Here at SDRplay we are great fans of active magnetic loop antennas which can offer much superior performance at HF and lower frequencies when compared with wire antennas. Their two distinct advantages are resilience to electric noise and their physical size. They also are very effective when mounted close to the ground or on a rooftop.
I recently met with Mike Harwood at his home in Northamptonshire – he has had a distinguished career working in the field of high speed and analogue circuit design. More recently he’s been exploring amplifier designs for small loop antennas.
We asked him to make some real time comparisons of some popular active loop antenna amplifier designs using real signals to help give people a practical feel for how well they work against that well established favourite – the Wellbrook 1530AN.
This introductory video shows Mike starting with a long-wave comparison of his own compact prototype design alongside the Wellbrook, using the RSPduo to allow simultaneous visualisation of the 2 loops in action:
You can see that he has lined up several other active loop antennas/amplifiers to demo in future videos, including the Bonito Megaloop FX, the LZ1AQ amp and the Cross Country Wireless amp.
Over time we hope to be able to formally endorse the better performing designs with a mention in our antenna suggestions page: https://www.sdrplay.com/antennasuggestions/