Thank you all for your inputs and thoughts on the subject of Frequency performance of FR-4 material.  This is an interesting Discussion.  Hope it continues.
        The "problem" we were observing was that when a signal was injected into one end of a unterminated 50 Ohm transmission line and a scope was placed at the point of injection, the signal amplitude almost disappeared above 150 Mhz.  When the "problem" was properly instrumented and the results properly analyzed, we concluded that the result was correct.  The reflection at the source end of the line totally subtracts from the source resulting in a signal amplitude which is almost 0.  If the probe is placed at the end of the (unterminated) transmission line the signal level is twice the source level.  When the transmission line is properly terminated, the signal level is correct.
        The Rise time of 175 psec was degraded to 375 psec.

Moral: 	
        Use proper equipment and understand the theory before jumping to conclusions:

Tenative conclusion:
        FR-4 is acceptable for rise times of 500 psec and frequencies up to 1 GHz.

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