When evaluating HF (High Frequency) antennas, you must prioritize the Frequency Range (typically 3MHz to 30MHz) to ensure it covers your required bands. Key performance metrics include the VSWR (Voltage Standing Wave Ratio), which should ideally be less than 1.5:1 for optimal power transfer, and the Power Rating (Wattage), which must exceed your transmitter's peak output to prevent hardware failure. Additionally, consider the Antenna Gain (dBi) and Radiation Pattern (Omnidirectional vs. Directional) based on whether you need point-to-point or broadcast communication.