If you are a radio amateur, you may be familiar with the magnetic loop antenna. It’s different from most traditional cable antennas, taking the type of a tuned circuit with a extremely big single-turn coil as well as a tuning capacitor. Magnetic loops have the advantage of extreme selectivity as well as great directionality, however the risk of a high voltage induced across that tuning capacitor as well as the inconvenience of needing to retune each time there is a frequency change.
[Oleg Borisov, RL5D] has a magnetic loop, as well as soon exhausted of the constant retuning. His service is an stylish one, he’s made a remote retuning configuration utilizing a stepper motor, an Arduino, as well as a Bluetooth module (translated here). The stepper is linked to the capacitor through a short versatile coupling, as well as tuning is carried out with the assist of a customized Android app. We’d be interested to understand what the impact of a high RF field is on these components, however he doesn’t report any type of issues so it should be working.
He’s published a video of the system in operation which we’ve published below the break, if you’ve ever had to continuously retune a magnetic loop you will appreciate the convenience.
We’ve only brought you one magnetic loop antenna in the past, whose special function was that it is portable.
