Topband: NW6S -- Question on coax mismatch

[Jim & Carolyn Kingsbury]

I'm putting up a pair of inphase broadside pennant receive antennas.  I 
would like to use type 6 (75 ohm) coax to phase the antennas and then use RG 
8 (50 ohm) coax from the junction box into the shack.  Assuming correct 
matches at the antennas, I beleive the mismatch will be 50/37.5 or an swr of 
about 1.33:1.  How detremental will this be on the receive signal?  Is it 
bad enough for me to insert an unun to improve the match?  Thanks for any 
help.

73 Jim Kingsbury NW6S