[TowerTalk] Hy Gain HY Tower vertical

[Van Fair]

I just finished erecting a hy Gain HY tower vertical which is 1/4  wave for 75 meters and this one is set up to work only on 75 meters.  The only ground I have thus far is one ground rod.  The hard work is still ahead.  The Unit appears to work ok with resonance about where I want it but it hears about 1.5 s units below my slopers. The SWR is very low but I am sure it will go up with a good ground field in place.   My questions are. (1) Will the addition of a good ground field have the same positive effects on receive that I should expect on the transmitted signal . 
(2) Will the addition of a good ground field have any effect on the resonant frequency that it now has with only a single ground rod.  Van W4GIW