My End-Fed Half Square Antenna

[Captain Kilowatt]

End fed antennas are in a sense half of a dipole because there is no return current flowing in a equal path.

Anytime you NEED a transformer, coil, or other matching device this means there will be losses in that device. Judging an antenna by the contacts made isn't a good judgment.

Many people think a transformer balun does indeed work as they intended because their SWR went down when they put one in. This is possible but only over a short span of frequencies in a one band
antenna. More realistically it is more probable that loss has been introduced into the system. Loss anywhere always makes the SWR read lower.

What I said is what I stand behind, "A simple dipole antenna would be much better"

Not disputing most of what you said other than that an end fed halfwave is like half a dipole. That would be an end fed quarterwave. YES you need return currents however the much higher impedance of the halfwave means that the ground losses are not nearly as important as in the case of a quarterwave. You would not use a balun on an EFHW but rather a simple transformer or as I dislike it called, an Un-Un. Neither the coax feedline nor the EFHW is balanced so no need for a balun . If the transformer is properly made using large wire and the proper core material very little losses are introduced. In fact while measurable in a lab, they will never be seen on-air. With a 49:1 transformer, the feedpoint impedance can vary greatly while still maintaining a relatively narrow excursion range on the low impedance side. This is why an EFHW can present a decent match on several bands even though the feedpoint impedance on the different bands may be quite different. It is all about ratios. As for a simple dipole being better, probably but only on the fundamental frequency. The EFHW will exhibit gain on the higher bands. If you want that with a dipole you need to introduce balanced feedline and a balun and we are back to introducing those losses you mentioned unless we go with balanced feedline all the way but we still need something to match the impedance. I have used just such a doublet antenna in the past and it worked decent.......but then again so does my EFHW. I will be MUCH happier next year however when the yagis go up and I can get rid of the wire antennas.....for the most part. I just need to take the tower down and convert it a tilt-over first. BIG job.

 

[fourstringburn]

I will be MUCH happier next year however when the yagis go up and I can get rid of the wire antennas.....for the most part. I just need to take the tower down and convert it a tilt-over first. BIG job.

Now you"re talking (or will be doing some talking)!

I'm waiting for delivery on a Mosley 5 band MP-33 NW and will only use a wire for 30 to 80m. Should have mine by January 20th.

Good luck with your tower set up!

 

[Captain Kilowatt]

Now you"re talking (or will be doing some talking)!

I'm waiting for delivery on a Mosley 5 band MP-33 NW and will only use a wire for 30 to 80m. Should have mine by January 20th.

Good luck with your tower set up!

Yeah thanks. It's going to be quite a project. I have seen lots of smaller towers converted to tilt over but this one is a bit different and a LOT bigger to deal with than Rohn-25. It is a 64 foot Tryon T-500. It weighs 1000 pounds itself plus another 200 pounds of mast and antennas, rotator etc. The base tapers from 42 inches at the base to 18 inches at the top. Simple is better but those kind of loads REALLY need to be taken seriously.

 

[The DB]

The first thing I thought of when I saw the half square antenna design is bobtail curtain, which, offhand, I think would likely get you a little more gain.

After playing with the half square, if you have the room, you might try one of these as well.


The DB

 

[marsofold]

An update on my 20M half square antenna: it seems to be working exactly as designed. And that is a problem for me, since I now believe that the mountain ridges around me are blocking most of the main low angle vertical lobe. I cannot hear anything within 300 miles of me, so there is nil high angle reception, as it should. Yet I can hear Texas, Oklahoma, and faraway states whose angles from me correspond to the dips in the nearby mountain ridges. On 40M it is a high angle NVIS antenna and I can easily hear everything out to about 800 miles, just like an NVIS should. But I like having dx as an option. I can see having an NVIS antenna for 80M, since I've always considered it kinda local. And I'm really a bit disappointed at the thin participation I see on 20M. 20M isn't dead, but often I see only a few active SSB conversations on the na5b online waterfall, and nothing after sundown. 40M by contrast seems to have much more traffic, so instead of making 40M my secondary band of interest, I'm gonna make it my primary band of interest. Getting moderately low wave angles on 40M for the same height is a bit more challenging than on 20M, due to the wavelength being twice as long.

 

[Greg Troubles]

Hi Im new to this forum however found your post on Half Squares which are end fed.

I also have bee using two configurations of Half Square using a 40m endfed design and installing the wire as per a 20m half square and using a unun to match in which I have achieved excellent DX performance across the bands from 14mhz to 28 mhz and NVIS strong signals across Australia which can be a considerable distance. I have even worked into EA twice on 7mhz which totally surprised me as it should be high angle radiation on that band.

I am about to reconfigure the half square again to favour European dxing more on 14 mhz and my qrz page shows photos and my Log book of who and as far as I have been working on this great antenna.

A quiet but excellent antenna overall

Cheers VK3KV