Perfect antennaFirst you must download paraframe program from Neil Gershenfeld's fablab homepage for generating forms in SVG files. When we used (October 2004) paraframe it had some errors. We decided to let the antenna curve be smooth.
Here are the setting in the paraframe program we used to create our antenna mould:
focus = 15 # focal length (inches)
A = 1/(4.0*focus)
width = 23 # 0 <= x,y <= width (inches)
base = 2 # parabola base height (inches)
slotwidth = .24 # slot width
nslices = 4 # number of slices
notchwidth = 1.0 # wire notch width
notchdepth = .05 # wire notch depth
notchedge = .8 # wire notch edge spacing
nnotches = 6 # number of notches
npts = 1000 # number of points in curve
In the next step you must use the cam program from Neil Gershenfeld's fablab homepage to convert SVG files to either epi files (lasercutter) or camm files (Vinyl cutter). You can use a cad tool to view the forms before you cut them out. We used Corel Draw.
Assemble the forms to get the antenna mould.
Cut the material you have chosen to fit the mould.
Mount the cutted material pieces together, we drilled holes in the strips and popped them together.
And then we got this almost perfect antenna.