During 2020 active loop antennas were my primary focus. Everything turned out pretty well with great performing wideband results.
Wideband active loops became my passion a few years ago. After learning the theory and experimenting with some DIY designs, my 2020 active loop experiments took a sharp turn towards a commercial solution.
In February, I got my first AAA-1C active antenna amplifier kit from LZ1AQ. While such a small antenna does not perform as well as a beam or dipole on a tower, I found that these loops come within 6-10 dB of the full size gear while providing better noise immunity and comparable SNR. Particularly so below 15 MHz.
My AAA-1C provides remote switching between two magnetic loops or a small electrical dipole. I experimented with different configurations, including dual loop and crossed loop configurations, as shown above. My trusty 3D printer was used to create mounting brackets for the loops and a remote control box as well.
To be honest, this solution works so well that I have probably reached the end of the road on experiments. For under $200 each, the AAA-1C plus aluminum core PEX loops in the crossed (orthogonal) configuration is probably as good as it gets.
Directivity is great on Medium Wave. HF sensitivity is also good as sunspots return. My loops are sturdy and lightweight and handle winter weather well.
Year in Review 2020 Active Loop Overload
While wideband antennas match up nicely with wideband SDR receivers, I did discover some challenges with overload from local AM broadcasters. This has a lot to do with gain distribution and front-end filtering. If you are going to use a wideband antenna-receiver combination, you need some medium wave attenuation or bandstop filtering.
During the fall, I built a Wideband Loop Helper – a combination of switched 18 dB attenuation and medium wave bandstop filters to improve system performance with various receivers.
So, my neighbors wonder why I have large egg beaters on the fence. Happy New Year to Chavdar LZ1AQ. By the way, the plastic mounting structures for my loops are available on Thingiverse.