[TowerTalk] F12 Delta 240 performance observation

[SPWoo]

Hi All,

I have a D240 and I haven't 
used it much since I put it up this past spring.  Tonight I decided to 
run some performance tests.  I found a DX station and I turned the attenuator on such that that my S-meter was reading S9 when the beam is pointed at him.  When I turned the beam 90 degrees away I saw an S7 which is 12 db less than the maximum signal strength.  When the beam was turned 180 degrees away I saw an S9 which is the same signal strength 
as when the beam was pointed directly at him.  I'm a little confused about this.  This is 
supposed to be a yagi and not a rotary dipole!  The listed spec. for F/B ratio is 20db at its peak.  I do know that F/B is not constant across the band for a yagi.  What kind of front to 
back and side rejection ratios should I expect to see on this particular antenna?  I haven't asked Mark at F12 about this.  I don't want to waste his time until I have more info.  Perhaps I'm missing something on the test or that I made an error in my antenna assembly.  Your help on this is greatly appreciated.  73.

 
Jonathan Woo W6GX