W.T. HARPSTER RADAR DECEPTION JAMMER

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP81-00120R000100050062-4
• Release Decision: RIFPUB
• Original Classification: K
• Document Page Count: 3
• Document Creation Date: December 20, 2016
• Document Release Date: January 3, 2000
• Sequence Number: 62
• Publication Date: June 28, 1966
• Content Type: CONT

Approved For Release 2007/09/21: CIA-RDP81-0012OR000100050062-4
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June 28, 1966 W. T. HARPSTER 3,258,771
RADAR DECEPTION JAMMER
Filed Dec. 30, 1964
18
PULSE AMP
DELAY
16 12
IWIDE - BAND
20
22
R-F NOISE
SOURCE
INVENTOR,
WARREN T. HARPSTER
BY ~~ G 2Gt ~rfz.~~
Q. G,z,
Approved For Release 2007/09/21: CIA-RDP81-0012OR000100050062-4
 Approved For Release 2007/09/21 : CIA-RDP81-0012OR000100050062-4 D58,771
nice ttt .T CI1 L 'I" Itented June 28, 1966
1 2
3,258,771
RADAR DECEPTION JAMMER
Warren T. liarpster, Sudbury, Mass., assignor, by direct
and mesne assignments, to the United States of America
as represented by the Secretary of the Army
Filed Dec. 30, 1964, Scr. No. 422,473
4 Claims. (Cl. 343-18)
This invention relates to radar system and more par-
ticularly to a radar deception jammer.
It is frequently desirable to deceive and confuse a
functioning radar system, that is, to provide ambiguous
signals which the radar system is incapable of discriminat-
ing from true target indications. Such radar jamming or
countermeasure radar systems usually require compli-
cated circuitry to first determine the frequency and pulse
width of the radar to be jammed, and then to adjust the
frequency of the jammer transmitter before it is ener-
gized.
It is an object of the present invention to provide an
improved radar deception jamming system.
It is another object of the present invention to provide
an improved radar deception jamming system capable of
providing wide-band frequency jamming signals without
determining the frequency of the received pulse.
In accordance with the present invention there is pro-
vided a radar deception jammer which, includes an antenna
for detecting radar pulse signals and means responsive
to the output of the antenna for producing a video out-
put pulse for each radar pulse signal detected. Also in-
cluded is an RF noise source and a normally quiescent
TWT amplifier. The video output pulses are applied as
gating pulses to the TWT amplifier and the RF noise is
applied as the RF signal Ito the TWT amplifier whose out-
put is applied to said antenna as the jamming signal to
be transmitted. The TWT amplifier is gated on only by
the video output pulses so that amplified RF noise is
produced at the output -of the TWT amplifier only for the
duration of the video pulses which correspond to the
pulse widths of the detected radar pulse signals. The
amplified RF noise is then transmitted as the jamming
signal. A duplexer is provided in the usual manner to
isolate received and transmitted signals.
frequency band of interest. Wide-band receiver 12 is in said video pulse producing means comprises a wide-
preferably of the crystal video type and is adapted to band crystal video receiver and a pulse -amplifier.
detect the signals passed by filter 16. As shown, the 55 3. The radar jammer in accordance with claim I where-
detected video Output from receiver 12 is applied to a in said pulse amplifier further includes means for delay-
pulse amplifier and delay circuit 18. The delay circuit ing- the amplified video output Pulses with respect to as-
of stage I8 may be adjustable to provide prescribed de- sociated antenna detected signals.
lays of respective video output pulses with respect to 4. A radar deception jammer adapted to detect radar
associated input pulses to simulate discrete distances of 60 pulse signals and to transmit jamming RF noise pulses of
radar target echoes. The output of pulse amplifier and the same pulse width as said detected radar pulse signals
delay Circuit 18 is applied as a gating pulse of a normally comprising,
quiescent or cut-off travelling-wave tube (TWT) ampli- an antenna for detecting said radar pulse signals,
Fier 20. An RF noise energy source 22 adapted to gen- a prescribed frequency band-pass filter responsive to
crate nt.7-- ..^.x,nr svrr Ihp frpnnp.ncv hump of interest fill said detected radar pulse signals,
Approved For Release 2007/09/21 : CIA-RDP81-0012OR000100050062-4
has its output coupled to the travelling wave tube ampli-
fier 20. The TWT amplifier 20 is of conventional con-
struction and as such includes an axial electron-beam
generating element and an axial slow-wave structure
which surrounds the electron beam and is provided with
the usual input and output signal coupling means. The
RF noise energy source 22 is applied to the slow-wave
structure and the video pulses from amplifier and delay
circuit 18 may be applied as gating pulses to the electron-
beam generating element of TWT amplifier 20. By this
arrangement, the amplified noise power is produced at
the output of the travelling-wave tube amplifier 20 only
when it is gated on by the pulses derived from pulse am-
plifier and delay circuit 18. As shown, the amplified RF
noise power output of travelling-wave tube 20 is applied
as the transmitter energy through duplexer 14 to antenna
In operation, the system shown in the drawing will
transmit one pulse of broad-band noise energy for each
radar pulse received. The transmitted pulse will thus
have the same pulse width as the received pulse, anil
because broad-band RF noise is used as the carrier, the
transmitted signal will be capable of being received by
any receiver in this frequency band. Thus with this
system it is not necessary to determine the frequency of
the received pulse and to adjust the frequency of the
transmitter before the jammer is energized as heretofore
required.
While there has been described what is at present con-
sidered to be the preferred embodiment of this invention,
it will be obvious to those skilled in the art that various
changes and modifications may be made therein without
departing from the invention, and it is therefore aimed
in the appended claims to cover all such changes and
modifications -as fall within the true spirit and scope of
the invention.
What is claimed is:
1. A radar deception jammer comprising
an antenna,
means responsive to the output of said antenna for
producing a video output pulse for each radar pulse
signal detected by said antenna,
an RF noise source,
and a normally quiescent TWT amplifier having its
For a better understanding of the -invention, together
with other and further objects thereof, reference is made 45
to the drawing which is a schematic block diagram of the
radar deception jammer.
Referring now to the drawing, a receiving antenna 10
is adapted to detect an incoming pulsed radar signal
which is coupled to a wide-band receiver 12 through 50
duplexer 14 and filter 16. Duple xer 14 is of conven-
tional design and filter 16 is designed :to pass the entire
slow-wave structure responsive to the output of said
RF noise source and also responsive to said video
output pulses such that amplified RF noise is pro-
duced at the output of said TWT amplifier only for
the duration of said video pulses, the output of said
TWT amplifier being coupled to said antenna where-
by said amplified RF noise is transmitted.
2. The radar jammer in accordance with claim 1 where-
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3
a wide-band receiver of the crystal video type respon-
sive to the output of said filter for producing a
respective video output pulse of the same pulse
width as respective detected radar pulse signals passed
by said filter,
a pulse amplifier responsive to said video output pulses
and including a delay producing means for delay-
ing the amplified video pulses with respect to as-
sociated detected radar pulse signals,
an RF noise source,
and a normally quiescent TWT amplifier having its
slow-wave structure responsive to the output of said
RF noise source and also responsive to said delayed
amplified video pulses such that amplified RF noise
is produced at. the output of said TWT amplifier
only for the duration of the pulse widths of said
amplified video output pulses,
the output of said TWT amplifier being coupled to
said antenna whereby said amplified pulsed RF
noise is transmitted.
CITESTER L. JUSTUS, Primary Examiner.
P. M. IIINDERSTE-IN, Assistant Examiner.
ZV
Approved For Release 2007/09/21: CIA-RDP81-0012OR000100050062-4