ARLA/CLUSTER: NASA convida radioamadores a transmitir mensagens para a nave Juno em 28 MHz

João Costa > CT1FBF ct1fbf gmail.com
Sexta-Feira, 6 de Setembro de 2013 - 17:12:01 WEST


Faço minhas as tuas saudades.

Nunca como naquela epoca gostei tanto de fazer satelite. È capaz de
ter sido pelo "primeiro amor", mas que me deu um grande gozo fazer o
RS12/13 naquelas condições, lá isso deu.

João Costa (Ct1FBF)

2013/9/6 Jose Miguel Fonte <etjfonte  ua.pt>:
> Com upload em 21 MHz, o modo K e T... E os footprints enormes... que
> saudades do RS12/13 (K) e 10/11 (T).
>
>
> On Thu, 2013-09-05 at 21:28 +0100, AV wrote:
>> Em tempos houve alguns satélites de amador com emissão nos 10m e eram
>> bem fáceis de receber.
>>
>> Julgo que o problema maior deste caso terá a ver com as
>> caracteristicas do receptor.
>>
>> 73,
>>
>> António Vilela
>>
>> CT1JHQ
>>
>>
>>
>> On 5 September 2013 17:34, Paulo Faria <pauloafaria  sapo.pt> wrote:
>>         Como se isso fosse mais fácil.
>>         Fazer passar 28MHz pela ionosfera, é milhares de vezes mais
>>         difícil, do que 144MHz. E se houver boa ionização, pior ainda,
>>         volta tudo para terra.
>>         O sistema detector não é um vfo sensível, nem o sistema será
>>         capaz de (ler) os indicativos.
>>         Sugere a Nasa, key down durante 30 segundos entre 28.001 e
>>         28.450. Só espero que se lembrem dos beacons, e não estraguem
>>         o dx a ninguém.
>>         Os americanos não têm limites para infracção de regras, mas
>>         nós temos.
>>         Finalmente, provavelmente os piratas dos camionistas
>>         brasileiros, espalhados por todo o espectro, devem cumprir a
>>         missão com sucesso, transmitem em AM, durante mais de 30
>>         segundos de cada vez, e estão espalhados pela banda de 10
>>         metros, entre outras.
>>
>>         Cumprimentos
>>         Paulo Faria CS8ABA
>>
>>
>>         Sent with AquaMail for Android
>>         http://www.aqua-mail.com
>>
>>
>>         On 5 de Setembro de 2013 15:00:12 Carlos Fonseca wrote:
>>
>>         > Aos que se choram de nao conseguirem chamar a iss,
>>         > aproveitem esta oportunidade pata depois nao dizerem que nao
>>         > avisaram......
>>         >
>>         > 73's de CT1GFQ
>>         > REP#1406
>>         > SKCC#466C
>>         >
>>         > Cump.
>>         > Carlos Fonseca
>>         >
>>         > (Email enviado via plataforma movél).
>>         >
>>         > No dia 5 de Set de 2013 13:04, "João Costa &gt; CT1FBF"
>>         > <ct1fbf  gmail.com> escreveu:
>>         >         Radio hams to say 'HI' to Juno on 10m
>>         >
>>         >         NASA's Juno mission is inviting amateur radio
>>         >         operators around the
>>         >         world to transmit a coordinated message on the 28
>>         >         MHz band to the Juno
>>         >         spacecraft
>>         >
>>         >         NASA's Juno spacecraft will fly past Earth on
>>         >         October 9, 2013 to
>>         >         receive a gravity assist from our planet, putting it
>>         >         on course for
>>         >         Jupiter.
>>         >
>>         >         To celebrate this event, the Juno mission is
>>         >         inviting amateur radio
>>         >         operators around the world to say "HI" to Juno in a
>>         >         coordinated Morse
>>         >         Code message. Juno's radio and plasma wave
>>         >         experiment, called Waves,
>>         >         should be able to detect the message if enough
>>         >         people participate.
>>         >
>>         >         Juno will have a better chance of detecting the
>>         >         signal from many
>>         >         operators if the signal is spread out across the
>>         >         spectrum. The Juno
>>         >         Waves instrument is a broadband receiver, and the
>>         >         detector being used
>>         >         for this event has a band width of 1 MHz. It is
>>         >         better for detection
>>         >         of the signal to have a broadband signal coming in.
>>         >
>>         >         For this experiment, we would like to ask those
>>         >         participating to
>>         >         spread out in frequency across the 10 meter band. We
>>         >         have supplied a
>>         >         table of suggested frequencies between 28 and 29
>>         >         MHz, based on the
>>         >         last letter of your call. When the HFR receiver is
>>         >         tuned to 28MHz, the
>>         >         center frequency is 28.5 MHz. A 50 kHz high pass
>>         >         filter limits low
>>         >         frequencies hitting the detector, so the frequency
>>         >         table excludes 28.5
>>         >         MHz ±50 kHz. The natural signals we expect to
>>         >         measure at Jupiter will
>>         >         consist of a large number of discrete tones, so
>>         >         spreading the signals
>>         >         out in this manner is a good approximation to the
>>         >         signals we expect to
>>         >         detect. But at Jupiter, we don't expect to be able
>>         >         to decode CW in our
>>         >         telemetry!
>>         >
>>         >         The 28 MHz band was chosen for this experiment for
>>         >         several reasons.
>>         >         The Waves instrument is sensitive to radio signals
>>         >         in all amateur
>>         >         bands below 40 MHz, but experience with the
>>         >         University of Iowa
>>         >         instruments on the Galileo and Cassini earth flybys
>>         >         shows significant
>>         >         shielding by the ionosphere at lower frequencies. As
>>         >         sad as it sounds,
>>         >         we hope for lousy band conditions on October 9, so
>>         >         an appreciable
>>         >         fraction of the radiated energy escapes the
>>         >         ionosphere into space, and
>>         >         is not refracted back down to the ground somewhere
>>         >         else on the planet.
>>         >
>>         >         Juno's antenna consists of a pair of tapered 2.8
>>         >         meter long titanium
>>         >         tubes, deployed from the bottom deck of the
>>         >         spacecraft under the +X
>>         >         solar array and magnetometer boom. A high impedance
>>         >         radiation
>>         >         resistant preamp sits at the base of the antenna and
>>         >         buffers the
>>         >         signals from 50 Hz to 45 MHz. The elements are
>>         >         deployed with an
>>         >         opening angle of about 120 degrees. Ten meters is
>>         >         above the resonant
>>         >         frequency of the antenna and NEC analysis indicates
>>         >         a lobe generally
>>         >         along the spin axis of the spacecraft. This will be
>>         >         good for detection
>>         >         on the inbound part of closest approach to Earth.
>>         >
>>         >         The Waves instrument uses four receivers to cover
>>         >         the frequency range
>>         >         of 50 Hz to 41 MHz. Signals up to 3 MHz are bandpass
>>         >         filtered, sampled
>>         >         by A/D converters and FFT processed into spectra
>>         >         using a custom FFT
>>         >         processor developed by The University of Iowa under
>>         >         a grant from the
>>         >         Iowa Space Grant Consortium.
>>         >
>>         >         Please join in, and help spread the word to fellow
>>         >         amateur radio enthusiasts!
>>         >
>>         >         NASA - Say "HI" to Juno!
>>         >         http://www.jpl.nasa.gov/hijuno/
>>         >         See How do I participate ? for the frequency list.
>>         >
>>         >
>>         >         _______________________________________________
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>>         >         CLUSTER  radio-amador.net
>>         >         http://radio-amador.net/cgi-bin/mailman/listinfo/cluster
>>         >
>>
>>
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