Hi Xavier, welcome to the forum !
![:beer:](http://orbiter.dansteph.com/forum/Smileys/orbitersmiley/smiley20.gif)
To find the radio frequency of a ship, you can simply tap the "F4" button, then click on "Object Info" tab. In the new menu, select "Vessel" in the first field and the Arrow on the second field. Then, you should see on the "Docking port status" graffic the IDS of the docking pad.
However, the automatic docking of the DG-IV takes the fastest way to the ship. Therefore, your vessel will surely pass thrue your Arrow which is less realistic. So, I recommand a manual docking with the Arrow or, if you want to test this fantastic autopilot, try it with ISS.
I hope I helped you
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