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Патент USA US2112547

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March 29, 1938.
K. VOGT
2,112,547
ANTENNA COUNTERPOISE SYSTEM
Filed Oct. 10. 1936
/
W
(E
INVENTOR
KARL VOGT
ATTORNEY
2,112,547
Patented Mar. 29, 1938
UNITED STATS e
since
2,112,547
ANTENNA COUNTERPOISE SYSTEM
Karl Vogt, Berlin, Germany, assignor to Tele
funken Gesellschaft fiir Drahtlose Telegraphic
m. b. PL, Berlin, Germany, a corporation of
Germany
Application October 10, 1936, Serial No. 104,920
In Germany November 12, 1935
2 Claims.
It is known to substitute a counterpoise ar
rangement for the ground for the elimination
of losses occurring in grounding arrangements.
Counterpoises are constructed in such manner
that radially running insulated wires are stretch
ed over the ground at a height of about .5 to 5
meters. The length of the counterpoise wires
is mostly small compared to the wavelength for
antenna systems for medium and long waves.
10 In antenna systems for short waves the wire
length is chosen about equal to the height of
the mast, the maximum length used being about
one-quarter wavelength,
If we have a ?xed antenna and a counterpoise
and wish to make a quick change of the Wave
length, then we must choose the counterpoise
length as long as possible for good ei?ciency and
at the same time so that optimum coupling re
actance is substantially the same for all wave
lengths. If there is a ?xed antenna and counter
poise, and if it is desired that there be a quick
change of wavelength, one must choose that
counterpoise length which is as long as possible
for good e?iciency, and at the same time such
that the optimum coupling reactance is substan
tially the same for all wavelengths. Since the
counterpoise wires are insulated, the current
flowing therein will have a spatial distribution
similar to the distribution in horizontal antennas
over the ground. The current distribution and
natural oscillation depend in this type on its
capacity with respect to earth. If the distance to
earth is small, the natural oscillation of a hor
izont'al conductor is about equal the double wire
length plus 10%.
In distances, however, that
are larger than
A
2
(one-half wavelength), the natural oscillation
All) of the horizontal conductor is greater than the
double wire length by only about 5%.
Now, if the operating Wavelength in an antenna
system is about equal the double length of the
counterpoise wires, high resistances exist at the
base point of antenna, For somewhat longer
waves the resistance decreases to the size of the
radiation resistance of antenna and decreases
still further with longer waves.
In View of the above, and in accordance with
(Cl. 2250-33)
by the coupling resistances are to vary very little.
The optimum value for insuring the most favor
able antenna e?iciency over the entire wave range
is calculated from the disclosed values for the
natural oscillations of a horizontal conductor at
different heights. For small distances above
ground the maximum length of the counterpoise
wires amounts to about Ax, for greater heights
about .45)\ of the shortest operating wave.
The single ?gure of the drawing shows an em 1O
bodiment by way of example. The two masts M
sup-port antenna A insulated with insulators J.
Lead line Z is connected through coupling coil
S with counterpoise wires G likewise insulated
(insulators J). The length of the counterpoise
wires shall, in accordance with the invention, be
somewhat smaller than half of the shortest oper
ating wavelength.
'
The excitation of horizontal conductors to
harmonic oscillations, as is well known in prior
art, may also apply to counterpoise wires having
a longer length than indicated above, resulting
in a current distribution corresponding to that
of a horizontal antenna excited to harmonic
oscillations. It will suit the purpose best to
choose in this case the length of the counter
poise wires as an integral multiple of the value
indicated for the shortest operating wave. The
wave range towards the longer waves is, however,
limited in this case since the current distribution 3O
in the wires with increasing wavelength is formed
in the manner that a current nodal point is lo
cated at the base of antenna. Thus the resist
ance varies at this point from a few ohms to
several thousand ohms. Considerable di?iculties 35
would accompany the coupling of transmitter in
this case. If the length of the counterpoise wires
is chosen equal to A, that is, equal to double
half of the wavelength, the longest wave coupled
with small resistance to transmitter is somewhat
larger than the double length of the counter
,poise wires. If, on the other hand, the length
of the counterpoise wires is chosen as a higher
multiple of M2, the useful wave range tends to
become smaller and smaller.
What is claimed is:
.
1. In combination, an antenna circuit compris
ing an antenna and an open-ended counterpoise
wire insulated from ground, said circuit being ar
ranged to operate over a wide band of frequencies,
the invention, the counterpoise wires are chosen
smaller than half the wavelength of the shortest
operating wave for the purpose of coupling an
antenna system with insulated counterpose to
a source of oscillations adapted to function over
a wide range of frequencies, a ?xed inductive
a transmitter within a wider wave range, where
measured from its open end to the base of said
coupling device between said antenna circuit and
source, the length of said counterpoise wire, as
2
2,112,547
antenna, being less, but not much less than one
half the minimum wavelength of said range,
whereby the effective antenna circuit resistance,
a source of oscillations adapted to function over
a wide range of frequencies, a ?xed inductive cou
including counterpoise, antenna, and connecting
source, the length of said counterpoise wire, as
portion, decreases as the operating frequency de
creases so as to compensate at least partially for
measured from its open end to the base of said
the decreasing mutual impedance of said ?xed
minimum wavelength of said range, whereby the
effective antenna circuit resistance, including
coupling.
2. 'In combination, an antenna circuit compris
pling device between said antenna circuit and
antenna being approximately equal to .4 of the
counterpoise, antenna, and connecting portion,
10 ing an antenna and'an open-ended counterpoise
decreases as the operating frequency decreases.
Wire insulated from ground, said circuit being ar
ranged to operate over a wide band of frequencies,
KARL VOGT.
10.
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