Topband: Question on HyTower 160M Inverted L Config

[Tony Gargano N2SS]

This is a question for those of you using the Hygain HyTower on 160 meters 
in the inverted L configuration, i.e. with the 40M trap and ~100' 
horizontal wire.

I'm trying to do this but the lowest resonant frequency I can get is 2480 
kHz. That's with 120' of wire. I'm finding every 6' increase in length 
drops the resonant frequency by about 20 kHz. At that rate I would need to 
add another 30-35' bringing me to in excess of 150'. All the information I 
have shows that resonance on 160M should be obtained with about 110' of 
horizontal wire. I'm looking for anyone else's experience and what you 
might have encountered. Appreciate any comments or suggestions anyone might 
have. Thanks, Tony N2SS