ฝัง
- เผยแพร่เมื่อ 12 มิ.ย. 2024
- This is my first attempt at a ferrite core crystal radio. It cost around $40 in new components I had to buy. The build went well. There might be some tricks worth copying. I won't recommend other people build it, it has low sensitivity and the selectivity does not matter because there's nothing to select!
MATERIALS
- Ferrite Rod 100x10mm, manganese zinc magnetic permeability 1K
- 2x hold down blocks
- 32 AWG wire 0.2032mm; Windings: 10/60/40 in the SAME DIRECTION
- Resistor 10k-40k ohms
- Variable cap: 0 to 400 pF or 0 to 500pf
- Variable cap mount
- Brass washers
- Stainless screws
- Crystal earphone
- 1N34a diode
3D Printed Ferrite bar holders www.thingiverse.com/thing:652...
3D Printed Mica Variable Capacitor Mount www.thingiverse.com/thing:652...
CHAPTERS
00:00 Introduction
00:15 Parts
01:38 Circuit diagram
04:03 Parts dimensions
04:52 Construction, ferrite rod wrapping
08:11 Main coil
09:00 Slider plan
10:03 Slider cores in place
11:49 Ferrite coils done
12:23 Board parts layout
14:17 Build it
15:39 Built & Fixes
18:00 On the scope
20:36 Conclusion - วิทยาศาสตร์และเทคโนโลยี
Hmm... I guess this is an edit of your first attempt, as opposed to a new video? I don't see MrDovie's (correct name?) post, where he commented on the ring termination on the coils. I inquired of him, in that regard, as to the nature of the problem. I see that you have made the correction, in this video. I am proud of you for sticking with it and I celebrate your success with you. I am sure you where driven by curiosity. That is a great character quality. It is also why your content is interesting. Thanks for sharing.
I deleted the original video because I don't want to give wrong information. The internet has too much of that without me adding to it. And one benefit of a youtube channel is I get to learn from others. I fixed the problem, then fixed the video and reposted it.
Nice device! I experimented (before the war in Ukraine) with passive MOSFET detector. I used a coil without a variable capacitor to achieve maximum quality factor. A gate was connected to "hot" wire (antenna). Source was connected to 1/4 part of coil. Drain was connected to RF blocking capacitor (that was grounded) and to an electrolytic capacitor (other wire of a capacitor was connected to 200 Ohms phones). The antenna was roughly 15meter (like an arrow - from two wires). The mosfet was BF998 with shorted gates. The much better results with selectivity was with two coupled LC circuits - the first connect direct to an antenna and ground, the second has a small capacitor (50-80pF). I used two coils with 25mm diameter, wire diameter - 0.3mm, step 0..5mm. I am sure - you will not be disappointing when try this circuit!
Sounds very interesting. I have seen a video on that, but have not tried it. Thanks for the information.
Sounds very interesting. I have seen a video on that, but have not tried it. Thanks for the information. The circuit in this video is unacceptable. Maybe too much resistance in the wire. I'm going to remake it with a different coil design.
@@tsbrownie I was disappointed in my childhood when I made a crystal radio with variable capacitor and small coil .Quality factor is essential for simple receivers.To achieve it we can use gap between windings (step) . And increase diameter of coil (2-3 times). There musn't be any variable capacitors! Good luck!
Sweet Build, Clean And Perfect, When I Made ferrite Antennas I Found That 10ml Syringes Are perfect for the comercial ferrite sizes and they slide in and outt, make sure you add rubber band on itt and it will slide it on will, can show you some examples if You want, it works perfectly good, i have even made variable capacitor with diferent syringes, at first i coiled up a copper wire on to one syringe and tthe other that slides in and out, but its not needed, just use copper tape or in best case, copper sheets and solder them into place around the syringes, the 50ml serynge outside will be good housing for 20ml syringe with the all coil added, that will make perfect variable resistor, for coolness You can put it inside in a casing and put pullies tthat will put it in or out more or less :)
Thanks for your comment. Interesting about the syringe.
@@tsbrownie I did edit it, but strange because if you where real human you would know that the real germanium diodes are faked all over nowdays and if someone would say that they have it you would not threaten them people like you threatened Me just now. Weird thing you did, what is the rrleason for that?
Like, i dont see reasoning, i run many discord servers and facebook groups about eletronics and radios and i would never ever do such thing what You did, i mean, if someone would scam people then he gets ban, yes, otherwise, do what You want in my grouos, sell, buy, just be respectfull to others.
You say my ADD, It is not an add, i just said that i have germanium diodes for sale, so, if a guy who works in mercedes dealership watches your videos and he just throws in that he sells mercrdeses, you would do the same thing to him as you did for Me? I really dont think so.
I did not say where can buy them, i just wrote that i happen to sell them, i did not add ANY INFORMATION whrre or how ;D i just said it for sake of it and you label thatnas an ad and say to me that you will delete my channel, you know that things like these can destroy reputation of you because i have facebook group that have almost 100k members, imagine if i put out all of this info? Younwould be witchhunted down for it.
Im mot saying il do suxh things, im a ok dude, but you might see from side how it looks what you did, i know you are small youtuber and stuff and you dint rrlecognise danger, im giving you legit MILLION DOLAR LESSONS IN THIS COMMENT. You can Man up or You can Delete All of these comments and axts like you did not say what you say, but youneat what you plant or how that saying was ;D
Have a great day and thunk more, think more of what are you outputing and dont put ferrite beads on people who watxh your videos and are the ones who are creating who you are on this platform, im on youtube sinxe 2007 and i have tens of channels and half of them are pretty big and i know ins and outs on what to do to not end yourself on this platform. Like i said, this comment is worth millions for some who actually can digest it. 73
Great, I once ordered ferrite rods from China, and they came in 100 or so pieces. I glued some and used the short pieces for Joule Thieves.
Thanks for your help. I was getting ready to surrender. I just knew it should work and tested everything I could test including running a signal and tracing it with my oscilloscope to various points and found the signal was not moving along the ferrite. I also tested the ferrite to see if it would work in the AM band. Everything checked. It took about 1 minute for what you said to sink in. Then I went to work and minutes later it was fixed. I'm getting ready to repurpose these parts into a radio style that works better (at least with an air core, let's see how that same design works with ferrite. I am just starting on the equivalent coil calculations.)
I was really amazed that shorting those turns would kill nearly all the signal. You would think some of it would get through.@@tsbrownie
I am amazed too. Never would have though it and still trying to understand why.@@mrdovie47
@@mrdovie47 I thought of a transformer where the windings have a dead short. Besides also catching fire, the output drops to zero. As soon as I made that connection, what you said hit home. All of the power is going to take the lowest resistance path, and that's the short. In my case SIX shorts, each one at the beginning and end of each coil. I could not have done a better job at sabotaging the electromagnetic field if I had worked at it!
Wow, I just realized, what you made was a Guard Ring! Its a great way to keep noise from getting into sensitive circuits.@@tsbrownie
I built one you posted years ago. This one looks like another project... thanks for your content.
Cool. Thanks for letting me know. Which did you build, the single wiper? I can't recommend building this one. It has low sensitivity (too quiet). I'm working on a video ranking the radios I've built for skill required, cost, best listening, etc.
@@tsbrownie I built the 170 turn single wiper no capacitor version. Just coil, resistor, and diode. 20 awg wire.
@@AtomkeySinclair Good choice. That radio is really hard to beat for ease of construction and sensitivity. My all time favorite as of today is the dual wiper one. It's still relatively easy to build, has really good sensitivity, and adds better selectivity.
@@tsbrownie Sorry to bug... I've built another of the same I previously mentioned. Now I'm hooked. I think the next one should have a variable plate capacitor - I see a few on Amazon but they vary in farad... Do you have a video that uses one of these? Thanks for your content and time.
@@AtomkeySinclair No problem. This one is the cheapest/easiest and I like it most: th-cam.com/video/0AvTO588SyU/w-d-xo.html
This one is a little less sensitive and costs significantly more, but works OK:
th-cam.com/video/VJ80Nm9KSkE/w-d-xo.html
Your way of terminating the coils on the rod looks like a shorted turn, this will probably rob some energy from the circuit or lower the Q of the coil. I've done similar but used foil based copper tape stuck to the paper and soldered the coil ends to that. If you're quick with the iron you don't burn the paper or cause the adhesive to let go.
I had to go back and cut them because indeed they were shorted windings.
@@tsbrownie did it make a difference?
@DavidMills_Physicist Ok yeah. It went from not even a whisper to working.
@@tsbrownie I'm glad I found your channel - a dear friend of mine was very into making crystal radios, he died last year and left me all his radio parts. I built a few crystal radios as a kid, but there's only really one strong station around here, and selectivity was never good so it got a bit boring to listen to.
@DavidMills_Physicist Sorry for your loss. My Elmer passed a few years back. He really liked these and antennas.
It was a good and useful experiment. It showed other experimenters what not to do. If I can overcome my extreme laziness, I plan to make some more videos about crystal radio experiments. I made one showing that you can use the 1N5711 diode to make a fairly good crystal radio. They cost a lot less than the 1N34.
Yes, indeed. I thought though that the 1N5711 type diodes had a rather non-linear response, therefore, a rather distorted signal -- lots of total harmonic distortion.
@@franzliszt3195 Getting the loading resistor right makes the 1N5711 work OK. In my setup, the 2K value worked best. To my ear, it sounded no worse than the 1N34. I have two real 1N34A diodes and one works a lot better than the other when there is no load resistor.
@@kensmith5694 how is the loading resistor placed for n circuit? In series or parallel with diode. I guess in series.
@@franzliszt3195 At 15:36 in the video you will see a resistor in parallel with the earphone. The Brown, Black, Orange stripes make it a 10K. This is the one I call the loading resistor.
@@kensmith5694 god dang it, I have to get off my but and try it.
Is it necessary to wind the coils in same direction?. Only the first coil is having one end grounded. Others are floating. For the last coil, it hardly matters which half of the wave is rectified.
There's the option to ground the other circuits and if they are not wound in the same direction that option goes away.
Very interesting point. The electrons coming out one coil will collide with electrons coming out the oppostely wound coil, thus no electrons will move.@@tsbrownie
I just order some of those Fahnestock spring wire tie down clips. Maybe I'll order some
more stuff, later on. I would like to build one.
If you want to build a crystal radio, I would not recommend this one. The wiper radios have much better sensitivity.
Did you say there's a hole in your ferrite rod? I wonder what effect sliding a magnetic material such as a nail down the core would have? Aren't those tuning slugs on transistor radios made with an adjustable iron core?
No it's solid.
I don't think it makes a difference, but could be wrong. I think the magnetic field will take the path of least 'resistance'.
@@franzliszt3195 It must make some difference or there would be no difference in this radio with coils wound over a wooden dowel compared to it's ferrite rod.
I mentioned "magnetic" because "ferrite" is an iron based material that's embedded in ceramic.
Another interesting test would be to slide a piece of iron pipe into the coil of a crystal radio with a coil wound on a paper or plastic tube to see if it has any effect on performance good or bad.
What you suggest is easy enough tested. However, I'm an arm chair engineer -- to lazy to do anything myself.@@tenlittleindians
Strange that it doesn't work? Then something must be wrong!
windings wrapped the wrong way?
wrong ferite?
is there anything left to experiment?
(There must be a reason why it doesn't work well!
Maybe next time a SW version?
Healthy and Friendly Greetings from the Netherlands!
Rob
I'm going to redo it to try to make it louder. I used to go to NL on business. Nice country!
How are you not coming to the Netherlands anymore?
I live in the Rotterdam area!
(I am a radio amateur and also a radio pirate on all kinds of bands)🏴☠
.
well, don't put it aside, that's such a shame!
I'm glad you're trying to figure out what's wrong.
(I'm curious now too! What makes the RX insensitive?)
Healthy and Friendly Greetings from here!
Rob.
If you take an ohm meter and measure the resistance of the ferrite and its really high, I would think the paper between the wire and ferrite would be unnecessary; anyway the wire is varnished so its insulated from the ferrite. The gap between the wire and ferrite should cause loss, I guess.
I think the concern is that the ferrite is extremely abrasive (think of a finger nail file) and that vibration will scrape off the enamel.
This may sound really stupid, but as the magnetic field has to go all the way around then putting some ferrite on the OUTSIDE would give an easier path for the magnetic field to go on the outside. I would think it might double your signal strength; really I can not think of a reason it should not at least help.
If you look at high frequency coils, they are wrapped around a (tiny) rod that is inside a ferrite "can". So it must work because they are doing that!
Can i use bigger diameter of copper wire?
You have to do the math. I don't recommend this radio, it has poor sensitivity.
@@tsbrownie what's the best kind to build?
@@honeybadger2371 I did a video comparing radios on how well they work verses how hard/expensive they are to build. So you can choose which is best for you.
th-cam.com/video/f54BfiRNH9I/w-d-xo.html