The Bias-T ( power / splitter ) required to power the mini whip antenna designed by PZ0RDT for 10kHz to 30MHz. If you want to improve it to resonate better on lower frequencies you could replace C4 with a 1uF capacitor / non-polarized ( up to 10uF depending on the NPN transistor / please test ). The performance of the antenna depends a lot on the location and how well it was grounded. I did not specified the connectors so I can let you pick the ones you prefere. I left big pads on the PCB board for the antenna connector and the RF-Out, so you can either solder the board straight on the connectors ( BNC, SO239, etc. ), solder wires that go to the connectors, or to solder the coax cable directly on the PCB board. More details coming soon in the blog article.

You can optionally order the Mini Whip Antenna Board Here.