Explanation: At VHF frequencies, radio waves behave differently than at lower frequencies; even short conductors can act as efficient antennas, and RF energy can readily radiate from poorly shielded equipment. If an RF signal generator has "signal leakage," its internal signal can escape the enclosure or cabling and couple into the device under test (DUT) through unintended paths, bypassing the intended input port or filtering. This becomes critically important for accurate measurements, especially when testing receiver sensitivity or filter attenuation, where very low signal levels are involved. A leaked signal, even if weak, can easily overwhelm the carefully controlled signal being delivered to the DUT's input, leading to false readings or inaccurate alignments. While frequency accuracy and modulation capabilities are important for specific applications, ensuring the signal generator's output is delivered *only* via its intended port, without external radiation, is paramount for reliable and repeatable test results at VHF.