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<DIV>
<H1>JT4 on the Microwave Bands</H1>
<P><FONT face=Verdana>A growing number of Radio Amateurs are using the JT4 mode
on the microwave bands with excellent results.</FONT></P>
<P><FONT face=Verdana><STRONG>JT4</STRONG> is part of the WSJT weak signal
software developed by <STRONG>Joe Taylor, K1JT</STRONG>.</FONT></P>
<P><FONT face=Verdana>It uses 4-tone FSK, so it can also also include both a
sync bit and a data bit in each symbol. Again the keying rate is 4.375 baud, and
a number of different tone spacings are offered.</FONT></P>
<P><FONT face=Verdana>Reports on the UK Microwave reflector indicates it very
tolerant of radar, aircraft scatter, fading, and rig drift and tests on 10GHz
with heavy rainscatter worked 100% over a very obstructed 70km path.</FONT></P>
<P><FONT face=Verdana>As far as is known no-one has yet tried JT4 on Low Earth
Orbit (LEO) Amateur Satellites where the high levels of doppler (6-18 Hz a
second) have proved problematic for traditional digital modes such as
PSK31.</FONT></P>
<P><FONT face=Verdana>UK Microwaves reflector<BR></FONT><A
href="http://groups.yahoo.com/group/ukmicrowaves/" target=_blank><FONT
face=Verdana>http://groups.yahoo.com/group/ukmicrowaves/</FONT></A></P>
<P><FONT face=Verdana>WSJT Website<BR></FONT><A
href="http://physics.princeton.edu/pulsar/K1JT" target=_blank><FONT
face=Verdana>http://physics.princeton.edu/pulsar/K1JT</FONT></A></P>
<P><FONT face=Verdana>Further information on JT2 and JT4<BR></FONT><A
href="http://physics.princeton.edu/pulsar/K1JT/JT2_JT4.TXT" target=_blank><FONT
face=Verdana>http://physics.princeton.edu/pulsar/K1JT/JT2_JT4.TXT</FONT></A></P>
<P><FONT face=Verdana>Southgate 2007 - Two new DigiModes - JT2 &
JT4<BR></FONT><A
href="http://www.southgatearc.org/news/october2007/two_new_digi_modes.htm"
target=_blank><FONT
face=Verdana>http://www.southgatearc.org/news/october2007/<BR>two_new_digi_modes.htm</FONT></A></P></DIV></BODY></HTML>