I presume you realize that a 3/2 wave dipole has multiple lobes, with
nulls between. At many or most angles, a half wavelength dipole has
greater gain.

You can get just two narrow lobes from a 3/2 wave dipole by rotating the
wires 30 degrees to form a horizontal "V" having a 120 degree included
angle. I've used this trick with a 40 meter dipole being used on 15
meters -- it doesn't have much effect on the 40 meter pattern. (You'll
see some TV antennas made this way for the same reason -- the high TV
channels are about 3 times the frequency of the low channels.) But
again, if a station isn't in the right direction, you'll do better with
a half wave dipole than a 3/2 wave one.

A "gain" antenna isn't of much use if the gain is in the wrong
directions. In fact, it's worse than a lower gain one, since the higher
gain it gets in a few directions comes at the expense of lower gain in
the remainder.

Roy Lewallen, W7EL

Buck wrote:

When trimmed to SWR, I get less than 1.5:1 on fifteen meters. My
plans are to build a multiband antenna, parallel elements, where each
band is 3/2 wave dipoles and fed with 50 or 75 ohm coax. I haven't
tried this yet, but I would hope I can have a few gain dipole antennas
in a multi-band format.