based on ibcrazy's design: http://www.rcgroups.com/forums/showthread.php?t=1377791 and partly on mictronics dimensions: http://www.mictronics.de/2011/07/5-8-ghz-helix-antenna/ the grove is for a 1mm wire. there's a cavity in the middle for a M3 nylon nut. pause the print when there's enough space for the nut. height of the cavity is 12mm high, so no need to hurry. in makerware i added a tall enough object far away from the antenna, so i can pause the print when the extruder is far away. check the links for further info print with 1 shell, low infill (5% or less), and NO supports easily flew 11km with the blue antenna from the first photo and a immersionrc 600mw tx and a far from optimal setup, so it works :-) update: i've made a pcb which acts as the reflector of the helical. on the backside there's the footprint of a rx5808 module, and the wire of the antenna solders directly to the module! the keep it small, the module had to go over the hole for the screw, so the 3d-printed part now has to be glued to the pcb. i've modified the 3d file (helical1.30-5.8brd.STL), so instead of the hole for the screw and nut, there's a piece that fits into the pcb and centers it perfectly. it also has a slightly larger grove so the 1mm wire fits better. the pcb also has footprints for 2x 1210 caps for the powersupply of the module, solderpads for wires, mounting holes and a led. i've used enig (gold) coating which costs extra but looks better and could potentialy work better for the antenna. here's the pcb (14$ free shipping for 10pieces, i get 1$ from each order): http://dirtypcbs.com/view.php?share=3039&accesskey=e696102560b3dfbac885f18af5cd0822