Terminated Dipole Update

The design and layout has changed somewhat from my original proposals. I found that I had to take up some slack with the wire lengths. I decided to change the direction through the garage to avoid close proximity with the neighbour's satellite coax cables. In total there is about 240 feet of wire in the antenna, 120 feet each leg. Re-routing the remainder around the loft perimeter sorted that out.

Ok so the antenna performed well, but I had to avoid those frequencies above about 18MHz. The SWR from 1.8MHz through to 14MHz was absolutely fine, below 2:1. It was really bugging me why I couldn't operate on the higher frequencies. So I decided to delve deeper into the problem. After much researching, I came across the KISS 16:1 balun. This was the only thing I hadn't deployed in this project. My transformer arrangement comprised of 20 turns x 5 turns of wire through the ferrites. The KISS design is much simpler employing just one coil of 4 turns, with a tap on the first turn for the 50 Ohm feedpoint. This is a link explaining the KISS balun. http://hflink.com/antenna/#BALUN

Because of the reduced number of turns, I could use much thicker wire (1mm sq).  Wow! Big difference. I can even tune the antenna on 50MHz. It has cost me the 1.8 MHz band but I rarely use that anyway except to listen to AM broadcasts. I couldn't resist testing on 144 and 430MHz. OMG. It works ok on these frequencies too.

Here is a quick summary of the SWR readings I got on each band:

50MHz - 1.4:1

28MHz - 2.4:1 

24.89MHz - 1.2:1

21MHz - 1.5:1

18.068MHz - 1.4:1

14MHz - 1.7:1

10.11MHz - 1.5:1

7MHz - 1.7:1

3.5MHz - 2.4:1

1.81MHz - OFF SCALE > 10:1

Let's face it. We all know that a dummy load has a perfect SWR, but it's a complete waste of time as an antenna! But overall I can recommend building this antenna as an all-rounder, or fall-back antenna. It seems to perform well, but I have nothing to compare it to really. All I know is that it is much more practical than the 1/2 wave 10m horizontal dipole in the loft, but when listening to voice transmissions, it does seem to lose the audio quality and clarity that you get with a normal dipole. Because I haven't had a voice QSO on it yet, I don't know how well it 'gets out'. The high readings on 28 and 3.5MHz could not be determined, however the on-board ATU of the IC-7300 dealt with this adequately. I feel I have accomplished what I set out to do in building a multi-band and stealthy HF antenna (and a bonus VHF/UHF too). I am getting contacts all over Europe on FT8 and 10 Watts of power on multiple bands, but as yet, not tested on SSB voice. I feel another antenna build coming on. So on to the next project.............