4 element cubical quad 11 meters

When almost all companies are baking some sort of "doing good" into their business models, how do you measure the impact of the innovations?

Cubical Quad - Signal Engineering
11 Meter Antennas. Home . Lets take a look at some 4 element cubical quads. Figure 6 shows a 4 element cubical quad fed for horizontal polarization.
http://signalengineering.com/ultimate/cubical_quad.html

2 Element Cubical Quad for 10 or 11 Meters by N1UUE
A 2 Element Cubical Quad for the 10/11 Meter Band . The pipe is secured to the end hubs with 1/4 x 2 1/2 inch stainless machine thread carriage bolts and nuts .
http://www.hamuniverse.com/n1uue2el1011quad.html



Quad Antennas - Antennas: Quad
Includes design for 2 6 10 12 15 meter bands; 2 element Quad .
http://www.dxzone.com/catalog/Antennas/Quad/

Antenna for 2 meters - Antennas: 2M
Site listings. Home : Antennas : 2M, Add a link. Most Popular.
http://www.dxzone.com/catalog/Antennas/2M/