Boas João<div><br></div><div>Esse novo modo descodifica sinais de -40dB em relação a que?</div><div><br></div><div>-40dBm certamente não será, pois isso é um sinalão.</div><div><br></div><div>Não estarão a referir-se à relação sinal-ruido??</div>
<div><br></div><div>Adiante lá.</div><div><br></div><div>73, Renato<br><br><div class="gmail_quote">2012/11/21 João Costa > CT1FBF <span dir="ltr"><<a href="mailto:ct1fbf@gmail.com" target="_blank">ct1fbf@gmail.com</a>></span><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">New Mode for MF and LF<br>
<br>
If you are on 160 meters, or perhaps on 472 or 137 kHz, you may be<br>
interested in a new mode called JT9, designed especially for making<br>
QSOs on these bands. JT9 uses the structured messages introduced in<br>
2003 for the JT65 mode, now widely used for EME and for QRP operations<br>
at HF.<br>
<br>
JT9 can operate at signal levels as low as -27 dB (in a 2500 Hz<br>
reference bandwidth), with one-minute timed transmissions. It also<br>
offers slower transmissions of 2, 5, 10 and 30 minutes duration, and<br>
the slowest mode can decode signals as weak as -40 dB. With one-minute<br>
transmissions, submode JT9-1 has a total bandwidth of 15.6 Hz -- less<br>
than one-tenth the bandwidth of a JT65A signal. The other submodes are<br>
narrower still: a JT9-30 signal occupies about 0.4 Hz total bandwidth.<br>
<br>
JT9 is implemented in an experimental version of WSJT called WSJT-X.<br>
Some further details can be found at<br>
<a href="http://www.physics.princeton.edu/pulsar/K1JT/WSJT-X_Quick_Start_Guide.pdf" target="_blank">http://www.physics.princeton.edu/pulsar/K1JT/WSJT-X_Quick_Start_Guide.pdf</a> ,<br>
and an early version of WSJT-X can be downloaded from<br>
<a href="http://physics.princeton.edu/pulsar/K1JT/WSJTX_01r2695.exe" target="_blank">http://physics.princeton.edu/pulsar/K1JT/WSJTX_01r2695.exe</a> .<br>
<br>
If you want to try JT9, I suggest using dial frequency 1838, which is<br>
also used for JT65A, PSK31, and MFSK. In default configuration WSJT-X<br>
allows transmission and reception 1 to 2 kHz above the dial frequency.<br>
<br>
Please note: WSJT-X is in an early development stage. Your feedback<br>
(direct email to me is best) will be much appreciated. And feel free<br>
to email me for a sked!<br>
<br>
-- 73, Joe, K1JT<br>
<br>
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<br></blockquote></div><br></div>