The DELTA-40HP, DELTA-20HP, DELTA-15HP and DELTA-10HP are all full wave loops with a 4:1 balun at the feedpoint enabling 50ohm coax feed and multiband use. 

The DELTA-40HP is a full wave loop designed to operate on 40m (7MHz), 20m (14MHz), 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.

The DELTA-20HP is the same but cut as a full wave on 20m and also to operate on 10m.

The DELTA-15HP is cut as a full wave on 15m with a total perimeter of 13.60m.  No ATU is needed on 15, 12 and 6m but an ATU is required for use on 20, 17 and 10m

The DELTA-10HP is cut as a full wave on 10m.  With no ATU it can be used on 10m and 11m but with the addition of an ATU operation is possible on all bands from 20m up.

The loop comes complete with three insulators to provide anchor points.  It may be mounted flat (horizontal) or raised to a vertical or near vertical postion.  It may be configured as either a square loop (Quad) or equilateral triangle (Delta).

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 LOOP If 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.