> On 09/05/2010 06:12 PM, Peter Krengel wrote: >> Hello, >> >> I just did some experiments using a ceramic patch antenna inside a >> small plastic (80 x 30 x 20mm) screw box and experienced much bader >> signals at lower elevations. >> The plastic is marked as PS (I guess polystyrole ?). Further experiments >> covering a GPS with the same kind of box seemed to effect the signals >> too. On the other hand covering the patch with a flat pcs of the same >> material didnt effect the antenna. >> > > Finding a suitable top for that gps module/patch/.. that is both the > right material and the right shape is hard. Just the right shape is > much easier. So: > > I have had good success with vacuum forming such a beast. One particular > glass cup I have in the kitchen is flat top conical, of just the right > size. I put it on top of the ground plane, a 1mm sheet of > clear polycarbonate above that, and with an air pump and heat gun I > pulled the PC down around it. A bit of white paint on the inside, and > it looks really good. > > > /Kasper Pedersen
Many swedish reference stations have a snow cone made of (iirc) Plexiglass - Polymetylmetacrylic (PMMA). It should be formable using Kaspers above method. http://swepos.lmv.lm.se/stationer/hjo.htm -- Björn _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.