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We're using Roger's Corp RT-Duroid 5880 0.031" thick 1oz electroplated PCB material (an 18" x 16.5" piece, nonetheless) for the antenna. A big thanks to Rogers for donating two sheets of it! Hooray, we're going to have an antenna.
- See the attached docs below for more information on the material.
- For more technical articles on the 5880, see http://www.rogers-corp.com/mwu/litintbl.htm (including articles on strain releif, rolling/bending, etc).
- We're creating a PCB layout.
- We're exporting Gerber files and having them made into artwork.
- We're etching the Duroid PCB.
- We're pre-rolling the etched boards so we don't break things when we bend it around the airframe.
- We're mounting the antenna onto part of the rocket's fiberglass skin.
These people - http://www.eccosorb.com/eccostock - make a foam in place polyurethane that is 2lb density and has a Er = 1.1. But it's (FPH: 1.3 lb - $62.42, Cat: 0.9 lb - $56.72) and all together is $155 to ship since it's a class B poison (joy).
Here's some more notes on polyurethane foam: From http://www.atnf.csiro.au/projects/ska/techdocs/Lens_Weight.pdf:
- Polyurethane 160kg/m^3 Er = 4.0
- Polystyrene 1050kg/m^3 Er = 2.5
- "low density" foam = 40 kg/m^3
Interesting: variable dielectrics: http://wwwnew.towson.edu/mesrp/TheResearch2000.htm
What is the dielectric constant of "plumber's foam", a 2lb density polyurethane foam?
- Here's some tests we did on Tap Plastic's X-30 expanding polyurethane (EPU) foam on Thursday July 31st 2003.
- Here's a mock up test of the CPA using 0.005" PCB and 0.01" Copper: Friday August 16th 2003.
We've finally found something that seems to work: double sticky Polyethylene foam tape.