Mohave County miner and our mineral wealth., 1922-05-19
tf:z2s:XE 5 51!l]| M D sk1
by J. F. Davidson

by J. F. Davidson
 The interested but unsophisticatec
 radio fan" would like to know the
 answer to an all important question
 "What is Radio?' The Signal Corps
 of the United States Army very aptly
 answers this question thus: "Radie
 communication is the art of sending
 information from one point to a dis.
 tant point by means of free electric
 waves". To fully understand. this art it is therefore necessary to study the
 methods used in producing these waves, the action of ithe waves, and
 the methods of receiving the waves
 Waves on the surface of a body of
 water may be studied to advantage.
 A light breeze, causing friction, be.
 tween the moving air and the water, disturbs the surface of the water so that small waves are set in motion. The stronger the wind blows the high CT She waves. In observing the waves we notice first their height. The cor rect way to measure the height of waves is to measure from the crest of a wave to the surface of the water when smooth. The technical term for the height of wave so measured is "amplitude". Thus We say that a cer- tain wave has an amplitude of ten inches, another wave an amplitude of one inch, an ocean wave during a storm an amplitude of twenty feet, etc. In the study of radio we always speak of the amplitude of waves, not their height.
 We all know that water waves have energy. A small wave may be able to move only a small object which it strikes. A big wave is able to tear to pieces a big dock or other structure near the waters edge. Thus we See that the larger the ~anphtude of a wave. the greater energy it has.
 While observing the water waves, we see that they also have definite length. We are able to measure the distance between the crest of the next wave, or, more generally speaking, we are able to measure the distance in a straight line from any certain point on one wave to corresponding point on the next wave. This distance is the length of the wave. It may be expressed in inches, feet, yards, miles; or centimeters, meters, etc., if the Metric system of notation is used. In radio measurements it is customary to use the Metric system, and wave length is expressed in meters.
 We also notice that the waves fol- ow each other at equal intervals of time. The number of waves passing a given point in one second is said to be the frequency of the waves.
 We have now observed that the water waves have the following char acterisrics: (a) Amplitude, (b) Length, and (c) frequency, and also that the energy, frthe wave is in pro portion to its amplitude. Radio waves are disturbances in ether, just as water waves are disturbances of water. Ether is the medium which carries radio, light, and heat waves. Air is the medium which carries sound waves. Water is the medium which carries water waves. Very little is known about ether. We know it car ries waves very rapidly and that it is everywhere; in the air, in the earth, in water, in all material, in the space between the earth and all the heaven lys bodies--it isrindeed everywhere. It carries radio and light waves at a ter rife velocity, 186,00o miles in one second, seven times around the earth in a second if it could keep going. In radio We measure this velocity in Meters, not Miles. This velocity is approximately 3OO,000, 900 meters per second Ca meter being a few inches longer than one yard). This velocity is constant.
 If a wave is a certain number of meters long, and the waves are nov ing at a certain frequency, the veloc- | ity of the waves is given by the pro- duct of the wave length times the frequency. Thus: If a wave has a length of IS meters and has ire luency of 20 (that is, twenty waves pass given point in one second) then the velocity of the waves is 15 20 equals 300 meters per second. Since the velocity of radio waves is con- stant, 30O,OO0,OO0 meters per second, either the frequency or wave length nay be determined provided the other quantity is known. Thus: A radio wave having a length of POO meters ,as frequency of O0,000, 900 divided ,y 200 equals 1,500,000. In other words, 100000 waves each 200 meters