Forgot antenna, can an relay solve the problem?

[magnemoe]

I have an asteroid grabber who I forgot antenna on, it worked well for the initial adjustment burns around mun orbit however an final adjustment burn was so far away I lost contact, now this correction burn is not critical however the intercept and early correction burns are critical.
This makes me thinking, I have plenty of satellites in Minmus orbit with RA-2 relays, it would be easy enough to just fuel one of them up and send to the intercept area. 
Perhaps cannibalize some other satellites for fuel tanks. 
However will this work with no antenna and how close do I have to get? 

[PrvDancer85]

Maybe that help

[bewing]

All command pods and probe cores have a built-in 5k  antenna. So Range = Sqrt (5 thousand * 2 billion) = 3.1 Mm, if I did my math in my head right.

 

 

[magnemoe]

Yes it match my estimate of 3000 km who is more than enough. 
Thinking about it, it has docking ports so I could dock an probe with antenna but an relay should work well enough and have lots of spare around minmus. 

[Tex_NL]

Yes, a properly placed and powerful enough relay would enable you to stay in control of your asteroid interceptor.
However there is a big but. (Isn't there always?) As @bewing already stated probe cores have a build-in antenna, but this antenna is NOT capable of transmitting science. If you want your asteroid interceptor to transmit science back to KSC you'll need to physically attach an antenna to it.

Edited March 5, 2018 by Tex_NL