I am thinking about stretching a multi-band dipole up in my attic and just want to make sure I have the math right. The number I get by dividing 468 by frequency in megahertz is the total length of the antenna? For instance, for a 160 meter antenna at 1.8MHz I would need a wire approximately 22 feet, 11 feet on each side or do I need 22 feet each side?