Melody is correct.....the minimum angle of elevation, from John's perespective, will occur at E, since this is the greatest distance from "h."
To find this angle of elevation, we need to know what EK is
Melody has already calculated angle E = cos-1 (1/9) = about 83.62°
And since triangle AED is isosceles, angle DAE = (180 - 83.62)/2 = 48.19°
And angle KAD can be found using the Law of Sines, thusly
sin KAD/KD = sin90/AD and KD = 112/tan30 and AD =2h = 224
So we have
sin KAD =(112/tan30) /224 so sin-1 ((112/tan30)/224) = 60°
So angle DAE + KAD = angle KAE = 48.19 + 60 = 108.19°
And using the Law of Cosines, we have
EK^2 = AK^2 + AE^2 -2(AK)(AE)cos(108.19)
EK^2 = (112/tan30)^2 + 168^2 - 2(112/tan30)(168)cos(108.19)
EK = about 293.6
And the angle of elevation from E is given by
tan-1(112/293.6) = about 20.88°

Edit ....I have given the wrong measure for KA...it should be 112/tan 45 = 112
So we have
EK^2 = (112)^2 + 168^2 - 2(112)(168)cos(108.19)
EK = 229.162
And now my angle of elevation will = Melody's answer...!!!! {more or less}