                                  T H E

                               Z E P H Y R

                      __     M A G A Z I N E
                     {__]++++++++++++++++++++++++++[]
                     Issue #44                8-16-87

                A weekly electronic magazine for users of
                            THE ZEPHYR II BBS
                        (Mesa, AZ - 602-894-6526)
                    owned and operated by T. H. Smith

                        Editor - Gene B. Williams

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                                (c) 1987

    THIS ISSUE:

       Over the last week several things have come up on the
    public board. I figured, why not turn some of the answers
    into a Zephyr Magazine article.
       There was the question of sound versus radio and light.
    That leads into the relationships and characteristics. That
    brought us to a beginning discussion on light speed and
    relativity.
       The issue is going to ramble a bit, but it's all connected.

                  SOUND, LIGHT, ANTENNAS AND RELATIVITY

       It's not that difficult to understand, really.
       Right off, you have to know that sound and electromagnetic
    energy are two completely different things. It has nothing
    to do with frequency.
       To exaggerate, a particular magazine comes once each month.
    A newspaper comes once each day. The newspaper has a higher
    frequency. But even if you keep getting something more often -
    it's frequency increases - it's still printed matter. It
    doesn't suddenly become something different.
       Now think of the speed of sound. A 20 Hz signal moves at
    the same rate as a 20,000 Hz signal which moves at the same
    rate of a 200,000 Hz signal (assuming that the media is the
    same).
       That speed is somewhere around 1100 feet per second, depending
    on what the sound is traveling through. It's faster in a solid
    than in air, for example. It also varies with humidity, temperature,
    pressure, etc., but that variance is never by a whole lot.
       Light books along at roughly 186,000 miles per second. This
    also varies. It slows slightly when traveling through a more
    dense media, and can be slowed or bent with a magnetic field.
    But again, the variance is negligible.

       Your ears begin working at about 20 Hz. You hear a deep
    bass. Below this, the sound is still there, but your ears
    can't detect it. As the frequency goes up, so does the tone,
    until somewhere around 20,000 Hz you can't hear it. (That
    range varies from person to person, sex to sex, and age to
    age, by the way. A 16-year-old girl might be capable of hearing
    that entire range, while a 37-year-old fart like me with ear
    damage will be lucky to pick up a range of 100 Hz to 15,000.)
       The speed remains the same throughout.
       Say there is a guy with a guitar several hundred feet away
    from you. Better yet, say he's 1100 feet away and has a big
    amplifier. He twangs across an entire chord. From your spot
    you'll see his hand move across the strings, and one second
    later you'll hear the chord.
       You'll hear all of it, all at the same time. It won't be
    like hearing the higher notes first, then the lower notes. All
    the tones reach your ears at the same time because they all
    travel at the same speed. The higher tones - higher frequencies
    aren't moving faster. They're just higher in frequency.
       The same is true of light and radio waves (which aren't waves,
    by the way, but that's another subject). Frequency has nothing
    to do with speed.
       So, you turn the knob on your fancy sound generator and keep
    increasing the frequency. At 20,000 Hz you can't hear it any
    longer. Your dog can, but you can't. At 40,000 Hz even the dog
    won't be able to hear it. You're in the ultrasonic range.
       Nothing magical has happened. It's just that your ears can
    no longer detect the sound. It hasn't increased in speed - just
    in frequency. Keep increasing the frequency as far as you
    like and it will still be the same.
       It travels along at about 1100 feet per second at 20 Hz, and
    at 1100 feet per second at 20,000 Hz. There is no point - magical
    or otherwise - where that sound suddenly speeds up from that
    1100 fps to 186,000 miles per second.
       Sound requires a physical medium. It works by compression
    and rarifaction, sorta like /// / /  /  / ////// /  /  / ////;
    kinda like clapping your hands. Without a physical medium to
    compress, sound won't go anywhere.
       Take a best speaker in the world and take it into space - a
    dead vacuum. Now feed it a signal through a 1000 watt amplifier.
    With your ear just an inch from the speaker, you still won't
    hear anything. Give it 100,000 watts and you still won't hear
    anything. No medium of travel, so no sound. (Of course, if you
    try the experiment you won't be around to describe the results.
    You need air as much as sound does.)

       Electromagnetic waves don't need a medium. In a sense, they
    are their own medium.
       To date, no one has come up with a 100% valid explanation
    for electromagnetic waves. They're not waves, but act as though
    they are at times. At other times they act like physical
    particles. They exist - yet they don't.
       The present description involves bundles of energy - quantums -
    with no physical existence. This allows them to fit in with the
    theories of relativity and also serves to accurately and
    mathematically describe what is otherwise a contradiction.
       As with sound, electromagnetic waves can be of virtually any
    frequency. The frequency has nothing to do with the speed. That's
    more or less a constant (depending on conditions).
       Divisions in the spectrum are based on characteristics, uses,
    and convenience. Microwaves are radio waves, but of a higher
    frequency, with some different characteristics and different
    uses. Radar is a microwave, which is a radio wave. Go just a
    touch higher and you have light, including the narrow band of
    the visible spectrum.
       At the bottom is infrared. You can't see it, but the
    characteristics of light are all there. Then comes red and
    on up through the visible spectrum to violet, then out of
    the visible range again and into ultraviolet. It's still
    light.

       Subsonics, like all sound, can set up a vibration in objects
    that are struck by the sound waves. At certain frequencies and
    at sufficient power, the rough vibrations can cause physical
    objects to crumble. Subsonics have been used experimentally as
    a destructive force.
       Ultrasonics also cause a vibration. Brittle objects can be
    made to shatter - right out of a Memorex commercial, huh? The
    high rate of vibration, with sufficient power, can cause the
    object to heat. This is somewhat like the action of a microwave
    oven, but not really. A more common use of ultrasonics is as
    a means of cleaning things such as jewelry. The jewelry gets
    vibrated, and the dirt is almost literally "shaken off" (although
    usually some kind of cleaning fluid is used to help the process
    so that not as much power is needed, which in turn reduces the
    risk of damage to the item being cleaned).
       Then there's resonance.
       Set up a hollow box with a tuning fork mounted on top. Aim
    the opening of the box toward an identical box with an identical
    tuning fork. Strike the first tuning fork. It will set up
    sound vibrations which resonate inside the first box, move across
    to the second, which also resonates, which causes a vibration
    that in turn makes the second tuning fork ring.
       Physical objects, solid or hollow, have characteristic
    resonant ranges. That again is how they shatter the glass in
    those Memorex commercials.
       Rub your finger around the top of a fine quality glass. The
    glass will ring with its resonant frequency. The glass is
    physically vibrating to make that sound. If you induce that
    frequency into the glass from an outside source of sufficient
    strength, the glass again will vibrate. If it vibrates strongly
    enough, it will break.

       What confuses some people is that those same things are found
    in electromagnetic waves. Different frequencies have different
    physical effects; and there is resonance. But, the WAY it
    happens is quite different. The names used to describe the effects
    are the same simply because the effects are much the same.
       In energy waves there is a relationship between frequency and
    wavelength. Since speed is a constant (under the same conditions),
    one frequency moves at exactly the same speed as signals of any
    other frequency.
       Electromagnetic waves appear as sine waves - like smooth and
    even waves on the water.

         .  		.a .     	    . b.
     	.	      .	     .	 	  .	 .
    --------------------.----------c--------.----------d---------.-----
    	   .      .             .      .	     .      .
    	     .  .		  .e .                 .f .

       Well, something like that.
       Between a and b, between c and d, between e and f - that's
    one cycle. The number of cycles per second is the frequency,
    measured in hertz.
       The physical distance covered by one cycle is the wavelength.
       Move your hand up and down as you swing your arm from left to
    right. In other words, make a sine wave in the air. The distance
    between when you hand reaches the top once and reaches the top
    again is the wavelength.
       Now move your hand up and down more rapidly, while keeping
    the speed of your arm motion the same. You'll see that the
    wavelength gets shorter.

         .  	.a     	    .b		. .
           .      .    . 	  .    .       .   .        .
    -------------.------c----.------d-----.-----.------.
            .   .        .  . 	 .   .       .    .
             . .	      .e          .f           . .

       So, as frequency goes up, wavelength goes down in an inversely
    proportionate ratio. Speed remains constant and a part of the
    whole formula.

       Wavelength = speed of electromagnetic energy/frequency,

       or more simply

       Wavelength = c/f

       By using this formula, you can design an antenna for any
    given frequency. The "c" is a constant - 186,000 or 300,000,
    depending on whether you're using the English or the metric
    system.
       To successfully use the English version, you have to convert
    the miles into feet. Lots of fun! The metric version is easier.

       Say you want to build an antenna for picking up a radio station
    that broadcasts on 700 KHz (700,000 cycles per second). The
    antenna is built around the wavelength because of electromagnetic
    resonance.

       Wavelength = 300,000,000 meters / 700,000 cps = 428.6 meters
    (about 1400 feet)

       The wavelength of KZZP (104.7 MHz on your dial) comes out as:

       W = 300,000,000 / 104,700,000 = 2.9 meters
    (a little over 9 feet)

       The wavelength of a satellite channel on 4.7 GHZ comes out as:

       W = 300,000,000 / 4,700,000,000 = .064 meters = 6.4 centimeters
    (roughly 2 1/4 inches)

       The basic antenna is a halfwave dipole, which means that the
    total antenna is 1/2 the total wavelength, with that antenna being
    divided into two equal parts.
       Like this (sorta):

    ________________________________  ______________________________
                                   / /

       The whole thing is 1/2 of a wavelength, with each leg being
    1/4 of a wavelength.
       So, a simple dipole for 700 KHz would be 214.3 meters long,
    with each quarter-wave leg being 107.15 meters long.
       The dipole for KZZP would be 1.45 meters long, with the legs
    each being .725 meters in length.
       That satellite dipole antenna for 4.7 GHz would be 3.2 cm
    overall, and 1.6 cm per leg.

       One side of the antenna serves as a positive leg, while the
    other works as a ground. One leg *can* be a literal ground, leaving
    the quarter-wave. Quite a few antennas are built around this
    principle. When you see a "whip" antenna on a car, you can bet
    that it's something like this, with the car itself acting as the
    ground side. You can also estimate the frequency by looking at
    the length of the antenna you can see.
       From there it starts getting complicated. For example, there
    are 1/4 wave antennas. There are also 1/8 wave, 5/8ths wave,
    and antennas that are electrically "loaded" with resonant
    combinations of coils and capacitors that make the radio transmitter
    or receiver "think" it has a resonant antenna out there.
       Especially with higher frequencies, even the material used
    to build the antenna comes into play. Different materials conduct
    electricity differently. Copper is more efficient than aluminum,
    for example. It conducts better. Gold is better yet - although
    you're unlikely to see *anyone* make an antenna out of gold. (Too
    expensive and too soft.)
       For better efficiency, directors and reflectors can be added,
    thus creating a "beam" antenna. Or you can "phase" several antennas
    together.
       Then there's the standing wave ratio - SWR - of an antenna.
    Because of the positive/negative nature of electricity, and the
    nature of alternating current, the signal is going out and coming
    in (reflected) at the same time. This creates an electrical
    standing wave on the antenna.
       The prime would be a ratio of 1:1 - equal in both directions.
    The higher the ratio, the less efficient the antenna. A SWR of
    1:3 is okay but not very good. A SWR of 1:100 or 1:1000 means
    that you may not be able to pick up very much signal.
       It's worse when it comes to transmission. A high SWR for a
    receiver just means that you won't pick up as much. A high SWR
    to a transmitter means that the transmitter has to work harder to
    force the signal out. It can even mean that the transmitter will
    burn out - and possibly the antenna - or its parts - as well.
       Even the cable comes into play. Shielded or not, it's still
    conductive wiring and plays an active part in the overall system.

       What it comes down to is that the basics are simple, but the
    details require a LOT of time and research. You won't pick them
    up from a single short article.

       And finally there is the speed of light and relativity.
       Same thing. The basics are pretty easy. To get deeper into
    it requires some heavy study and a LOT of time.
       According to the theory, as physical matter increases in
    speed, it becomes physically smaller while also becoming
    physically more massive. (Meanwhile, relative time for that
    object slows down.)
       Relative to itself, nothing has changed. If you're on a
    mile long spaceship zooming along at near the speed of light,
    your ship (and you) will have shrunk in size while it has
    increased in mass. To you on board, everything is exactly the
    same.
       The increase in mass is very real, and has been measured in
    the laboratory. Same for the decrease in size and the decrease
    in relative time.
       It takes a certain amount of energy to accelerate an object
    of given mass to a given speed. It will take more energy to
    accelerate a more massive object.
       As the object approaches the speed of light, its mass
    approaches infinity, which means that more and more energy is
    needed for further acceleration. It eventually reaches a point,
    just short of the speed of light, where the mass is so close
    to being infinitely large that an infinitely large force is
    needed to push it faster. To actually REACH light speed, where
    the mass becomes infinite, an infinite amount of energy is
    needed.
       That's an over simplification but you see the problem.
       The only way to travel at light speed is to find a way to
    get the physical object to not be a physical object. That's
    what stimulated the idea of converting something physical into
    pure energy, transmitting that energy, and then reassembling
    it on the other end.
       We're a long LONG way from something like that, if we ever
    discover how to do it (other than in a special effects
    department). Think of some of the problems involved. Converting
    mass to energy is already possible. Convert less than 1% of
    mass into energy and you've got . . . an atomic bomb. To
    convert all the mass you're facing the e=mc2 formula, which
    shows that if you could convert a paper clip totally into
    energy, you'd have enough to power all of Phoenix for some
    time to come.
       Imagine the energy that has to be controlled in the conversion
    of a 200 pound man - or a 200,000 ton ship if you want life
    support to go along with you.
       All that energy has to be controlled. So for a moment think
    of the chamber that would be needed to hold in and control
    all the force of an atomic bomb, when just a tiny fraction of
    about a pound of mass is converted.
       And even if we do overcome all of that, it won't do all
    that much good for space exploration.
       First, there would still be the time to get the receiving
    end of the device at the target. Without the receiver, the
    problem of transmitting and reassembling something physical
    becomes even more difficult. And of course, without a
    transmitter, you're stuck anyway. You can't get back.
       And even without a receiving station, there is time. The
    speed of energy might seem fast, but it's a snail's crawl
    in space. The nearest star system outside our own is more
    than 4 years away at the speed of light. There are only a
    handful of star systems within 100 years of earth even if
    you're travelling at the speed of light.
       100 years there - 100 years to get back (if you can). To
    cross just our relatively insignificant galaxy would take
    100,000 years at the speed of light.
       So, you start with a virtually impossible assumption and
    end up with an absolutely impossible situation.

       Faster than light travel? Now you have a new set of
    problems that are even tougher. There are some weak
    indications of particles that travel faster than light, but
    the evidence so far is not conclusive by a long shot. Even
    if it turns out to be, the same indicators say that those
    particles are trapped on their side of the barrier every
    bit as much as we're trapped on our side.
       Space warps? Those are the invention of science fiction
    writers who needed SOME way to get their characters across
    the impossible. There is scientific basis for it except in
    the imagination. Again, it's just great for the special
    effects department, but inappropriate in the real universe.
    (In other words, just because you want something to exist
    doesn't mean that it will exist.)
       Crossing other dimensions? Same thing.

       "We don't know enough" is a fine excuse for believing. It's
    true, in essence. I hope I'm crediting this right - I think
    it was Jim Lippard who said something along the lines of, "Sure
    we've been wrong in the past, but think about all the times
    we've been right."
       Einstein's ideas have been shown to be remarkably accurate.
    When tested in the labs, the predictions are shown to be
    true in virtually all cases. Modifications to the theories of
    relativity he developed over a half-century ago have all been
    rather minor, and mostly done in an effort to create the
    so-called Unified Theory to tie everything in together.
       It's always possible that one day in the far distant future,
    assuming our planet lasts that long, someone will discover a
    way to meet or exceed the speed of light. It's more likely that
    what will be discovered is that Einstein was essentially right
    all along.
       There was the "discovery" of gravity. Newton was essentially
    correct. Modifications have been needed, but he did a remarkable
    job under the circumstances. As time goes by, the theories of
    today will be further modified by new evidence. However, it's
    extremely unlikely that anyone will discover that the laws of
    gravitation are all wrong.
       Most of the common excuses and statements have been already
    said over on the Public board. Things like how we used to think
    it was impossible to fly, or impossible to reach the moon. But
    there is a major difference between all of those and the
    present discussion.
       First, saying that we thought flight was impossible is
    misleading. Quite a few of the best known scientists all through
    our past believed it possible, and inevitable. Back in ancient
    Greece there was the mistaken idea that it would be done
    with wings and feathers. DaVinci, and others, took it farther,
    believing all along that it was just a matter of time. By
    the time the Wright Brothers came along, the idea of powered
    flight was already accepted.
       Sure there were some who didn't believe it possible. More
    knew that it was, and that the laws of physics fully supported
    their ideas.
       Same for flight to the moon, and a vast number of other ideas.
    Check it out thoroughly and you'll find that most of those who
    objected weren't exactly well known scientists. Often they
    were well known deacons (or whatever) of the church. Other
    times they were politicians. Mostly they were just narrow
    minded people who really didn't understand science and who
    couldn't be bothered to take the time to learn, or refused to
    because new ideas and new facts interfered with their own
    preset nonsense.
       "It's against the laws of God for man to fly - therefore
    flight is impossible."
       "God created a perfect universe - therefore any idea that
    the earth isn't at the center, or that planetary motion isn't
    done in a perfect circle is heresy."

       Tis the stuff dreams are made of.
       Cranking up the frequency of sound until it becomes light.
    Or cranking down the frequency of light until you can hear it.
    Travelling physically at the speed of light. Or converting
    mass to energy, making the trip, and changing back into mass
    again.
       Dreams. Unsubstantiated and unsupported.
       It's frustrating, but that's just the way it is.
       "We don't know enough."
       "Yup. That's true."
       "And maybe some day we'll find out how to travel faster than
    light."
       "Yup. Possible. But highly unlikely."

       We have some very scientifically people on the board here.
    This next week should be rather interesting!

    Until Next Time

       I have a spare issue ready. And there's the "Chris for
    Governor" story; and a story written by one of the other
    users that is nearly ready to go.
       Now I have to decide which should go up next. And who knows,
    maybe something elsewhere on Zephyr - or here - will stimulate
    something totally different from what I already have in mind.
       You'll just to wait and see.

       Meanwhile, there's a lot of information in this week's
    issue on a variety of related subjects. Take your pick and
    have at it.
       Wanna talk about becoming a ham radio operator? Fine. I'll
    be glad to answer your questions. Neighborhood Pro is also a
    ham operator, as is Dave Kelly; Chris Mitchell was.
       Maybe you're trying to figure out how to design an antenna
    so you can pick some radio station out of Tucson. (I did that
    a few years ago when Prarie Home Companion was available only
    from the Tucson NPR station.)
       Probably most popular will be the things on space travel and
    light speed and relativity, which is also fine. I *do* request
    (but not demand) that you take a bit of time to do some studies
    on your own so you have some idea of what you're saying. You
    can just bet that if you put your foot in your mouth, someone
    is going to help you shove it down to the kneecap. (We have some
    VERY smart people here! Trying to tackle someone like Jim
    Lippard or even myself on a scientific matter when you yourself
    have no scientific backing is kinda like jumping off a cliff and
    expecting to flap your arms and fly away safe.)
       So the caution is for your own benefit.
       Say whatever you wish, but don't be surprised - or offended -
    when some knowledgeable people toss it right back at you.

Zephyr Magazine is © Gene Williams. All rights reserved.