Lightning H Field Antenna Fittings (Mk 2)

thingiverse

Human: Note this is a redesign of http://www.thingiverse.com/thing:1713141 - it's much more compact and far more effective. Attached STLs are junction fittings used to build a 38cm diam H Field loop antenna as part of a lightning detection system (see http://en.blitzortung.org). The two junction fittings secure the 1/4" Copper tube loops (6mm) in place, also housing the ferrite toroid Transformer. The plastic tube between the top & bottom mount is just electrical PVC conduit. The two loops are offset vertically from each other to ensure they're electrically isolated. Print Settings: Printer Brand: RepRap Printer: Mendel 3 Rafts: No Supports: Doesn't Matter Resolution: 0.2mm first layer, then 0.3mm using slic3r Infill: Hex @ 50% Notes: I used PLA, ABS might be a better option. As the parts will be exposed to the weather, they should be painted to slow down degradation. Post-Printing: The holes for the tube to pass through are angled (for the loop), and may need to be reamed out with a suitable size drill. The Copper loops are formed first in the 38cm diam circle (but don't join the circle ends until fully assembled into top & bottom fitting). The Copper loops are carefully slid through both housings, also including the wound toroid inside the bottom housing. The PVC conduit should be cut to length after placing both tubes into the fittings. Final step is to solder the tubes together, a small piece of brass or copper tube as an internal sleeve at the joint will assist the solder jointing. It's crucial that the tube is electrically joined as the H fields from lightning need to induce a current in the loop (which in turn is coupled into the ferrite toroid windings).