Square antenna

[K8YS]

I used to have a schematic for the 6m square loop antenna in my files, but now that i want to build one, I cannot find it... does anyone have the plans for building a 6 meter square loop from 1/2in copper pipe?

The overall perimeter of the loop (in feet) will be 1004/f, where f is the frequency in MHz.  Since pipe is a larger diameter than wire, this may result in a resonant frequency slightly below the desired freq, but you can always trim the lengths until you get it where you want it.

The impedance of a square loop is around 100 to 140 ohms, so you will need some kind of matching arrangement to get low SWR on the 50 ohm coax.

Instead of a square loop, consider a design where the overall perimeter is the same, but the sides are twice the length of the top and bottom. When fed at the center of the bottom (or top) section, this will give a feedpoint impedance very close to 50 ohms, so you can feed it directly with coax and have a low SWR.

This idea is from a QST article a few years back; I don't remember what issue.

[W5AX]

There is one here on eham.

Go to the article section. Look up an article by K0FF.
He wrote two of them one for 6meters and one for 2meters.

[K5LDL]

To be quite honest, I've tried these squared halos, have tried round halos, and am in the process of trying out something called an OmniAngle, (check these out at their website: http://www.parelectronics.com. I also plan on reviewing these antennas for eham. ).  Something in the form of an antenna that I came across while researching omnidirectional/horizontal antennas for 6m was this thing called a Hen Antenna.  It's called a Hen Antenna by the Japanese.  These folks LOVE 6m.  One of the curious things to come of their love for 6m ops was this thing.  Check it out.  I've tried it and the silly thing works!  I think I might have spent all of  $7.85 US and maybe about 35 minutes in stringing this this this THING up in the air.  Give 'er a try!  What can you lose?  I tried it, liked it, and use it on camping trips and other outings.  The word 'Hen' in Japanese means mysterious, or curious.
From what I understand, this curious antenna can also be adapted in size to work on 10m, 2m, and even 70cm.
You can find out more about this curious antenna at the following website.    
http://member.nifty.ne.jp/tasaki/Hentenna.html