Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Hollmike-at-aol-dot-com>
Hi, 
 The transparency sheets are very likely mylar.   Now there are some
translucent sheet protecters that are polypropylene. 
Mike 
     
>
> Suggest you check what material it is made of and look at dielectic loss of 
> it before spending too much time, it could be lossey 
> Best 
> TEd L in NZ