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Патент USA US2125969

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Àug. 9, 1938.
A_ H, TURNER
ULTRAHIGH FREQUENCY OSC ILLATOR
Filed Aug. 29, 1935
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2,125,969
PatèntcdAíug. 9, 193s
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UNITED STATES PATENT .o1-‘FICE '
ULTBAHIGH FREQUENCY OSCILLATOR
Alfred
Turner, Collingswood, N. J., assignor '
to Radio Corporation of America, a corpora
tion of Delaware
Application August 29,1935, serial No. 38,314
«i` claims. (ci. 25o-sc)~
My invention relates to oscillators. More particularly, my invention is an ultra high frequency
transmitter in which the oscillatorv proper is
contained within a small Vshielded metal con-
nection with the metal tubes. but also form a
tight mechanical ñt to hold the adjusted tubes
_at .the proper position and keep out moisture.
The grid leak, cathode and one of the heater
5 ' tainer which may be positioned intermediate the
ends of an antenna.
»
`One of the objects of my invention is to enclose
leads 3| may be connected'together and to the
metallic shield at a p_oint remote’ from the axial
sockets. 'I'he other heater lead and choke lead
themionic tube within a metallic shieldwhioh is
part of the-tank circuit of the tube.
l
10
Another object is to enclose an oscillator within
a metallic shield which may be included in the
antenna system of an ultraA highv frequency
transmitter.
_
A still further object is to combine the oscilla-
15 tor, shield and antenna of an ultra high frequency system.
, ,
are insulated and brought out. through suitable
holes inthe shield. These leads are vconnected
to a power source 33, such as a battery, motor- l0
generator, or the like. The power source 33 may
be remote from the shield, and may be at ground _
potential with respect to »radio_ frequency
currents.
_
`
` -
~ The arrangement described maybe operated as 15
an ultra high frequency oscillator, or a receiving
Further objects will appear in the accompanying specification and claims.
i
device.- The tuned or resonant tank circuit con
sists of the inductance of the copper shield mem
Figure I is a view, partly in section, of one
ber and the variable capacity composed of the
20 embodiment of my invention,
l
Vslidable armatures 3_5. _The variable capacity 20
. Figure II is a view, partly in section, of a modi- -_ is coupled through the metal bands 'I-9 to the
ñcation of Figure I,
Figure III is an illustration, partly in section,
of a push-pull ultra high frequency oscillator
‘l5 adapted- to my invention, _
Figure IV is an illustration, partly in section,
of a modified form of push pull device, and
grid and anode electrodes. ',The circuit ar
rangement of Figure I is that vof a single tube
Hartley oscillator.
4 r,
_
f By way of example, the shield may be made of 25
a pair of copper cans, about two inches in diam
eter and four inches long.V The copper tubes
Figure V is a‘diagram showing an embodiment ‘ may be made of rods of %" outside diameter.l
of my invention which is suitable for frequency
30 control.
.
The glass tube may be made of Pyrex vor other
suitable insulation.
In Figure I within a suitable glass tube I are
slidably mounted two metal tubes 3-f-5.
The walls of the glass tube» 30
may be about 515'/ thick. The copper bands are
These . about 1A" wide.' ‘With valuesof the order given,
»
tubes are preferably good conductors, such as _stable oscillations may be generated from 400 to
copper, closed at their inner ends.- They form
‘.15 the two armatures of an adjustable condenser.
600 mégacycles.
._
w
"
‘ _- `
y -'I'he arrangement I have described maybe 35
Two metallic bands, 1_9, of copper or like con-
combined with a4 direct radiating antenna s'ys-
i '‘
ductor, are mounted on the outside of the glass
tube.` The two bands are insulated from each
tem.` 'I‘he radiating antenna conductors :i5-_31 >
_may be connected directly to the metallic shield
'
other. `One of the bands 1-is connected, prefer-
becausepat _the high `freuuencic‘es employed the ,
40 ably directly, to the grid lead II of a thermionic- shield has a suitable impedance for a direct an- 40
tube, such as an RCA type 955. The other band tenna connection. Each ¿of the `antenna con
9 is` connected to the plate >lead I 3 of the same ductors 35-31 are preferably a. quarter wave
` tube. The grid isl connected through a grid leak ` length long. At the lower'y frequencies the an
resistor I5 of the order of 50,000 .ohms to the _tenna conductors may be connected to the me
’45 cathode lead I1._ A suitable radio frequency
tallic shield at points adjacent the axial poles. 45
choke I9 is mounted adjacent the plate lead I3 _ At higher frequencies a betterimpedance match
and is connected thereto. -
’
Í `
`
`
__
will be _found- at a pair of points nearer the equa
Ahollow metallic shield 2|, which may be fab- ` torial region of the shield.> The antenna.’ con
ricated from. two hollow copper hemispheres ‘ ductors may be wires oi'4 tubes of suitable cross
50 23-'---25 or the like. surrounds the adjustable con- j section. They may be iixed to the shield by soi- 50
denser and tube.
The shield is made with in-
Wardly turned sockets‘21--29 adjacent the axial
dering, brazing, or the like.
'
'
‘ The construction is designed to makeA a-weath
poles.> rlfhe sockets make good spring contacts `_ erproof unit. Afterthe frequencyhas been ad
_- with the slidable armatures _of the condenser. justed by positioning the armatures, they maybe
55‘ The sockets not ronly make good electrical con-
soldered or sealed to the _shield to make the as- 55
,
2
2,125 cee
sembly weatherproof. The unit may be sup
ported or self supporting. It may be used with
or without a reflector. _ The antenna wires may
be vertical or horizontal. It is especially adapt
able to aircraft or other mobile units.
connected to the shield 233 and the negative
terminal of the B battery. Due to the increased
capacities of this circuit, the range of oscillation
is not as great as found in the circuits of the
other figures. In the matter of frequency sta
bility, the single tube Hartley circuit has proven
to be the most stable; while the push pull Hartley
Figure II illustrates an embodiment of my in
vention not unlike the arrangement shown in
Figure I. 'I'he essential differences in the two' arrangement is the least stable for variations in
arrangements will be found in the substitution
plate potential. If an amplifier stage is desired,
of a cylindrical shield 4| for the spherical shield ' the amplifier may likewise be included within a 10
2| of Figure I. Thev metallic plate band I3 in metallic shield.
Figure II has been shown as approximately twice
'I‘he circuits described above approach the opti
the width of the grid band 45. >This arrangement mum for the generation of ultra high frequencies.
has been found to better balance the inter-elec
The several illustrations indicate coupling be
trode capacities of the oscillator. _It should be tween the oscillator electrodes and sections of
understood that other departures may be made in the resonant tank circuit near anti-nodal poten
the arrangements shown.
tial points. 'I'he resonant circuit is of relatively
A pair of oscillators may be arranged in push low impedance but the tube impedance acts as a
pull connection as illustrated in Figure III. In load across the anti-nodal potential points and
20 this connection within the glass tube 5| are'slid
tends to reduce frequency stability. The fre 20
ably mounted two metallic armature members quency stability may be greatly improved by
53-55. On the outside of the glass tube are . coupling the oscillator to that portion of the tank
Apositioned a pair of metallic bands 51-59. One circuit which lies near the equatorial region or
of the bands 51 is connected to the grid lead 6|
adjacent current anti-nodal points of the shield.
25 -of the thermionic tube 63. The other metallic 'I‘his type of connection places the load where it
band 59 is connected to the grid lead 65 of the will minimize the effect on the resonant circuit
other thermionic tube 61. These thermionic tubes andthe frequency stability of the oscillatory
may be of the small acorn type known‘ as RCA currents.
955. The plate leads 69 of these two tubes are
In Figure V the shielding member 30| has
connected together. 'I'he center point 1| of this mounted at its axial poles a pair of screws 303
connection is the terminal to be connected to the 305. On the inner ends of the screws are fixed
positive pole of the plate battery 13. Separate armature members 301-309. The shield forms
grid leaks 15-1] are connected between -the the inductance and the armatures the capacity
grids 10-3I and cathodes 83-85. The two grid of an adjustable resonant circuit. The_anti
35 circuits are tuned by the slidable armature mem
nodal current points lie near the equatorial region
bers 51-50. Two of the filament leads 81-80 of the shield. Adjacent these points are mounted
are connected to the tubular members 9|--93, condenser plates 3||--3|3 which are supportedv
and the other filament leads 95-91 are run with respect to the shield by suitable insulators
within the tubular member. 'I'he filament leads 3|5, 3|1. 'I'he grid ofthe thermionic tube 3|9 is
.40 are connected to a suitable _source of power '99.
connected to one condenser plate 3|5 and the 40
The negative terminal of the plate battery 13 plate is connected to the other condenser plate
may be connected to the ñlament battery or 3|1. A grid leak resistor 32| is connected be
cathode. In the arrangement shown in Figure tween grid and the shield. A radio frequency
III the tubular members 9|-93, connected be
choke 323 is connected between plate and the
tween the cathodes 83--85, form a tuned cathode positive terminal of the B battery 325. 'I'he 45
circuit. A suitable adjustable conductor |0| may cathode and one heater lead are connected to
be used to vary the length of the tuned circuit` the shield. The heater is energized by a battery
and hence its resonant frequency. 'I'he tubular 321. The circuit arrangement of Figure V is
members may be eliminated by including a suit
most suitable for the generation of oscillations of
50 able inductance coil within the shield. In the substantially constant frequency because the tube 50
connection shown the grid circuits are tuned by load is connected across anti-nodal current points
the inductance oi' the shielding member’ |03 and in the resonant circuit.
capacity of the adjustable armatures which are
It should be understood that the precise shape
connected to the shield. The shield may be of the shield is not essential. I prefer the spheri
cal, but cylindrical and other shapes may serve
55 cylindrical or spherical, and fabricated from two
or more pieces. The antenna wires are not shown equally well. Other -obvious modifications within
-.but may be of a quarter wave length long and the scope of my invention will occur to those
connected to points on the shield which offer skilled in the art. I do not intend to limit >my
suitable reactance for the frequency chosen.
invention except as required by the prior art and
'I‘he arrangement shown in Figure IV is not the appended claims.
_
60
unlike Figure III. The essential difference is
I claim as my invention:
I
found in the circuit which is a push pulloscil
l. An oscillatory system comprising a shield, a
lator of the .well known Hartley type. In this adjustable capacity disposed within said shield, `
»Figure both the grids 20|-203 and the plates said shield and said capacity forming a resonant
65 205--201 of the thermionic tubes 20S-2H are
tank circuit, an electronic oscillator disposed 65
connected respectively to metallic bands 2|), Ill, within said shield, and means coupling said os
2|1 and 2|9. 'I'he several bands are separated cillator adjacent an anti-nodal current point ‘
from each other but are capacitively connected to within said shield.
the adjustable armatures 22l-223.
'I'he grids
70 20 |--203 are connected to the shield by grid leak
resistors 22B-221. The plates are connected by
an inductor 229 which is tapped at its mid-point
for the connection of the positive terminal of the
B battery 23|. The filaments may be connected
75 in the conventional manner. The cathodes are
2. An oscillatory system comprising a shield, an
adjustable capacity disposed within and con 70
nected to said shield, said shield and said ca
pacity forming a resonant circuit, a pair of elec- '
tronic oscillator tubes arranged in push pull con
nection and disposed within said shield, and
means coupling the input of said oscillator tubes 1I
3
2,125,969
to points adjacent anti-nodal current points on
said resonant circuit.
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,
3. An ultra high frequency-device comprising a
hollow metallic shield, an adjustable capacity
centrally Ídisposed within said shield and con
nected thereto, said shield and; saidv capacity
forming an adjustable tank circuit, a thermionic `
~tube disposed within said shield, means coupling
said thermionic tube to said tank circuit, and a
cuit, a thermionic tube having grid, iilament, and
plate electrodes disposed'within said shield, means
coupling said grid to one armature of said ad
justable capacity, means coupling said plate to
the other armature of said adjustable‘capacity,
said means for coupling the plate and adjustable
capacity being of different coupling value from
the means coupling the grid and said adjustable
capacity, a grid leak resistance connected be
10 pair of oppositely disposed quarter wave length tween gridand shield, a radio frequency choke 10
coil connected to -said plate, a source of power
antenna conductors connected to said shield.'
4. In an ultra high frequency system. a shield, ' disposed external to said shie1d.,and connections
an adiustable capacity substantially centrally dis
v posed within said shield, said shield forming an
'15 inductance, means lconnecting said shield and ad
justable capacity to form a tunable resonant cir-`
from said source to said electrodes and choke
u coll.
i
ALFRED H. TÜRNER.
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