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My thoughts on Cable design.

jsrtheta

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Just to inform you all, my writing skills are zero, I blame my dyslexia and autism for it but it got much worse since the stroke I had , so please forgive me, and cringe less.

I HAVE NOW REMOVED THE UN-READABLE GARBAGE.
Please remove me from this forum Amirm thank you.

No need to explain.

You see nothing but friends here.
 

pma

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Before the thread may get closed I would like to say that it was a good and interesting topic. Please let me continue, as I did a lot of similar work as Colin posted, in my research institute years and also had several publications.

To measure H and B we may use a simple loop probe and the induced voltage will be proportional to H and B as per Fig. 2.

loop_probe.JPG

Fig.1. Simple loop probe

loop_voltage.png

Fig.2. Calculation of induced voltage (reprinted from my article for Slaboproudy Obzor)

Now let's make a simple test. The probe from Fig.1 is used to measure magnetic field radiated from the
1) magnetically shielded power cord
2) unshielded power cord
We will measure loop probe voltage with power cord connected to 230Vac and
a) unloaded
b) loaded with 1500W, resistor load

1a - magnetically shielded cord no load
loopprobe_magshieldcord_noload.png


1b - magnetically shielded cord 1500W
loopprobe_magshieldcord_1500W.png


2a -unshielded cord no load
loopprobe_unshieldcord_noload.png


2b -unshielded cord 1500W
loopprobe_unshieldcord_1500W.png


One may use his own head to calculate radiated H and B from 2b plot and 4cm probe diameter as a homework.

@amirm , before you potentially delete this thread would you please move my post to a new thread. Thank you.
 
OP
Colin James Wonfor

Colin James Wonfor

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No do not move it very interesting.
Did the test cable have a magnetic covering as well. A iron pipe would do. What material was it ?? I tried NeO compound it was the best but I also found it got magnetized then became useless.
Tried Fe,Ni,Co but the best result was odd it was a SrNeCo mix it proved to be best. Then I tried due to cost just SrO compound in the mix the surprise was it was not magnetic i.e. a magnet did not stick but the rejection was very interesting in the BW 10 -500Hz and a peak at 5Ghz the figures are long gone now. The mix was only 5% by weight with bog standard recycled PVC (shit grey colour).
At Norwich Uni I tried with help from Doctor Salmon, liquid N and He. He was the best but the plant was as big as bus. Using 99.999% etc pure Cu.
 

pma

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Nice to see you did not give up, Colin.

The tested shielded cable is flexible, as yours. It is a professional product. More later.

I did read and downloaded your PDF that was attached in post #1. It think you might consider re-posting, as it will be interesting at least to some members, if not for the majority. Please overlook the aggressive posts, it is just a forum.
 

Thomas savage

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No do not move it very interesting.
Did the test cable have a magnetic covering as well. A iron pipe would do. What material was it ?? I tried NeO compound it was the best but I also found it got magnetized then became useless.
Tried Fe,Ni,Co but the best result was odd it was a SrNeCo mix it proved to be best. Then I tried due to cost just SrO compound in the mix the surprise was it was not magnetic i.e. a magnet did not stick but the rejection was very interesting in the BW 10 -500Hz and a peak at 5Ghz the figures are long gone now. The mix was only 5% by weight with bog standard recycled PVC (shit grey colour).
At Norwich Uni I tried with help from Doctor Salmon, liquid N and He. He was the best but the plant was as big as bus. Using 99.999% etc pure Cu.
Great to see your still here Colin!
 

audio2design

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High frequency signals that require co-ax are typically narrow band, and hence can be filtered to remove magnetic interference the odd time it occurs.


Low frequency signals can use twisted pair which is very effective at negating magnetic interference, not to mention putting a few inches of spacing in.

@pma, you say what the load is on the power cord, but what is the loading on the loop antenna?
 

thunderchicken

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I think like most people, my cables don't run anywhere near magnetic sources, so nothing to shield against. And even if cables happen to get near a magnetic source, that's why we have arms/hands to move said cables. ;)
But... your speaker is literally full of big ass magnets.
 

MakeMineVinyl

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But... your speaker is literally full of big ass magnets.
But permanent magnets are DC, not the AC type interference which would be problematic. And regardless, the leakage from the magnetic pots on speakers is not all that great.
 
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Colin James Wonfor

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Yep sorry guy's still alive and questioning all things as normal. I do believe out teacher just teach what they learnt and never questions on the basic question WHY? I am aware mum if your reading this as a kid it was my favourite word along with "actuality " just for my cousin Les.
My dad was a writer/engineer and he loved words, but the sad thing is he had 5 kids and 2 adopted kids and 3 of us are dyslexic .
He did a few plays for the BBC I see if I can find them.

Any how , how do you think electron move in a wire conducting AC, not forgetting there charge or if in rotation the reaction of central petal force applied to the mass, and the effect of higher frequencies on there change of direction. ?

And not how this idiot thinks they move:-
 

ZolaIII

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I personally think Graphite - plastic compounds are the best for magnetic shielding (cost, characteristics, flexibility, waight). I think they will have a great future regarding cases and culling across many industrial applications.
Best regards and keep it up mate!
 
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Colin James Wonfor

Colin James Wonfor

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Zola, Very interesting article, but I think the terms are wrong, EMC OK but I am doing that but also magnetic interference rejection as in a magnet field or coupling. Normally done with either a tube of steel/iron or another magnetic metal based compound, I have discovered a way to use a non metal based compound to do the same job and be flexible. OK the molecule is massive but bonds well to PVC and PTFE a odd result. We had lots of mishaps including Nitric Acid burns and some tummy trouble when I got some dust on my Applewood Cheese sandwich. But once formed at about 200C no problem at all.
NO I AM TELLING WHAT IS IN THE COMPOUND BUT IT COST £12K/1kg not cheap. And the extrusion tool was made from steel but it died now made from ceramic evil stuff the cable is to work with but simple.
 

ZolaIII

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Graphite granulate is relatively cheap (compared to copper) how you mix it and into what is another pair of slippers, depending mostly of what you want to do with it. That will also dictate a price. For example there are a lot of non electric conducting thermal pastes with graphite.
 

audio2design

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I too would like to know the load on the antennae. What happens when its loaded with an active buffer as most IC are in operation.
I was thinking more like the likely loading would be out of minimum the output buffer impedance of a DAC, preamp, etc. or may a few K at most and likely less.
 

KSTR

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Cbdb2

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But the differences are below 1khz, almost entirely at 50hz as expected for a constant current. It would be interesting to see how much that would change if the current was pulsed like the current into many power amps at higher power.
 
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