<p><em class=""><span class="">At Jupiter, part of the auroral radio emissions are controlled by the Galilean moons Io,</span><span class="">&#160;</span><span class="">Europa and Ganymede. Until now, they have been remotely detected using ground-based </span><span class="">radio-telescope or electric antenna aboard spacecraft. The polar trajectory of the Juno</span><span class="">&#160;</span><span class="">orbiter leads to cross the magnetic flux tube connected to these moons, or their tail, and&#160;</span><span class="">gives a direct in-situ measurements of the characteristics </span><span class="">of these decametric moon induced radio emissions&#160;</span><span class="">(such as the electron population, size of the source, and beaming</span><span class="">&#160;</span><span class="">angle and growth rate of the emission)</span><span class="">. In this study,</span><span class="">&#160;</span><span class="">we focus on the crossing of the Ganymede flux tube. The study of Juno/JADE-E and</span><span class="">&#160;</span><span class="">Juno/Waves data leads to an estimated source size of a few 100s km,</span><span class="">&#160;an electron population of energy&#160;</span><span class="">E</span><span class="">= 8</span><span class="">&#177;</span><span class="">2 keV and an emission beaming angle</span><span class="">&#160;</span><span class="">of&#160;</span><span class="">&#952;</span><span class="">= 80</span><span class="">&#177;</span><span class="">2</span><span class="">&#176;&#160;</span><span class="">from the magnetic field lines. Finally, this crossing of a decametric radio emission induced by a moon brings us new constrains on the Cyclotron Maser Instability process</span></em></p>