[Elecraft] [OT] Antenna Question

[rick jones]

 Ok sorry for not providing enough info! Consider this scenario: I have a portable vertical with 4 counterpoise wires that is resonant on 20. Lets say I want to tune the antenna up on 40. I can have a tuner right at the base of the antenna OR I can just use a balun at the base of the antenna and use the built in ATU in the K3. Is there a difference in how much power is getting to the antenna? I assume the tuner at the base is the best option which always makes me doubt the usefulness of having an ATU built in to a rig in terms of getting the most power to the antenna. Am I on the right track? Thanks! Rick