ARLA/CLUSTER: 10GHz : JT4 on the Microwave Bands

[João Gonçalves Costa]

[http://tbn2.google.com/images?q=tbn:MdquvN8uYBIhWM:http://www.kwarc.org/10ghz/steve-dishes.jpg]<http://images.google.pt/imgres?imgurl=http://www.kwarc.org/10ghz/steve-dishes.jpg&imgrefurl=http://www.kwarc.org/10ghz/10GHZ-4.htm&usg=__sa8nZvlGXUlhseFvxaNnKap1ReU=&h=400&w=300&sz=32&hl=pt-PT&start=112&um=1&tbnid=MdquvN8uYBIhWM:&tbnh=124&tbnw=93&prev=/images%3Fq%3D10%2BGHz%2BAntenna%26ndsp%3D20%26hl%3Dpt-PT%26safe%3Dactive%26sa%3DN%26start%3D100%26um%3D1>[http://tbn2.google.com/images?q=tbn:bX9iSeq9ulZe3M:http://www.schwarzbeck.de/Bilder/9120b.jpg]<http://images.google.pt/imgres?imgurl=http://www.schwarzbeck.de/Bilder/9120b.jpg&imgrefurl=http://www.schwarzbeck.de/artikel.php%3Flang%3D1%26kat%3DA&usg=__gy_viTgImY6cDh1KmHxkTz3uMVw=&h=420&w=560&sz=28&hl=pt-PT&start=67&um=1&tbnid=bX9iSeq9ulZe3M:&tbnh=100&tbnw=133&prev=/images%3Fq%3D10%2BGHz%2BAntenna%26ndsp%3D20%26hl%3Dpt-PT%26safe%3Dactive%26sa%3DN%26start%3D60%26um%3D1>[http://tbn2.google.com/images?q=tbn:ScvepSd7cajAvM:http://www.pi6alk.com/10ghz_dishes.jpg]<http://images.google.pt/imgres?imgurl=http://www.pi6alk.com/10ghz_dishes.jpg&imgrefurl=http://www.pi6alk.com/&usg=__039-lsm89Ad8Jwhslv8fbGaLbKM=&h=358&w=378&sz=33&hl=pt-PT&start=87&um=1&tbnid=ScvepSd7cajAvM:&tbnh=116&tbnw=122&prev=/images%3Fq%3D10%2BGHz%2BAntenna%26ndsp%3D20%26hl%3Dpt-PT%26safe%3Dactive%26sa%3DN%26start%3D80%26um%3D1>[http://tbn1.google.com/images?q=tbn:aYgtRlB_M4ImMM:http://www.df9cy.de/dl0shf/images/dl0shf_10ghz.jpg]<http://images.google.pt/imgres?imgurl=http://www.df9cy.de/dl0shf/images/dl0shf_10ghz.jpg&imgrefurl=http://www.df9cy.de/dl0shf/dl0shf.html&usg=__b5TaQ0leXlWxnqtHa9nFwrTf-wI=&h=1024&w=681&sz=173&hl=pt-PT&start=99&um=1&tbnid=aYgtRlB_M4ImMM:&tbnh=150&tbnw=100&prev=/images%3Fq%3D10%2BGHz%2BAntenna%26ndsp%3D20%26hl%3Dpt-PT%26safe%3Dactive%26sa%3DN%26start%3D80%26um%3D1><http://images.google.pt/imgres?imgurl=http://www.kwarc.org/10ghz/steve-dishes.jpg&imgrefurl=http://www.kwarc.org/10ghz/10GHZ-4.htm&usg=__sa8nZvlGXUlhseFvxaNnKap1ReU=&h=400&w=300&sz=32&hl=pt-PT&start=112&um=1&tbnid=MdquvN8uYBIhWM:&tbnh=124&tbnw=93&prev=/images%3Fq%3D10%2BGHz%2BAntenna%26ndsp%3D20%26hl%3Dpt-PT%26safe%3Dactive%26sa%3DN%26start%3D100%26um%3D1>
JT4 on the Microwave Bands

A growing number of Radio Amateurs are using the JT4 mode on the microwave bands with excellent results.

JT4 is part of the WSJT weak signal software developed by Joe Taylor, K1JT.

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.

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.

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.

UK Microwaves reflector
http://groups.yahoo.com/group/ukmicrowaves/

WSJT Website
http://physics.princeton.edu/pulsar/K1JT

Further information on JT2 and JT4
http://physics.princeton.edu/pulsar/K1JT/JT2_JT4.TXT

Southgate 2007 - Two new DigiModes - JT2 & JT4
http://www.southgatearc.org/news/october2007/
two_new_digi_modes.htm
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