Customizable Cassegrain Dish

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This thing creates a customizable Cassegrain Reflector dish. It was created using equations from Peter Hannan's paper, "Microwave antennas derived from the cassegrain telescope," in IRE Transactions on Antennas and Propagation, vol. 9, no. 2, pp. 140-153, March 1961. Suggestions for use as a tool: • Stick the waveguide into your ear to see what you can hear. • Glue aluminum foil to the main and secondary reflectors, then use an LED in the waveguide to make a flashlight. • Glue aluminum foil to the main and secondary reflectors, stick a coil of wire in the waveguide, and use it as a radio receiver. • Glue aluminum foil to the main and secondary reflectors, stick an IR photodiode in the waveguide, and use it in photo-communications projects. Bonus points if you modify one of your home entertainment systems to use this! Print Settings Rafts: No Supports: Yes Resolution: Normal/Medium Infill: Doesn't matter Notes: If you're using customizer, play with values in "mockup" mode. If you want to print it straight (which you should only do if you're using a resin printer or Shapeways or another fused dust printer), then use "solid". For printing on an FFF printer (most of you), use "For printing", and the pieces are arranged so that they can be printed best on a flat bed. Feel free to rearrange the pieces on your slicer. The STLs provided will work if scaled all by the same amount, but the physics won't work out if you have different scaling for x,y,z. If printing on an FFF printer, use supports for the dish. Infill doesn't matter as long as there are no holes in your pieces. Post-Printing Once all the pieces are printed, glue the waveguide to the back of the main reflector with clear superglue like cyanoacrylate. Glue the struts to the main reflector and the secondary reflector. The bulge on the secondary reflector is supposed to point towards the concave part of the main reflector. Stick the thin end of a ruler into the hole of the main reflector, and the secondary reflector sits on top of the ruler so that you know how far apart they are supposed to be. The thin part of the ruler measures the distance between the reflecting face of the main reflector, and where the focus/sensor/microphone/speaker/lightbulb is supposed to be. Check "mockup" mode if you're unsure how the pieces are supposed to be arranged. Remove the ruler once you have assembled the struts and secondary reflector. Theory Cassegrain reflectors are used in radio telescopes, based on optical Cassegrain Telescopes. While they will work theoretically with any wave, the physics assumptions they're designed with assume that the distance between the main and secondary reflectors is more than 3 wavelengths. This can present problems if you're using this for Radio or Sound waves. But, if you know enough physics to want to use a Cassegrain reflector as a tool, you can figure out how to calculate the wavelength of the signal you're using (Hint: λ=v/f).