Re: Shotgun parabolic, was Re: Seeking advice for a beginner

["Walter Knapp" waltknapp]

Posted by: "Lou Judson"

> Idle curiosity, mostly. I have not used parabolics. Perhaps you'd put =

> the shotgun back far enough from the dish to encompass its entire
> diameter... what, a foot, a meter?

Remember that the dish has a standing interference wave out in front of
the dish.  Having the mic in that area will result in a big notch in
gain at lower frequencies.

You need the mic diaphragm at the focal point of the dish regardless of
the mic design.  And for a good parabolic that focal point will be
inside the outer plane of the dish so as to avoid the interference wave.

Walt