DESIGN SPECIFICATION FOR A TERRAIN AVOIDANCE RADAR SYSTEM

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP89B00709R000400890022-4
• Release Decision: RIFPUB
• Original Classification: C
• Document Page Count: 54
• Document Creation Date: December 27, 2016
• Document Release Date: December 6, 2011
• Sequence Number: 22
• Publication Date: June 28, 1957
• Content Type: REPORT

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DESIGN SPECIFICATION FCR A
Submitted by:
WESTINGHOUSE ELECTRIC CCRPC RATION
Air Arm Division
Baltimore, Maryland.
(Westinghouse Reference: G.O. AAD30465)
June 2a, 1957
NOTICE: This document contains information affecting the national defense
of the United States within the meaning of the Espionage Laws, Title 18,
U.S.C., Sections 793494. The transmission or the revelation of its con-
tents in any manner to an unauthorized person is prohibited by law.
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TABLE OF CONTENTS
Summary
System Considerations
Antenna Considerations
Proposed System Specification
System Placement
Antenna Stabilization & Vertical Scan
Antenna Design
Synchronizer
"X" Scope
"E" Scope
PAGE NOS.
49 5 & 6
79 89 99 109 11 & 12
139 149 17 & 19
209 21 & 22
26
28
29 & 31
33 & 34
36 & 39
419 429 44 & 45
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LIST OF ILLUSTRATIONS
PAGE NO.
Fig. 1
KA Radar Range VS Antenna Gain
15
Fig. 2
Crossed Array Antenna Pattern
16
Fig. 3
Fig. 4
Parabola and Crossed Array Gain VS Area
Terrain Avoidance Radar System Diagram
23
Fig. 5
Components of Terrain Avoidance Radar
24
Fig. 6
Scanning Antenna & R?T Assembly
25
Fig. 7
Fig. 8
Location of Terrain Avoidance System in Aircraft
Simplified Horn Feed Sketch
30
Fig. 9
Horn Feed Sketch
32
Fig. 10
Synchronizer Block Diagram
35
Fig. 11
Transverse Profile Display Optical System
37
Fig. 12
Pilot's Profile Display
38
Fig. 13
"X" Scope Block Diagram
40
Fig. 14
"E" Scope Block Diagram
43
Fig. 15
Profile Display
46
Fig. 16
Power Supply Block Diagram
54
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SUMMARY
This specification describes a radar which functions as an aid in low
altitude flight. A sector in space centered about the aircraft's projected flight
path is presented in a three dimensional display. Azimuth and elevation are pre-
sented in true perspective. The third dimension, depth or range, is effected by
presenting the picture in colors as a function of range. This is the basic display
commonly referred to as a transverse profile or "X" Scope. An additional display is
incorporated whose use is optional. This display presents a range vs elevation pro-
file of the vertical plane containing the aircraft's flight path. This is commonly
referred to as a profilometer or "R" Scope. As an added feature, this profile plane
may be positioned at some angle in azimuth with respect to the vertical plane con-
taining the aircraft's flight path to enable exploration in detail of terrain to
either side of the flight path. The selected profile can be marked by a line on the
transverse profile to enable correlation of the two displays.
Detailed specifications of the system are as follows:
ANTENNA CHARACTERISTICS
Antenna beamwidth:
C. Vertical 10
Horizontal 1.50
Scan Sector:
Vertical 10?
Horizontal 30?
Scan Rate:
Vertical 2/3 cps modified sinewave
Horizontal 16.5 cps linear sawtooth
Drift Angle Stabilization: To 150 from aircraft centerline in any
direction (to correct for drift angle at
any bank or roll angle).
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Magnetron Type:
Frequency:
Power:
Pulse Width
System noise figure:
Receiver gain:
Receiver IF bandwidth:
Klystron types
Receiver Tuning:
Local Oscillator frequency:
Intermediate frequency:
Range Gate:
Minimum range
Maximum range
Presentation:
CRT Type:
Marks:
TRANSMITTER CHARACTERISTICS
MAm207
349900 ? 350 MC
60KW (nominal)
.25 microseconds
1365 pulses per second.
RECEIVER CHARACTERISTICS
12.5 db
91 db
4.2 MC
Varian VA-97
Manual or AFC
45 MC above transmitter
45 MC
.25 ?.1 N. Miles
10 or 20 N. Miles, variable ? 25%.
INDICATOR CHARACTERISTICS
Azimuth vs elevation in 3 colors to
represent range segments.
RCA C73703B storage tube with selective
erase gun.
Aircraft's flight path Horizontal
reference.
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OPTIONAL PROFILE INDICATOR CHARACTERISTICS
Presentation: Type C (Range vs Elevation).
CRT Type: 5 UP 7
Marks: Cursor, 1000 ft. elevation marks.
Electronic, 1 mile marks.
Weight: Basic System 206 lbs.
Optional navigators 'r' and-"C" Scopes
35 lbs.
Environmental Conditions: -550C to +55?C
Altitude to 15,000 ft. operating
Vibration per mil E-5400
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SYSTEM CONSIDERATIONS
In a terrain avoidance radar it is desirable to have high scan rates and
narrow antenna beamwidths from the system performance point of view. This involves
large antennas which are aerodynamically undesirable and the larger the antenna,
the more difficult it is to scan at high rates. These are not the basic limitations
in this system, however. A certain minimum number of hits per beamwidth are re-
quired to insure detection of small targets. The product of beamwidth and scan
rate or beamwidths scanned per second multiplied by the number of hits per beam-
width required determines the PRF. This is the basic limitation. Unless severe
restrictions are placed on all three parameters the PRF is so high that, using the
minimum pulse width which it is possible to generate with the magnetron, the
average power rating of the magnetron is exceeded. Reducing the pulse power is
not practical since this leads to difficulty with the magnetron not operating in
the desired mode. Attempts along these lines with presently available magnetrons
lead to a broad spectrum and unsatisfactory power output at best. Thus, it is
necessary that resolution, scan rate and hits per beamwidth be no better than re-
quired. This is particularly true if the 6799 magnetron with a .0002 duty cycle
is used. The MA-207 with a .0004 duty cycle will allow better resolution or scan
rates but its peak power is only 70 KW maximum as compared to 200 KW maximum for
the 6799 magnetron. These are the two highest power magnetrons presently available
for Ka band. Due to the nature of the targets and the near grazing incidence
angles, the return signals will be small. In addition the C Scope type presenta-
tion where noise is integrated over a long time or range interval requires a better
signal to noise ratio than a radar system using narrow range gates. The minimum
detectable signal is not determined by received power but by its ratio to the noise
level. Since noise is a function of receiver bandwidth, it can be minimized by
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using a wide pulse. The PRF is determined by considerations of beamwidth, scan
rates and number of hits per beamwidth so that it may be considered independent
as far as signal to noise considerations are concerned. Thus the maximum usable
pulse width is determined by the maximum power capability of the magnetron. The
pulse width may be increased until the maximum permissable average power is dissi-
pated in order to realize minimum receiver noise, assuming that the peak pulse
power was made maximum to obtain maximum signal return. Any further increase in
pulse width requires that the pulse power be decreased and the signal decreases so
that the signal to noise ratio decreases. Thus the magnetron is a primary limita-
tion in this system.
The question of resolution capability involves a compromise between
practical antenna size and resolution desired. This resolves into a question of
aircraft performance and minimum clearance above terrain obstacles the pilot would
desire to maintain. The minimum clearance is determined by flight conditions, type
of terrain, the individual pilot concerned and aircraft speed. This is displayed
as an angular clearance. Range segments are identified by colors. Range is thus
known accurately where the display changes color. If we choose red for the shortest
(or most dangerous) range, the pilot must steer to keep all red targets below the
aircraft. It is desirable to make the range below which this angular clearance is
maintained the minimum consistent with safety. For a given aircraft and speed it
is a function of the number of degrees an obstacle will be allowed to extend above
the flight path in the preceeding range interval or display color. The minimum
angular clearance is limited by antenna beamwidth or resolution. The shorter the
range at which the desired absolute clearance can be steered for, the larger the'
clearance angle becomes and, the wider the permissable beamwidth becomes. For a
given beamwidth, the shorter the range at which the desired clearance is maintained,
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the smaller the desired clearance may be. Two parameters, minimum clearance and
maximum angle which an obstacle is allowed to extend above the flight path up to the
point where minimum clearance is steered for, must be selected on the basis of ex-
pected aircraft performance. Once these are selected, the range at which minimum
clearance is steered for can be determined on the basis of ground speed and maximum
number of g s turn desired, assuming the maximum constant-speed climbing angle of
the aircraft is not exceeded. If a minimum clearance of 150 feet and a maximum
angular elevation of an obstacle of 50 above the flight path (the top of the display)
are selected then the range at which this clearance is steered for is 9000 feet for
an aircraft traveling at 300 MPH if a lg turn and a linear climb angle of 7.50 is
utilized to climb over the obstacle. This allows 2 seconds for pilot reaction,
1.5 sec. scan time and 1 sec. for aircraft response. A 1.5 sec. frame time is the
minimum that will allow the desired coverage and resolution without exceeding mag-
netron capacity. The scan time is 1.5 seconds only at the edge of the display and
decreases to .75 seconds at the center. Thus, this scan time is necessary only in
the case of an obstacle extending to the limit of the display. It should be noted
that this range and minimum clearance can be varied to suit different aircraft by
adjusting the range gating of the red display. Thus, to clear an obstacle the
pilot must pull up until the desired clearance angle is indicated, then he must hold
this climb angle to clear by some distance. If he continues to use the terrain
avoidance display to maintain the desired clearance angle, he must continually
decrease his climb angle and will steer into the peak of the obstruction. A speed
of 300 MPH was chosen as a realistic condition. For a slower aircraft the problem
is less severe. For a faster aircraft it is only necessary to lengthen the red
range gate.
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The resolution required must be determined on the basis of the clearance
angle and how close together it is desired to separate two objects. The resolution
in terms of beamwidth is a function of the gain and display brightness adjustment.
The worst case must be where the resolution is equal to a beamwidth and will be used
as the basis to determine beamwidth required. A minimum clearance of 150 feet may
be accepted as reasonable. This can be resolved at 1.5 H. Miles or 9000 feet by a
10 beamwidth. Thus, a one degree beamwidth'will allow 150 feet resolution at the
limit of the red range. This appears adequate for vertical resolution. A narrower
beamwidth may be advocated for better display resolution, but the extra capability
it would permit is not adequate to justify the additional antenna size and the re-
duced sector coverage or scan rate necessary to stay within ratings on the magnetron.
The possibility of multiplexing two magnetrons to allow higher scan rates was con-
sidered, but this would require two complete radars except for a common antenna and
indicator. It is not felt that this is practical. A more satisfactory solution
would be the development of a magnetron with a higher duty cycle rating. This could
not be undertaken within the time span of the present contract. How close it is
desired to separate two objects laterally is determined by how narrow a path between
two objects it may be desired to fly. If it is assumed two objects must be at least
300 feet apart for an aircraft to fly between them, an antenna beamwidth of 1.5
degrees will allow them to be resolved at 2 miles. Thus, vertical beamwidth of
1.00 and horizontal beamwidth of 1.50 should be adequate. To steer around an object
rather than over it is considerably easier in terms of aircraft performance so that
the requirements for vertical clearance may be used for horizontal clearance.
Closer clearance could be used which would require a narrower horizontal beamwidth
if it would increase aircraft capability. It is not necessary to fly as close to
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an object when flying around it as when flying over it to avoid radar detection so
that nothing would be gained by increasing this capability over that set by the
1.50 horizontal beamwidth.
A desirable presentation would be one in which red is used to indicate
the nearest or most dangerous range, yellow for medium range and green for maximum
range. The red range must extend to 9000 feet or 1.5 N. miles to determine the
range at which minimum clearance is steered for. Yellow covers the range over
which an object is allowed to extend 50 above the flight path (assuming no possi-
bility of steering around the object). This range should be small so that the
range where no restrictions are imposed on aircraft attitude may be large. It
should also be small so that a higher effective signal to noise ratio and, conse-
quently, more reliability achieved in this region preceeding the danger zone. A
range extending from 1.5 to 3 miles appears reasonable. Thus green represents a
range of from 3 miles to the maximum of which the radar is capable.
The horizontal or line scan rate should be made as slow as is consistent
with a sufficient number of scans per vertical beamwidth so that the PRF may be as
low as possible and still achieve a sufficient number of hits per horizontal beam
width. The PRF should be low so that the widest pulse possible can be used, con-
sistent with magnetron average power capability. A wider pulse results in less re-
ceiver bandwidth and consequently a lower noise voltage and a higher signal to
noise ratio. Thus, horizontal scan rate and hits per beamwidth conflict with
signal to noise ratio. A horizontal scan frequency of 16.5 cps appears to be about
the minimum permissable. This will allow at least 1 scan per vertical beamwidth for
a target of zero height. Two scans per vertical beamwidth will be achieved for a
target 105 feet high at 1 mile, or 210 feet high at 2 miles. Thus, most targets of
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interest will be scanned at least twice. This is based on a vertical scan having
a maximum speed of .0613 second per beamwidth. This is midway between the maximum
slope of a sinewave and a linear scan. This appears to be a reasonable compromise
between the desired linear scan and a reasonable drive power requirement during scan
reversal.
The PRF should be made the minimum that will insure target detection
since the signal equal to the RM'3 noise level (and consequently having the same
probability of being exceeded by noise) is directly proportional to the PRF, since
PRF determines maximum pulse width for a given magnetron. Thus, if twice as high
a PRF is used to achieve more hits per beamwidth, then twice the signal voltage is
required to be detected with the same reliability. The horizontal sector scanned
should be 30? wide to present an adequate view of the surrounding terrain. With
this coverage a PRF of 1365 cps will be used. This will allow a pulse width of
.25 usec., with the MA-207 magnetron. For a zero width target, 4 hits per beamwidth
will be achieved.
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ANTENNA CONSIDERATIONS
!1 ( ' c C ) l A ' C
There are two basic antenna configurations to choose from. One consists
of a so-called pencil beam antenna which focuses the energy into a narrow solid
angle. This requires an antenna with a relatively large frontal area. This an-
tenna serves as both a transmitting and receiving antenna. Typical examples are a
paraboloid of revolution or a cylindrical parabola fed by a sectoral horn. The
other type consists of crossed fan beam antennas. Separate receiving and transmitt-
ing antennas are used. One focuses energy into a narrow beam in one plane, but is
relatively broad in the perpendicular plane. Another similar antenna rotated 90?
is used also. The effective receiving area (or beamwidth) is then the intercept of
the two. These antennas are relatively long (length determining beamwidth) and
narrow. This type antenna system is commonly referred to as a crossed array, since
they usually consist of linear arrays.
A pencil beam antenna is necessary if this system is to have sufficient
gain to give adequate range coverage. Crossed arrays achieve a frontal area reduc-
tion at the expense of gain.
Without attempting to evaluate target characteristics, an estimate of the
antenna gain necessary may be made by interpolation from other Ka band radars de-
signed and built by Westinghouse Air Arm. It may be assumed that system gain, ex
elusive of antenna gain is comparable except as noted. An experimental terrain
avoidance radar has an antenna gain of 40db and an additional gain of about 10db
derived from a coherence detector. This detector involves considerable extra equip-
ment and must use standardized video, thus deteriorating angular resolution. For
these reasons it is not planned to use it in the present system. Thus the correct
relative antenna gain is 50 db for the experimental radar.
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ANTENNA CONSIDERATIONS (Contod.)
The range for "strong signal" return is approximately 4 miles. Another
radar has an antenna gain of 90db plus an additional gain of 25db attained through
film integration. Thus the correct relative antenna gain is 115db. This radar has
a strong signal range of approximately 18 miles. These points are plotted in
Fig. 1 . Interpolation from this graph reveals that an antenna gain of 90db is
needed for a range of 10 miles. A pencil beam antenna having a beamwidth of 1? by
1.5? will have a gain of 87db. This indicates a range of.about 905 miles. These
are reliable ranges where good terrain coverage may be expected. Under most condi-
tions larger targets should give returns at ranges up to 20 miles or better.
It may be shown that a crossed array can achieve an area reduction over
a pencil beam antenna for a given beamwidth only at the expense of antenna gain.
The two-way gain of a crossed antenna array for a given wavelength may be expressed
G = K Area :l XArea 2 where subscripts 1 and 2 refer.
19Vl % N2
"V2 6Hl
to the two crossed antennas and H and V refer to horizontal and vertical. Refer-
ence to Fig. 2 will help clarify this. The areas represent the gain of the antennas
while the denominator represents the crossing loss or the fractional intercept in
the two planes. Since area = length X width and since the angular beamwidths are
proportional to the proper linear dimension, this may be expressed
G = K L1 W1 X I2 W2 = KW12W22. Thus the gain varies with area as in
L1KL2
W2 W1
any antenna, provided the proper area is considered0 This area W1W2 is the inter-
cept area and is independent of the antenna lengths and consequent beamwidth.
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Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
GONFIDENiIAI.
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
ANTENNA CONSIDERATIONS (Cont'd.)
A family of curves, one for each beamwidth, may be plotted of area vs
gain for crossed arrays. Such a plot is shown in Fig, 3 for arrays having two
identical antennas. The area vs gain and beamwidth curve for a parabola is shown
for comparison. Interpretation reveals that a crossed array having the same beam-
width as a parabola has 10db less gain for the same total area, ?21db for * the area,
and -32db for j the area of a parabola.
A parabola having the desired 87db gain has an effective area of 376 sq.
in. A crossed array having the desired 10 X 1.50 beamwidth and 87db gain would
have a total area of 564 inn but an intercept area (Wl 'W2) of only 200 in 2 The
only usable configuration would be to make Wl = W2 = 14,1 in, Thus two antennas
14.1 x 16 and 14,1 x 24 inches would be required. The beamwidths would be 1,68? x
1.50 and 1,680 x 10. This would not be a very practical antenna system since both
antennas must be scanned in both planes.
It appears that 70db is about the highest gain obtainable with a crossed
array suitable to this system. It would be 2.38 x 16 inches and 12.3 x 24 inches
so that one antenna would have a beamwidth 100 x 1.50 and would need to be scanned
in only one plane if oriented so the 100 is vertical to cover the desired sector,
The other antenna would have a beamwidth of 10 x 20 and would have to be scanned in
both planes. This antenna array would have 330 in? fromtal area as compared to
376 in 2 for a parabola having the same beamwidth and 87db gain. In all cases no
allowance has been made for cross polarization loss with crossed arrays.
It is felt that feed scanning of a sectoral horn represents a satisfactory
method of achieving a rapid scan.
A simplified laboratory set-up using linear reciprocal feed movement pro-
duces the required 300 scan, This set-up is now being extended to test the scanning
CONFIDENTIAL
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
n u ^-_ KEUFFEL & ESSER 'aJR t IN U.S.A.
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Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
ANTENNA CONSIDERATIONS (Contd.)
obtainable with a circular feed mechanism to use simple rotary movement of the feed.
This method promises to be simpler and less critical of mechanical tolerances than
the moving backwall method of scanning used in a present,experimental model,
CONFIDENTIAL
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
PROPOSED SYSTEM SPECIFICATIONS
It is proposed to cover a sector 30 degrees wide horizontally by 10 degrees
vertically. This appears to be a reasonable compromise between sector coverage on
one hand and scan rate and beamwidth on the other. On the basis of considerations
of aircraft performance as previously discussed, an antenna beamwidth of 10 verti-
cally by 1.5? horizontally in the center of the display will be the nominal objec-
tive. Some deterioration of the beamwidth at the edge of the display will occur.
A moan rate of .67 cps (or an up and down moan in 1,5 sec.) in the vertical plane
and a 16.5 cps sawtooth scan in the horizontal plane will be the objective. This
will depend on the feasibility of a horn feed moan system covering 30?. If this
does not prove feasible, the horizontal moan rate will be made .67 cps and the verti-
cal moan rate 33ops. This will require a horn feed scan through only 100.
The antenna will consist of a seotoral horn feeding a cylindrical parabola.
The rapid moan will be effected by scanning the feed across the throat of the horn.
The slow scan will be effected by rocking the entire antenna and receiver-transmitter.
An antenna gain of 45db (one way) will be the design objective. It is expected that
the parabolic antenna will have a 24 inch x 24 inch frontal area.
It is desirable to control the antenna orientation to compensate for
drift angle so that the display is centered about the flight path. It is planned
to compensate for a drift angle up to 15? maximum. This correction will be per-
formed when the aircraft is banking also, thus requiring two degrees of freedom.
It is planned to allow t15? of freedom in the vertical plane so that a 15? drift
angle can be corrected for with the aircraft banking at 90?. Provision will be
made to allow manual correction for variation of aircraft trim angle with changes
in load.
CONFIDENTIAL
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
PROPOSED SYSTEM SPECIFICATIONS (Cont'd.)
It is planned to use the MA-207 magnetron for a transmitter. While this
magnetron has a maximum pulse power rating of only 70KW as compared to 200KW for
the 6799, its duty factor is twice that of the 6799. A pulse width of .25,usec can
be used as compared to .1 }sec with the 6799. The relative range may be expressed
as:
R PP(6799) (6799) _ 200 x _ 103
(m207) P
70 .l .
p(07) (1`'207)
Under actual conditions the MA207 with a Phillips cathode will produce a 50 or 60KW
pulse for an appreciable life, while the 6799 will not produce 100KW for any sub-
stantial period. It produces only about 50 or 60KW for any appreciable time.
Thus the MA-207 in practice may be expected to actually have considerably greater
range. Even assuming the 6799 may be improved to have adequate life during which
it will produce 200KW, it is not felt that the small additional range advantage
justifies the extra weight. At least 40 lbs, can be saved in magnetron and modula-
tor weight. If we estimate a possible range of 20 miles for the system with a
MA_207, the range would be only 20.6 miles using a 6799.
The transverse profile display (tentatively referred to as an "X" scope
on drawings, pending assignment of an official nomenclature) is the basic system
display which is presented to the pilot. A flight path profile is also displayed
on an "E" scope. This scope will be located at the navigators position along with
an additional "X" scope. These two scopes are optional and may be removed from the
system at will. Means will be provided whereby the navigator may display profiles
to either side of the aircrafts flight path on the "E" Scope. A line will be dis-
played on the navigator's "r Scope indicating the location of the profile being
displayed.
CONFIDENTIAL
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
PROPOSED SYSTEM SPECIFICATIONS (Cont'd.)
It is planned to incorporate means to enable monitoring of system perfor-
mance. On the basis of experience with another Ka radar it is believed to be
feasible to measure altitude up to possibly 1000 feet. This will serve to prove
that the radar is operating satisfactorily as well as indicating altitude. This
will be displayed by displacing the "E" Scope trace once every vertical (or slow)
scan and gating the receiver on during this interval when the receiver is normally
off. Sufficient energy should be available from the antenna side-lobe for the
altimeter function. An alternative possibility for checking radar performance
would be a small antenna and untuned echo-box located so that energy is directed
into it at the top of the vertical scan.
CONFIDENTIAL
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
."T.. & R. F. HEAD
ECHO BOX
PO
ALT.
(ON SIDE
LOBE)
16.5 CPS
HOR,
DRIVE
--OTOR;
SCAN
REF.
IXMITTER
VERT.
DRIVE
MOTOR
VERT
SWEEP
GEN.
2/3
CPS
CONFIDENTIAL.
SCAN
LIMIT
SELECTOR
SWITCH I
ANT. EL.
STABILIZATION
SERVO
ANT. AZ.
STABILIZATION
SERVO
CRYSTAL
AFC
REC.
2
MONITOR
(SYNCHRONIZER
ROTARY
,IatNT
MIXER
R,.ECEIVER
ATR
ST C &
RANGE
GATE
ISOLATOR
SYSTEM- CHECK
DISPLAY
NORMS V I E O
ALT.
ALT
\MARKS~
MIXER
I
AFC
RANGE
RANGE
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FLIGHT(
ALT.
LINES
PATH RANGE
PROFILE MARKS,.
SCOPE
HEADING 8RI TNESS
r/G,- TCRRAIAI AlJflU AMI'C DAnAn CV[rru n.ilnnAlDeclassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
{ PROF (,LE SELECTOR
BRIG~4tNESS
IMAGE BOSITION
SUPPLY
DRI T
A LE
PROFILE
LOCATION
CONFIDENTIAL
 POWER SUPPLY
W T. 2 5 L85.
VOLUME 18901~1
CONFIDENTIAL
6n
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
SYNCHRO1,S1Z
WT, G LBS.
VOLUME 3241N'
X,. SCOPE
WT. 20 LBS.
VOLUME 1443 IN.
8
MODULATOR
WT. 12 LBS.
VOLUME -678 INS
(OP -r o ,. L.)
?.
E..5C0PEr
WT. \ L85.
VOLUME 2 2 G 8 INS
r.
AZIMUTH AND ELEV. SERVO
W T. 8 LBS.
V ~LttMi; 53 9 trs
6
FIGS C OM Q IEE`sT~ OF TERRA`vN 4,VO\DANCE R 4,D AR
I&
2EC~I'v'ER TRAN'SMTTER
WT. 3Z LE,S.
VOLUME G801N3
CONFIDENTIA4
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
SYSTEM PLACEMENT
The recommended placement of the equipment is shown in Fig. 7. The
navigators "X" Scope and "E" Scope with synchronizer attached will be located at
the navigators station in a manner dictated by the available space. The exact lo-
cation of the pilot's indicator is not known at present. It is assumed that some
panel space will be available as shown, The optical system shown attached to the
front of the "X" scope in Fig. 5 is the basic arrangement which is suitable'at least
to the navigator's indicator. The image may be projected onto a screen at a greater
distance placed at an angle with respect to the indicator if, as seems likely, this
is required to fit the indicator in the available space. The possibility of having
the indicator head located remotely from the associated circuitry was explored and
discarded due to the excess circuitry required.
The power supply, modulator and azimuth and elevation servo will be lo-
cated in the forward equipment bay in a manner suitable to the available space.
The R.F. head, consisting of the antenna and associated drives, receiver,
transmitter and AFC could be located in a chin radome as shown. The exact location
of this radome depends upon aerodynamic considerations and the field of view of
other radars. Part of this assembly will project into the aircraft to minimize ex-
ternal surface. It is apparent that the frontal area of the antenna does not nec-
essarily represent additional frontal area on the aircraft. Instead it represents
a modification of the contour. The feasibility of placing the antenna so as to
merge the radome with the radome of another nose radar will be investigated.
- 26 -
CONFIDENTIAL
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
- I NS'f UMIEN T
i'ANEL
FIAT' I CAT AS
P O S I T I CNI
"Es" SCE &
S E'NCH .2N ZER
P :;WER SUP L93
MDULA d ``I'
AZ. & Q. . SERVO
FIG-IF L'JCAT 1' N F Tien AIN A1010ANC: S` : TFX IN A1Rc! AFT
CONFIDENTIAL
t 1 1 1 t I f f
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFkDEH~
ANTENNA-
DISH
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
ANTENNA STABILIZATION AND VERTICAL SCAN
It is planned to mount the antenna on gimbals so that it has two degrees
of freedom. Hydraulic actuator mechanisms will be used to save weight and size.
Drift angle must be provided as a shaft position. This can be supplied
automatically by a doppler radar or manually by the navigator. Roll angle must also
be supplied. The feasibility of obtaining this information from the doppler radar
will be investigated. If not available, a reference gyro will be used to furnish
this information. To correct for drift angle when the plane rolls (or is banking)
requires that drift angle be resolved into components referenced to the aircrafts
vertical and horizontal. That is, elert(AC) = sin eroll X 9drt and 9Hor(AC) _
cos eroll X edrift. This requires a resolver to operate on the required roll and
drift angles to convert to correction voltages. Servos will position the antenna
in accordance with these correction voltages. One servo and associated drive will
control antenna position in the aircrafts horizontal plane. Fifteen degrees of
travel to either side of the aircrafts centerline will be permitted. The antenna
must scan 100 in the aircrafts vertical plane at a 2/3 cps rate. A hydraulic
actuator will be used to drive the antenna. This scan in the absence of a drift
angle will be 50 above and below the aircrafts centerline. A drift angle component
in this plane will cause the center of the scan to shift with respect to the air-
crafts centerline. This will be performed by the other servo loop. The objective
will be .250 static and .50 dynamic accuracy in the two servo loops.
CONFIDENTIAL
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
ANTENNA DESIGN
The design problem is that of obtaining the desired beamwidth and scanning
motion while simultaneously maintaining minimum beam distortion. The 10 vertical
and 1.50 horizontal beamwidths are to be maintained within 0.5? throughout the 100
vertical scan and the 300 horizontal scan. The beam shape is to be optimized in
the straight-ahead position.
The plan for attacking this problem is to design the antenna feed system
such that the 30? horizontal scan is obtained by using simple circular motion at a
frequency of 16.5 cps. The feed will be of a suitable configuration to beam-shape
the power distribution into the required 1.50 horizontal beam. The feed will
irradiate a cylindrical parabolic reflector that will shape the energy into a 10
vertical beam. The scanning action in the vertical plane will be obtained by
having the feed horn and reflector combination sweep through a 10? angle at the
rate of 2/3 CPS.
The following description of a scanning antenna configuration is the
direction the antenna design is proceeding.
A simplified view of the feed is shown in Fig. 8. Outline AFBCD is a
view of a pair of parallel plates spaced approximately /l/2 apart. Consider the
horizontal beamwidth required and aperature CD is fixed approximately. Bisect CD
at G and make 150 angle lines with the bisecting line, GEF. Sketch waveguide feed
horn outlines on the ?15? lines such that the power distribution clears aperature
DC at least -12 db down. With G as center, draw are AFB. Sketch another wave-
guide feed horn at F on the bisecting line GEF. Its power distribution pattern
should clear aperature CD like positions 1 & 2 and all intermediate positions.
Far field patterns for all these positions should show little or no distortion of
the primary power distribution.
- 29 -
CONFIDENTIAL
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
F7 G. 8 SIMPLIFIED HORN FEED SKETCH
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
Are AFB is the locus of waveguide horn scan movement. To simplify the
waveguide horn scan motion, the parallel plates are folded into a circle at AFB
so that A and B Join. See figure 9.
Since it is necessary for a 1.5? beam to emerge from aperature CD, beam
shaping of the waveguide feed horn power distribution is necessary. For this reason
aperature CDG is formed to approximate a parabola and parallel plates DGCH of
Figure are placed so as to change the power direction by 90? while narrowing the
power pattern in the horizontal plane.
The final feed aperature is CHD as shown in Figure which feeds a cylin-
drical parabolic reflector narrowing the beam in the remaining vertical plane.
The result is an antenna unit that scans ?15? in the horizontal plane at
16.5 cps. The 2/3 cps vertical scan is obtained by nodding the entire antenna
unit.
CONFIDENTIAL
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
F16.9 HORN FEED SKETCH
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
SYNCHRONIZER
The synchronizer chassis provides the following:
(a) System repetition rate pulses.
(b) Color display switching time pulses.
(c) Stretched video pulses for the X-Scope.
(d) Color display position marks.
(e) Monitor for system voltages., receiver and AFC crystal
detector currents, and magnetron average current.
The repetition rate is obtained by means of a crystal-controlled transis-
torized bistable divider chain which converts the 81.94KG ? .02% crystal oscillator
frequency into pulses occurring at a repetition rate of 1365 ? 0.1% pulses per se-
cond.
The use of silicon transistors for this function enables considerable
weight and power savings.
The color display switching time pulses determine the radar range at which
received ethos are changed from a red display to a green display on the indicator CR
storage tube.
The stretched video pulses enable the storage tube to produce the desir-
able brilliance from the narrow video echo. Video amplitude variations are pre-
served in the stretched video so that echo shading is provided in the display.
Stretched video is removed during the fly-back time of the horizontal sweep by means
of the horizontal reset pulse from the antenna unit.
The color display position marks enable the operator to properly orient
the storage tube display with respect to the optical system. These marks are pro-
duced when the antenna is in the maximum vertical position and mid-point of hori-
zontal sweep.
- 33 -
CONFIDENTIAL
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
SYNCHRONIZER (Cont?d.)
The monitor section provides (by means of a rotary switch and panel meter)
rapid checking of all system supply voltages and also of crystal mixer current in
both the Receiver IF and fFC IF units, The average value of the magnetron current
is also indicated.
Weight of the synchronizer chassis is estimated at 6 lbs. The volume is
325 cu. in.
- 34 -
CONFIDENTIAL
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
81i9~3KC
OSC
1 10
VIDEO INPUT
FROM POST AMPCIFIER10
HORIZQ SWEEP
RESET PULSE
ANTENNA MICROSWITCH
PEAK VERTICAL TIME
HORIZ. SWEEP
CENTER PULSE
SHAPER
y 60
MILE
MARKERS
COLOR SWITCH ENG
DELAY (36 " S)
2 STAGE
VIDEO AMPLIFIER
RETRACE
BLANKING
CIRCUIT
IMAGE
POSITION
MARKER
GEN.
OR
CIRCUIT
SYSTEM SUPI;LY VOLTAGES,
RECEIVER IF CRYSTAL MIXER
CURRENT, AFC IF CRYSTAL
MIXER CURRENTIMAGNETRON
PULSE CURRENT
ROTARY
SWITCH
BLOCKING
ip, (FOR USE WITH OPTIONAL)
E TYPE DISPLAY
BLOCKING
OSCILLATOR
PULSE
STRETCHER
P
INDICATING
METER
FIG-10 SYNCHRONIZER BLOCK DIAGRAM
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
1365
REP. RATE
OUTPUT
TOTUBESTORAGE
30. INDICATOR
VIDEO & POSITION
4" MARK TO X SCOPE
35
CONFIDENTIAL
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
X-SCOPE
A transverse profile display will be provided for the pilot and will be
installed on, or near, the instrument panel. This display may also be remoted for
the navigator's observation. The transverse profile and display will be a modified
"C" scope in which range will be quantized and presented by the use of three con-
trasting colors. Such displays have often been referred to as type "X" indications.
The display presented to the observor will be projected data; originating
in two images on a single storage cathode ray tube. The optical system is shown in
Fig. 11. These time shared images correspond to the video profile data contained in
two different range segments and will have the dimensions of azimuth and elevation
angle. These images are color filtered, optically combined and then projected into
the viewing screen. Normally such a system would yield two colors after projection;
but due to a time overlap (as a result of "stretched" video) a third color is pro-
duced. The three colors will be red, green and their optic combination - yellow.
Near targets will appear in red, far targets in green and those targets in an inter-
mediate range will appear yellow. A storage type CRT is necessary to provide ade-
quate brightness at the slow scan rate used.
In addition to the color profile display, certain navigational indices
will be provided. Among these are a set of parallel lines, indicating the aircraft
bank angle, and an aircraft heading mark at the center of the display. Another
feature may be the indication of altitude. An artist?s conception of the indicator
is shown in Fig. 12. Since the antenna is wind stabilized, the center of the pic-
ture will always represent the terrain directly in the flight path of the aircraft.
The flight profile will normally be selected along this line. However, its position
may be shifted to the left or right. An electronic marker on the "X" Scope will
- 36 -
CONFIDENTIAL
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
2 MIRROR
C~ DICHROIC
4 SCREEN
FIG? f/ TRANSVERSE PROFILE DISPLAY OPTICAL SYSTEM
CONFIDENTIAL
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
a.v~rvc~ ^a~
Vi
Figure/2 Pilot's Profile Display
-38-
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 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
X-SCOPE (COIN' D, )
indicate the profile selected. It is not felt desirable to display this on the
pilot's scope, however the two "X" scopes are identical and it may be displayed
on either or both.
The block diagram of the "X" scope is shown in Fig. 13.
The RCA Type C73703B is a developmental 2-writing gun storage tube. The
viewing gun is used somewhat conventionally; however, one of the writing guns is
used for erasure. Both guns are driven by the same deflection signals with a phase
shift between the two in the vertical direction. This allows erasure just prior to
writing which conserves storage but elliminates flicker.
The vertical deflection signal is a DC signal derived from a pot located
at the antenna. A trigger pulse at the start of each horizontal scan actuates the
start of the horizontal sweep. The phase shift between the horizontal writing and
erase signals is synchronized by pulses from the antenna at the extreme excursions
of the antenna. Video signals and blanking pulses are amplified by the video ampli-
fier and applied to the cathode ray tube.
- 39 - CONFIDENTIAL
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
'H ORIZ.
. ANT.
I TRIG
VERT. ANGLE DATA
UP
DOWN'
VERT.
DEFLECTION
DRIVER
O
SLE
rrTTTt .
COLOR GATE
TRIG.
BLANKING
"STRETCHED" VIDEO
SYNCHRONIZER -j
HORIZ,
DEFLECTION
DRIVER
HORIZ.
ERASE
DRIVER
VIDEO
AMP.
VERT.
ERASE
DRIVER
v SCnPF fl nCK DIAGRAM
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
60,000 ' A
SNEER
GEN.
ANT. SWITCHES
CONFIDENTIAL
CRT
C73703B
CONFIDENTIAL
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
E SCOPE UNIT
The E Scope or Profilometer is an auxiliary unit which will provide the
system with additional information, which could be utilized by a copilot or naviga-
tor.
The E Scope unit contains a 5 inch Cathode Ray tube which displays aircraft
altitude information and terrain profile information. It also provides video for
use with a companion X Scope unit.
The face of the E Scope contains cursor marks which indicate altitude for
both the altitude and terrain displays. The altitude display cursor consists of a
horizontal line in the upper half of the tube face which is marked in intervals of
100 feet. The profile display cursor consists of horizontal elevation lines which
indicate heights in intervals of 1000 feet for objects in the profile display which
appear either above or below the aircraft altitude. The corresponding radar range
of these objects are indicated electronically by means of markers occurring at
appropriate intervals during each sweep.
The aircraft altitude information is displayed once during each vertical
cycle of the antenna when the antenna is at its maximum depression angle.
The terrain profile information is displayed by sampling the echo returns
from any one sector of the antenna's azimuth coverage. The azimuth sector sampling
is subject to operator control by means of a calibrated "Profile Selector" dial.
The azimuth sector which is being displayed is continuously indicated on
the companion X scope by means of a brightened vertical line. With this provision,
the operator may observe the X scope while turning the profile selector dial on the
E Scope unit until the brightened vertical line coincides with the terrain to be
observed. Altitude and range information for objects in the selected terrain sec-
tor may then be obtained from the terrain profile display on the E Scope.
- 41-
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 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
The E Scope may also be used to monitor certain test points in the system'
by rotating the display switch on the E Scope unit.
CIRCUITRY (Refer to Block Diagram Fib{. 14
All inputs (except the antenna vertical sweep voltage) are supplied auto-
matically to the E Scope unit whenever the synchronizer unit is plugged into its
receptacle in the E Scope unit. The only electrical output of the E Scope unit is
the video which supplies information to the companion X Scope.
With reference to the block diagram, it is seen that the horizontal sweep
gate controls all displays on the E Scope. This horizontal sweep gate is started
whenever the and circuit receives two inputs simultaneously. One of these inputs
is the rep. rate pulse and the second input may be either the altitude display gate
or the profile display gate. This arrangement guarantees synchronization of dis-
play sweeps with the rep. rate.
When the gate is started it unblanks the E Scope and starts the horizontal
sweep generator. The horizontal sweep generator drives the horizontal deflection
amplifiers which in turn apply the horizontal sweep voltage to the E Scope.
It is planned to provide for switching on either a 10 mile short range or
a 20 mile range gate for long range surveillance. The 10 mile gate is preferable
for close-up use as it provides better resolution.
The gate also enables the vertical sweep generator which converts the
voltage from the antenna vertical sweep potentiometer into a linear sawtooth sweep
voltage which is then applied to the vertical deflection amplifiers which in turn
supplies the vertical sweep voltage to the E Scope.
By moving the display switch from the "normal" position to the "video"
position, the vertical sweep is removed from the vertical deflection amplifiers and
input video signals are substituted. This permits observation of video from
-42-
CONFIDENTIAL
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 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENtIAL
MILE MARKERS
FROM SYNCHRONIZER
VIDEO FROM
SYNCHRONIZER
VERTICAL
DEFLECT
AMPL.
VIDEO `'NORMAL
DISPLAY
SWITCH
REP. RATE PULSE .
FROM SYNCHRONIIER
VIDEO
AMP L.
AND
CIRCUIT
MIXER
ANTENNA MICROSWITCH
PEAK VERT. TIME
r
HORIZ.
DEFLECT.
AMPL.
HOR I Z.
SWEEP
GEN.
HORIZ. SWEEP
RESET PULSE
10 MILE
HORIZ, SWEEP
GATE
PROF I LE
SELECTOR
CIRCUIT
CALIBRATED
PROFILE
SELECTOR
DIAL
PROFILE
DISPLAY
GAT E
PROFILE
MARK
GEN.
VIDEO & POSITION
MARK PULSES FROM
SYNCHRONIZER
F~G?14 E SCOPE. BLOCK DIAGRAM
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
ALTITUDE
DISPLAY
GATE 3000 AS
UNBLANKING
CIRCUITRY
ALTITUDE
SWEEP
SPEED-UP
VERT.
SWEEP
GEN.
ANT EN$A
V ERT CAL
SWEEP
POT.
"-VIDEO, POSITION MARK,
& P OFILE MARK TO
NAVIGATOR X SCOPE
43 '
CONFIDENTIAl.
 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
receivers or other system test points when connected to the video input Jack of the
synchronizer unit.
When the antenna moves to the extreme vertical position, the altitude dis-
play gate is triggered by a microswitch on the antenna assembly. When the altitude
display gate is triggered, a step is applied to the vertical deflection amplifier
which causes the sweep to be positioned in the upper portion of the E Scope. The
altitude display gate enables the 10 mile horizontal sweep gate and, since the al-
titude display gate is approximately 3000 microseconds wide, four display sweeps at
the rep. rate frequency are produced on the E Scope. The altitude display gate also
triggers the altitude speed up circuit which in turn causes the horizontal sweep
generator to produce a much faster sweep. This is necessary because the altitude
information display on the Z Scope requires a 2is sweep to display 1000 feet of
altitude.
The profile selector circuit produces a linearly variable delay which can
be controlled by the operator by means of a calibrated dial. The profile selector
circuit is triggered by the horizontal sweep reset pulse from the synchronizer unit.
This reset pulse occurs at the beginning of each horizontal sweep of the antenna.
The profile selector circuit triggers the profile display gate and the
profile marker generator. The profile display gate (approximately 3000}is wide)
enables the horizontal sweep gate to produce four sweeps at the rep. rate frequency
as previously noted. The profile marker generator produces a pulse which is added
in the mixer to the video and position marks from the synchronizer unit. This
mixer output becomes the signal input to the companion X Scope. Hence by means of
the profile selector dial, a profile mark appears on each horizontal sweep of the
X Scope and these individual marks form a brightened vertical line on the X Scope
presentation.
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 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
The mile markers and the video signals from the synchronizer are mixed
and continuously applied to the cathode of the E Scope. The unblanking circuit
operation permits these signals to appear as bright spots on the tube face,
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 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
1~1F1DEIm~I
ALTITUDE
3 +~:
< ?r
AALT,'TUDF
THOUSAND
FEET
FIG.-Is' PROFILE G15PLAY
46
CONFIDENTIAL
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 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
MODULATOR
The modulator is a line type resonant charging pulsar driving the MA207
magnetron through a 4:1 step up transformer. The repetition rate is 1365 pps,
while the pulse width is 0,25 jas. The. input power is 30 at 115V and approxi-
mately 1 amp per line. The power supply designed to deliver 4KV at 35MA consists
of a 30 plate transformer, delta primary, star secondary, and a bank of silicon
rectifiers with a 64Y connection, Filtering consists of an 0,5uf contenser,
Resonant charging is achieved with a 16,5h choke,
The discharge circuit consists of an E-36(5956) thyratron and a 38 ohm
network, The thyratron driving pulse is derived from an imput trigger pulse of
30 volts amplified by a modified blocking oscillator.
It is estimated that by careful packaging the size can be maintained
less than 400 inches and the weight less than 12 pounds,
The transmitter consists of high voltage: and plumbing compartments and
the MA207 magnetron,
The high voltage unit contains a 4:1 pulse transformer and a magnetron
filament transformer in addition to the various components associated with the
magnetron current metering circuit.
The, plumbing compartment contains the duplexer, consisting of the
6546ATR and the 6545TR tubes, a waveguide load isolator (KA131), the L.O. (VA97)
and the receiver and AFC units,
The power input consists of 115V 34, +400VDC, +150VDC and -150VDC.
The high voltage pulses from the modulator are 3KV at 80 amps, The peak pulse
RF power output is 60KW (max.) with a 0,25)is width and 1365pps rate,
- 47 -
CONFIDENTIAL
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 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
BALANCED MIXER, CRYSTALS AND IF AMPLIFIER
The crystals used are matched reversible pairs (D938MR). The crystals are
used with a "rat race" type of balanced mixer. The balanced mixer and crystal
holders can be used either for the reversible matched pairs or the normal matched
pairs. However, the input coil of the IF amplifier is designed as a single ended
input and requires that only reversible matched pairs be used.
The input stages of the amplifier are subminiature triodes (5718's) and
make up a low noise (1.5 db @ 45 mcs) capacitance neutralized cascode circuit. The
cascode circuit is followed by five subminiature pentode (6205) stages of amplifi-
cation. The interstage coils are stagger tuned and comprise three maximally flat
two pole networks in cascade with the wider bandwidth transitionally coupled input
transformer. The manual gain control (MGC) and sensitivity time control (STC) vol-
tages are applied to the control grids of the first three pentode amplifier stages.
The second detector is followed by a 5718 cathode follower output stage
which drives a 90SL coaxial cable.
The crystal currents are individually monitored by means of an external
milliammeter.
The amplifier has a 3 db bandwidth of 4.2 mc, nominal operating gain of
91 db and a system noise figure (including TR and duplexer losses) of not more than
12.5 db.
-48_
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 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
STC AND RANGE GATE
The positive trigger (t = 0 yds) is used to trigger a variable delay
multivibrator with a nominal delay of 2 to 4 usec. The output triggers another
multivibrator that generates a positive range gate that is variable from 90 to
150 usec maximum range.
An additional range will be available which may be se-
lected. This will be variable from 200 to 300 usec.
The STC exponential waveform is variable in amplitude and duration and
is mixed with the range gate.
Every one and one half seconds an altitude check is made by bypassing
the 2 to 4 usec delay multivibrator. The variable range gate now starts at
t = 0 yds and the receiver is turned on to amplify the ground return and main bang.
Normally the main bang is blanked out by the 2 to 4 usec delay before the range
gate is applied.
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CONFIDENTIAL
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 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
The AFC consists of an IF amplifier and discriminator and a diode-
transitron control circuit, The IF section is a stagger tuned three stage
amplifier with a bandwidth of 10MC centered at 46.5 MOPS approx. The Weiss
discriminator circuit peak-to-peak separation is 6MCPS with the cross over
point at 46.5 MOPS. This point can be adjusted to compensate for overall
loop gain variations so that L.O. lock-up occurs at 45MCPS. The discriminator
output, after being amplified by a video stage is fed to the control circuit,
This consists of a search stopping diode detector and a phantastron. The
plate voltage of this tube sweeps until positive pulses appearing at the
input are rectified by the diode detector producing a negative bias. At
this time the phantastron (or transitron) acts as a normal d-c amplifier
with a gain of approximately 50. The plate voltage determined by the magni-
tude of the positive pulses then supplies the correct klystron repeller vol-
tage for a 45 MOPS I.F.
Since this is not a null seeking device and operates on a certain
error signal, the resultant IF signal can not be maintained exactly. Under
most conditions the difference will not be in excess of 1 MOPS resulting in
only minor system loss. If a true null seeking system were utilized, a dis-
proportionate increase in size,weight and complexity would occur.
The klystron chosen for this application is the Varian VA-97, This
tube is small, rugged and operates on readily available voltages.
tronic tuning range of 60 MOPS for the most part determines the pull-in range
- 50 -
CONFIDENTIAL
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 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
AFC (Contd.)
of the AFC. The power output of 10 MW provides adequate excitation of the
receiver and AFC mixer crystals.
- 51 -
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 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
CONFIDENTIAL
POWER SUPPLY
The power supply will require three phase 115V, 400 cycle and +28DC
volt inputs. The three phase voltage will be rectified, filtered, and regulated
to provide outputs of +400, +300, +150, -300, and -150 volts. The +28 volts will
be dropped and regulated by a transistorized power supply to furnish a +22 volt
output. Filament power will be transformed from the 115V, 400 cycle line in each
major unit to avoid the distribution of this relatively high current from a cen-
tral source.
Rectification will be accomplished with three phase silicon bridge
rectifiers. Each complete bridge will have dimensions on the order of 1i'" x 21"x
4--" or roughly the size of one rectifier tube. Since five D.C. voltages are re-
quired, and each would need at least three tubes, this results in a substantial
space reduction. Utilization of three phase full wave rectification tripples
the ripple frequency over that of a single phase full wave rectification and
hence considerably reduces the filter requirements.
Series regulation will be performed with type 6080W1 dual-triodes, and
the reference voltage frnished by Zener diodes. Error amplifiers with gain on
the order of 106 should provide regulation greater than 0.1%.
Series regulator tubes are quite bulky, relatively heavy, and require
a large quantity of filament power. Recently Texas Instruments announced the
availability of a junction silicon transistor type 221389 which shows promise in
this application. Though the savings in weight, space, and power would be sub-
stantial, immediate utilization would be pre-mature. Therefore, design is going
ahead with conventional components to insure the existance of a suitable supply
when needed. However, every consideration is being given to layout and design
- 52 -
CONFIDENTIAL
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 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
%.vnruuCn111AL
POWER SUPPLY (ContId.)
so that these units may be incorporated with a minimum effort should they prove
feasible. This consists primarily of mounting the transformers, time delays,
filters, and other unaffected items on one chassis, and the regulators on a
separate chassis. Utilization of a transistorized version would require only
the construction of a small regulator to replace the original vacuum tube model.
The conventional system would occupy a cube roughly 9" x 15" x 14" and
weigh on the order of 25 pounds. If the transistored version proves practical,
the dimensions could be reduced to perhaps 9" x 12" x 14" and weight to about
20 pounds.
Line power required for the entire system will be on the order of 1500
volt-amperes.
- 53 - CONFIDENTIAL
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 Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4
IRL
O~
39
PWR
XFMR
ICON
RIRECT
[B''DSGE"
J SILICON
BRIDGE RECT
E
DELAY
6.3 VAC
VA
VB
FILAMENT
TRANSFORMER
3 V SILICON
BRIDGE
RECTIFIER
FILTER
SERIES
REGULATOR
CO TROL
AMP
FILTER
FILTER
SERIES
REGULATOR
CONTROL
AMP
SERIES
REGUI* LATOR
CONTROL
AMP
TRANSISTORIZED
+22V REGULATOR
3 SILICON
BRIDGE
RECTIFIER
3 SILICON
BRIDGE
RECTIFIER
F I LTERI
FILTER
FIG. 16 POWER SUPPLY BLOCK DIAGRAM
+400
+300
-300
~---+150
-150
+22
CONFIDENTIAL
SERIES
REGULATOR
CONTROL
AMP
MUES
REGULATOR
CONTROL
AMP
Declassified and Approved For Release 2011/12/06: CIA-RDP89B00709R000400890022-4