Tuning the Butternut HF2V

Like with any other multi-band vertical the different bands are coupled with each other. This means that modifying the settings on one band will influence the others. This effect is worst on the low bands (40 and below) and less noticeable on the higher bands. If you only have the basic two-band HF2V there are only two bands/parameters to adjust and you can easily get through the alignment by doing a few iterations on each band. However, if you have the 30 or the 160 (or both) extensions mounted, aligning all 3 or 4 bands can become an endless process.

The Solution

As it turns out – at least with my HF2V – adjusting the lower band coil has greater influence on the higher bands than the opposite. Therefore, the only way to achieve proper alignment on all bands was to start with the lowest band, in my case 80. Once it was aligned, I continued with the next band and so on.

I do not know whether it also applies with the 160 meter extension kit, since I have not mounted it yet.


Below you can see a table summarising the parameters and measurements I ended up with. I believe I obtained very good results, considering the difficulties caused by cross-band coupling normally encountered on multi-band verticals.


Band [m] Length [cm] Shorted [turn] fc [MHz] SWR Width [khz]
80 22.5 0 3.580 1.30 75
40 26 8 7.009 1.10 360
30 26 2.5 10.060 1.23 much
15 21.000 1.20 2000


HF2V SWR on 80m HF2V SWR on 40m HF2V SWR on 30m HF2V SWR on 15m HF2V SWR on HF


April 2010 Update

It is now more that three years ago that I have mounted the Butternut HF2V multi-band vertical antenna outside and it was time to perform a maintenance check. You can read the full report in this article posted on April 3, 2010. The full HF SWR scan is reproduced below. Note that I have also got a resonance in the 10 meter band!

From Butternut HF2V

HF2V on the Air Videos

I have also recorded some videos showing the signals booming in from the HF2V. There is one video for 160, 80, 40, 30 and 20 meter bands each. I skipped the 15 and 10 meter bands due to the current solar activity – these bands are pretty much dead at my location. Yo can also watch the videos in higher resolution on my YouTube channel.

Author: Alexandru Csete

Embedded software engineer in the satcom industry during the day. Radio amateur and SDR hacker during the night.