The X-Quad is an improved development of the well-known multi-element quad. Its special characteristics developed for ham radio use are as follows:

polarization switchable (horizontal/vertical, circular right/circular left, diagonal)
High gain compared to other antenna designs due to stacking effect
short boom length and compact profile
Fore-mast or center mounting

The driven element is a stacked quad- element showing comparable characteristics in the linear plane as compared to a cross-
slot aerial radiator. The advantage of the X-quad is that by choosing a different feed point it can be easily switched to the required polarization. Compared to the cross yagi all secondary elements of a X-quad (e.g. directors, reflectors) are active elements which contributes to the compact size of the X-Quad.
As with the cross yagis the polarization switching is done with a coaxial relais or one of our remote-control polarization switches directly at the antenna feed point. In this configuration only one feed cable is required whereas two feed cables are needed in case the switch is located at the transceiver.
The antenna can be configured for fixed circular polarization by means of a phasing harness (see also the table).
The secondary elements are located diagonally in relation to the driven elements which leads to the most favorable result. When mounting the antenna below the roof there will be little interference caused by stray fields compared to the performance of yagi antennas.

Each and every single element is electrically connected to the boom and the shield of the coax cable. It nullifies interference caused by static discharge. Both feed lines are connected through N-type connectors and the connection box is water-sealed. Boom and elements are made of aluminium, all hardware is stainless steel. The antenna design and make is protected under German patent law (DBGM). The antennas are designed for fore-mast installation but the mast clamp can be mounted in the middle of the boom as well. In this case, a supporting mast made of fiberglass is required however.

                                                                    Horizontal                            Vertical                           70cm                                               2m

	2m X-Quad	70cm X-Quad
No. of elements per polarization plane	12	18
Gain	10,5	12.8	dBD
3-dB beamwidth horizontal (E-plane)	47	36	Degrees
vertical (H-plane)	46	36	Degrees
front to back ratio (f/b)	19	21	dB
Power handling	1500	1000	Watt
Stacking distance	2.8	1.1	m
Length	1460	1270	mm
Height	730	220	mm
Weight	2.3	1.6	Kg
Wind Load at 160km/h	74	48	N
Connector	2xN-type connectors

vy 73's

(source internet)