2. I think it costs more.
3. Dr Howard Johnson ("High Speed Digital Design", p. 159) considers it
unnecessary at 1 GHz and below.
At 01:33 PM 8/27/97 +0100, you wrote:
>During the course of designing PCBs for operation at frequencies >70MHz
>our OCB manufacturer has offered us the use of 'PPE' rather than FR4.
>Does anyone out there have any experience or info about PPE including
>what it stands for!