The basic formula for determining the wire length of a center fed, 1/2 wave wire dipole or inverted Vee antenna is:
143 ÷ freq(mhz) = Length(metres).
The inverted Vee antenna will be shorter by 2 – 5% depending on the angle from horizontal.
Dipoles have a feed point of about 75Ω in free space, and can be fed with 50Ω to 75Ω coax with or without a 1:1 balun. Inverted Vee’s present closer to 50Ω due to the effect of the ground being close to the tip of each leg. Feed your inverted vee with 50Ω coaxial cable, with or without a 1:1 balun. You can also feed with 300Ω or 450Ω balanced feeder into an ATU with balanced terminals. This will then work better as a multiband antenna.