Archives

All posts for the month December, 2012

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

Bias tee PCB

 

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

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

 

Remote amp. and antenna

Remote amp. and antenna

 

 

Bias tee mounted in a nice box

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.

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

 

Remote antenna amplifier schematic

Remote antenna amplifier schematic

 

Bias tee schematic

Bias tee schematic