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.

Bias tee PCB

Left: Remote amp. with telescopic car whip Right: Bias tee

Remote amp. and antenna

Bias tee mounted in a nice box

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

Remote antenna amplifier schematic

Bias tee schematic