An update to the 40M Half Square antenna

I thought I’d give an update on this antenna since I’ve had several emails and messages enquiring about it. The antenna has been up for 3 weeks, and I’ve had over 500 QSO’s and worked some great DX, mainly using FT8 mode on 17, 20, 30 and 40M.

I ended up with a broken support after some strong winds so I had to buy a new squidpole for the fed end support. This new 9M pole ended up being about 1 metre shorter than the existing pole when added to the extensions. This has bought the feed point about a metre closer to the ground, and I’ve added a 200cm piece of fibreglass rod to the tuning cap shaft, to make it easier to adjust. I didn’t bother with adjusting the other vertical support leg lower to match, the antenna still works!


The angle of radiation is also low on 20 Metres and I’m using a 49:1 broadband matching transformer to put power into the antenna and touching up the match via my Radio’s internal antenna Tuner. It’s a reasonable performer on 20, but not as good as it is on 40

Another surprise is the 30M band. Although the modeling suggests the radiating pattern is quite potato shaped, I’ve been able to work pretty much everything I hear when the band is open. I do better into Europe on this band than 40 and 20 Metres

Best DX on 40M looking West (Africa) to date would definitely be Charles, 5H3DX in Tanzania…Al time new country!


and looking East to the Central America and the Carribean, Dev, 9Y4DG in Trinidad on 30M…(Then Frank, HB9EUW in Switzerland called me!)


I have been delighted so far with the performance of the antenna, especially since we are at the bottom of the cycle with no sunspots. I am at 199 DXCC countries worked. Who knows what will happen when ‘ol Sol wakes up!

I have also experimented with a 20M version of this antenna for portable operation. It fits in a plastic sandwich bag, takes minutes to set up, as it is only 2×5 metre lengths and 1×10 Metre length of wire that’s suspended between 2 squidpoles on stands. For the 20, however, I fed this at the 50 Ohm point with some coax at the top of a vertical section. The bottom of the vertical legs were about 1.5M  above ground, to get them away from the stands. This was very promising, as after adjusting the antenna to be resonant at around 14.1 Mhz, I was easily hearing stations from South Africa on the litte FT817. I didn’t bother to reply to them with my 5 watts, but they were good copy. I did have a good contact with Gerard, VK2IO, on 40 Metres, just before I packed up the antenna after my experiments. Gerard was operating from the Yellowmundie Regional Park, VKFF-0558. He gave me a 57, not bad for 5 watts.

The next outing for the antenna will be to use it on an activation in a VKFF park. On 40 and 30 Metres as an end fed, this antenna is looking promising as a decent NVIS radiator, ideal for this king of operating. Stay Tuned!

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s