I have personally used a 160 meter band Horizontal Full Wave Loop antenna with very good success. I worked all 50 states and several countries with 100 Watts using the antenna on the 160 meter band. With a good antenna tuner the antenna will work 6 through 160 meters. I currently use a 75 Meter Full Wave Delta Loop on the 6 through 75 Meter bands with a tuner. I am very pleased with it!
These Omnidirectional antennas offer Horizontal polarization, and about 2.1 dbd of gain. They are much quieter than a dipole or a vertical, have a broader bandwidth and will usually out perform a dipole antenna.
Feed 1 wavelength of wire with a piece of either 50 or 75 ohm coax. I am using 75 ohm because I had some.
To determine the approximate length in feet of a Full Wave Loop antenna use the formula
1005/Freq in Mhz = length in feet.
For 160 meters a full wave loop antenna resonant at 1.9 Mhz would be about 529 feet long.
For the 75 meter band a full wave loop antenna resonant at 3.85 would be about 261 feet long. A full wave for 3.9 MHz = 257 Feet 8 inches.
These length antennas may require some pruning or trimming of the wire to obtain a low VSWR. But if you measure carefully you should get very close.
Do not connect the antenna wire to the tower on this antenna.
This type of antenna doesn’t depend on an efficient ground system for efficient performance. The impedance of a Full Wave Loop antenna is theoretically in the vicinity of 100 ohms.
Connect one end of the wire to the coax center and Connect the coax shield to the other end of the wire. Be sure and seal the end of the coax against water. Form the wire in a loop and run it horizontally to trees or whatever supports are handy. Be sure to insulate the wire from the supports.
Extend from the wire with ropes if necessary to reach your supports.
On the higher frequency bands a full wave loop antenna can be oriented as a vertical diamond or vertical cube. Fed at the top or bottom corner of a diamond this antenna has horizontal polarization.
Let me clearly state this Fact.
“A vertically oriented horizontally polarized one wavelength loop antenna with the bottom of the loop 1/2 wave length above ground is a FINE antenna”.
Do NOT put the bottom of the vertically oriented loop more than 1/2 wave length above ground.