[time-nuts] Neoprene rubber drops GPS multipath signals to zero

MLewis mlewis000 at rogers.com
Sat Feb 11 17:51:30 EST 2017

My guess wasn't a material made for RF but a carbon added to give a 
decent black colour.

"It is not inconceiveable that off-spec or scrap materials from the 
production might end up as mousemats."  and "stealth material".
Very interesting.
At an airshow many years ago, these mouse pads were a promotional 
give-away by the Department of National Defence in Canada...

I'm now seeing some multipath signals sneak through, usually in the 
single digital strength but for brief moments as high as 15 dBs. Coming 
from elevation 5 to 10 degrees, between azimuth 300 to 330 and also 
azimuth 30 and 60. I'm suspecting the office tower at 135 that sticks up 
above the bank of buildings. I'll have to add a 1" strip up to 3" high 
in LOS to that building to see what that does.
The other multipath signals remain at 0.0.


On 11/02/2017 1:22 PM, Poul-Henning Kamp wrote:
 > --------
 > I can guarantee you that it is not the neoprene itself which does it.
 > It could be residual ZnO, used to catalyze polymerisation of the 
 > but more likely it is metal deliberately added to the neoprene to
 > change the RF impedance of the material.
 > ...
 > [1] If you arrange for the imperance to ramp from open to short you
 > have a "stealth material".

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