Does the slight permeability difference between air and vacuum around a conductor make an audible difference?
Theoretically shouldn’t we have the best preserved EM transmission if all cabling was vacuum encased with suitable radii?
I would think air impedes EM more than what the permeability constant tells us. Just a belief.
Hi Arenith,
Getting to minutia, the effects of a ground around a wire (braid over a coaxial cable) are a LOG function that changes the capacitance. It isn’t the “same” all the time or we could not make different impedance cables.
Air is good because we can have a low capacitance (total plate value) wit the least material used. Also, plastic dielectric act like R, L and C and dissipation factor and loss tangents describe how a dielectric iasn’t a perfect time based solution. Air is the best we have.
The EM wave’s Vp depends on the Vp in the exact spot it is in at any point in time. Changes in the dielectric from the wire surface to the inside of the braid aren’t always the same. The EM wave can’t be “there” at the same time or something really amazing is happening. The EM field has to be created and destroyed and that takes time. A semi-solid material over a wire compared to a step dielectric air filled tube around a wire will be different from an EM wave perspective to some SMALL degree.
Be aware this stuff is happening at percents of the speed of light in a vacuum or the dielectric so it is still FAST. We know plenty based on the dielectric constant of perfect air (1 or 100%) and other stuff worse than that. It is how we calculate the capacitance! I have charts that show the capacitance to the dielectric constant changes.
And no, a vacuum is BAD for making a really good cable. It pulls in outside air and contaminants through eventual leaks. We can PRESSURIZE the cable with nitrogen or a known gas to push out stuff trying to get in. Hard line uses this tech all the time so it is hardly a new idea. GOOGLE the tech, pretty cool.
Best,
Galen
Does nitrogen, or really anything less impermeable than vacuum not cause the EM wave to have to deal with hitting all those atoms and diffracting ever so slightly? Can I not relate the wave to how light travels in differing mediums, as in having to be absorbed-emitted with all those virtual-baryonic antipairs acting as mediators etc? With the EM wave we are partly dealing with virtual photons that are “orthogonal” to the electric field, is this through virtual photon polarity? Do the “photons” we’re dealing with not care about hitting electron clouds all the time, with the mandatory all-the-time energy conservation interactions happening? No diffraction? Surplus energy transfer jumble? Is it not even measurable?
Or is it rather that we utilize the given diffraction for ex. nitrogen since it stays the same throughout?
I must be thinking of the EM wave wrong.
Does the non-zero permeability of the vacuum arise from the all-encompassing “virtual” particle shower impeding the field?
What’s happening in these mediums…!?
Remember the basics…the medium, any medium, is acting like the dielectric. We can measure the dielectric constant of various material and the word “virtual” is just that. It says something is “almost” but not exactly the same; Nitrogen is virtually a vacuum.
I’m not sure the accuracy and STD deviation of dielectric tests near a vacuum so you got me there. Is the measurement accurate or hidden in the error of the test?
I do understand your idea, any wave that is EM in nature must interact with the medium it is in. And yes, the use of better and better dielectric pretty much proves that to be the case.
The medium the EM field is in absorbs and dissipates the energy in the EM fields hence the words dissipation factor and loss Tangent (a value in the dissipation factor).
I would say once past dry air or VERY high frequencies there are better improvements that could be made. Geometries that cancel EM fields to where we don’t have to worry as much about all that stuf! This shows up in inductance values. Can the EM field be easily created and destroyed in time? It doesn’t change on its own. The energy has to be created and once created it has to be removed.
Inductance just gives you an idea how easy a current can be changed in time.
Curiously pure electric fields (static electricity) or magnetic fields (bar magnets) are kind of cool to play with as they are examples of the extreme isolation of an EM fields two components; electric and magnetic fields at ninety degrees to one another. The are “virtually” separated in pure static or pure magnetic fields.
Each can stay around forever until something interacts with the field (moisture in the air bleeds off static) or randomly re-aligns the atoms in a magnet (heat does it). So we see the relationship you are pointing out. If an EM field is BOTH a B and E field, can we mitigate each one to virtually “zero” change as the composite EM wave moves along.
So we know we need to address BOTH attributes and what interacts with each one. The problem gets harder!
Best,
Galen
The idea of pulling a vacuum in a coaxial cable makes my head hurt. It’s a challenge in my business (aerospace flight hardware) to pull and maintain a vacuum in a chamber we use for testing even with an ion pump. Evacuating a cable for a vacuum that would hold long term. Not a chance.
Let’s just use a diode vacuum tube as a cable. If it’s a quality constructed tube would its transfer function rival copper cable?