Joshua Putnam wrote:
I've looked rather closely at my coax entrance -- only the outer
conductor is grounded. The center conductor is not. (Shouldn't be too
surprising, if you shorted them both to ground, it would attenuate the
signal a bit, no?)

What, other than a surge protector, stops transients on the center
conductor of cable TV?

Generally all protectors attentuate signals. In earlier days, I
always wondered why center core connection was not performed. Some
experienced professionals in the rec.radio.amateur.antenna newsgroup
confirmed what I had been told. Leakage from the center conductor to a
well earthed outer conductor provides sufficient protection. A
capacitive protector on center core would only attentuate signals;
provide little protection advantage. But then some legendary
manufacturers do make protectors that include that center core.

You are not earthing a 200,000 amp direct strike - which you probably
will never see in your lifetime. Using a ground block to earth the
outer braid is a massive protection improvement. If you still need
better, then visit some expensive and superior protector manufacturers
such as www.polyphaser.com .

Nothing 'stops transients on the ... conductor'. Anything that
stops or blocks such transients is not effective. Effective protection
is diverting. Destructive transients seek earth. Therefore the sooner
that transient is diverted / earthed (meaning a shorter connection to
earth and farther from transistors), then the better that protection.