An Active Antenna for 160 to 4 metres

摘要

This active antenna has been doing its job in my loft for well over 10 years. I've seen a number of designs over the years, and this is the simplest, deriving from experiment. When I recently saw a highly sophisticated-looking commercial unit, I felt it was time to 'go public'. Active antennas rely on a combination of an antenna element (such as a dipole, monopole, or loop) and an am- plifier, which is the 'active' part. The antenna element is non-resonant, and tends to be physically small. They have broad operating bandwidths, so don't need to be tuned. In comparison, a resonant antenna would need tuner adjustments to cover the whole HF and lower VHF spectrum. So, the attraction of active antennas is convenience.