I think there are 3 main reasons for active antenna popularity. Physical properties, relative performance and coverage. Let’s consider these.

Over recent years, use of active antennas – mainly loops – has really taken off. I find this the case for both shortwave listeners and hams. Why did these little guys become so popular?

First, there are the physical properties. Popular small antenna designs, such as the1 meter wideband active loop shown above, consume little space and are unobtrusive. In a world of small city lots, shared housing and homeowner restrictions, the days of large antenna farms are long gone for most of us. Wideband active loops are easy to build and install near ground level, say 5 to 10 feet. Much easier than hanging wires from trees or putting up a tower.

And with all the RFI from neighboring houses, most people find it hard to get wire antennas or verticals far enough away from these sources of interference. Loops have less sensitivity to nearly E-field interference, and come with nulls to reduce many sources.

Second, there is relative performance. Sure, tons of copper in the air will collect radio signals, but they also collect tons of noise. Well designed active loops are great at improving signal-to-noise.  Typically, a good loop will give you better SNR than a dipole or long wire, even if the S-meter reads lower on the loop.

And generally, loops are mostly omni-directional on HF for distant skywave signals, while maintaining directional lobes on LF and MF. And with the right amplifier, they can cope with strong local signals at the same time as weak distant ones.

Active Antenna Popularity – Wideband Performance

Third, the recent switch to using wideband software defined radios finds complimentary performance from active antennas. These loops easily perform well from 300 kHz to 30 MHz, so you can user one antenna all across your listening spectrum. And you can combine two loops into an array for modern diversity reception quite easily.

Yes, active loops will be more expensive than a dipole or long wire, but you get what you pay for. To find out more about how these work, check out my series on active loop antenna theory.