LIST OF Abbreviation

HF High frequency

UHF Ultra-high frequency

VHF Very high frequency

FOT Frequency of optimum transmission

MUF Maximum usable frequency

SID Sudden ionospheric disturbance

CW Continuous wave

Pe Power of error signal

PJ Jammer power

PT Transmitter power

B Bandwidth

BR Bandwidth of the receiver

K Boltzmann constant

T Temperature

S/J Signal to jamming ratio

USB universal serial bus

IEEE Institute of Electrical and Electronics
Engineers

AM Amplitude modulation

FM Frequency modulation

PM Phase modulation

FSK Frequency shift keying

TFT Thin-Film Transistors

DB Decibel

DBM Decibel-mill watts

MHz Megahertz

SA Spectrum analyzer
 CHAPTER ONE
INTRODUCTION

HF jammer devices are electronic warfare devices used to prevent

illegal jammers from jamming the HF communication system because
communications held in this range of frequency needs security and they
are almost governmental and military communication system.

Communication jamming devices were first developed and used by

military. Tactical commanders use RF communications to exercise
control of their forces, spy adversary information, attacks and deceive
adversary’s communication system.

A HF Jammer (sky wave communication jammer) is a system that

transmit signal on the same frequency at which the high frequency
communication system operates that is in the range of 1.5 MHz – 30
MHz to interrupt, disturb and decept the communication system or
blocking the communication in this range of frequency from reaching to
its desired destination. The jamming success when the communication
system in the area where the jammer is located is disabled.
Problem statement

Since almost all military and non-military agencies needs high security
to keep their privacy. Electronic protection and electronic attack
plays a great role to secure the privacies. Especially electronic attack
team takes two responsibilities in this job, decepting and attacking the
adversary or illegal jammers. To do this job electronic attack team must
have a deep knowledge and understanding about the HF communication
system, and able to protect from accessing by enemy and controlling the
air space for its own privacy and exploiting the spectrum for own use. In
the previous projects, this is done for UHF and VHF but not for HF
communication.

So the main purpose of this project is to realize an effective HF jammer

that enables us to decept, interrupt, attack and block illegal jammers
from accessing high frequency communications held by our friendly
agencies. Generally this project is applicable in the range of 1.5 MHz –
30 MHz which is the sky wave communication.
 Objective of the Project

General objective:

The general objective of this project is to control the HF spectrum and

exploit the spectrum for own use.

Specific Objective:

Understanding the ionosphere properties

Understanding the propagation properties of HF signal through
Ionosphere.
Raytracing the jammers signal path
Determining the power level and losses along the path
Realizing effective HF jammer
 CHAPTER TWO
2. THE IONOSPHERE, HF JAMMER PROPAGATION
AND TECHNIQUES

To understand sky wave propagation, you need to consider the effects of

the ionosphere and solar activity on HF radio propagation. We must also
be familiar with the techniques used to predict propagation and select the
best frequencies for a particular link at a given time.

2.1 THE IONOSPHERE NATURE

The ionosphere is a region of electrically charged particles or gases in

the earth’s atmosphere, extending from approximately 50 to 600 km
above the earth’s surface. Ionization, the process in which electrons are
stripped from atoms and produces electrically charged particles, results
from solar radiation. When the ionosphere becomes heavily ionized, the
gases may even glow and be visible. This phenomenon is known as
Northern and Southern Lights (ionization) [1].

Also the ions and electrons formed by the solar radiation are lost through
recombination, and a simple form of the continuity equation which
determines the ionization balance is [2]:

(1)
Where N+ is the positive ion density and 𝛼𝑒𝑓𝑓 is a constant, the effective
recombination rate, x is the solar zenith angle. The height and intensity
of each layer varies in a systematic manner with solar elevation [2].

Why is the ionosphere important in HF radio? Well, this blanket of gases

is like nature’s satellite, making HF radio communications possible.
When radio waves strike these ionized layers, depending on frequency,
some are completely absorbed, others are refracted so that they return to
the earth, and still others pass through the ionosphere into outer space.
Absorption tends to be greater at lower frequencies, and increases as the
degree of ionization increases [1].

The angle at which sky waves enter the ionosphere is known as the
incident angle (Figure 2-1). This is determined by wavelength and the
type of transmitting antenna. Like a billiard ball bouncing off a rail, a
radio wave reflects from the ionosphere at the same angle it hits it [2].

Thus, the incident angle is an important factor in determining

communications range. If you need to reach a station that is relatively far
from you, you would want the incident angle to be relatively large. To
communicate with a nearby station, the incident angle should be more
acquit.
Figure 1: Ionosphere incident angle

The incident angle of a radio wave is critical because if it is too nearly

vertical, it will pass through the ionosphere without being refracted
back to earth. If the angle is too great, the waves will be absorbed by the
lower layers before reaching the more densely ionized upper layers. So,
incident angle must be sufficient for bringing the radio wave back to
earth, yet not so great that it will lead to absorption [2].

2.1.1 LAYERS OF THE IONOSPHERE

Within the ionosphere, there are four layers of varying ionization (Figure
2-2). Since ionization is caused by solar radiation, the higher layers of
the ionosphere tend to be more highly ionized, while the lower
layers, protected by the outer layers, experience less ionization. Of
ethese layers, the first, discovered in the early 1920s by Appleton, was
designated E for electric waves. Later, D and F were discovered and
noted by these letters. Additional ionospheric phenomena were
discovered through the 1930s and 1940s, such as sporadic E and aurora
[1].

Figure 2: The ionosphere layers

In the ionosphere, the D layer is the lowest region affecting HF radio

waves. Ionized during the day, the D layer reaches maximum ionization
when the sun is at its zenith and dissipates quickly toward sunset.

The E layer reaches maximum ionization at noon. It begins dissipating

toward sunset and reaches minimum activity at midnight. Irregular
cloud-like formations of ionized gases occasionally occur in the E layer.
These regions, known as sporadic E, can support propagation of sky
waves at the upper end of the HF band and beyond [1].

The most heavily ionized region of the ionosphere, and therefore the
most important for long-haul communications, is the F layer. At this
altitude, the air is thin enough that the ions and electrons recombine very
slowly, so the layer retains its ionized properties even after sunset [1].

In the daytime, the F layer consists of two distinct layers, F1 and F2. The
F1 layer, which exists only in the daytime and is negligible in winter, is
not important to HF communications. The F2 layer reaches maximum
ionization at noon and remains charged at night, gradually decreasing to
a minimum just before sunrise [1].

During the day, sky wave reflection from the F2 layer requires
wavelengths short enough to penetrate the ionized D and E layers, but
not so short as to pass through the F layer. Generally, frequencies from
10 to 20 MHz will accomplish this, but the same frequencies used at
night would penetrate the F layer and pass into outer space. The most
effective frequencies for long-haul nighttime communications are
normally between 3 and 8MHz [1].

2.1.2 FACTORS AFFECTING ATMOSPHERIC

IONIZATION
The intensity of solar radiation, and therefore ionization, varies
periodically. Hence, we can predict solar radiation intensity based on
time of day and the season, and make adjustments in equipment to limit
or optimize ionization effects on the communication system [1].

Ionization is higher during spring and summer because the hours of

daylight are longer. Sky waves are absorbed or weakened as they pass
through the highly charged D and E layers, reducing, in effect, the
communication range of most HF bands. Because there are fewer hours of
daylight during autumn and winter, less radiation reaches the D and E
layers. Lower frequencies pass easily through these weakly ionized
layers. Therefore, signals arriving at the F layer are stronger and are
reflected over greater distances [1].

Another longer term periodic variation results from the 11-year sunspot
cycle (Figure 2-3). Sunspots generate bursts of radiation that cause
higher levels of ionization. The more sunspots, the greater the ionization.
During periods of low sunspot activity, frequencies above 20 MHz tend to
be unusable because the E and F layers are too weakly ionized to reflect
signals back to earth. At the peak of the sunspot cycle, however, it is not
unusual to have worldwide propagation on frequencies above 30 MHz
[1].
Figure 3: ionosphere FOT

In addition to these regular variations, there is a class of unpredictable

phenomena known as sudden ionospheric disturbances (SID), which can
affect HF communications as well. SIDs are random events due to solar
flares that can disrupt sky wave communication for hours or days at a
time. Solar flares produce intense ionization of the D layer, causing it to
absorb most HF signals on the side of the earth facing the sun [1].

Magnetic storms often follow the eruption of solar flares within 20 to

40 hours. Charged particles from the storms have a scattering effect on
the F layer, temporarily neutralizing its reflective properties.
2.2 HF JAMMER SIGNAL PROPAGATION AND PATH

OPTIMIZATION

a) HF jammer signal propagation

To gain a better idea of the characteristics of HF propagation using the

ionosphere, it is worth viewing what happens to a radio communications
signal if the frequency is increased across the frequency spectrum. First it
starts with a signal in the medium wave broadcast band. During the day
signals on these frequencies only propagate using the ground wave. Any
signals that reach the D region are absorbed. However at night as the D
region disappears signals reach the other regions and may be heard over
much greater distances [3].

If the frequency of the signal is increased, a point is reached where the

signal starts to penetrate the D region and signals reach the E region.
Here it is reflected and will pass back through the D region and return to
earth a considerable distance away from the transmitter [3].

As the frequency is increased further the signal is refracted less and less
by the E region and eventually it passes right through. It then reaches
the F1 region and here it may be reflected passing back through the D
and E regions to reach the earth again. As the F1 region is higher than
the E region the distance reached will be greater than that for an E
region reflection [3].

Finally as the frequency of the radio communications signal rises still

further the strength of the signal also increase and it will eventually pass
through the F1 region and onto the F2 region. This is the highest of the
regions in the ionosphere and the distances reached using this are the
greatest. As a rough guide the maximum skip distance for the E region is
around 2500 km and 5000 km for the F2 region [3].

b) HF jammer path optimization

Because ionospheric conditions affect radio wave propagation,

communicators must determine the best way to optimize radio
frequencies at a particular time. The highest possible frequency that can
be used to transmit over a particular path under given ionospheric
conditions is called the Maximum Usable Frequency (MUF).
Frequencies higher than that of MUF penetrate the ionosphere and continue
into space. Frequencies lower than the MUF tend to refract back to earth
[1].

As frequency is reduced, the amount of absorption of the signal by the D

layer increases. Eventually, the signal is completely absorbed by the
ionosphere. The frequency at which this occurs is called the Lowest
Usable Frequency (LUF). The “window” of usable frequencies,
therefore, lies between the MUF and LUF. The Frequency of Optimum
Transmission (FOT) is typically 85 percent of the MUF. Generally, the
FOT is lower at night and higher during the day. These frequencies are
illustrated in Figure 2-3 [1].

In addition to frequency, the route the radio signal travels must also be
considered in optimizing communications. A received signal may be
comprised of components arriving via several routes, including one or
more sky wave paths and a ground wave path. The arrival times of these
components vary because of differences in path length; the range of time
differences is called the multipath spread. The effects of multipath
spread can be minimized by selecting a frequency as close as possible to
the MUF [1].

c) Multiple hops

Whilst it is possible to reach considerable distances using the F region as

already described, on its own this does not explain the fact that radio
signals are regularly heard from opposite sides of the globe using HF
propagation with the ionosphere. This occurs because the signals are
able to undergo several "reflections". Once the signals are returned to
earth from the ionosphere, they are reflected back upwards by the earth's
surface, and again they are able to undergo another "reflection" by the
ionosphere. Naturally the signal is reduced in strength at each
"reflection", and it is also found that different areas of the Earth reflect
radio signals differently. As might be anticipated the surface of the sea is
a very good reflector, whereas desert areas are very poor. This means
that signals that are "reflected" back to the ionosphere by the Pacific or
Atlantic oceans will be stronger than those that use the Sahara desert or
the red center of Australia [3].

It is not just the Earth's surface that introduces losses into the signal
path. In fact the major cause of loss is the D region, even for frequencies
high up into the HF portion of the spectrum. One of the reasons for this
is that the signal has to pass through the D region twice for every
reflection by the ionosphere. This means that to get the best signal
strengths it is necessary signal paths enable the minimum number of
hops to be used. This is generally achieved using frequencies close to the
maximum frequencies that can support communications using
ionospheric propagation, and thereby using the highest regions in the
ionosphere. In addition to this the level of attenuation introduced by the
D region is also reduced. This means that a radio signal on 20 MHz
for example will be stronger than one on 10 MHz if propagation can
be supported at both frequencies [3].
2.3 JAMMING TECHNIQUES

2.3.1 Jamming Strategies

It has been shown that jamming approximately 30% or more of a voice

transmission degrades the intelligibility significantly enough to deny an
effective transfer of information. Therefore, denying 30% of
transmissions represents a reasonable goal to strive for and serves as a
useful threshold to achieve for such communications [4].

Jamming of substantially less than 30% is effective against coded or

uncoded digital data communications, as will be shown. Jamming
effectiveness criteria for digital communications will be substantially
different from that for analog, voice communications. All-important
SS communication systems utilize digital signaling techniques [4].

There are several possible strategies that a jammer can employ against a
communication system to include AJ systems. Some techniques are
more effective than others, and a successful strategy depends on the
particular type of AJ employed [4].

Two fundamental waveforms are typically used against AJ

communication systems. A carrier signal centered on the transmitting
frequency is unmodulated, modulated with one or more tone signals, or
modulated with a noise signal [4].
2.3.1.1 Narrowband Noise Jamming
Narrowband noise (NBN) jamming places all of the jamming energy in
to a single channel. The bandwidth of this energy injection could be the
whole width of the channel or it could be only the data signal
width or the complementary signal width. Pe for jamming both data
paths is given by the same expression as for BBN with Pn = J [4]. When
there is a noise signal of average power J injected into the data channel
only, the overall BER is calculated by then Pe can be calculated
𝑅
𝑃𝑡 (− )
𝑃𝑒 = 𝑒 2𝑃𝑁 +𝐽
2𝑃𝑁 + 𝐽

Where PN is the thermal noise power and J is the average jammer noise
power [4].

a) Possible strategies a jammer may use based on the channelized

spectrum

b) narrowband noise jamming (NBN)

The bandwidth of the noise can be varied. When the carrier is not
modulated, the jamming waveform is a single tone. When
modulated with more than one tone, then multiple tones are
emitted by the jammer. Usually, the placement of these tones is based
on some knowledge of the target or targets to be jammed. Noise is used
to raise the background noise in the spectrum in which the AJ
system is operating [4].

The taxonomy of jamming strategies consists of how the available

jammer power is distributed with frequency, the type of modulation
transmitted (if any), the time-sharing of the jammer among several
targets, and power sharing, where the instantaneous power can be
distributed among several targets [4].

2.3.1.2 Tone Jamming

In tone jamming, one or more jammer tones are strategically
placed in the spectrum. Where they are placed and their number
affect the jamming performance. Two types of tone jamming are
illustrated in the figure (b). Single-tone jamming places a single tone
where it is needed and is illustrated in Figure. Multiple-tone jamming
distributes the jammer power among several tones and is illustrated in
Figure(c) [4].
The phase of the jammer tone relative to the target signal can be an
important parameter. Suppose that the data symbol is a mark. Further,
assume the jammer signal level is sufficiently greater than the noise that
it can be neglected [4].
When n = 1, in a jammed channel the single jammer tone present is
either at the mark or the space frequency. If it is at the mark
frequency, then the phase can present a problem if the jammer
tone is sufficiently out of phase as explained below. If it is at the
space frequency, then if the JSR is large enough, the symbol is jammed
independent of the phase relationship.
When n > 2 and the tones are present in a contiguous band of channels,
then jamming performance, the same as that for PBN jamming is
achieved. For PBN jamming, it makes no theoretical difference whether
the jammer power that makes it through the detector filters is a tone with
or without noise modulation. Thus, we have partial-band multi tone
jamming.
For n = 2 there will be a symbol error if the channel is jammed at all
and the jammer tone power in the complementary channel is greater than
the power in the symbol channel, which consists of the symbol tone and
one of the jammer tones. The power in the symbol channel depends on
the phase relationship between the symbol signal and the jammer tone.

a) Single Tone
A jamming signal transmitted at a single frequency was shown in Figure
(b). Thus, the jamming signal is a CW tone placed at a single frequency.
Single-tone jamming is also called spot jamming.
 a) Possible strategies a jammer may use based on the channelized
spectrum

b) Single tone jamming

Single-tone jamming may be useful, for example, against DSSS AJ
systems by overcoming the processing gain of such systems at the
receivers and causing deleterious effects at the dispread level.
When the total jammer power is fixed, more power can be placed in a
single tone than in each of multiple tones, thereby increasing the
probability of overcoming the processing gain. When there is a single
tone and it is placed in the data channel, while the complementary
channel has only thermal noise, then the jammer can enhance the ability
of the receiver to correctly decode the data bit, depending on the
phase relationship between the interfering tone and the data tone
and the relative magnitudes of the tones. The probability of bit error is
given as
Which is

When the single tone is correctly placed in the complementary channel,

Pe is given by
2.2.3.1 Broadband Noise Jamming
Broadband noise (BBN) jamming places noise energy across the entire
width of the frequency spectrum used by the target communication
systems. It is also called full band jamming and is sometimes called
barrage jamming. This latter appellation, however, also refers to cases
where less than the full band is jammed [4].
This type of jamming is useful against all forms of AJ
communications. It is generally useful for coverage of an area for
screening purposes as well. In this EP role, the jammer is placed
between an adversary’s ES system(s) and friendly communications.
Directional antennas are, of course, required to be pointed in the
direction of the ES systems if friendly fratricide is to be
minimized. If used correctly, this prevents the adversary from
intercepting friendly communications at least for a time [4].
Since BBN jamming generates signals that are similar to broadband
noise, the level of jamming power is sometimes referred to as J0 and
is measured in watts/hertz just as background noise is specified. The
primary limitation of BBN jamming is that it results in low J0 as limited
jammer power is spread very wide [4].

a) Possible strategies a jammer may use based on the channelized

spectrum
 b) Broadband Noise Jamming
BBN jamming is a direct assault on the channel capacity of a
communication system. This capacity, assuming the noise is
Gaussian, was first investigated by Shannon in 1948 [2]. It
expresses the maximum data rate that the channel can carry with an
arbitrarily small error rate. If an attempt is made to transmit a digital
signal through the channel with a higher bit rate than that given by the
capacity, then errors are assured in the received signal. The capacity of a
channel corrupted by such noise is given by
𝑅
C = W 𝑙𝑜𝑔2 (1+
𝑃𝑡
)
Where W is the bandwidth of the signal, R is the average power of the
signal, and Pt is the total average noise present given by
Pt = W (N0 + J0).
Clearly, as the noise level is raised by intentionally inserting Gaussian
noise into the channel, the SNR decreases, thus decreasing the channel
capacity [4].
2.2.4 Sweep Jamming
A concept similar to broadband or partial-band noise jamming is swept
jamming. This is when a relatively narrowband signal, which could be as
narrow as a tone but more often is a PBN signal, is swept or scanned in
time across the frequency band of interest. At any instant in time,
the jammer is centered on a specific frequency and the only
portion of the spectrum being jammed is in a narrow region around
this frequency. However, since the signal is swept, a broad range of
frequencies can be jammed in a short period. When implemented
digitally, for example, the jammer may spend 100 µs at any one
frequency before moving on to the next band to be jammed. Normally
these bands would be consecutive, but do not have to be the bands
could actually be selected randomly with digital synthesizers
generating the jamming waveform. In this way this jammer could
cover the whole 1.5 – 30 MHz band in about 120ms.
The net effect of such a jamming strategy is similar to a barrage jammer
except that the full power of the jammer is employed at each dwell
bandwidth. It is also possible to sectorize the jamming strategy and
avoid certain bands that might be in use by friendly forces. This is true
only when the timing is tailored to the target receivers so that the
jamming signal is present at the receiver for an adequate dwell
time. The characteristics of the target receivers must be taken into
consideration for swept jamming to be effective.
It is also important to note that the characteristics of the target
receiver are important for evaluating the effectiveness of swept
jamming. The filtering process in the receiver has considerable
impact on the dwell duration required
The main purpose for sweeping the partial-band noise waveform is to
ensure that the jammer enters the frequency spectrum where an
FHSS target net is located. Normally FHSS AJ networks do not use
every channel from, say, 1.5 MHz to 30 MHz, but only a portion, called
the hop set. These hop sets need not be that large to be effective. It
could be that a partial-band jammer permanently situated in a portion of
the spectrum does not cover any of the hop set frequencies, or perhaps
just a few of them. This renders the partial-band jammer ineffective. By
sweeping the jamming waveform over the whole range, then the jammer
is ensured to jam at the entire set of hop frequencies.
Timing is one of the more important parameters for a swept
jammer. The sweeping must be fast enough to ensure that the
whole band is covered in a sufficiently short period or hops will
occur for which no jamming signal is present. On the other hand,
sweeping cannot be so fast that when a hop is jammed, an
inadequate fraction of the hop is jammed. A BER of 10−1 means that it is
necessary to jam 1 bit out of 10, or for an AJ system that is sending data
at 20 kbps, 2,000 bits must be jammed to produce this BER.
The trade-off with these numbers is that as the instantaneous
bandwidth is increased, the power per channel decreases if the total
jammer power remains fixed. Obviously, when the instantaneous
bandwidth gets large enough to be equal to the total target system
bandwidth, the results are the same as BBN jamming. In that case, there
is no point in sweeping at all.
 CHAPTER THREE
3. SYSTEM DESIGN AND PARAMETERS
3.1 Design Parameters
3.1.1 Ionospheric models
Ionospheric modeling for HF-communication purposes aims at a
description of the ionosphere and its variations in time and space, which
allows prediction of propagation parameters. The model must therefore
be simple enough to be practical, and sufficiently complete and accurate
to be useful. The degree of complexity and sophistication in a model
depends upon the requirements and resources of the user, and the
practical solution is always a compromise between the needs for
simplicity and for accuracy. There are two different approaches to the
modeling of ionospheric circuits. The first is to fit empirical equations
to measurements of signal characteristics for different times and paths,
the other is to estimate these characteristics in terms of a number of
separate factors known to influence the signal (Bradley 1979), such as
critical frequencies, layer heights, absorption etc. When a large data
base exists for a particular circuit, the former may be useful, but it lacks
generality. The second approach has the advantage that a limited data
base can be combined with knowledge of physical principles to guide a
description of the behavior of the ionospheric layers.
The first approach has been successfully applied to medium frequency
(MF) propagation, whereas it is generally agreed that the second method
is the most efficient one for HF propagation.
3.1.1.1 Modeling of the ionospheric layers
If the ionospheric electron density height profile is known at every point
along a propagation path, the signal characteristics at the receiver may
be calculated using some form of raytracing procedure. A useful
approximation is to neglect variations along the path and assume that the
profile at the reflection point (or points if there are more than one hop)
may be used in the raytracing.
The problem is then to describe this profile in terms of a few measurable
parameters, so that the raytracing through the simplified model
ionosphere yields realistic signal characteristics, for vertical incidence
raytracing should reproduce an ionogram typical for the time and
location of the reflection point.

3.1.1.2 Modeling of ionospheric absorption

Most of the ionospheric absorption of HF-waves occurs in the D-region.
D region electron densities are, however, small and difficult to measure,
and the ionospheric loss is therefore normally modeled by means of
empirical equations based upon absorption measurements. The
absorption of the ordinary wave may be written (Budden 1966).
1
𝑁 𝜐𝑑𝑠
µ 𝑒
L = const ʃ𝑠 𝜐
(𝑓+ 𝑓𝑒 )+ ( )2
2𝛱

B 3.1.2 Signal to Noise ratio calculation Effectiveness

In order to disrupt a communication system, in a given location and at a
given time, two fundamental questions arise for the jamming. One is,
what is the best jamming waveform and strategy and the second, how
effective will jamming be against the system.
Today, development of communication techniques has severely
curtailed the possibilities of intercepting and communications. Thus, it
seems inevitable that military communications, in the battlefield, is
forced to operating in a jamming environment.
Intercepting communication is more difficult since the communication
energy is usually not directed toward the jammer and also the jammer
may be farther away from the communication receiver than the
communication transmitter is, so the jammer power must exceed in a
considerable amount than the adversary transmitter. This is why the
Signal to jamming ratio calculation is needed.
In assessing the potential effectiveness of jamming it is useful to
calculate a signal to-jamming ratio at the communication receiver.
Figure A.3.1 illustrates the geometric configuration, where𝐷𝑇 , is the
distance between the transmitter and the receiver, and 𝐷𝐽 , the distance
between the jammer and the receiver. The average power of the desired
signal at the input of the communication receiver is:

Where P, is the desired signal power, P. is the average transmitted

power. GR is the gain of the transmitter antenna in the direction of the
receiver, G, is the gain of the receiver antenna in the direction of the
transmitter, / is the wave length, and LR represents propagation and
equipment losses. Similarly power at the receiver antenna due to the
jammer ideally should be:
Where Pj is the average jamming power, G, is the gain of the jammer
antenna in the direction of the receiver, D, is the distance between
jammer and receiver. L., represent propagation and equipment losses of
jammer and receiver, and P, is the desired signal power received from
the jammer.
The amount of jamming power which reaches the receiver may be
reduced by two factors. First, there is a polarization loss due to the
jammers different polarization. This may be described by a factor P
which has the range 0 < P < 1. A second jamming power reduction may
be caused by receiver band pass filtering. This effect is described by
the function f (BR, B,), which has the range 0 < ABRB) < 1, where BR
is the effective bandwidth of the receiver band pass filter, and B, is the
Bandwidth of the jamming signal. If the jamming spectrum is included
in the receiver band pass (B < BR) then:
J (BR, Bs) = 1
If jamming spectrum includes the entire receiver passband (B1 > BR)
then:

Hence the net jamming power effecting the receiver becomes

At the communication receiver, the environment noise is equal to KT,

BR. where K is Boltzmann's constant and T, is the effective noise
temperature. The total interference power is the sum of the
environmental power and the jamming power. Thus the signal-to-
jamming ratio is

If the jamming- is to be effective, it is generally necessary that P2>KTB,

hence
3.1.3 The distance to be jammed (D)
This parameter is very important in our design, since the amount of the
output power of the jammer depends on the area that we need to jam.
Later on we will see the relationship between the output power and the
distance D.

3.1.4 The frequency bands

The frequency band to be jammed is in the range of high frequency from
1.5MHz – 30MHz. during the time to be jammed this range of frequency
may vary to some interval. The adversary communication to be jammed

3.2 System Design

3.2.1 Power calculation
3.2.2 Parts of the jammer devices

1. Power Supply:
 This is used to supply the other sections with the needed voltages. Any
power supply consists of the following main parts:
Transformer: -is used to transform the 220VAC to other levels of
voltages.
Rectification: - this part is to convert the AC voltage to a DC one. We
have two methods for rectification:
A] Half wave-rectification: the output voltage appears only during
positive cycles of the input signal.
B] Full wave –rectification: a rectified output voltage occurs during
both the positive and negative cycles of the input signal.
The Filter: used to eliminate the fluctuations in the output of the full
wave rectifier “eliminate the noise” so that a constant DC voltage is
produced. This filter is just a large capacitor used to minimize the ripple
in the output.
Regulator: this is used to provide a desired DC-voltage. The HMF
2525/2550 can operate at a maximum power of 30 watt

Transformer Rectification Filter Regulator

Figure: Parts of the power supply

In our project we need 12, -12, 5 and 3.5 volts.
2. Arbitrary Function Generator (HMF 2525/2550)
HMF 2525/2550 is an arbitrary function generator that generates
different types of wave forms (sine, Square, Pulse, Triangle and
Arbitrary waveforms) in the range of 10μHz...25MHz/50MHz
frequencies. In this project the device generates simply a base band
signal with a very low power in the range of 1.5MHz – 30MHz.

Specifications:
Frequency range 10μHz...25MHz/50MHz Output voltage
5mVpp...10Vpp (into 50Ω) DC Offset ± 5mV...5V Arbitrary
waveform generator: 250MSa/s, 14Bit, 256kPts
Sine, Square, Pulse, Triangle, Ramp, Arbitrary waveforms incl.
standard curves (White, pink noise etc.).
Total harmonic distortion 0.04% (f‹100kHz)
Burst, Sweep, Gating, external Trigger Rise time ‹ 8ns, in pulse
mode 8ns...500ns variable-edge-time
Pulse mode: Frequency range 100μHz...12.5MHz/25MHz, pulse
width 10ns…999s, resolution 5ns
Modulation modes AM, FM, PM, PWM, FSK (int. and ext.)
10MHz Time base: ± 1ppm TCXO, rear I/O BNC connector
Front USB connector: save & recall of set-ups and waveforms
8,9cm (3.5") TFT: crisp representation of the waveform and all
parameters
USB/RS-232 Dual-Interface, optional Ethernet/USB or IEEE-488
3. Power amplifier (3061 / 3062)
Since 29.5 dBm output power from the arbitrary function generator does
not achieve the desired output power of the HF jammer, we had to add
an amplifier with a suitable gain to increase the function generator
output to 57 dBm or 60dBm.
We found CODAN HF power amplifier which is reliable, affordable and
designed for use with CODAN HF transceiver. The CODAN3061 and
3062 provide 500W PEP and 1000W PEP output power respectively,
and are suitable for voice and data operation.
Specifications:

RF power
output 500 W PEP ±1 dB, 300 W average
Type 3061 1 kW PEP ±1 dB, 600W average
Type 3062

Frequency 1.5 to 30 MHz

range

Input/output 50 Ω
impedance
Operating –10 to +60°C
temperature
Duty cycle 100%: normal speech over full temperature
range
100%: all modes up to maximum ambient of
45°C
Power supply 100–240 V AC ±10%, 50/60 Hz single phase
Power
consumption

Type 3061 800 VA (two-tone), 900 VA maximum

Type 3062 1.6 kVA (two-tone), 1.8 kVA maximum
Protection Safe under all load conditions
Bypass to 125W PEP from transceiver in the
event of excess VSWR, excess heat sink
temperature & internal fault conditions
Spurious and Better than 60 dB below PEP
harmonic
emissions
Intermodulation Better than 26 dB below each tone
(two-tone test) Better than 32 dB below PEP
Cooling Fan forced front panel exhaust
Thermostatically controlled dual speed
Low: > 45 degree Celsius
High: > 55 degree Celsius
Size Amplifier (5RU 19" rack): 222 x 483 x 410
mm (H x W x D)
Power supply (5RU 19" rack): 222 x 483 x 410
mm (H x W x D)
 Weight

Type 3061 Amplifier: 15.4 kg, Power supply: 6.7 kg

Type 3062 Amplifier: 23.6 kg, Power supply: 10.0 kg
ALC A 10 dB increase in signal input above
compression threshold produces < 0.5 dB
increase in power output
Maximum ALC range > 30dB
ALC attack time approximately 2ms

4. Antenna
A proper antenna is necessary to transmit the jamming signal. In order to
have optimal power transfer, the antenna system must be matched to the
transmission system. In this project, we used one 1/4 wavelength
directional antennas, with 50 Ωinput impedance so that the antennas are
matched to the system. We used directional antenna since the radiation
is directional. The purpose of that directionality is improving
transmission and reception of communications and reducing
interference.
The HF directional Antenna offer optimum performance, fully
automatic, low SWR operation over the entire HF band 1.5 – 30 MHz
and suitable for transmitting, receiving or HF spectrum monitoring or
surveillance.
Specifications:
Frequency range 1.5 – 30 MHz
Gain
Polarization Horizontal
Bandwidth
Input impedance 50 ohm
Radiation pattern Directional
RF Power Handling 500 watt to 1kw
Capacity
Input Termination
CHAPTER FOUR
RESULT AND CONCLUSSION
 Signal power of Waveforms by (dbm)
Frequency Amplitude sine square triangul pulse arbitrary
(volt) ar
1.5Mhz 1 -53.60 -51.37 -55.35 -79.1 -53.51
2 -47.55 -45.40 -49.30 -73.10 -47.5
4 -41.60 -39.30 -43.50 -65.10 -41.42
6 -37.97 -35.79 -39.74 -61.40 -37.91
8 -35.50 -33.30 -37.24 -58.69 -35.41
10 -33.55 -31.36 -35.30 -56.80 -33.48
12 -35.79 -29.76 -33.72 -55.30 -31.89
14 -30.63 -28.43 -32.38 -53.97 -39.89
16 -29.48 -27.27 -31.23 -52.78 -35.42
18 -28.48 -26.26 -30.30 -51.80 -34.40
20 -27.53 -25.35 -29.29 -50.91 -33.42
 Signal power of Waveforms by (dbm)
Frequency Amplitude sine square triangular pulse arbitrary
(volt)
3Mhz 1 -48.30 -46.20 -50.10 -66.73 -48.23
2 -42.00 -40.00 -44.20 -59.71 -42.19
4 -36.16 -33.97 -37.93 -40.10 -36.12
6 -32.66 -30.40 -34.42 -36.53 -32.6
8 -30.16 -28.00 -31.93 -34.02 -30.10
10 -28.23 -26.04 -29.99 -32.07 -28.18
12 -26.64 -24.46 -28.41 -30.50 -26.58
14 -25.31 -23.12 -27.07 -25.25
16 -24.16 -21.98 -25.96 -24.10
18 -23.14 -20.97 -24.90 -23.07
20 -22.22 -20.06 -23.99 -22.16
 Signal power of Waveforms by (dbm)
Frequency Amplitude sine square triangular pulse arbitrary
(volt)
4.5Mhz 1 -45.77 -43.58 -47.53 -49.65 -45.73
2 -39.56 -37.53 -41.46 -43.58 -39.63
4 -33.65 -31.47 -35.43 -37.52 -33.60
6 -30.13 -27.96 -31.90 -34.00 -30.00
8 -27.63 -25.50 -29.40 -31.52 -27.58
10 -25.70 -23.53 -27.47 -29.58 -25.64
12 -24.11 -21.95 -25.88 -24.05
14 -22.77 -20.61 -24.54 -22.71
16 -21.61 -19.45 -23.38 -21.55
18 -20.56 -18.44 -22.36 -20.53
20 -19.67 -17.53 -21.44 -19.62
 Signal power of Waveforms by (dbm)
Frequency Amplitude Sine square triangular Pulse arbitrary
(volt)
6Mhz 1 -44.25 -46.10 -46.10 -42.20 -44.30
2 -38.08 -36.07 -40.00 -36.09 -38.18
4 -32.20 -30.01 -33.97 -30.12 -32.14
6 -28.67 -26.51 -30.45 -26.60 -28.62
8 -26.17 -24.05 -27.94 -24.11 -26.13
10 -24.25 -22.11 -26.02 -22.19 -24.20
12 -22.67 -20.54 -24.44 - -22.62
14 -21.33 -19.20 23.10 - -21.28
16 -20.18 -18.05 21.95 - -20.12
18 -19.16 -17.03 20.93 - -19.10
20 -18.24 -16.13 20.19 - -18.19
 Signal power of Waveforms by (dbm)
Frequency Amplitude Sine square triangular Pulse arbitrary
(volt)
7.5Mhz 1 -43.40 -41.38 -45.38 -47.44 -43.5
2 -37.28 -35.31 -39.22 -41.32 -37.38
4 -31.43 -29.25 -33.18 -35.28 -31.35
6 -27.90 -25.74 -29.66 -31.77 -27.83
8 -25.40 -23.32 -27.16 -29.34 -25.33
10 -23.46 -21.37 -25.22 -27.40 -23.39
12 -21.88 -19.78 -23.63 -25.81 -21.80
14 -20.54 -18.44 -22.29 -24.48 -20.47
16 -19.38 -17.29 -21.14 -23.33 -19.31
18 -18.38 -16.27 -20.11 -22.31 -18.28
20 -17.44 -15.36 -19.20 -21.40 -17.37
 Signal power of Waveforms by (dbm)
Frequency Amplitude Sine square triangular Pulse arbitrary
(volt)
9Mhz 1 -43.12 -40.90 -44.95 -46.97 -43.01
2 -36.74 -34.84 -38.70 -40.90 -36.85
4 -30.92 -28.77 -32.66 -34.84 -30.82
6 -27.40 -25.25 -29.13 -31.32 -27.30
8 -24.89 -22.87 -26.63 -28.44 -24.90
10 -22.95 -20.92 -24.69 -26.97 -22.86
12 -21.37 -19.32 -23.10 -25.39 -21.27
14 -20.02 -17.99 -21.76 -24.05 -19.93
16 -18.87 -16.83 -20.60 -22.90 -18.77
18 -17.84 -15.81 -19.58 -21.88 -17.73
20 -16.93 -14.90 -18.67 -20.97 -16.84
 Signal power of Waveforms by (dbm)
Frequency Amplitude Sine square triangular Pulse arbitrary
(volt)
10.5Mhz 1 -42.50 -40.55 -44.55 -46.55 -42.63
2 -36.30 -34.45 -38.40 -40.60 -36.44
4 -30.52 -28.38 -32.35 -34.55 -30.40
6 -26.99 -24.87 -28.82 -31.04 -26.88
8 -24.50 -22.52 -26.33 -28.70 -24.38
10 -22.50 -20.56 -24.50 -26.74 -22.44
12 -20.98 -18.97 -22.80 -25.15 -20.55
14 -19.64 -17.65 -21.48 -23.82 -19.52
16 -18.48 -16.49 -20.32 -22.67 -18.39
18 -17.46 -15.48 -19.30 -21.66 -17.35
20 -16.55 -14.57 -18.38 -20.75 -16.44
 Signal power of Waveforms by (dbm)
Frequency Amplitude Sine square triangular Pulse arbitrary
(volt)
13Mhz 1 -42.2 -40.2 -46.4 -42.20
2 -35.84 -34.10 -40.40 -35.98
4 -30.12 -28.02 -34.30 -29.92
6 -26.59 -24.60 -30.78 -26.40
8 -24.08 -22.22 -28.52 -23.89
10 -22.14 -20.26 -26.56 -21.95
12 -20.55 -18.67 -24.96 -20.38
14 -19.20 -17.33 -23.36 -19.03
16 -18.06 -16.07 -22.47 -17.87
18 -14.04 -15.16 -21.45 -16.85
20 -16.13 -14.25 -20.55 -15.94
 Signal power of Waveforms by (dbm)
Frequency Amplitude Sine square triangular Pulse arbitrary
(volt)
14.5Mhz 1 -42.30 -40.07 -46.2 -42.00
2 -35.70 -34.00 -40.20 -35.77
4 -29.98 -27.92 -34.03 -29.73
6 -26.47 -24.4 -30.52 -26.2
8 -23.95 -22.15 -28.30 -23.70
10 -22.01 -20.20 -26.32 -21.75
12 -20.42 -18.61 -23.40 -18.83
14 -17.93 -16.12 -22.24 -17.67
16 -16.91 -15.10 -21.22 -16.65
18 -15.99 -14.19 -20.31 -15.75
20 -15.02 -13.28 -19.40 14.85
 Signal power of Waveforms by (dbm)
Frequency Amplitude Sine Square triangular Pulse arbitrary
(volt)
16Mhz 1 -41.78 -39.35 -46.01 -41.78
2 -35.50 -33.85 -40.01 -35.50
4 -29.80 -27.77 -33.96 -29.47
6 -26.28 -24.17 -30.45 -25.95
8 -23.77 -22.06 -28.26 -23.49
10 -21.84 -20.11 -26.30 -21.50
12 -20.25 -18.52 -24.72 -19.93
14 -18.92 -17.19 -23.39 -18.60
16 -17.78 -16.05 -22.24 -17.45
18 -16.77 -15.04 -21.23 -16.43
20 -15.85 -14.13 -20.32 -15.52
 Signal power of Waveforms by (dbm)
Frequency Amplitude Sine Square triangular Pulse arbitrary
(volt)
17.5Mhz 1 -42.01 -39.93 -46.01 -41.65
2 -35.47 -33.87 -39.93 -35.37
4 -29.78 -27.78 -33.84 -29.35
6 -26.26 -24.29 -30.33 -25.83
8 -23.75 -22.12 -28.18 -23.32
10 -21.82 -20.16 -26.22 -21.38
12 -20.23 -18.58 -24.63 -19.80
14 -18.90 -17.24 -18.46
16 -17.75 -16.09 -17.30
18 -16.73 -15.07 -16.28
20 -15.81 -14.16 -15.39
 Signal power of Waveforms by (dbm)
Frequency Amplitude Sine Square triangular Pulse arbitrary
(volt)
19Mhz 1 -41.75 -39.93 -46.12 -41.50
2 -35.44 -33.88 -39.94 -35.25
4 -29.77 -27.81 -29.22
6 -26.24 -24.31 -25.69
8 -23.73 -22.18 -23.18
10 -21.79 -20.22 -21.24
12 -20.21 -18.64 -19.66
14 -18.88 -17.30 -18.32
16 -17.72 -16.16 -17.16
18 -16.70 -15.13 -16.15
20 -15.79 -14.22 -15.23
 Signal power of Waveforms by (dbm)
Frequency Amplitude Sine Square triangular Pulse arbitrary
(volt)
20.5Mhz 1 -41.74 -39.94 -41.36
2 -35.43 -33.92 -35.01
4 -29.76 -27.85 -29.07
6 -26.76 -24.35 -25.55
8 -23.72 -22.24 -23.03
10 -21.78 -20.29 -21.09
12 -20.20 -18.71 -19.51
14 -18.87 -17.37 -18.17
16 -17.71 -16.22 -17.02
18 -16.69 -15.20 -16.00
20 -15.78 -14.29 -15.09
 Signal power of Waveforms by (dbm)
Frequency Amplitude Sine Square triangular Pulse arbitrary
(volt)
23Mhz 1 -41.73 -39.96 -41.9
2 -35.43 -33.98 -34.85
4 -29.76 -27.93 -28.81
6 -26.24 -24.44 -25.29
8 -23.72 -22.37 -22.77
10 -21.78 -20.42 -20.84
12 -20.20 -18.84 -19.26
14 -18.87 -17.51 -17.92
16 -17.71 -16.35 -16.77
18 -16.69 -15.34 -15.75
20 -15.78 -14.42 -14.84
 Signal power of Waveforms by (dbm)
Frequency Amplitude Sine Square triangular Pulse arbitrary
(volt)
24.5Mhz 1 -41.77 -40.00 -40.98
2 -35.46 -34.03 -34.70
4 -29.77 -27.98 -28.67
6 -26.25 -24.25 -25.14
8 -23.73 -22.46 -22.63
10 -21.79 -20.51 -20.69
12 -20.2 -18.93 -19.11
14 -18.88 -17.60 -17.78
16 -17.73 -16.45 -16.62
18 -16.71 -15.43 -15.60
20 -15.80 -14.52 -14.42
 Signal power of Waveforms by (dbm)
Frequency Amplitude Sine Square triangular Pulse arbitrary
(volt)
26Mhz 1 -41.75 -40.05
2 -35.47 -34.07
4 -29.78 -28.03
6 -26.27 -26.57
8 -23.74 -22.54
10 -21.81 -20.60
12 -20.23 -19.02
14 -18.90 -17.69
16 -17.75 -16.54
18 -16.73 -15.52
20 -15.83 -14.61
 Signal power of Waveforms by (dbm)
Frequency Amplitude Sine Square triangular Pulse arbitrary
(volt)
27.5Mhz 1 -42.08 -40.09
2 -35.55 -34.17
4 -29.81 -28.13
6 -26.29 -24.65
8 -23.76 -22.65
10 -21.83 -20.71
12 -20.25 -19.23
14 -18.92 -17.80
16 -17.76 -16.65
18 -16.74 -15.63
20 -15.83 -14.72
 Signal power of Waveforms by (dbm)
Frequency Amplitude Sine Square triangular Pulse arbitrary
(volt)
30Mhz 1 -41.76 -40.20
2 -35.57 -34.39
4 -29.84 -28.27
6 -26.32 -24.81
8 -23.80 -22.83
10 -21.86 -20.89
12 -20.28 -19.31
14 -18.95 -17.99
16 -17.80 -16.85
18 -17.78 -15.83
20 -15.87 -14.92