Pass the Test > Technician

My dumb questions

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Sacajawea:
OK, that didn't take long. I figure I better put these all in one place. Maybe my questions don't matter; maybe it's just my resistance to certain subject matter... sigh... but this is what stops me (right at the beginning) every time.

The books and other material tell you these things without explaining how it works; I recognize I don't know how it works -- and my brain freaks out until it solves those "mysteries".
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How can a radio wave travel at the speed of light? Wouldn't it travel at the speed of sound, instead? Doesn't it stop being sound at that higher rate of speed? [you were warned about the nature of the questions...]

What makes a signal change direction in an antenna -- and how does it break out of that cycle to the open air?

ghrit:
Sac, the only dumb question is the unasked one.

Radio waves are simply the same thing as light waves and travel at the same speed.  The only real difference is the energy contained in the photons that make up the waves.  Sound is a mechanical disturbance of the medium and is WAY slower, as well as being unable to travel in vacuum (like space.)  If they weren't different, we could not communicate with satellites in space, since there's no air to carry the sound.

So far as the antenna question goes, you can visualize it (tho' highly inaccurate) as the radio wave in the antenna has no place to go when it gets to the end, so it escapes by jumping off the side.  For now, that's the best visualization I can come up with.  As you go further into the theory, you should be able to get a grip on the reality of radiation off the antenna.

AD:
SAC

You are way over thinking. 

First question
Radio waves travel at the speed of light.

You are confusing the sound out put from a radio(speaker) which travels at the speed of sound with the electromagnetic portion of the spectrum.

Light, radio waves, xrays, microwaves are all part of the same spectrum
http://www2.lbl.gov/MicroWorlds/ALSTool/EMSpec/EMSpec2.html


All of these move at the speed of light.

The same way you can feel heat from a camp fire(radiant heat) or a stove, electromagnetic waves(radio) will radiate from an antenna when conditions are right: input to the antenna by the radio and the physical/electrical properties of the antenna.  The antenna needs to be the proper configuration(length for instance) for the radio waves to radiate from it like heat from a camp fire.

Clear as mud?

AD:
Here is a reference site at ARRL

http://www.arrl.org/ham-radio-license-manual

And

https://hamstudy.org

Sacajawea:
Thanks!!
It's not so much overthinking; it's that faced with a simple scientific statement I feel I have no context to assimilate it into. (It's not true; it's conditioning - long story). I know a lot about light, transmitted vs reflected and the color spectrum.

After a couple meltdowns with that much, I went & looked at the sample questions for that chapter - yeah, the info stuck despite the hysterics - and I could pretty much answer all those. If that's the biggest hurdle - in it's preposterous-ness - I'll be OK. I think I might do better with the online materials info-presentation. But I'll the AARL book another chance.

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