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‘Sept, 10, 19460
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2,407,359
S. Y. WHITE
,RADIO’APPARATUS
Original Filed Dec. 8, 1942
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Patented Sept. 10, 1946
_ 2,407,359
UNITED ‘STATES PATENT OFFICE
2,407,359
RADIO APPARATUS
Sidney Y. White, Wilmette, 111., assignor to Victor
S. Johnson, Chicago, 111.; Alex Thomson, ad
ministrator of said Johnson, deceased
Original application December 8, 1942, Serial No.
468,195.. Divided and this application October
15, 1943, Serial No. 506,372
20 Claims.
(Cl. 250——40)
I
9
which any transmitter is operated in the stand
,_.
This invention relates to radio apparatus, and
is particularly, although not exclusively, con
cerned with‘ mobile radio apparatus suitable for
meeting the exacting requirements of military
service on land, at sea, and in the air
Such apparatus may be carried on a wide va
riety of vehicles such, for example, as a truck,
a tank, or a naval airplane catapulted from a
cruiser. It may be subjected, therefore, to vio
lent shock and to extreme and protracted vibra
tion. Again it may be carried on the back of a
soldier.
Such apparatus may be used in every condition
of climate and weather to be found on the face
ard broadcast band.
.
.
Accuracy within one per
cent can be depended upon to bring in the de- _
sired station. For such simple and coarse oper
ation, the dial is a mere convenience; it is by
no stretch of the imagination a precision instru
mentality relied upon to show the exact fre
quency for which the home receiver is set.
In the ultra-high frequency military ?eld con
ditions are entirely diiferent, the requirements
being incomparably more severe. The transmit
ter is not constantly in operation, so that there
is no signal to search for. Contact must be
established through pre-setting the transmitter
of the earth, and in every season. It may be 15 and the receiver to the precise frequency as
signed. There can be no twiddling of dials at
exposed to dust, mist, rain, sleet and snow from
the receiver. Where accuracy of tuning within
the air, and to mud and oil spray thrown up
one per cent would su?ce to bring in the stand
from roadways. It may be exposed to radical
and abrupt changes of temperature, humidity
ard broadcast station, a one per cent error of
and air pressure by being carried in the space 20 tuning in the range of 150 me. would constitute
of only a few minutes from a tropical desert into
the substratosph'ere, or vice versa.
.
It is often desirable that many communica
tion channels be made available, and that the
distance at which a transmitter may be received ‘
shall be limited, in order that the same com
munication channels may be used in different
.regions without the possibility of mutual inter
ference, and also as a safeguard against listen
ing in by the enemy. For these reasons, among
others, it is often desirable that apparatus for
military use be designed to operate in the ultra
high‘ frequency range. The ultra-high frequency
range has important uses for non-military as
well as military purposes, but its use imposes se
vere requirements.
.
The nature of these requirements may be well
appreciated if the conditions met when tuning
in a broadcast station on a home radio receiver
are contrasted brie?y with the conditions met in _ .
an error of 1500 kc.; i. e., an error in excess of
the entire standard broadcast frequency range,
or enough to miss one hundred channels as there
made available and ?fty more besides. The same
degree of inaccuracy that is permissible in tun
ing a home set to bring in a broadcast station
would miss a range wider than the entire stand
ard broadcast band. The further point should
not be overlooked that the transmitter in accord
ance with the present invention, as well as the
receiver, is generally a light, mobile unit, and
is subject to the same limitations as the receiver.
Since errors of the transmitter and the receiver
may be equal and cumulative, the receiver can,
not be allotted a tolerance representing more
than one-half of the permissible lack of corre
spondence of transmitter and receiver frequency,
because a like tolerance must be accorded to the
transmitter.
In addition to the foregoing, these mobile
effecting communication between mobile units
operating in the ultra-high frequency range.
transmitters and receivers are required to oper
The broadcast station is an elaborate and ex
The source of voltage may be a storage battery
pensive, stationary installation, and is under the
varying between 20 and 30 volts; and the line
voltage for operating A. C. transmitters and re
supervision of a staff of highly trained radio
engineers. No pains or expense is spared to
assure that the station is maintained precisely
on the assigned frequency. The station is con
stantly on the air. The home set user can search
for the station signal and can adjust the tuning
to the signal when he ?nds it. The broadcast
station, moreover, is allotted a 10 kc. channel
.which represents nearly one per cent of the en
tire standard broadcast band and approximately
two-thirds per cent of the highest frequency at
ate under varying conditions of power supply.
ceivers may vary between 95 and 135 volts.
The crucial elements a?ecting the precision
and the permanence of precision of receiver tun
ing and of transmitter tuning are found in, or
in close association with, the ultra-high fre
quency circuits. In accordance with the present
invention these elements are chosen of such ma
terials, are constructed in such forms, and are
associated and combined with one another into
a head unit in such manner that the in?uence of
2,407,359
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temperature changes upon frequency is drasti
cally and de?nitely limited, and that such slight
of the invention not claimed herein are disclosed
and claimed in my parent application, Serial No.
468,195 and in other divisional applications there
changes of frequency with temperature as do
occur are unalterable, so that the initial limita
of, to wit, Serial No. 506,373, ?led October 15, 1943
for Radio apparatus, Serial No. 506,374, ?led
tion will be dependably maintained.
It is a salient feature of the present invention
that the electrical elements of the head unit are
mounted in an airtight housing in which they
are rendered immune to dust, dirt and weather,
October 15., 1943, for Electrical condenser, Serial
No. 506,375, ?led October 15, 1943, for Method of
lining up unicontrolled tuned radio apparatus,
‘Serial No. 506,376, ?led October 15, 1943, for
Method of making inductance coils, Serial No.
506,377, ?led October 15, 1943 for Method of lim
iting changes of frequency of tuned circuits in
response to ‘temperature changes and Serial No.
555,805, ?led August 30, 1944, for Electrical con
densers.
In the drawings forming part of this speci?ca
and substantially free from changes of humidity
and air pressure, the entire head structure being
shock-insulated.
The head should desirably be capable of per
forming certainly and dependably without over
hauling or readjustment for .a period {equal at
least to the lives of the-tubes; namely, ‘500 hours
of actual service, or one year of service in elapsed
tion
time.
.Fig. Us a diagrammatic view illustrating prin
It is the primary object of the present ‘invention
cipally circuits employed in a receiver which em
to provide universal head units for incorporation 20 bodies features of the invention;
in radio receivers and transmitters, ‘capable of
Fig. '2 is a view similar to Fig, 1 villustrating
pre-set dial tuning with the precision required
principally circuits employed in a transmitter
to establish communication in the ultra-high fre
which embodies features of the invention‘;
quency range, and capable of withstanding with
Fig. 3 is a horizontal sectional view illustrating
out detriment or permanent change, and even
important parts of the receiver unit;
without temporary incapacity, the most severe
4 is a fragmentary sectional view taken
conditions of every type of service, yet su?iciently
upon the line 4-4 of Fig. 3 looking in the direc
light and compact to admit of ‘incorporation in
tion of the arrows;
transmitters and receivers intended to be used in
Fig. 5 is a view in side elevation, partly broken
aircraft ‘or ‘to be carried into action on the backs - away, of the structure illustrated in Fig. 3;
of soldiers.
Fig. 5a is a fragmentary View showing the
It is a further ‘important object of the inven
thrust rod and tuning core assembly;
tion to provide head units of the kind referred to
Fig. 6 is a transverse vertical sectional view
which can be produced in quantity with liberal
taken upon ‘the line lie-6 of Fig. '5’1ooking in the
and comfortable manufacturing tolerances for
direction of the arrows, the view being‘on a larger
most of the parts, in some instances tolerances of
scale than Fig. 5;
as much .as two per cent.
Fig. 7 is a fragmentary detail view of the struc
It is a still further important object of the in
ture'illustrated in Figs. 5 and '6;
vention to provide a head unit ‘adaptable ‘for op
Fig. 8 is a sectional view similar to Fig. 6 but
eration in .any selected range from three to 600 40 taken on the line 8-8 of Fig_ 5 looking in the
megacycles, through the mere selection and in
direction of the arrows;
sertion of a small unitary readily replaceable
Fig. 9 is a fragmentary detail sectional view
tuned circuit assembly and the selection and in
taken upon the line 9-9 of Fig. ‘5 looking‘in the
corporation of a dial mechanism which ‘is cali
direction of "the arrows;
M
brated to cover the desired range.
‘Fig. ‘10 is atop plan ‘view of a coil and con
Quantitatively, the more important require
denser supporting plate employed in ‘the trans
ments to be met in service are roughly (1) that
mitter and in the receiver;
the head shall be capable of pre-set tuning with
Fig. _11 is a sectional ‘View of the vsupporting
an accuracy within one .10 kc, channel at 150,000
‘block shown in 'Fig. 10, taken on the line ll—l|
kc.; (2) that it shall suffer no detriment from ;;L of Fig. 10 looking in the direction of the arrows;
shocks of 8 Gs, such as will be encountered in a
Fig. 12 is .a sectional View of the block shown in
tank or when an airplane carrying the vunit is
Figs. 10 and 11 taken upon the line l'2—l"2 of ‘Fig.
catapulted from a cruiser; (3.) that ‘it shall not
11, looking in the direction of the arrows;
I
be rendered inoperativenor temporarily incapaci
Fig. 13 is an end view of a coil form employed
tated by vibration; (4.) that it shall not be tem- :,
porarily incapacitated nor permanently altered
in its frequency characteristics by temperature
variations from —40° F. to +180° F.; (5) that
.it shall not be incapacitated by variations of at
mospheric humidity ranging from 5% to 100%;
in ‘both the transmitter and the receiver;
Fig. 14 is a plan view of the coil "form shown
in Fig. 13;
'
Fig. 35 is a longitudinal sectional View showing
to
(6.) that it shall not be incapacitated by any air
pressure variations to which aircraft are subject;
and (7) that ‘it shall not be permanently affected
the plate of Figs. 10 to 1'2 and the coil form of
Figs. 13 and '14 in assembled relation and with a
coil wound on the latter, the section beingtaken
nor temporarily incapacitated by any combina
on the line |5——l'5 of Fig. 17 ‘looking in ‘the direc
tion of the arrows;
Fig. 16 is a plan view .of the coil ‘assembly of
tion of two or more of the conditions referred to =
Fig. 15;
under (2) to (6.), inclusive.
Other objects and advantages will hereinafter
appear.
This application is a division of my pending
application, Serial No. 468,195 ?led December 8,
1.9512, for Precision radio apparatus- The present
application is directed primarily to the features
of rendering the apparatus immune to humidity
‘changes and adaptable for operation in any one
of a large number of frequency ranges. Features
Fig. 1'7 is a rear end view showing the: coil as
sembly of Figs. 15 and 16 'together'with an assoc—
iated tank condenser;
Fig. 18 is a view in side elevation of the coil and
condenser assembly of Fig. 17;;
Fig. .19 is a bottom view of the coil and conden
ser assembly shown in Fig. 17;
Fig. .20 is a longitudinal sectional view showing
details of the condenser of Figs. 17 to 19, inclu
sive;
2,407,359
5
6
Fig. 21 is a rear end view of a modi?ed form of
Fig. 48 is a graph provided for use in explaining
the alignment of the receiver and/ or transmitter
coil and condenser assembly;
Fig. 22 is a view in side elevation of the assem
with the precalibrated dial;
bly of Fig. 21;
Fig. 49 is a fragmentary detail View of mechan
ism employed in the train between the dial knobs
and the tuning cores used after preliminary ad
justments for securing and ?xing the precise cor
respondence desired between the dial calibrations
and the carrier frequency in megacycles at a mul
Fig. 23 is a sectional view taken upon the line
23-23 of Fig. 21 looking in the direction of the
arrows;
Fig. 24 is a. rear end view of a further modi?ed
form of coil and condenser assembly;
Fig. 25 is a view in side elevation of the as
sembly of Fig. 24;
10 tiplicity of predetermined points, as, for instance,
every megacycle; and
Fig. 50 is a fragmentary sectional view taken
upon the line 50-50 of Fig. 49 looking in the direc
Fig. 26 is a sectional view taken upon the line
26—26 of Fig. 24;
Fig. 27 is a sectional view taken upon the line
tion of the arrows.
21-21 of Fig. 26 looking in the direction of the 15
An illustrative embodiment of the invention is
arrows;
shown in connection with a superheterodyne ra
Fig. 28 is a sectional view similar to Fig. 26
dio receiver for receiving radio waves of ultra
showing a further modi?ed form of coil;
high frequency. In Fig. 1 reference numeral I
Fig. 29 is a rear end view of a modi?ed form of
designates the antenna, 2 designates a 36 ohm
coil and condenser assembly;
20 coaxial transmission line. the outer conductor of
Fig. 30 is a View in side elevation of the assem
which is grounded and is connected to a switch
bly of Fig. 29;
I
contact 3, while the inner conductor of the line
Fig. 31 is a view in side elevation of a further
modi?ed form of coil and condenser assembly;
Fig. 32 is a sectional view, partly broken away
intermediate its ends, of a condenser which may
be advantageously employed in the transmitter
is connected to a switch contact 4.
. and 8 of a tuned circuit assembly 9.
Fig. 33 is a sectional view taken upon the line
33-33 of Fig. 32 looking in the direction of the
arrows;
Fig. 34 is a graph illustrating the various re
lationships of tuning core movement in mils to the
frequency in megacycles of circuits tuned and
controlled by various diameter cores;
ed by means of a movable core 12 which may be
of the powdered iron type. An intermediate tap
i3 on coil I3 is connected to switch contact ‘I to
provide a 35 ohm coupling point for the trans
mission line, the connection to switch contact
Fig. 35 is a graph showing mils of core move
ment required to change the frequency one mega
cycle in the range of 100 to 140 megacycles, for
various coil and core combinations;
Fig. 36 is a fragmentary bottom plan view illus 40
mounting of an adjustable permeable element
that forms a part of the assembly;
Fig. 37 is a fragmentary view showing a com
posite core, as for instance iron and copper;
Fig. '38 is a view in sectional elevation of an ‘un
proved condenser which may be reduced in capac
ity to predetermined accuracy by grinding, and
which may then be employed to advantage in the
transmitter and in the receiver;
Fig. 39 is a plan view of the body of the con
denser of Fig. 38;
Fig. 40 is a fragmentary view illustrative of a
difficulty which the condenser of Figs. 38 and 39
is designed to overcome;
Fig. 41 is a fragmentary view in sectional eleva
tion further illustrating the dif?culty which the
condenser of Figs. 38 and 39 is designed to over
come;
The assem
bly 9 comprises an inductance coil I 0, whose
ends are connected to switch contacts 6 and 8
and a ?xed condenser II, the tuning of the cir
cuit to different carrier frequencies being effect
and in the receiver;
trating a coil assembly which includes a modi?ed
A third
switch contact 5 is provided, the aforesaid switch
contacts cooperating with switch contacts 6, 1
1 being designated by reference numeral M. The
slope of the tuning curve of circuit 9 is adjusted
to a desired value by means of a movable slug
[5 positioned alongside the coil NJ, whose effect
on the tuning of the circuit will be hereinafter
described. The core I2 is adjusted by the oper
ator to tune in the desired station by means of
a unicontrol knob i3 associated With a precali
brated dial l7. In order that the resonant fre
quency of circuit 9 may be made to agree with
the calibrations of dial i'i', adjustable means as
indicated by the arrow i3 is provided whereby the
relative position of the coil H} and core I2 may
be adjusted through a slight range independently
. of the dial setting. A full discussion of the man
ner of effecting the adjustments of elements I5
and I8 will be hereinafter described.
The voltage developed in circuit 9 is supplied
to the control grid IQ of radio frequency ampli?er
tube VTI through the condenser 20. Grid 19 is
connected through the circuit shown, including
resistors El and 22 and ?lter capacitor 23 to a
source of AVG voltage or source of bias potential
such as the voltage source indicated at point A.
Capacitor 23 is of a type of construction. found
Fig. 42 is a fragmentary view in sectional eleva
tion showing the grinding away of surplus capac
highly advantageous and desirable, and univer
ity units of the condenser of Fig 38 to produce a
sally employed by me in the ultra-high frequency
condenser of the desired ?xed capacity;
Fig. 43 is a fragmentary plan view illustrating
range, and consists of a sheet of metal separated
the effect of the grinding of Fig. 42;
65 from the body of the set by a sheet of mica,
Fig. 44 is an end view of the oscillator assembly
forming a non-inductive bypass to ground. This
cooperating with any one of tuned circuit assem
blies of Figs. 16 to 19, 21 to 28, and 29 to 31;
Fig. 45 is a view in elevation of the structure
shown in Fig. 44 as seen from the left of Fig. 44;
Fig. 46 is a fragmentary view looking down on
the structure of Figs. 44 and 45;
form of construction insures freedom from un~
wanted
the
wiring
resonant
of the circuit
set andcombinations
wherever a bypass
formedcon
denser to ground is indicated in the drawings it
is of this type. All leads have resistances in them,
also to prevent formation of resonant loops. Re
Fig. 47 is a sectional View taken on the line
sistance 22 is of the wire wound type being eme
41-41 of Fig. 44, looking in the direction of the
bedded in a grounded metallic block 22a. (see Fig.
arrows, and with the tube of Fig. 44 removed;
75 3) and acts as a radio frequency choke to prevent
2,407,359
7
8
all radio frequency voltage from entering the
supply leads.
The tube VT! is supplied with the usual volt
ages for its electrodes andsuitably bypassed. The
source of .B voltage. Isolation is effected ‘by con
denser 59 in the usual ‘manner. Capacitor .60
performs the same function as vH in tuned cir
cuits 9 and 24, but it has been found desirable
to also employ .a condenser 61 for more complete
thermal stability of the oscillator. “The action of
condenser 6| will be more fully discussed later
This circuit differs from circuit '9 mainly in ‘the
herein.
position of the tap 2'! on the coil '23 of the circuit,
The oscillator circuit 34 is tuned by means of
this tap being connected to switch contact 29,
which engages a switch contact ‘3!! by means in— 10 a movable core l2a which is in turn operated
‘plate of VTI is connected to a ‘resonant mixer Fcir
cuit :24 through a pair of switch contacts Eli-26.
dicated by reference numeral 3!,the construction
of which will ‘be hereinafter described in detail.
through the adjustable connection l8 and control
knob l6, thereby providing unicontrol tuning of
The other connections of circuit 24 are similar
to those of circuit 9 and are indicated by the same
reference numerals. The tap 2.1 is provided to .
the resonant circuit 9, mixer circuit '24 and os
cillator circuit 34.
The oscillator 62 of Fig. '2 shows the same
minimize grid circuit leading.
Switch contact
general structure used as a transmitter instead
.5 is connected to a suitable source of B voltage
through a resistor 32, and is also ‘bypassed to
ground as shown. The input and output circuits
of a receiver. The entire oscillator assembly 62
is identical in :every way with the oscillator as
sembly shown in .Eig. 1. It is possible at times
that this oscillator will be fed ‘with somewhat
higher plate voltage. Its components ‘and per
of VT! are electrically shielded from each other ,
by a grounded shield as diagrammatically indi
cated at 33 in Fig. 1, and physically illustrated as
frame member 95 in Fig. 3.
Mixer circuit 24 is tuned to the signal fre
formance will be otherwise identical.
The RF
ampli?er shown in Fig. 1 is physically reversed so
that ‘its input and output circuits are inter
quency by means of a second core l2 and the 25 changed, forming the buffer ‘tube 63. Its ‘input
adjusting means 18 and 15 for this circuit are
circuit may well ‘be untuned and a coil 28 used
similar to those described in connection with cir
to pick up some energy from ‘the oscillator for
cuit 9. Voltage is injected into the resonant
exciting the grid through the ‘condenser ‘31, its
mixer circuit 24 from a resonant oscillator cir
grid leak being 38 as shown. ‘The ‘tube is ener
gized in the usual way and its output goes to
cuit 34 whose coil 35 is mounted coaxially with
the coil 28, and at a critical distance therefrom.
tuned circuit assembly 9 through the contacts
5 and 8. Tuning condenser H resonates this
combination whose frequency is controleld also
by the core l2 physically connected to the dial
through the adjustable means ‘18. The ‘output
transmission line is connected .to the tuned cir
Voltage is supplied to the signal grid 35 of mixer
tube VT2 through the circuit shown including a
condenser 31, and bias is supplied thereto through
the circuit shown including resistors 38——3€!, the
latter resistor being connected to bias point A.
Suitable voltages are supplied to the other ele
cuit 9 through contacts 4 and '1, and plate voltage
ments of tube VT2 through the circuits shown,
and the output of the tube is connected to a res
is applied to contacts 3 and B ?ltered by the
condenser 23 and a resistor 22. Contact 3, being
onant circuit 40, which in the illustrated embodi
40 at ground potential to radio frequency by virtue
ment of the invention is tuned to a frequency of
5.2 megacycles. Resonant circuit 40 is coupled to
a transmission line 4| through a transformer 42
or other suitable coupling means, as it has been
found desirable in some cases to allow for a con~
‘siderable physical separation of the whole tuning unit from its intermediate frequency ampli~
her and power supply, and also from its antenna.
The oscillator circuit shown is of the “ultra-~
audition” type, which combines the advantages
of requiring no feedback winding, as well as al
lowing grounding the heater and cathode. The
fact that tuned circuit 34 is at high potential to
ground is of little interest in core tuning, and
grounding the cathode is of great practical ad
vantage, as it has been found that the capacity
from heater to cathode is effective in introduc
ing circuit noises, which show up as frequency
fluctuations in the oscillator if it is attempted to
run the cathode at some potential higher than
ground. The plate of tube VT3 is connected to
one end of coil 35 through a pair of switch con
tacts 43-44, and the other end thereof is con
nected to the grid of the tube through the switch
contacts 45-456 and capacitor 47. The oscillator
grid 43 has a divided grid leak consisting of re
sistor 49, choke 50 and resistor 5| to ground, and
an isolation condenser 52. By suitable propor
tioning of resistor 49 and resistor 51 a negative
voltage is built up at A suitable for supplying bias
to the control grids of mixer tubes VTZ and/or
of condenser v23, ‘is connected to an output'trans
mission line shown through condenser 64 and
contact 4, likewise connected to ‘the ‘line ‘by con
denser 65, the purpose of condensers 64 and 65
being to remove D. C. potential from the line.
This assembly, therefore, forms a very ‘low
power continuous wave transmitter, but its main
use is to energize either a ?nal ‘stage or a buffer
meeting a final stage to provide reasonable power
outputs.
As has already been indicated, the crucial and
signi?cant parts of the transmitter ‘and of the
receiver from "the standpoint of this invention
are those parts which control the frequency
characteristics of the ultra-high frequency cir
cuits of the structure, and those parts included
in or closely associated with such circuits, which
bear upon the precision of such control.
Important and signi?cant elements, combina
tions and sub-combinations will be described and
explained fully hereinafter. It is the present
purpose to outline in a brief and general way
the association with one another of the principal
elements and assemblies and to describe the
means for supporting and housing those elements
in order that the place in the general scheme
of the elements and combinations hereinafter de
scribed will be evident as the description pro
ceeds.
.
vacuum tube V'I'l .
The showing of Figs. 3 to 9, inclusive, is speci?
cally of what may be termed the receiver head,
Tap 53 is brought out through switch contacts
55 and “56 by connector 54 and is energized
through resistor 51 and choke 58 by a suitable ;
but it is to be understood that the transmitter
includes a similar .head, ‘differing from the re
ceiver head only in such minor details as will
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