The New York herald., 1922-04-23
LIGHTNING DANGER
TO ANTENNA SMALL
Wire Less Likely to Be Struck
Than Tin Roofs or Metal
Cutters on House.
REAL FORCE OF A BOLT
/.
Energy Only About as Much as
Is in Pint of Gasoline,
Declares Expert.
BY q. X. THOMPSON,

Il INote-THE New YORK HERALD re-
Gently published on this page instruc-
tons for protecting from lightning by
grounding switch or approved spark or
vacuum tube gap. In this article Mr.
Thompson discusses lightning and static
in general.1
If your radio installation is not al
ready installed according to regulations
you should attend to the matter at once.
aThe regulations are in force the year
sround and should be complied with as
afar as possible. That they are not COM
splied with is we'll known fact, but TINS
snegligencc means that after the first
sthunderclap thousands OF people VIII
torn dealers in radio equipment Tor
sprotective devices and their meager sup
splies will be exhausted within few
shours.
One of the first questions that comes
Unto the mind of the would be radio user
concerns lightning. ''Will my antenna
attract lightning and cause my home TO
eb; struck 2" he asks. To the general
spublic wireless and lightning seem to be
rtwin brothers-probably because the
manifestations Of both are unc1nny and
smysterious. NA
: Hosting a radio antenna over your
property does not endanger your dwell
sing your Instruments or your family II
You have never felt apprchensive oVei
the presence OF the telephone wire rum
ming from the pole on the sidewalk TO
syour house. You do not regard the bel!
wire circuit running from the front door
to the kitchen as a lightning conductor,
nor have you been nervous over the
presence of wire clothesline in your
back yard. the tin roof over your mead
or the metal cutters and leader pipes.
Conductors About House.
All these common and familiar metal
surfaces and conductors will convey
electricity from point to point. The
average radio antenna differs very little
from these other conductors and objects,
and in so far as lightning Is concerned
the radio antenna Is much less likely to
be struck during heavy thunder storm.
Let us consider the electrical action
t,at takes place in the antcnna before
and during 4 summer thunderstorm.
There is always a certain amount OF
atmospheric electricity present In the
air In cold weather the amount is very
sight and manifests itself IN the radio
vset by what is familiarly known as
. s,atic. When warm weather comes at
lirrspheric electricity is generated in
sn,uch larger quantities.
The intense heat of the summer sun
! cNaporates the moisture on ~ surface
,f the earth and water from ponds and
lakes very rapidly. This c.aporated
moisture or vapor. becoming heated,
,-i',ses to the upper atmosphere and upon
reaching the higher levels. where the
temperature Is lower the water va3or
condenses into minute drops OF moisture
and forms clouds. Each moisture par
aticle becomes charged with 4 very small
-amount of electricity
As the moisture particles III the upper
.air become more dense the particles
slowd together and one particle COM
a,,Iaes with another. This combination
.ircreases the electrical charge on each
article until finally thunder cloul is
: crmed which is very highly charged
th electricity.
sheet Lightning Results.
1t is known fact that wheE thuncer-
orms arc in formation electric dis
/. argos occur within the ciodd. These
charges are popularly known as sheet.
: htning. Every time such u discharge
.cs place radio waves a-e emanafed
i these waves impinge doon your
tenna, causing sharp crash or
lckle In the telephone receivers II YOU
sippen to be listening in.
y thunder cloud must be regarded as
huge bubble containing electricity.
scharges are constantly taking place
-nithin the bubble and inc easing in
ssze. When a certain critical point Is
achcd the bubble bursts. t.c pent up
.olcctricity discharges N ono swoop to
s,ie earth and we hear migSt,. thunder
sciap. III this lightning bot strikes
within onc-half mile of you. anter ma.
considerable cirrent will b. induced in
your aerial system. This induced cur
}i"nt will pass harmlcssly to me ground
ard you will be unconscious nf its pres
ence IL YOU have taken the proper
sl"ecautions.
Let us consider the great bubble once
more. IL we prick tiny holes in this
bubble while II Is in process of forma-
ation, the pcnt up electricity will gradu-
ally discharge. III we prick enough
holes in the bubble, the electric chargp
may leak away so fast that the guam
tiiy OF electricity within ,may never
reach the point where the bubble will
burst. The function of the common
lightning rod and the properly grounded
or protected antenna IL to prick holes
A. the great electric bubble in the sky
and convey its charge silently TO the
ground. For this purpose the average
radio autenna is exactly as effective as
the lightning rod.
IL Antcnna In struck.
What will happen II a lightning bolt
actually strikes my antenna?" Is a IA
mlisr question. Let us consider the
nature of a lightning bolt The heavy
thunderclap which attends it's appear
ance gives the impression of tremendous
energy.
II is true that lightning Is dcstruc-
tive. but as a matter OF fact its bark
deceives one of ts might. The average
lightning bolt contains about as much
energy as represented In a pint of gaso-
limo. The only difference Is that the
energy OF lightning Is exertcd instan-
taneously.
Take. for instance. a cupful of gasoline
and ignite IL under n saucepan con-
tanning a tailow candle. The heat OF
the burning gasoline will melt the
candle. The phenomenon IL silent and
harmless. Take another cupfu OF gass-'
,Iino and dump II into the gas tank OF
the family flivver, crank up, and drive
thirty miles an hour. head-on into
sconcrete wall. The effect is startling
Even Henry Ford himself could not
put together the remains and make them
rattle once more. Yet the energy i'm
evolved was no more than that necessary
to melt the tallow candle. The essential
difference lies In the fact that In the
ffrst case the energy was released grad
ualy and IN the second case the energy
was released instantaneousy.
bolt OF lightning represents an
electrical collision. This accounts for