Sounds like as soon as you get out of the probe core range you loose control are you sure the antenna was on just after you decoupled ? and you sure it's not just delay getting you ? EDIT have seen at times if docked or coupled and you turn them on when undock or couple the antenna shows deployed but some how got turned off then, I would then have to launch a manned craft to get with in range 3k and turn it back on but have had that happen only 4 x maybe a mod, I was using at the time it didnt like.