HF Station (3.5-30MHz)

Last Updated on December 1, 2025 by John Berry

My HF station is (deliberately) very simple.   The monopole antenna is a 18m ‘fishing pole’ with a single wire up the middle. That is formed into a classic ground plane arrangement with 30 radials ranging from 6 to 16 metres in length buried just under the soil and paths. The ARRL Antenna Book notes that for optimum operation, the radial length should be at least 20% of the wavelength of the lowest intended operating frequency. I just about achieve that.  

Auto-tuner

I’ve mounted an MFJ automatic tuner, the 998RT on the ground at the foot of the monopole. Power for the remote tuner is via the coax. The arrangement is like that discussed in Section 10.4 Multiband Vertical Antennas in the ARRL Antenna Book.

I couple the antenna to the tuner via a 4:1 unun (unbalanced to unbalanced transformer).

The unun ensures that high impedances outwith the tuner capability are avoided.

HF station operation

I’ve a simple setup – an Icom IC-7300 driving an RM Italy BLA600 solid state PA. The combination gives 500W down the coax with about 400W to the antenna.   Tune up is done by placing the amp in passthrough. Then keying a carrier and allowing the auto-tuner to do its stuff. Once the VSWR has settled, the amplifier can be switched in and operation can commence.

Here’s a video of the tune procedure, switching quickly between bands.

And on air? It works like you might expect. It’s perhaps not as good as a high-mounted big HF beam on the upper bands, but it’s as good as a wire dipole on the lower. DX performance will be better than any horizontal wire antenna.