no, a multimeter doesn't measure voltage or current past a few kHz. you need a reflectometer (also known more commonly as an SWR meter). plus, at 446MHz, you will need one for the UHF part of the spectrum, a typical HF SWR meter that you would find at a Radio Shack store is not going to work because the directional coupler section is too long, and the diodes have too much junction capacitance.