[Lowfer] Interesting finding

[Ed Phillips]

Dale Parfitt wrote:
> 
> >  Is glass-epoxie any good? (as in double sided pc board stock)
> >
> > Thanks!
> >
> > Bill
> >
> 
>  Hi Bill,
> The G-10 and FR-4 materials are quite poor as a dielectric.
> We use Rogers Duroid 3003 2X boards for hi frequency capacitors- pretty much
> teflon for the substrate except this stuff shears like a dream. The 0.062
> material is 23pF/" and the DF is 0.0013.
> 
> Dale W4OP

	Duroid is great for the intended purpose, but still a lot lossier than
Dale is looking for, besides being floppy and expensive (unless you're a
good scrounger).  I don't recognize that particular grade but suspect it
has glass or quartz in it; maybe not.  Note that a DF of 0.0013
corresponds to a Q of not much over 750, unless you mean 0.0013% which I
doubt.  Polystyrene is a bit better than teflon:  my handbook lists a DF
of "<0.0001 @ 10^6 cycles per second)"   compared to "<0.0002" for
Teflon.  Of course, which is the most "<"?

Ed