Ken Bessler wrote:
"My question is what impedance (SWR) would this antenna show on 446
MHz?"

An antenna operating on its 3rd harmonic may be roughly a 1/4-wave
connected to the drivepoint through an additional 1/2-wavelength of
antenna.

The 1/2-wave portion repeats the impedance it "sees" at its ends,
therefore the drivepoint "sees"the same impedance that the length in
excess of 1/2-wavelength presents. If this is a good match to the
drivepoint, as it well may be, you will have a low SWR.

Best regards, Richard Harrison, KB5WZI