<p>Aos que se choram de nao conseguirem chamar a iss, aproveitem esta oportunidade pata depois nao dizerem que nao avisaram......</p>
<p>73's de CT1GFQ<br>
REP#1406<br>
SKCC#466C</p>
<p>Cump.<br>
Carlos Fonseca</p>
<p>(Email enviado via plataforma movél).</p>
<div class="gmail_quote">No dia 5 de Set de 2013 13:04, "João Costa &gt; CT1FBF" <<a href="mailto:ct1fbf@gmail.com">ct1fbf@gmail.com</a>> escreveu:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Radio hams to say 'HI' to Juno on 10m<br>
<br>
NASA's Juno mission is inviting amateur radio operators around the<br>
world to transmit a coordinated message on the 28 MHz band to the Juno<br>
spacecraft<br>
<br>
NASA's Juno spacecraft will fly past Earth on October 9, 2013 to<br>
receive a gravity assist from our planet, putting it on course for<br>
Jupiter.<br>
<br>
To celebrate this event, the Juno mission is inviting amateur radio<br>
operators around the world to say "HI" to Juno in a coordinated Morse<br>
Code message. Juno's radio and plasma wave experiment, called Waves,<br>
should be able to detect the message if enough people participate.<br>
<br>
Juno will have a better chance of detecting the signal from many<br>
operators if the signal is spread out across the spectrum. The Juno<br>
Waves instrument is a broadband receiver, and the detector being used<br>
for this event has a band width of 1 MHz. It is better for detection<br>
of the signal to have a broadband signal coming in.<br>
<br>
For this experiment, we would like to ask those participating to<br>
spread out in frequency across the 10 meter band. We have supplied a<br>
table of suggested frequencies between 28 and 29 MHz, based on the<br>
last letter of your call. When the HFR receiver is tuned to 28MHz, the<br>
center frequency is 28.5 MHz. A 50 kHz high pass filter limits low<br>
frequencies hitting the detector, so the frequency table excludes 28.5<br>
MHz ±50 kHz. The natural signals we expect to measure at Jupiter will<br>
consist of a large number of discrete tones, so spreading the signals<br>
out in this manner is a good approximation to the signals we expect to<br>
detect. But at Jupiter, we don't expect to be able to decode CW in our<br>
telemetry!<br>
<br>
The 28 MHz band was chosen for this experiment for several reasons.<br>
The Waves instrument is sensitive to radio signals in all amateur<br>
bands below 40 MHz, but experience with the University of Iowa<br>
instruments on the Galileo and Cassini earth flybys shows significant<br>
shielding by the ionosphere at lower frequencies. As sad as it sounds,<br>
we hope for lousy band conditions on October 9, so an appreciable<br>
fraction of the radiated energy escapes the ionosphere into space, and<br>
is not refracted back down to the ground somewhere else on the planet.<br>
<br>
Juno's antenna consists of a pair of tapered 2.8 meter long titanium<br>
tubes, deployed from the bottom deck of the spacecraft under the +X<br>
solar array and magnetometer boom. A high impedance radiation<br>
resistant preamp sits at the base of the antenna and buffers the<br>
signals from 50 Hz to 45 MHz. The elements are deployed with an<br>
opening angle of about 120 degrees. Ten meters is above the resonant<br>
frequency of the antenna and NEC analysis indicates a lobe generally<br>
along the spin axis of the spacecraft. This will be good for detection<br>
on the inbound part of closest approach to Earth.<br>
<br>
The Waves instrument uses four receivers to cover the frequency range<br>
of 50 Hz to 41 MHz. Signals up to 3 MHz are bandpass filtered, sampled<br>
by A/D converters and FFT processed into spectra using a custom FFT<br>
processor developed by The University of Iowa under a grant from the<br>
Iowa Space Grant Consortium.<br>
<br>
Please join in, and help spread the word to fellow amateur radio enthusiasts!<br>
<br>
NASA - Say "HI" to Juno!<br>
<a href="http://www.jpl.nasa.gov/hijuno/" target="_blank">http://www.jpl.nasa.gov/hijuno/</a><br>
See How do I participate ? for the frequency list.<br>
<br>
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<br></blockquote></div>