October 23, 2026

Mobile-Whip: A Compact Battery Powered Mini-Whip Style Active HF Antenna for Handhelds and SDRs

Thank you to RTL-SDR.COM reader Ernie (NH7L), who wrote in and wanted to share news about the “Mobile-Whip” antenna, an open-source active receive antenna from GitHub user skuep.

The design is based on the well-known PA0RDT Mini-Whip, but it is built for portable use. It runs from a single 18650 lithium cell with an onboard USB charger, or from 5V USB, the 4.5V bias tee on the RTL-SDR Blog V4, or a standard 12-15V Mini-Whip bias tee. It uses an ultra-low input capacitance LTC6268 op-amp instead of a JFET, draws about 20 mA, and is only 200 mm long. That makes it small enough to mount directly on a handheld like an HF-modded UV-K5, a portable receiver, or a dongle SDR. It is designed for 100 kHz to 30 MHz, but the author says it also works reasonably well on FM and 2m.

The project is a first-revision preview with some known issues. A revision B with better VHF/UHF performance is reportedly in the works. There is no reverse-TX protection yet, so pressing PTT with it attached could destroy it. The KiCad files, simulations and JLCPCB-ready assembly files are on GitHub under the CERN-OHL-P-2.0 license. Assembled boards work out to roughly €25 each.

In two YouTube videos from a Polish ham, the Mobile-Whip is compared against a 27 MHz telescopic whip on several receivers, including the Radtel RT-950 Pro, UV-K5, ATS Mini, and Malahit DSP2. The tiny PCB antenna generally comes out ahead. On the RT-950 it even receives Polish Radio on 225 kHz longwave, which the telescopic whip could not. He does note that its high gain can overload receivers with poor front-end filtering.

The "Mobile-Whip" a PA0RDT Mini-Whip inspired portable antenna for HF

October 16, 2020

Easy-SDR: Open Source Designs for SDR Accessories

Back in 2018 we posted about Igor Yatsevich's Easy-SDR project which consisted of open source designs for a Mini-Whip antenna and upconverter. Igor has now added several new open source designs to the project including a bias tee, LNA, LNA with filtering, attenuator and SPDT antenna switch. On his Reddit post he notes:

The most interesting thing I've added so far:

Most of the devices are now prepared for installation in a metal case measuring 80 x 50 x 20 millimeters.

Completely redesigned LNA design. Now, Bias Tee powered amplifiers are housed in a 50 x 25 x 25mm metal case and have N-type connectors.

Added an amplifier based on the PGA-103 microcircuit.

Added the ability to install filters in final amplifiers (a separate printed circuit board, depending on the filter used).

Added a new device - SPDT antenna switch for receiving antennas.

The UP converter has been redesigned. Added intermediate buffer stage between crystal generator and mixer.

RF lines in all devices were recalculated to correspond to the characteristic wave impedance of 50 Ohm.

Reduced size of PI attenuator PCB.

In this project, I focused on the simplicity of self-assembly devices, which you can make at home. In the repository, you can find detailed assembly instructions, a list of necessary components for assembly, and GERBER files.