crystal radio: the first real free energy device

[gyulasun]

Hey Brian

....

Wonder if we made a huge coil. !6awg wire, etc.  Could there be more output?

Mags

Hi Mags,

Yes, I think you would get more output,  especially if you would use the coil as a multiturn loop antenna which would be tuned by a variable capacitor.  A multiturn loop like this from a random search: http://www.on4ceq.net/loop_80.jpg 

Gyula

[Brian516]

If you switch your scope input to a sensitive amplitude range, and you touch its direct hot input (no probe) with a small piece of bare wire you hold in your fingers, what can you see displayed? Of course this depends on the time base selection too, I mean the 1 or 5 millisecond per DIV, and I assume you will see a sine wave on the normal mains frequency 50 or 60 Hz you have. The amplitude of this signal will change as you touch anything nearby like the metal body of the scope with your other hand. If this is so, then this signal (your body picks up from the EM field of the house mains wireing) makes your audio amp pop and shut off, I think. It is also possible that your hand or body picks up some other unwanted local signals from your enviroment which is already able to drive the audio amplifier.

Yep, you are exactly correct.  When I tested myself on the scope, I was reading 60hz and +/- about 1.5V.  When I grounded myself, the signal stopped.  When I touched a variable capacitor that has a connection to the aerial, I was able to change the amplitude a little bit by adjusting the capacitor. When I touched the other variable cap that I have connected to the Amp HP in + 6pf condenser cap back to - HP connection, it instead made the sine wave all positive, from 0 up to about 1.5V.

IF you happen to have some Germanium transistors in your junk box (or in very old, at least 40-50 year old) discarded AM pocket radios, then you could test the base emitter diode of them as a diode, how they perform.

I don't have any of those just yet.

Also, you could test paralleling 2 or more 1N34A diodes (anodes to a common anode and cathodes to a common cathode) and hear how they perform.  You may try this parallel operation with the galena crystal and whisker too if you have more.

I'll try paralleling 1N34 diodes, and 1N60 diodes, but I don't have any more galena yet.  I'm currently bidding on some trying to catch a good deal.  I am probably going to order 2 grams of pure germanium to test also.

Maybe your variometer has too small inductance for the frequency your local AM station operates on.  At least each coil ought to have inductances above 100 uH at least or higher.

I'm able to pick up that one station just fine, but that's the only station I am able to get.  Maybe when their power output drops to 44Watts for the night I might get lucky and catch another station.
I don't think the inductance is an issue, it's the range that the variometer allows.  I built mine almost exactly to spec according to the plans at the bottom of the page from the link below.  The only difference between that setup and mine, is that I used SCH40 PVC pipes, outer is 3.5" and inner is 2.375".   
http://crystalradioclub.co.uk/g4wpw.htm

I found this link a very good experimental help on crystal radios, it is worth reading: http://www.bentongue.com/xtalset/xtalset.html    you can read on diode types and on the effect of giving some DC biasing to them and on several other topic important for reception.   

Addition:  this file includes good experimental findings on crystal receivers, their diodes tests etc: http://www.qrparci.org/wa0itp/chap4.pdf

Looks very interesting.  I will definitely give it a read.  I really don't know very much at all about radio waves, and learning calculations, good design ideas, and means of improvement are always great things, of course.

Hey Brian

If you dont mind me asking. Can you measure the resistance of your coils? Also, if you have a meter, measure the output?  The meter might lower the output being the meter a high impedance load.  Just curious.

Wonder if we made a huge coil. !6awg wire, etc.  Could there be more output?

Mags

Mags,

Check above for a link to the setup I built so you know pretty much what I am working with.  I will sketch up a diagram of the modifications I've made to it thus far and post it probably in the morning.
The resistance of the outer coil is .3ohm, and the inner is .4ohm, giving a total for the two at .7ohm.   I'll post some scope shots in the morning, and get into some detailed output measurements as well.   I assume you aren't talking about only a voltage reading, but some current readings as well.  I actually bought a couple CSRs with my last digikey order.... now I just need to learn how to use them.  .01ohm 5W and .1ohm 5W (both non-inductive Ohmite's).

Yes, I think you would get more output,  especially if you would use the coil as a multiturn loop antenna which would be tuned by a variable capacitor.  A multiturn loop like this from a random search: http://www.on4ceq.net/loop_80.jpg

Gyula

Gyula,

I mentioned before that I want to make an antenna or something with this 24awg solid silver wire that I have 40' of.   In your opinion, would that type of antenna be something worth using that for? or should I just make one out of copper and save the silver for something else?

Brian

[Brian516]

I figured out the issue where the galena was working better than the actual diodes, and it's all because of the crap radioshack binding posts I was using as my diode holder.  I placed the diode across my copper plating and it works great that way.  I'm even actually able to pick up more than just the one station, but that may be because they might have dropped down to 44Watts power for the night. I'll find out more on that tomorrow.    I'm going to replace my binding posts with drilled and tapped brass bolts with small brass bolts as the movable stud part, and hopefully that works close to as well as it would if they were copper.   

I guess that the lesson here is to make sure that the only materials that are used in any connections are copper or brass, and no nickel plated garbage like what RS is selling these days....

Also, I am getting 24mV and 24 microamps, and the nearest tower is broadcasting only 44watts at 1.2miles away.  No clear line of sight.

[scotty1]

Try adding a second diode the way I show mine on page two of the thread. I'm interested to see if it makes a difference.

[gyulasun]

...
I don't think the inductance is an issue, it's the range that the variometer allows.  I built mine almost exactly to spec according to the plans at the bottom of the page from the link below.  The only difference between that setup and mine, is that I used SCH40 PVC pipes, outer is 3.5" and inner is 2.375".   
http://crystalradioclub.co.uk/g4wpw.htm

Hi Brian,

Okay, that difference in the OD of the pipes practically increases a little the inductance of the coils so it is indeed no problem.

I mentioned before that I want to make an antenna or something with this 24awg solid silver wire that I have 40' of.   In your opinion, would that type of antenna be something worth using that for? or should I just make one out of copper and save the silver for something else?

I do not think you should use the silver wire for antenna wire purposes, you could save it for something else (when you need really high Q coils working in the several MHz range up to VHF.

When you have time to read through the hints in the different topics of this link I referred ( http://www.bentongue.com/xtalset/xtalset.html )  you will find that impedance matching is one "secret" for a good crystal set operation, besides diode selection and other aspects like dividing the total AM band (500 to 1700 kHz)  for several segments, etc.  For antenna size, basically the longer the better, though a 8-10 meter long piece of wire, insulated at its binding points and  together with a good ground, can give good results.  Alternatively, later on you may wish to build a multiturn loop antenna (with OD maybe 40-60 cm) and this coil would serve as the antenna and the resonant and tuned coil for the crystal set, the diode could connect to either a tap on the multiturn wire or to a second, coupling coil.
It is very good you found the Radio Shack's crappy product and stepped over it.

Gyula