Sunday, May 17, 2015

Shield stabilization

The 15mm copper pipes that shield the H-field antenna against E-field noise are not mounted to the center post in any rigid way. The are just pushed through 15mm holes in the center post and held in place by the blue wire running inside of them and some bare copper wires through small holes in the copper pipes.

The copper pipes can not be pulled out of the center post, but they can still wiggle around. To stiffen the whole antenna assembly I build a cross piece from aluminium and plexiglas.

According to the manual the shield must not cover the complete loop, otherwise the antenna will not work. That is the reason why I build the shield from two semicircles that are connected at the bottom and not connected at the top. The plexiglas acts as an insulator to avoid connecting the semicircles at the top.

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