What's an "Unloaded Relay"?

[Clipperride]

I've just built a simple 3 relay constellation around Minmus to aid my robotic missions and, for the first time, had a signal that went via a relay back to Kerbin.  When hovering over the signal strength meter I noticed that after the name of the relay that handled the signal was (unloaded)

What does "unloaded" (and presumably "loaded") mean?

[FullMetalMachinist]

1 hour ago, Clipperride said:

What does "unloaded" (and presumably "loaded") mean?

Pretty sure it's whether or not it's loaded into the physics calculations. In other words whether it's within physics range or not (2km, or 20km if in atmospheric flight). 

[Yoshidude]

As FullMetalMachinist said, unloaded just means that the relay you are using isn't in physics range of your ship. When it's not in range, it is sort of "imaginary" until you get closer.

[Clipperride]

That makes sense.

However!  I've just finished doing my first mission where a crewed lander loaded up the science data into the return capsule thingy, which returned to Kerbin - pointless but something I had not done before. (see Mission report for details).  I noticed that, when mouse-over the signal strength meter, the first leg was to the lander and was listed as (lander name).  So could it be to do with whether or not the relay is a part of another vechile?  Some experiments may be needed to find out for sure.

[Clipperride]

As ever, some experimentation provided the answer.  You are indeed correct - sat name (unloaded) means it is outside the current ships physics range and, as you get closer it is replaced with sat name (part name). So for my Minmus Orbital Lab it read "Min Lab* (cupola)" - which is where the relay dish is situated.  I guess that's for cases where there are multiple dishes on the same vechile, so you know which one is handling the signal and forwarding on.

I'm loving the pretty green lined patterns you can get from relay constellations!

*As you can see, I use highly inventive names when it comes to vechile designations!