[hpsdr] Error in IQ beamforming

[Robert McGwier]

Ooops.   I made a dumb error writing too fast in my IQ beamforming
notes.   The two antennas  with isotropic radiators with 1/2
wavelength spacing, phased to operate towards a source that is
collinear with the X Y elements will have pi (180 degrees) phase
different between them.  That is why, phased properly, there is a null
in one direction and gain in the other of course.

I was thinking IQ and wrote pi/2 (90) instead.

Thanks to Roger Rehr, W3SZ for catching my error.

Bob
N4HY