[Elecraft] resitance vs impedence

[Ken H]

While setting up a dipole antenna tonight a question come up while discussing the tuning with myself:  Which is the "most effective" antenna - understanding it will be matched with a antenna tuner, either the internal autotuner or an external manual tuner - a dipole type antenna with a resistance of R=6 ohms and impedance of X=16, or the same dipole type antenna with R=48 and X=146?  Both of these settings have the same SWR=6.5

I guess that same question would apply to a short vertical, or end fed zepp type antenna.  

Anyone care to comment on this?

Thanks,

73 de Ken
K9FV
K1 #1951