Delta Loop Antenna
A full-size Delta Loop, fed in the bottom corner, is a good low angle radiator and is great for working DX. This antenna normally has about a 3 DB gain over a 1/2 wave center fed dipole. The Delta Loop is not only a great transmitting antenna but a low noise receiving antenna. The direction of fire is broadside to the antenna. This means that if the base wire of the antenna goes from north to south, the direction of gain will be east and west.
This antenna is also rated at the full legal limit on all modes. It is made from 12-gauge insulated wire. The feed point insulator has a SO-239 connector. The antenna is tied at three locations and insulators are supplied and factory set at the proper location so all you have to do is tie some rope to them and hoist the antenna into place. One end of the base of the antenna is not connected at the factory. This is done so you can uncoil the antenna. It is a very easy task to attach this wire to the center insulator.
The feed impedance of a Delta Loop is around 100 ohms so you will have to use a quarter wave length of 75-ohm coax to feed this antenna which is user supplied. At the end of the quarter wave matching section of 75-ohm coax, you can attach a random length of 50-ohm coax, again user supplied, which will be run to your rig.
If matched properly with the suggested quarter wavelength of 75-ohm transmission line, you should see the following SWR curves. For the 10- through 40-meter bands, you will have less than a 2:1 SWR across the entire band. On 75 and 80 meters, you should have about a 220 kHz bandwidth. On 160 meters you should see about 110 kHz bandwidth.
Dimension "A" is the height of the antenna from the base to the apex, not the length of each of the vertical wires. Dimension "B" is the length of antenna wire called the base (width) of the antenna. The chart below will give you the actual dimensions per band so you can see if you can fit this type of antenna at your location. Remember to add at least 8 feet to dimension "A". This added height will be how high the base of the antenna will be above ground.
Note: Dimension "A" is not the length of the wires on
the sides of the Delta Loop but only the height the apex
is above the horizontal base wire of the antenna.