Hi, George!
Brown and Woodward did the tests in 1945, published in 1952, of the
impedance and patterns of conical and triangular antennas, both against
a ground plane and also biconical and triangular bow-tie dipole
antennas. Depending upon the length, impedance values ranging from much
less than 50 ohms to as much as 270 ohms were obtained. Their 120 deg.
flare biconical demonstrated a VSWR2 over a 6:1 bandwidth with a cone
diameter D=lambda at the lowest frequency.
I've made numerous VSWR tests of triangular dipoles of various flare
angles, trimming the length to obtain minimum VSWR at the mid-point of
the frequency band of interest. Mid-band VSWR was often in the 1.05 to
1.10 region. I've never done pattern measurements of these antennas,
but I rely on B&W's pattern measurements which show maximum radiation
normal to the line of the dipole. The gains they show are within +0.5dB
to -0.5dB relative to a 1/2 wave dipole for the shorter antennas.* I've
performed numerous pattern measurements of anything from 200 MHz Yagi
arrays to x-band horn, conical-scan, pill-box and large diameter
parabolic arrays. I've also done much testing of multipath reduction
fences to reduce pattern-interfering ground reflections into tracking
antennas at Vandenberg AFB.
*See "Antennas, John D. Kraus, 2nd Ed. pps. 354-358 Paul