Re: ARLA/CLUSTER: Construir uma Antena Loop para escutar Júpiter.
Carlos Mourato
radiofarol gmail.com
Quarta-Feira, 6 de Maio de 2009 - 14:50:06 WEST
Na maioria dos locais citadinos, uma antena destas deve ser optima para
escutar PLCs, em vez de Jupiter.
73 de CT4RK
2009/5/6 João Gonçalves Costa <joao.a.costa ctt.pt>
> *Loop Antennas*
> Loop antennas are a very controversial topic among Jupiter radio
> astronomers.
> Some say it works, some say it doesn't - if it works for you, compare your
> results with those from people with dipole(s) or yagi's made during a
> coordinated observing session (announced on the RadioJOVE maillist) and let
> us know the results on the RadioJOVE maillist, SARA maillist or in the
> forum <http://www.jupiterradio.com/j/forum/>.
>
> ------------------------------
>
> ------------------------------
> SIGNALS FROM SPACE
>
> *IS ANYONE OUT THERE?*
>
> [Connections] <http://www.jupiterradio.com/jove-loop-antenna.php#connect>,
> [Challenge] <http://www.jupiterradio.com/jove-loop-antenna.php#challenge>,
> [Flash Fact] <http://www.jupiterradio.com/jove-loop-antenna.php#flash>, [Teacher's
> Notes] <http://www.jupiterradio.com/jove-loop-antenna.php#teacher>
> ------------------------------
> Listen for signals from Jupiter with:
>
> - 6 pieces of wood 4 cm x 8 cm x 183 cm (for square frame)
> - 5 pieces of wood 4 cm x 8 cm x 80 cm (for upright supports)
> - U bolts (optional)
> - 4.2 m of 1 cm (3/8 ") soft copper pipe (plumbing supply)
> - 4 sq. m wire mesh (hardware cloth at hardware store)
> - 2.5 m twin lead antenna cable
> - portable radio with short wave band (SW 2)
> - assorted nails, screws and staples
>
>
> 1. Nail together the 183 cm square base.
> 2. Nail on the 5 upright supports.
> 3. Turn the base over and staple the screen to the bottom. The screen
> completely covers the bottom of the base. This screen is called the
> reflector.
> 4. Attach the antenna loop to the uprights with the U bolts. If you
> don't have U bolts, tie or wire the antenna loop in place. The distance from
> the wire mesh to the antenna loop is 68.6 cm.
> 5. Attach the twin lead antenna cable to the open ends or the antenna
> loop. You can do this by inserting the bare ends of the antenna cable into
> the open ends of the tube. Then, flatten the tube onto the wire with pliers,
> or use a large screw inserted into the ends of the tube.
> 6. Connect the other ends of the antenna wires to the radio. If your
> radio has a special place to connect an extra antenna, use that. If your
> radio just has a stick antenna, wrap 2 meters of insulated wire around the
> antenna. Attach the antenna cable to this wire.
> 7. Turn on the radio and select SW 2. Look closely at the numbers
> beside SW 2. They are 16 M to 49 M. Turn the volume up and tune towards the
> 16 M end of the dial. Your antenna will work best here.
>
> 8. Turn the tuning knob slowly as you listen. You should be hearing
> interesting sounds like hums, hisses and chirps, maybe even some foreign
> languages. You are detecting a variety of electromagnetic signals. Some
> might be coming from radio stations halfway around the world. Some could be
> secret codes from spies. Others will be signals from electrons stopping and
> going inside the machines close to you. Your refrigerator sends out signals
> and so does the transformer on a pole outside. But some of these sounds are
> signals arriving from planets and stars deep in space!
> 9. This antenna is designed to detect radio storms on Jupiter. You can
> check this out for yourself. First, find out where in the sky Jupiter
> appears. Then, tune the radio to a spot where nothing else is interfering.
> All you should hear is a steady, gentle hiss. Now, point the antenna at
> Jupiter and listen. If a radio storm is happening, you might hear something.
>
>
> ------------------------------
> CONNECTIONS
>
> Many scientists believe that other intelligent forms exist in the universe.
> They are using enormous radio telescopes that are aimed into space. With
> these sensitive instruments, they listen constantly for electromagnetic
> signals. Perhaps there are aliens trying to communicate with us! They could
> be using electromagnetic signals like we do. We will never know unless we
> listen!
> ------------------------------
> CHALLENGE
>
> *
>
> 1. Build a scale model of this antenna. Use cardboard, popsicle sticks,
> wire and your imagination.
> 2. Create a message that you would send out into space. Who might
> receive this message? How can you send it?
>
> *
> ------------------------------
> FLASH FACT
>
> Dave Hieserman wrote a book called Radio Astronomy for the Amateur. He
> says, "for the amateur radio astronomer, Jupiter is perhaps the most
> exciting and delightful radio source. Through a speaker, Jovian broadcasts
> are frequently reproduced as seashore sounds or very distinctive chirps or
> staccato noises." There are so many sources of electromagnetic signals that
> you might never be certain that you have heard Jupiter. But it sure is fun
> to try!
> ------------------------------
> TEACHER'S NOTES
>
> This sophisticated project appears in the TAB book, Radio Astronomy for the
> Amateur. The antenna was designed by a university student as part of his
> work for his master's degree. The antenna was intended to detect
> electromagnetic signals from the planet, Jupiter.
>
> All objects in space give off electromagnetic signals. Scientists who study
> these signals are called radio astronomers. Some astronomers are involved in
> a program called SETI, Search for Extra Terrestrial Intelligence. They are
> trying to detect signals from other intelligent life forms.
>
> This is a difficult search. An endless array of signals comes from all over
> the universe and the distances are vast. Even though electromagnetic signals
> travel at the speed of light (299 791 km per second), it takes these signals
> years to travel from the closest stars outside our solar system. If
> astronomers detected a signal from a planet revolving around the star
> Betelgeuse and decided to send a signal back, it would take 1400 years to
> arrive! If a group of students decides to try this project, they can
> substitute some materials. Any metal pipe will do for the main loop. Any
> kind of metal screen will make a reflector. To "aim" the antenna, prop it up
> with the upright supports.
>
> Many "ghetto blaster" type radios have shortwave bands. An amateur radio
> (HAM) Operator could help to interpret the sounds coming out of the radio.
>
> Trying a project like this fires the imagination. It could trigger a
> lifelong interest in electronics and space. There certainly is a future in
> it.
>
> For the interested:
> Dave Hieserman
> Radio Astronomy for the Astronomer
> Tab Books, # 714
>
> Roy L. Bishop
> Observers Handbook
> The Royal Astronomical Society Of Canada
> 136 Dupont St., Toronto
> M5R IV2
>
> The Young Astronomer
> Usborne - Hayes
>
>
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>
>
--
Best 73 from: regards from: CT4RK Carlos Mourato - Sines - Portugal
Save the Radio Spectrum! Eliminate Broadband over Power Line. Salve as
frequencias de radio. Não use a rede electrica para transmitir dados. O PLC
causa fortes interferencias noutro serviços sem voce se aperceber. Diga não
ao PLC. Proteja o ambiente
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