Radio JOVE Project at

Western State College

byAlan Piquette

Colorado Space Grant SymposiumApril 6, 2002

SubmittedMarch 22, 2002

RADIO JOVE PROJECT AT WESTERN STATE COLLEGE

Abstract

People have been studying the skies since the beginning of humanity, but until the 20th

Century all they could observe was the part of the universe that emitted visible radiation. Few

suspected that, beyond their range of vision, a richer and more complete cosmos was waiting to

be discovered. This paper discusses radio astronomy as a means to broaden our perspective of

the universe in which we live. The Radio JOVE Project is an educational outreach effort of

NASA, the University of Florida, and others, whose purpose is to educate people about planetary

and solar radio astronomy, space physics, and the scientific method by providing teachers and

students with a hands-on radio astronomy exercise. The specific scientific goal is to monitor

20.1 MHz radio emissions from Jupiter and the Sun using the Radio JOVE Project antenna and

receiver. The data collected by observers all over the Earth are sent to a central location for

analysis and comparison. The JOVE receiver kit and antenna can be assembled by anyone with

a moderate background in electronics and some soldering experience. The receiver put together

for this project required approximately 16 hours of construction time. Testing is now in progress

and data collection will hopefully soon follow.

Introduction

A Brief History of Radio and Radio Astronomy: Most people know that astronomy is

the study of the universe and the objects in it. When many of them hear the word astronomy,

however, they automatically assume that a form of optical science is being discussed. In other

words, images of telescopes and eyepieces come to mind, but the study of the cosmos is not

limited to visual means alone. While the visible sky contains all the familiar constellations and

the faint glow of our own Milky Way galaxy, there is another window to the universe open to

anyone with the proper equipment. This window can be thought of as the "radio sky," which is

filled with radio sources that only rarely match the positions of visible stars (Thurber, 1995).

The branch of science that deals with the detection and study of those sources is radio

astronomy.

Similarly when people consider of the word radio, they usually think of sound. While

everyday experience and Hollywood movies make people think of sounds when they see the

words radio waves, radio astronomers do not actually listen to noises. First, sound and radio

waves are different phenomena. Sound consists of pressure variations in matter, such as air or

water (Lea & Burke, 1997). Sound will not travel through a vacuum. Radio waves, like visible

light, infrared, ultraviolet, X-rays, and gamma rays, are electromagnetic waves that do travel

through a vacuum. When you turn on a radio you hear sounds because the transmitter at the

radio station has changed the characteristics of the radio waves to make them carry information

about the sound of voices and music. An AM/FM radio receives the radio waves, deciphers this

information and changes it back into audible sounds.

Following Guglielmo Marconi's successful transatlantic communications in 1901,

commercial use of radio mushroomed (Bracher, 2000). Ships were equipped with radio, huge

commercial stations were set up to handle intercontinental messages, and many other uses were

found for the new technology. In those days, it was thought that the only really useful

frequencies for long-range communication were the very low frequencies, or the very long

wavelengths (Thompson et al., 1991). Thus, when the first government regulations were

imposed on radio in 1912, the amateur operators (hams), whose interest in radio was personal

and experimental, rather than commercial, received the use of undesirable frequencies. They

were given the use of wavelengths of 200 meters and shorter, roughly the frequencies above the

current AM broadcast band. These were generally thought useless for long-range

communication (Bracher, 2000).

The wavelength restrictions were rather loosely enforced prior to U.S. entry into World

War I in 1917, when all amateur and other non-government use of radio was shut down. When

amateur operations resumed in 1919, it was much more imperative to abide by the rules, so the

hams had to find out just what they could do with the short waves (Thurber, 1995).

Starting in 1921, amateurs made concerted, organized efforts to communicate across the

Atlantic with short waves. In December of 1921, an amateur station in Connecticut was heard

by an American amateur sent to Scotland with state-of-the-art receiving equipment (Cornell,

1981). On November 27, 1923, amateurs in the U.S. and France made the first transatlantic two-

way contacts on shortwave frequencies. In the following two months 13 European and 17

American amateur stations had made two-way transatlantic shortwave contacts (Thurber, 1995).

Within a year, amateurs had communicated between North and South America, South America

and New Zealand, North America and New Zealand, and London and New Zealand.

These accomplishments proved beyond a doubt that ionospheric refraction could enable

worldwide communication by shortwave radio (Brinks & Dahlem, 1996). Further amateur

experiments showed that, by using a variety of frequencies in the shortwave region (3-30 MHz),

long-range communication could be maintained both day and night. In addition, the shortwave

communications were accomplished with transmitters of only modest power, unlike the giant,

many-kilowatt transmitters needed for long-range communication at the lower frequencies

(Thurber, 1995).

Naturally, once the hams showed the value of shortwave radio, many commercial firms

became interested. One of these commercial interests was the telephone company, which

thought that shortwave links might be used to carry intercontinental telephone calls, saving the

expense of laying cable on the ocean floor (Thurber, 1995). However, as any ham or shortwave

listener today knows, shortwave communication is subject to much noise and static. The

telephone company sought to identify and find ways to lessen or eliminate this noise.

In the early 1930’s, a radio engineer named Karl G. Jansky tried to determine the causes

of radio communications static on transoceanic telephone connections for Bell Telephone

Laboratories (Bracher, 2000). Jansky did not locate any specific source of the static and

interference. However, he did note that as he turned his antenna toward the galactic plane of the

Milky Way, he recorded an increase in static hiss. After much testing and verification, he

concluded that the source of the interference was from the direction of the center of the Milky

Way (Thurber, 1995). Jansky's discovery did not convincingly establish the existence of radio

emissions from the sky, and the broad beam of his antenna only vaguely suggested any details of

those emissions at 20.5 MHz. As a result, his work did not appear to create much interest, and

Jansky did not immediately have the opportunity to pursue his discovery in depth (Bracher,

2000).

Then, beginning in 1937 and continuing into the 1940’s, an amateur radio operator,

Grote Reber, built a 31-foot parabolic dish antenna in his back yard to continue Jansky's work.

By observing VHF and UHF as high as 500 MHz, Reber discovered particular regions of intense

radio emissions, or static hiss. Reber then plotted regions of the sky according to the intensity of

the radio sources. He eventually published a map in 1944 of a large part of the sky based on his

work (Thurber, 1995). Jansky's and Reber's efforts are considered by many to represent the

foundations of modern radio astronomy.

Thus, the accidental discovery of cosmic radio emissions was a direct result of radio

amateurs' success in developing shortwave communications. Then, for several years after this

original discovery, the only people following up with systematic and well-designed radio

astronomy observations were radio amateurs. Today, the connection between radio astronomy

and amateur radio remains strong. Many prominent radio astronomers first became interested in

science through involvement with amateur radio in their youth (Bracher, 2000).

The Basics of Radio Astronomy: Radio astronomy is the study of distant objects in

the universe by collecting and analyzing the radio waves emitted by those objects. Just as

optical astronomers make images using the visible light emitted by celestial objects such as stars

and galaxies, radio astronomers can make “images” using the radio waves emitted by such

objects, as well as by gas, dust and very energetic particles in the space between the stars. Radio

astronomy has been a major factor in revolutionizing our concepts of the universe and how it

works. Radio observations have provided a whole new outlook on objects we already knew,

such as galaxies, while revealing exciting objects such as pulsars and quasars that had been

completely unexpected (Harwit, 1984).

One of the primary sources of cosmic radio emission is the electron. Electrons, like other

charged particles, emit photons when they lose energy. For example, an electron can lose energy

when it decelerates or changes direction. The photons carry away the energy that the electrons

have lost, just as hot brake pads carry away the energy a car loses when the driver brakes (Brinks

& Dahlem, 1996). If the electrons lose only a small amount of their energy, they emit the

weakest type of photons: radio photons.

Not all radio photons are identically emitted. Their properties depend on where the

electrons are. In neutral gases, such as air, practically all electrons are bound. They are trapped

in orbit around the nuclei of atoms or molecules. In a bound system, an electron is not free to

move at will. It is forced into one of a limited number of stable orbits, each corresponding to a

certain amount of energy. When the electron drops from one orbit to a lower orbit, the photon

that it emits carries away the difference in energy between the two orbits (Atkins, 1999).

There are several types of galactic radio emissions. The first type, discovered in 1932 by

Jansky, is spread over a wide band of radio frequencies. It is produced when free electrons are

scattered by collisions with heavier ions in the ionized interstellar gases surrounding hot, bright

stars (Thurber, 1995). A second type, synchrotron radiation, is emitted by energetic electrons as

they quickly spiral within the strong magnetic fields in the surroundings of super-nova remnants

(Brinks & Dahlem, 1996; Thurber, 1995). A third type originates in interstellar matter, which

radiates at discrete frequencies characteristic of the quantum jumps made by electrons in atoms

and molecules, such as hydrogen and helium (Thurber, 1995).

Radio waves also come from beyond the Milky Way. Some extra-galactic radio sources

are detected only by their radio emissions, while others are correlated with optically observed

galaxies and other objects. Radio sources produce either continuum radiation, which covers a

broad range of wavelengths, or line radiation that is radiated at one specific wavelength, much

like an optical spectral line (Brinks & Dahlem, 1996).

Besides localized radio sources, there is also uniform low-level cosmic radio noise

coming from every direction in the sky. That cosmic background radiation (CBR) lends support

to the theory that the universe began with an explosive big bang, rather than always having

existed in an unchanging state having an isotropic (uniform in all directions) property (Thurber,

1995).

The antennas and receivers used in present-day radio astronomy vary widely, so it is

difficult to describe a typical arrangement. However, in general, the antenna intercepts and

collects the radio signal from the celestial source. After preamplification at the feed-point, the

signal is carried by cable to the main receiver, where it is selected according to frequency and

amplified. The intercepted signal is amplified further, detected, and integrated, and the output is

displayed on an analog recorder or other device. It also can be recorded in digital form on

magnetic tape for further processing by computers (Thurber, 1995).

The radio signals arriving on Earth from astronomical objects are extremely weak,

millions (or billions) of times weaker than the signals used by communication systems. For

example, a cellular telephone located on the moon would produce a signal on earth that radio

astronomers consider quite strong (Thompson et al., 1991). Because the cosmic radio sources

are so weak, they are easily masked by man-made interference. Possibly even worse than

complete masking, weaker interfering signals can contaminate the data collected by radio

telescopes, potentially leading astronomers to erroneous interpretations (Fridman, 2000).

By international agreement, radio frequencies are divided into bands designated for

different types of uses. For example, FM radio stations all are within a certain range of

frequencies that is different from the band of frequencies in which AM stations operate (Lazio &

Nordgren, 2001). Similarly, TV stations use different frequencies than police radios. These

international frequency designations are designed to prevent one type of station from interfering

with stations of another type.

A number of frequency bands are allocated to radio astronomy. Because radio

astronomers do their work with extremely sensitive receiving equipment, transmitting is

generally prohibited in the radio astronomy bands (Thurber, 1995). However, transmitters using

frequencies near those assigned to radio astronomy can cause interference to radio telescopes.

This occurs when the transmitter's output is excessively broad, crossing over into the radio

astronomy frequencies, or when the transmitter emits frequencies outside its intended range.

Other interference arises because radio transmitters often unintentionally emit signals at

multiples of their intended frequency (Fridman, 2000).

As use of radio for devices such as cellular telephones, wireless computer networks,

garage door openers, and a whole host of other uses continues to increase, the threats to radio

astronomy from inadequately engineered transmitters increases. A prime threat comes from

transmitters in orbiting Earth satellites, since those transmitters are located overhead, precisely

where radio astronomers must aim their telescopes to study the universe. In addition, many

types of equipment not normally considered to be radio transmitters, particularly computers or

systems incorporating microprocessors, emit undesirable radio signals (Thompson et al., 1991).

Good engineering can prevent or minimize interference to radio astronomy. Spillover

from overly broad transmitters and other unintended signals do nothing to improve the

performance of a communication system. Technology readily available to radio engineers can

eliminate or drastically reduce these unwanted signals that threaten radio astronomy. It is

especially important that such interference-reducing technology be included in orbiting satellites

(Thurber, 1995). Radio astronomers do much on their own to minimize the effect of interfering

signals, from locating radio telescopes far from urban centers whenever possible to designing

their antennas and electronic equipment with features that reduce interference.

Communication between radio astronomers and other users of the radio spectrum is vital.

Engineers at radio telescope facilities often can help with suggestions for ways to minimize

interference. There are numerous examples of situations in which a radio observatory and a

transmitting facility have cooperated to implement a technical solution allowing both to achieve

their objectives (Thurber, 1995).

Importance of Radio Astronomy: The purpose of a radio astronomer is to do

fundamental research on the nature of the universe in which we live (Finley, NRAO). This

research hopes to answer some of the biggest questions we can ask, such as how did the universe

begin (if it did begin), how big is it, how old is it, and how will it end (or will it end)?

Astronomy provides the background knowledge of where we, and the planet on which we live,

fit into the universe, which suggests it is a vital part of the culture of all mankind. A person

deprived of the broad aspects of astronomical knowledge is as culturally disadvantaged as one

never exposed to history, literature, music or art (Finley, NRAO). As astronomers make known

new discoveries about the universe, they potentially enrich the lives of millions.

From the dawn of civilization, astronomy has provided important stepping stones for

human progress. Our calendar and system of time-keeping came from astronomy (Funk &

Walls, 1995). Many of today's mathematics are the result of astronomical research. Hipparchus,

a Greek astronomer, invented trigonometry. The adoption of logarithms was driven by the needs

of astronomical calculations. Sir Isaac Newton invented calculus, the basis of modern science

and engineering, primarily for astronomical calculations (Finley, NRAO). Astronomy provided

the navigational techniques that allowed sailors and aviators to explore our planet. The space

age, which brought the communication and weather satellites upon which we depend each day,

would have been impossible without the knowledge of gravity and orbits discovered in part by

astronomers (Funk & Walls, 1995). Radio astronomers led to the development of low-noise

radio receivers that made possible the satellite communications industry. Image-processing

techniques developed by astronomers now are part of the medical imaging systems that allow

non-invasive examination of internal organs (Finley, NRAO).

From revealing the remains of the Big Bang to suggesting the existence of neutron stars,

radio observers have provided science with insights unobtainable with other types of telescopes.

Of the ten astronomers who have won the Nobel Prize in Physics, six of them used radio

telescopes for the work that won them the Nobel (Thurber, 1995). Radio telescopes today are

among the most powerful tools available for astronomers studying nearly every type of object

known in the universe.

It seems that astronomy has much still to offer to human knowledge and advancement.

From the space shuttle to the transistor, from television to lasers, the developments of the 20th

Century were based on the study of matter and energy. Astronomy offers scientists a wide range

of backgrounds with a virtually infinite variety of cosmic laboratories for observing physical

phenomena (Finley, NRAO). It is not likely that any laboratory on this planet will ever produce

gravity as strong as that of a black hole, matter as dense as that of a neutron star, or temperatures

as hot as inside a supernova.

The Radio JOVE Project: The Radio JOVE Project is an educational project developed

by NASA, the University of Florida, and others, whose purpose is to educate people about

planetary and solar radio astronomy. The JOVE project provides teachers and students with a

hands-on radio astronomy exercise that demonstrates the scientific method and is a good

introduction to space physics in general (http://radiojove.gsfc.nasa.gov). The primary goal is to

monitor radio emissions from Jupiter and the Sun using the Radio JOVE Project antenna and

receiver. Since monitoring Jupiter (associated with the term Jovian) is one of the specific goals,

it is clear to see why the project title is Radio JOVE. The JOVE receiver kit and antenna can be

obtained and assembled by anyone with a moderate electronics background, which includes

some soldering experience. The receiver put together for this project required approximately 16

hours of construction time and about one hour of testing and aligning. Upon successful

completion of the antenna/receiver kits, the JOVE detection system provides a means to detect,

amplify, and record radio emissions from Jupiter and the Sun having a frequency of 20.1 MHz.

It is important to study the radio emissions of both Jupiter and the Sun to better

understand their magnetic fields and their plasma environments (http://radiojove.gsfc.nasa.gov).

Studying other planets helps us advance our understanding of Earth. Earth also emits radio

waves by a process similar to that of Jupiter, which means we can better understand this

emission process on Earth by monitoring Jupiter with all sorts of radio antennas. Not only can

we learn about why the radio waves are created and how they move through space, but we can

also learn about Jupiter’s interior and about its moons (http://radiojove.gsfc.nasa.gov). Jupiter

radiates radio waves because the planet has a magnetic field, and this magnetic field originates

deep in the interior. The overall strength of the magnetic field directly affects the type of radio

emission. Knowing this type of information assists us with the theory of how the magnetic field

is created and in determining the composition of the various interior layers. The satellite Io is

close enough to Jupiter that they interact electromagnetically with each other

(http://radiojove.gsfc.nasa.gov). It is, therefore, possible to learn more about Io and the other

Jovian satellites as well.

By monitoring the radio emissions from the Sun, it will hopefully allow us to learn more

about other stars in general. Studying the Sun, using radio astronomy, allows us to find out

more about how the Sun affects the Earth and the other planets of the Solar System.

The remainder of this paper will deal with the construction of the Radio JOVE receiver

and antenna, and how the JOVE system detects, manipulates, and displays radio emission data.

Experimental

The Radio JOVE Receiver: The Radio JOVE receiver is a short-wave receiver that

detects radio signals from the planet Jupiter and also from the Sun. The JOVE receiver contains

more than 100 electronic components such as resistors, capacitors, inductors, and integrated

circuits (IC’s) as well as some other various pieces of hardware. Thus, as one might guess,

construction of the receiver included the handling of small, delicate, electronic parts, most of

which were mounted and soldered on a printed circuit (PC) board.

Radio signals from Jupiter are rather weak. In fact, they produce less than a millionth of

a volt at the antenna terminals of the receiver. Thus, these weak radio frequency (RF) signals

must be amplified by the JOVE receiver and converted to audio signals of adequate strength to

drive headphones or a loudspeaker (Flagg, 1999). The receiver also contains and acts as a

narrow filter, which is tuned to a specific frequency so as to hear Jupiter while at the same time

blocking out strong Earth-based radio stations on other frequencies. The receiver and its

accompanying antenna are designed to operate over a narrow range of short-wave frequencies

centered on 20.1 MHz. This frequency range is optimum for hearing Jupiter signals (Flagg,

1999). Before discussing the major electrical components and what they do, it would be

beneficial to take a brief look at the overall receiver in the form of a block diagram (Figure 1 in

the appendix).

The antenna, which will be discussed in more detail in the next section, intercepts weak

electromagnetic waves, which have traveled roughly one-half billion miles from Jupiter to the

Earth (Frazier, 1985). When this electromagnetic radiation strikes the wire antenna, a small RF

voltage is created at the terminals of the antenna (Flagg, 1999). Signals from the antenna are

delivered to the receiver by a coaxial-cable transmission line.

Signals from the antenna are filtered to reject strong out-of-band interference and are

then amplified using a junction field effect transistor (JFET) (Flagg, 1999). The RF bandpass

filter and RF preamplifier perform these filtering and amplification processes. This transistor as

well as some other nearby circuitry provide additional filtering and amplify incoming signals by

a factor of approximately ten. The receiver-input circuit is designed to efficiently transfer power

from the antenna to the receiver while producing a minimum amount of noise within the receiver

itself (Flagg, 1999).

The local oscillator (LO) and mixer carryout the significant task of converting the desired

radio frequency signals to the range of audio frequencies. The LO generates a sinusoidal voltage

waveform at a frequency in the vicinity of 20.1 MHz (Flagg, 1999). The exact frequency is set

by the tuning control on the front panel. The amplified RF signal from the antenna and the LO

frequency are both fed into the mixer, which develops a new signal that is the mathematical

difference between the LO and the incoming signal frequency. An example that is used by

Flagg (1999) in the JOVE receiver instruction manual is: suppose the desired signal is at 20.101

MHz and the LO is tuned to 20.100 MHz. The difference in frequency is therefore 20.101-

20.100 = .001 MHz, which is the audio frequency of 1 kilohertz. If a signal were at 20.110

MHz, it would be converted to an audio frequency of 10kHz. Since the RF signal is converted

directly to audio, the radio is known as a direct conversion receiver (Flagg, 1999).

To get rid of interfering stations at nearby frequencies, the JOVE receiver uses a low pass

filter that is similar to a window a few kilohertz wide through which signals from Jupiter can

enter. When listening for Jupiter or the Sun, the radio will be tuned to find a clear channel.

Since frequencies more than a few kilohertz away from the center frequency may contain

interfering signals, these higher frequencies must be eliminated, which is the purpose of the low

pass filter (Flagg, 1999). The low pass filter passes low frequencies up to approximately 3.5

kHz and does not pass higher frequencies.

The audio amplifiers that follow the low-pass filter take the very weak audio signal from

the mixer and amplify it enough to drive either a set of headphones or some form of an external

amplified speaker system directly. The information that is sent to the headphones or speaker can

also be sent to a computer with the proper software and put in the form of a graph.

The key to successful fabrication of the JOVE receiver kit is the builder’s ability to

solder. The PC board should be populated according to Figure 2 in the appendix. The soldering

process was (and is) best accomplished by installing the larger parts first, leaving the small,

delicate devices until last. This particular assembly order gives the builder a chance to sharpen

his or her soldering skills before getting to the integrated circuits and transistors, which may be

damaged by excess heat. It was important to mount the components as close to the PC board as

possible without putting large amounts of strain on the leads. Some of the component leads

matched the PC-board hole spacing and the components went in flush with the board. In other

instances, the leads had to be formed to align with the holes.

Upon soldering all of the electric components and encasing the circuit board, it was

necessary to test and align the receiver. There are four ways to test and align the JOVE receiver,

some of which are more sophisticated than others. The first method is to simply listen to the

output of the receiver with headphones or an amplified speaker. The goal is to adjust some

variable capacitors, inductors, and resistors to obtain the loudest signal at a certain frequency.

The other methods are similar except rather than trusting human ears, a voltmeter, an

oscilloscope, or the JOVE strip-chart recorder software was used to measure the output. For the

receiver used in this project, an oscilloscope was used to test and align the receiver.

The Radio JOVE instruction manual suggests that eleven hours is sufficient time to

construct, test, and align the receiver (Flagg, 1999). However, it took roughly sixteen hours to

assemble the receiver for this research project and an additional hour to test and align the

receiver.

The Radio JOVE Antenna: The Radio JOVE antenna intercepts weak electromagnetic

waves that have traveled roughly 500 million miles from Jupiter to the Earth or 93 million miles

from the Sun. When this electromagnetic radiation strikes the wire antenna, a small RF voltage

is developed at the antenna terminals. Signals from each single dipole antenna are brought

together with a power combiner by means of two pieces of coaxial cable. The output of the

power combiner is delivered to the receiver by another section of coaxial transmission line

(Higgins et al., 1999).

The antenna consists of several types of components including wire, coaxial cable,

connectors, insulators, rope, supports, and hardware (See Figure 3). The antenna was

constructed from two identical half-wave dipole antennas and phasing them together with feed

line. The entire length of the dipole is therefore, equal to the length of 1/2 of the wavelength ()

of radiation to be detected. Thus each side of the dipole antenna is 1/4 wavelength long. Since

the Radio JOVE receiver is tuned to the frequency of 20.1 MHz, the wavelength is 14.925

meters (48.968 feet). A useful formula for calculating the half-wavelength for an ideal dipole in

free space for a specific frequency is:

/2 (in feet) = 492 / frequency (in MHz)

/2 (in meters) = 150 / frequency (in MHz).

For practical antennas, however, the measured values are smaller than the ideal values. This is a

result of resistance in the wire and end effects of the dipole. These two properties effectively

shorten the length at which the wire will most effectively receive radiation at a frequency of 20.1

MHz. To calculate the practical half-wavelength of antenna use the formula:

/2 (in feet) = 468 / frequency (in MHz)

/2 (in meters) = 142.5 / frequency (in MHz).

For the antenna to be an effective receptor of signals, the wire dipoles must be mounted

horizontally above the ground by about /4 feet (2.44 - 3.66 m is acceptable). This is

accomplished by attaching the wire to poles held up by support rope (Higgins et al., 1999).

The purpose of the coaxial transmission cable used in the antenna is to feed the

intercepted signal by the antenna to the receiver (Higgins et al., 1999). Therefore the coaxial

cable was attached to the antenna wire by solder joints. The coaxial cable has a center conductor

surrounded by a dielectric insulator and a copper braided shielding. These help conduct the

signal from the antenna to the receiver with a minimum loss of signal. Because the cable is not a

perfect conductor, the speed at which the signal propagates along the wire depends on the type

of dielectric insulation used in the cable. For the coax included in the JOVE kit, the velocity

factor is 66% (Higgins et al., 1999). Therefore, the proper lengths for cutting the coax must take

this factor into account.

The connectors used for the Radio JOVE are called F-type connectors and were manually

twisted onto the ends of the coax line. These connectors were used to connect the cables to the

power combiner and to the antenna input on the JOVE receiver (Higgins et al., 1999). Insulators

are needed to keep the antenna from shorting the received signals to ground. Six insulators were

needed for the antenna, one in the middle of each dipole, and one on each end. Insulators are

usually plastic or ceramic cylinders with holes cut in each end for the wire and rope supports.

The insulators included in the JOVE kit assembled for this project were plastic. PVC piping was

used for the antenna support poles. PVC is a cheap and lightweight support structure that is

portable and effective. Rope, toroids, and basic hardware such as nuts and bolts were also used

in the JOVE antenna. The magnetic toroids are needed for the antenna assembly to restrict

current flow along the outer surface of the coaxial cable shielding. This allows for optimal

reception by creating a better antenna pattern (Higgins et al., 1999).

It is important to find an acceptable area in which to setup the antenna after it has been

assembled: measure and cut the wire and rope, wrap the insulators, prepare and solder the

coaxial cable, install the connectors and toroids, and assemble the mounting structure. The

antenna system requires a relatively large area for proper setup. The minimum site requirements

are a 25 x 35 ft. flat area that has soil suitable for putting tent stakes into the ground. Because

the antenna system is sensitive to noise it is best not to set it up near any high-tension power

lines or close to buildings. Additionally, for safety reasons, it is best to keep the antenna away

from power lines during construction and operation (Higgins et al., 1999). A prime location is

in rural settings where the interference is minor. Due to the fact that many of the observations

occur at night, it is sensible to practice setting up the antenna during the day to make sure the

site is safe and easily accessible.

The Radio JOVE instruction manual suggests that construction time for the antenna and

to setup the antenna system the first time takes a little under five hours (Higgins et al., 1999).

However, for this project, the antenna construction alone took longer than the suggested time.

Results and Discussion

Due to the fact that this researcher did not begin the Radio JOVE project until recently,

no data have been collected with the newly constructed receiver and antenna. However, the

JOVE website has numerous examples of data that have been sent in from around the globe by

people who have all ready assembled their JOVE radio telescopes. A few of these examples will

be presented to illustrate what will, hopefully, result when data collection begins.

The first example of data is a comparison of a Solar burst that took place on June 20,

2001 (Figure 4 in the appendix). One of the graphs came from Maryland while the other came

from Hawaii. It is clear to see that the graphs compare rather well. While this is only one case,

the comparison is indicative that the JOVE radio telescope is a reliable astronomical tool. The

horizontal axis for both graphs in the figure represents time (UT = Universal time) and the

vertical axis can be thought of as a measure of the relative amount of intercepted radiation with a

frequency of 20.1 MHz. Another comparison of a different burst is shown in Figure 5.

The data shown in Figure 6 is a graph that was obtained at a community college in

Hawaii on February 3, 2001. The data displays radio emission activity of Jupiter and Io-B. The

final two figures in the appendix (Figures 7 and 8) illustrate Jupiter S-bursts on March 3, 2002.

Figure 8 is simply a continuation of figure 7.

Conclusion

Some of the most amazing scientific discoveries in the last 100 hundred years are the

direct result of radio astronomy. From phenomena as bizarre as black holes and quasars to the

development of low-noise radio receivers used by the satellite communications industry, radio

astronomers have contributed an immeasurable amount to the scientific community as well as

the human race as a whole. It would be absurd to assume that there is nothing more to gain from

radio astronomy, which is why it is important to continue studying the topic. The Radio JOVE

Project is an educational undertaking that provides students, teachers, amateurs, and others with

an excellent hands-on radio astronomy exercise while instilling some of the most basic skills

needed by professionals in the radio astronomy field. At a relatively low cost, anyone who has a

moderate background in electrical physics with some soldering experience can assemble the

Radio JOVE telescope to monitor 20.1 MHz radio emissions from Jupiter and the Sun.

REFERENCES CITED

Atkins, P. (1999). Physical Chemistry: 6 th Edition . W. H. Freeman & Co.

Braher, K. (2000). The Beginnings of Radio Astronomy. Mercury. Vol 29 Issue 6, pp5-6.

Brinks, E.; Dahlem, M. (1996). The World of Radio Astronomy. Mercury. Vol 25 Issue 4, pp15-20.

Burke, J. R.; Lea, S. M. (1997). Physics: The Nature of Things.West Publishing Company.

Cornell, J. (1981). The First Stargazers: An Introduction to the origins of Astronomy.Scribner Press.

Finley, D. Why do Astronomy? Courtesy of National Radio Astronomy Observatory.www.NRAO.edu.

Flagg, R. (1999). Radio JOVE: Receiver Instructions Manual.

Frazier, K. (1985). Planet Earth: Solar System. Time-Life Books Inc.

Fridman, P. (2000). Radio Frequency Interference Rejection in Radio Astronomy Receivers. Mercury. Vol 30 Issue 3, pp625-630..

Funk and Walls. (1994). Infopedia. Funk and Walls, Corp.

Harwit, M. (1981). Cosmic Discovery: The Search, Scope and Heritage of Astronomy.Basic.

Higgins, C.; Reyes, F.; Greenman, W. Gass, J.; Carr, T. (1999). Radio JOVE: Antenna Instructions Manual.

Lazio, J. T.; Nordgren, T. (2001). Razor-Sharp Radio Astronomy. Mercury. Vol 30 Issue 3,

pp32-41.

Thompson, R. A.; Gergely, T. E.; Vanden Bout, T. A. (1991). Interference and Radioastronomy. Physics Today. November 1991, pp41-49.

Thurber, K. T. (1995). Radio Astronomy. Popular Electronics. Vol 12 Issue 10, pp42-49.

http://radiojove.gsfc.nasa.gov

APPENDIX OF FIGURES

Figure 1: Block Diagram of the Radio JOVE Receiver (from the Instructions Manual).

Figure 2: Electrical Component Population of the PC board

Figure 3: Radio JOVE Antenna (From the Instructions Manual).

Figure 4: JOVE Solar Burst Data (From the JOVE website).

Figure 5: Another Comparison of JOVE data (From the website).

Figure 6: Radio Emission data at 20.6 MHZ of Jupiter and Io-B (JOVE website).

Figure 7: S-Bursts from Jupiter on March 3, 2002 (JOVE website).

Figure 8: A continuation of Figure 7.