[TowerTalk] 2-el yagi gain vs boom length

[Pete Smith]

Can someone who has W2PV's book tell me what he says is the nominal 
free-space gain of a 2-element 40m DE/reflector yagi on an 18 foot (roughly 
.27 wavelength) boom?  I'm doing some modeling of a shortened yagi with 
that boomlength and want a point of reference.

Thanks!

73, Pete N4ZR