?
Pingback: 100 Summer Activities to do with the Kids | Houston Nanny
Pingback: Sensing Hot and Cold with Weekend Projects - Make: | Make:
Pingback: Cómo construir una radio con una botella de vidrio / EcoInventos.com
Pingback: Weekend Projects - Bottle Radio - Best Skills
Pingback: Eight for Each State - Wisconsin - Ed Snapshots
Pingback: This Day In 1910: The First Public Radio Broadcast was Transmitted #PublicRadioBroadcastingDay « Adafruit Industries – Makers, hackers, artists, designers and engineers!
Pingback: Weekend Projects – Bottle Radio | Login porn
Pingback: Cómo construir una radio con una botella de vidrio
Instead of a resistor I found the 300mh side of a transformer drove my crystal ear piece louder. I think any high inductor up to 1 henry should work down to 1300 uh.
This site was… how do you say it? Relevant!! Finally I have found something which helped me.
Thanks!
Send this to a friend