Here is an active antenna for higher LF and MF frequency range using an U310 N-Channel JFET as amplifier.
Antenna are based on a la8ak (sk) design. It has a decent performance given its small size.
However, on lower LF and VLF range it performs poorly.
A little tip for anyone interesting using this design or similar designs. Do not power it by a noisy switching power supply. Switching noise will go straight into the receiver.

Blue LED in remote amp. shows that power is present. Green LED on bias tee indicates normal current load.