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Патент USA US2404196

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JV‘ 36, 1946-
s. w. SEELEY
2,404,196
RADIO BEACON ‘SYSTEM
Filed April 30, 1940
11119.2
INVENTOR.
[STUART w SEELEY
BY
ATTORNEY.
Patented July 16, 1946
2,404,196 ‘
UNITED STATES
PATENT OFFICE P
2,404,196
RADIO BEACON SYSTEM
Stuart W. Seeley, Bayside, N. Y., assignor to Radio
Corporation of America, a corporation of Dela
ware
Application April 30, 1940, Serial No. 332,547
1
10 Claims.
( Cl. 250—11)
The present invention relates to radio beacon
sake of clarity, and Figure 3 is a‘developed pore
systems and, more particularly, to a novel type
tion of the antenna shown in Figure 2 wherein
of transmitting antenna for use in such system.
all of the connections are clearly shown.
An object of the present invention is to pro
Referring, now, to Figure 1, the cardinal com
vide an improved radio beacon system.
Still another object is to provide a system for 5 pass directions are indicated by lines N, S and
E, W. At their intersection is located a trans
determining the azimuthal direction of a trans
mitter
which is indicated by the reference letter
mitter from a receiver more et?ciently than by
T. The transmitter simultaneously radiates a cir
prior methods or means.
cular ?eld indicated by dotted lines fo and a spiral
Another object of the present invention is to
provide a beacon radiating system for radiating 10 ?eld fs indicated by the solid spiral line. The fre
quencies of the two signals radiated by the trans
simultaneously a plurality of waves of different
frequencies without interaction.
mitter differ by a small amount, for instance, 60
cycles.
Still a further object of the present invention
is the provision of a beacon radiating system for
As will clearly be seen from an inspection of
15
the
drawing, at a particular instant the phase
radiating simultaneously a plurality of waves
of
the
resultant detected beat note in a receiver
which are similarly effected by ground re?ections.
at any point around the transmitter at T will be
The present invention contemplates simulta
a function of the azimuthal direction from the
neously radiating from a transmitting location
transmitter
being simultaneously different at each
an unmodulated spiral ?eld and an unmodulated 20 location. For instance, along the line W, T the
circular ?eld of the same polarization and of
spiral ?eld leads the circular ?eld by 90 degrees
slightly different frequencies. The phase of the
while along the line E, T it leads the circular ?eld
resultant beat note in a receiver for said signals
by 270 degrees. The pattern shown in Figure
is then a function of the azimuthal direction of
1 may be considered to rotate at a rate corre
the receiver from the transmitter.
25 sponding to the difference in frequency of. the
In accordance with the present invention I also
spiral and circular ?elds. Along line N, T both
provide a third transmitter which radiates a ?eld
modulated 'by the diiferent frequency between
radiations are in phase and on the line S, T the .
radiations are 180 degrees out of phase. If a third
the ?rst two mentioned ?elds and which is also
transmitter, not shown, which is modulated by
received at the receiver. A phase meter is pro 30 the
di?erent frequency between J‘o and f5 issimul
vided for comparing the phase of the received
taneously received at any receiving‘ location
demodulated different frequency and the beat
with the two frequencies ,fo and is, the di
note between the received circular and spiral
rection
between the receiving location and the
?elds. The phase meter ‘may be directly cali
T can be directly read on a phase
brated in degrees to indicate the azimuthal di 35 transmitter
meter. The phase reading will be the number of
rection from some arbitrarily chosen direction at
degrees in azimuthal direction from the starting
the transmitting location.
'
direction, arbitrarily chosen as north in this eX-,
As a further feature of the present invention
ample, at which the signals are being received.
there is included a novel form of transmitting
Since the present invention isnot dependent upon
antenna which simultaneously radiates the here
tofore described circular and spiral ?elds with 40 the form of phase meter ‘used, any conveniently
available meter may be used. As an example,
the same polarization and without interaction
therebetween.
Since the same polarization is
the meter might take the form of a “Seisyn mo
tor” with the pointer for the scale reading on
used, ground reflections affect both ?elds alike.
the shaft oi the motor. The detected modulation
One very important source of error existing in
45 from the third above mentioned transmitter may
previously known systems is thus eliminated.
be applied to the ?eld of the “Selsyn motor” and
Further objects, features and advantages of the
the detected beat note applied directly to the
present invention will become apparent from
armature. Then the armature takes up a sta
the following detailed description which is ac
tionary position with the pointer indicating the
companied by a drawing, in which Figure 1 is a
diagram useful in explaining the types of ?eld 50 phase diiference between the two applied low fre
quency currents which will also be the azimuthal
radiated from a transmitter in accordance with
direction from the‘ transmitters to a receiving
my invention; Figure 2 is a perspective View of
point.
an antenna constructed according to my inven
As far‘ as: I am aware, there cannot be a ‘uni
tion with certain connections eliminated for the 55 form.
circular ?eld of horizontally polarized
.
H
w.
2,404,196
3
radiation simultaneously at all azimuthal direc
tions. All of the previously known antennas,
examples of which include crossed dipoles, turn
stiles, etc., which radiate horizontally polarized
waves uniformly in all horizontal directions must
of necessity produce spiral ?elds. On the other
hand, vertically polarized radiation can be of
either the spiral or circular type in all horizontal
directions.
For instance, a single vertical dipole
over an idealized earth surface will radiate a
perfectly uniform circular ?eld in all horizontal
directions. Likewise, a vertically polarized spiral
?eld may be radiated in all horizontal directions
with perfect uniformity by utilizing the antenna
4
around the top of IO and the bottom of II in
the same direction when viewed from one end,
thus radiating a spiral ?eld. The antenna is
energized from a pair of transmitters through
transmission lines I2 and I3, the transmission ‘
line I2 carrying the frequency for the circular
?eld and I3, that for the ‘spiral ?eld. At any
convenient point along transmission line I3 is
connected a third transmission line I 4. Trans
mission line I4 has a phase quadrature loop I5
therein so that above the loop there is a differ
ence of a quarter of the wavelength in the waves
carried by lines I3 and I4. The three trans
mission lines I2, I3 and I4 are connected to
radiating drums I0 and II at points A to H and
15
of my invention.
A’ to H’. The connections have been eliminated
Furthermore, in the radio beacon system, as
from Figure 2 in order to avoid confusion and
described above, it is desirable that both the
for their complete disclosure reference may be
spiral and circular ?elds be radiated from the
had to Figure 3 wherein the inner surfaces of
same antenna. It is not necessary that either
drums ID and II along their adjacent edges are
the absolute or relative intensities of the two 20 shownas being developed into flat planes. Here
waves be kept uniform at the receiving antenna,
the connections are clearly shown. The fre
but it is very essential that the relative phase
quency it carried by transmission line I2 is
after considering re?ection, etc., be accurately
directly applied to points A, C, E and G in one
maintained since the phase of the detected beat _
phase and to points A’, C’, E’ and G’ in the
25
note is a direct function of the instantaneous
other phase. The drums II] and II are, there
phase of the two received waves.
fore, simultaneously energized as a half wave
As far as the third above mentioned field is
doublet. For the spiral ?eld the drums I0 and
concerned, no speci?c phase, direction, amplitude
II are energized from transmission line I3 at
or frequency need be maintained, except that the
points D and H’ in phase and at points D’ and
modulation must be in exact phase and fre 30 H 180 degrees out of phase with points D and H’.
quency with the beat note in a predetermined
D, H and D’, H’ are at opposite ends of diameters
direction from the two ?rst mentioned ?elds.
of their respective cylinders. At points 90
The radiator of the refence phase or third ?eld
spatial degrees away from these points trans
need not be at the same location or even in the
mission line I4 is connected at points B and B’
same direction from the receiver as the radiator
directly and at points SF and F’ through phase
of the ?elds is and fo as long as the receiver
reversing connections. It should be clearly
can receive some signal therefrom.
understood that the actual connections to the
If the beat note between the spiral and circular
antenna of Figure 2 at points A to H and A’
?elds is ?xed at a low enough value it is pos
to H’ from the transmission lines I2, [3 and I4
sible to utilize the third transmitter for voice
are of equal length. The connecting wires are
modulation at the same time it is transmitting
preferably arranged substantially radially from
the refence phase. Since the voice modulation
the transmission lines near the vertical axis of
frequencies appear in only one portion of the
the antenna.
,
phase meter the meter would entirely disregard
It will be seen from an inspection of Figures 2
45
and 3 that a perfect bridge is formed and reac
them.
tion between the two systems generating frequen
Since, as I have pointed out above, it is neces
cies is and fo is almost entirely eliminated even
sary that the two ?elds, which differ in fre
though the antenna radiates both ?elds at one
quency by a discrete amount, both have the same
polarization and both be radiated from the same 60 and the same time.
location in order that ground re?ections, etc.,
While I have particularly shown and described
act the same on both, I have shown in Figure
several modi?cations of my invention, it is to be
2 an antenna which is capable of simultaneously
particularly understood that my invention is not
radiating both a circular ?eld and a spiral ?eld
limited thereto but that modi?cations may be
made within the scope of my invention.
with the same vertical polarization.
55
The antenna, constructed according to Figure
I claim:
1. In a radio beacon system, a. vertical dipole
2, consists of a pair of circular conductive drums
antenna, means for so energizing said antenna
or cylinders I0 and II, which are mounted in
that a uniform circular ?eld is radiated and
axial alignment with their axes vertical. The
spacing between the two drums is very small. for 60 means for separately and simultaneously so ener
example, 1/250 of the wavelength. The drums or
gizing said antenna that a uniform spiral ?eld is
cylinders each have a length approximately equal
to one-quarter of the length of the wave which
is to be radiated as a circular ?eld. For this
wave the antenna acts as a vertical half wave
dipole antenna. The diameter of each of the
drums is equal to
k
radiated.
2. In a radio beaconsystem, a vertical dipole
antenna, means for so energizing said antenna
that a uniform circular ?eld is radiated and
means for separately so energizing said antenna
that a uniform spiral ?eld is radiated.
3. In a radio beacon system, a radiator com~
prising a pair of coaxially arranged vertical con
11'
means for energizing said conductors in
where )\s is the wavelength of the spiral ?eld. 70 ductors,
an opposing phase relationship whereby a uni
The circumference is therefore equal to the
form circular ?eld is radiated and means for
length of the wave which is to be radiated as
simultaneously so energizing said conductors that
a spiral ?eld and in operation each cylinder has
a wave is caused to travel circumferentially about
a continuous rotating charge distribution there
said conductors whereby a spiral ?eld is radiated.
on with voltage maxima and minima traveling
2,404,196
4. In a radio beacon system, a radiator com
prising a pair of coaxially arranged vertical con
ductors, said conductors each having a length
equal to a quarter of the length of a ?rst wave
to be transmitted, means for energizing said con
ductors with said wave in an opposing phase rela
tionship whereby a uniform circular ?eld is radi
ated, said conductors each having a circumfer
for energizing said cylinders with said wave in
an opposing phase relationship whereby a uni
form circular ?eld is radiated, said cylinders each
having a circumference equal to the length of a
second wave to be transmitted, a second trans
mission line for energizing said cylinders with
said second wave in a circumferentially progress
ing phase relationship around said cylinders, said
ence equal to the length of a second wave to be
transmission line being connected to adjacent
transmitted, means for simultaneously so ener 10 edges of said cylinders at one side thereof and at
gizing said conductors with said second wave that
the opposite side in a reversed phase relationship, .
a spiral ?eld is radiated.
a third transmission line connected to said second
5. In a radio beacon system, a radiator com
line and similarly connected to said cylinders at
prising a pair of coaxially arranged vertical con
points intermediate the points of connection of
ductive cylinders, said cylinders each having a 15 said second line.
length equal to a quarter of the length of a ?rst _
9. In a radio beacon system, a radiator com
wave to be transmitted, means for energizing
prising a pair of coaxially arranged vertical con
said cylinders with said wave in an opposing phase
ductive cylinders, said cylinders each having a
relationship whereby a uniform circular ?eld is
length equal to a quarter of the length of a ?rst
radiated, said cylinders each having a circum 20 wave to be transmitted, a ?rst transmission line
ference equal to the length of a second wave to
for energizing said cylinders with said wave in an
be transmitted, and means for applying said sec
opposing phase relationship whereby a uniform
ond wave to said cylinders in a similarly pro
circular ?eld is radiated, said cylinders each hav
gressing phase relationship around each of said
ing a circumference equal to the length of a sec
cylinders.
25 ond wave to be transmitted, a second transmis
6. In a radio beacon system, a radiator com
prising a pair of coaxially arranged vertical con
ductive cylinders, said cylinders each having a
sion line for energizing said cylinders with said
second wave, said transmission line being con
nected to adjacent edges of said cylinders at one
length equal to a quarter of the length of a ?rst
side thereof and at the opposite side in a reversed
wave to be transmitted, means for energizing said 30 phase relationship, a third transmission line con
cylinders with said wave in an opposing phase
nected to said second line and similarly connected
relationship whereby a uniform circular ?eld is
to said cylinders at points intermediate the points
radiated, said cylinders each having a circumfer
of connection of said line, the length of said third
ence equal to the length of a second wave to be
line and said second line from their junction to
transmitted, and means for applying said second 35 the points of connection to said cylinders differ
Wave to adjacent edges of said cylinders circum
ing by a quarter of the length of said second wave.
ferentially progressing at a plurality of points
10. In a radio beacon system, a radiator com
along said edges, the phase of said second wave
prising a pair of coaxially arranged vertical con
at said points being progressively dilferent around
ductive cylinders, said cylinders each having a said circumference.
40 length equal to a quarter of the length of a ?rst
7. In a radio beacon system, a radiator com
wave to be transmitted, a ?rst transmission line
prising a pair of coaxially arranged vertical con
for energizing said cylinders with said Wave in an
ductive cylinders, said cylinders each having a
opposing phase relationship whereby a uniform
length equal to a quarter of the length of a ?rst
circular ?eld is radiated, said cylinders each hav
wave to be transmitted, means for energizing said
cylinders with said Wave in an opposing phase
relationship whereby a uniform circular ?eld is
radiated, said cylinders each having a circumfer
ence equal to the length of a second Wave to be
transmitted, and means for applying said second
wave to adjacent edges of said cylinders in a sim
ilar phase relationship and at a number n points
along said edges the phase relationship between
successive points being equal to
w.
n
ing a circumference equal to the length of a sec
ond wave to be transmitted, a second transmission
line for energizing said cylinders with said second
Wave, said transmission line being connected to
adjacent edges of said cylinders at one side there
of and at the opposite side in a reversed phase
relationship, a third transmission line connected
to said second line and similarly connected to said
cylinders at points intermediate the points of con
nection of said line, the length of said third line
55 and said second line from their junction to the
points of connection to said cylinders differing
by a quarter of the length of said second wave,
said ?rst transmission line being connected to the
8. In a radio beacon system, a radiator com
prising a pair of coaxially arranged vertical con 60 adjacent edges of said cylinders at a plurality of
points intermediate the points of connection of
ductive cylinders, said cylinders each having a
said
second and third transmission lines.
length equal to a quarter of the length of a ?rst
wave to be transmitted, a ?rst transmission line
STUART W. SEELEY.
degrees.
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