there's a lot of it to learn

no sweat! ... I'm just beginning to realize what I've gotten into ... but I'm quite perseverant, and I'll take this step by step

When you resume this Thread, we will need you to help us find how far you're gotten and where you want to go next.

I'll do my work here, you can count on it

there was a lot wrong in your post #65

Yeah, I've just re-read your and Bahn's posts, and now I see how far off the mark I was... it seems that F.M. is an entirely new dimension compared to A.M. To me, it feels like the difference between visualizing 2D and 3D objects.

Got a ton of work to take care of today, but I'll be back tonight. Thanks again! ... and you too Nsa

 

I would try to help, but I'm obviously out-classed here.
I also have difficulty with this. "So, it's like the magnetic field around a metal magnet, but it wiggles, and the wiggling energy radiates. So a magnetic field decreases to zero in a few inches or a few meters. So why do radio waves travel, like, forever?"

I can imagine the energy being radiated off a dipole, and I've measured microvolts per meter on a receiving antenna, but how that energy gets to the moon and past doesn't seem like the field around a magnet to me! I don't know if the impedance of free space changes in Earth atmosphere, and I don't know how radio waves travel bazillions of miles in a vacuum. That's why I stay out of the RF Forum. I'm incompetent in this field.

Yeah, "vacuum" seems misleading. There is obviously light all over the place, going in all different directions, and gas molecules rather far apart, I think, (What would the wind drag be on a square meter moving at c/10?) bits of rock and stuff, but nothing like Earth atmosphere where you can have a compression wave...or am I wrong?

This just seems like the magical, "aether" like there is no mass to use to transfer energy, so it must be propagating irrelevant to physical mass.

OK. I can fire a laser into space, and the light travels just fine. I think radio frequency energy would do the same. It can even be focused with a parabolic antenna. Just it isn't wiggling any mass so it must be just radiating like light??? It is, in and of itself, traveling on its own energy?

Hi there,

At the risk of trying to 'educate' you a little here (chuckle) i can help a little.

There are various properties of the universe which just seem to exist because we often describe them in a loop of internally consistent statements rather than try to dig out the most fundamental concepts.
One of these properties of the universe is inertia. There are various ways to explain this, but how do we explain that something with some mass can travel forever through the emptiness of space with just one small push of the index finger, as long as it does not come near any other objects.

A similar situation comes up when we consider radio waves that travel through the emptiness of space, except here we have some other phenomena that help understand this a little better i think, where we can render a simple explanation, even though it might also be self reciprocating as above.

The simple answer is that space is a lossless three dimensional transmission line, where the speed of light is the determining factor, and that factor forces a set value for the elemental capacitance and inductance of this transmission line through the wave equation which basically arises out of Maxwells equations. There is no loss because there is nothing in that space that dissipates energy, because if there was, all or part of that radio wave would be changed into another form of energy and so we would loose part of that wave. Without that interference though, the elemental capacitances and inductances are both lossless so the wave continues indefinitely reduced in amplitude only by means of the distribution of energy, which still admits no complete and total loss of energy in any direction in the classical sense.

I hope this helped at least a little, but to investigate this more you may want to look into the Wave Equation and the Transmission Line Equations.