The Full Wave Loop

The full wave loop has many characteristics that are favorable for amateur radio use. The best thing I like about them is that they are easy to get working correctly without A lot of fuss.

They can be hung verticle or horizontal and the sides doesn't have to be the same lenght, although it will probably work best if they are. Actually the best performance would be achieved if it were A perfect circle but, of course this is next to impossable and the advantage wouldn't be worth it. Do not be concerned about getting it perfectly symetrical and one end can be higher than the other. Just try and get it as high as possable and you will be pleased.

The loop situated horizontal in relation to the ground makes for A great antenna for 40 or 80 meters, especially for closer in work. Some refere to this as A cloud warmer because A considerable amount of energy is emmited directly overhead. Although the horizontal loop really shines for closer in work it will perform very well for dx as also.

The loop can be tuned (with A tuner) to any ham band higher than the designed frequency. The pattern of A resonate loop is broadside but will draw closer to the sides as the frequency is raised. Of course if you are useing it horizontally this will mean A lower angle of radiation makeing for A great DX antenna.

I prefer to feed them directly with coax at A corner and situated in A diamond configuration when hung verticle but, you can feed them in the center of eather side. If you feed A verticle strung loop on the side it will be verticly polarized and if you feed it on the bottom it will be horizontally polarized. I prefer the bottom mainly because it is more convienent. Of course, if you hang it horizontal it will be horizontally polarized no matter where you feed it.

Now, if you really want to melt antennas off of towers at 1000 miles then you can add A reflecter. You can do this by makeing A closed loop and situate it directly behind the vertically hung driven loop. Just make it 5% larger and put it about .15-.20 wavelenghts behind the loop. This setup would be refered to as A quad. To get the full benifits of A quad you should have the center near 1/2 wavelenght. Not very many hams have directional antennas on the lower bands so you can expect others to ask what kind of amplifier you are useing even when you're useing low power.

A little known fact is that you can add A half wavelength of wire behind the loop insted of the closed loop. This comes in handy where supports are not abundant.

I have routinely broke pileups with A 20 meter quad at 50 foot, even with many big guns all calling at once. The quad has the ability to hold the band open for dx longer than A yagi. I have saw this many times, just tune across A dead or dyeing band and many times the loudest stations heared will be useing A quad. I don't know why this is so, but it's A fact. Maby it's because the loop has A broader vertical beamwidth, has more capture area, is more resistant to fadeing and has A quieter noise floor.

I have never had A problem with matching directly to coax on frequencys below 20 meters. My 40 meter loop hung at about 45 degrees covers most of 40 meters with low swr. A quarter wavelength of 75 ohm coax (RG-11) between your antenna and 50 ohm coax will make for A better match on the higher bands. When you add A parisitic element you will have no problem matching. A 2 element quad is real close to 50 ohms.

Use the formula 1005 divided by the frequency in Mhz and it will be real close to your target frequency.