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

jimlux jimlux at earthlink.net
Sat Feb 11 19:11:59 EST 2017

On 2/11/17 10:22 AM, Poul-Henning Kamp wrote:
> --------
> In message <589F4A79.3050800 at rogers.com>, MLewis writes:
>> Late yesterday I placed old neoprene rubber mouse pads, rubber side
>> outwards, up the metal blinds between the blinds and the antenna.
> 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 neoprene,
> but more likely it is metal deliberately added to the neoprene to
> change the RF impedance of the material.

Or to make it heavy, so it lays on the table better.  They could just 
load it with sand or iron oxide or scrap whatever.

> Polymers with varying metal content offer a handy range of
> electromagnetic impedances between "short" and "open"[1], and it
> is used a fair bit in various niche markets.
> See for instance the first document here;
> 	http://www.eccosorb.com/resource-white-papers.htm
> It is not inconceiveable that off-spec or scrap materials from
> the production might end up as mousemats.

I don't know if the production volume is high enough.. one never knows..
Eccosorb and related RF elastomers are sufficiently expensive that they 
must do something with it.

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