http://www.hamuniverse.com/n1uue2el1011quad.html . I would look at the design and then try and change some things to use other parts.
There are plenty of cubical quad antenna calculators on the internet where you can get all the measurements you need to start the design process. Below is an example using one of the antenna calculators. You can see that I set it for channel 19 at 27.185 Mhz just as an example for the operating frequency for the cb 11 meter band. You can always adjust or change the operating frequency. What I like to do is try and design the antenna so it can be adjusted if necessary. As you can see the space between the reflector and the driven element is only about 66 inches, which is only a little over 5 feet. This does make the turning radius fairly small. That way it could fit into a smaller area. You can also see that you have the dimensions in case you want to add more elements. Just be aware that more elements means more weight. This means that in building for strength it will have to be taken into consideration.
In my design for a 6 meter quad antenna I use grey electrical uv protected pvc pipe and fiberglass driveway markers from lowes or home depot. I use dowel rod inside the pvc pipe and seat the fiberglass rod into it. This does make for a fairly light antenna. Of course if you want to use the fiberglass fence posts you can do that for some extra strength. Here are few pictures below to give an idea of how I am designing the antenna.
In the picture to the left you can see the grey pvc uv protected pipe.
In the picture to the right you can see the PVC pipe,
5 way PVC connector, Yellow Fiberglass Rod and the
Wooden Dowel Rod .
The driveway fiberglass rods are about 5 feet long and I insert anywhere from 6 inches to a foot of it into the wooden dowel rod. You will need some tools for working on this such as a hacksaw, long 3/8 inch drill bit, pvc pipe cutter and a drill. I did use some clamps to hold things in place while cutting.
Here is a list of some websites with Antenna Calculators.
Thank You for reading from Dan KC2YTI. 73s