Well... now that the digital broadcast transition has finally come, as I suspected, my old DarkStar D230 CATV tester will no longer verify an active line with the new signal.
Can someone recommend a similar, simple GO-NO-GO tester to verify that digital CATV signal is present on a cable line?
At this time, I don’t really need comprehensive signal analysis, so much as I just want to verify that a line is active without having to resort to something silly like carrying a small TV set around with me.

Thanks.

Turned out to be that it was just a happy coincidence.
The connection to the barrel connector in the end of the tester itself was the problem. I tightened the internal locknut on the connector and the tester is now working properly again.
I don't know why DarkStar stopped making this neat little tester.
It's perfect for quick and dirty verification of live, open, shorted or 75 Ohm terminated CATV lines. It can also determine if the cable is connected to the output side of a splitter.

Anyway, I'm just thankful that it is working again.

I didn't want to say anything that was wrong but I was curious why an analog detector couldn't see a digital signal, if all you were looking for was RF power.
I am glad it worked out for you.