Delta-15, 15m full wave loop antenna
The Delta-15HP
The DELTA-15HP is a full wave loop designed to operate on 15m (21MHz) and 10m (28MHz) without an ATU and other bands with an ATU. There is a 4:1 balun at the feedpoint enabling it to be fed directly with 50ohm coax - RG-213 or Mini 8 is probably the best but other variations of coax may be used so long as they are of a 50ohm impedance.
FULL WAVE DELTA LOOP. Configured as a delta loop or equilateral triangle, if laid flat will be good for near DX. If vertical, or near vertical, will provide low angle radiation which is good for long range DX in the direction of the loop (looking straight on at the front) and near DX off the sides. Gain 3.2dBd.
FULL WAVE QUAD LOOPIf laid horizontaly will be good for NVIS, if vertical 2.8dBd gain. Sloping at 45 degrees will provide low angle DX.
All the DELTA range will handle 500W CW or 600W PEP.
Or why not upgrade to a QRO (1kW) version