Tech Notes from the Field

What a week.  AT&T takes down our T-1 STL without notice.  An aerial to buried cut-over and their documentation is all screwed up.  Sure enough, off the air!  Then I discovered the hard way that when we switch to our aural STL the main transmitter, HTHD+, has no audio, yet the backup, HT-25, does!

What did I learn?  The AES audio from the 9003Q has a “no audio” bit set in the output card.  The Flexstar exciter reads it as no audio and thus no audio on the air.  Huh?  I receive a 3 year old tech sheet from Harris stating a modification to the Moseley output card.  I perform the modification and now everything works.  My question:  Why did this output work fine with our original Flexstar exciter but not this one?

Earlier this year we had an actual failure of the XLR input board on the Flexstar.  Exhibited the same no audio issue, but from both AES sources.  This time I assumed the same thing.  When I found out about this modification, I was floored.  My predecessor did not document this?  As I mentioned, we have used the auxiliary STL before without issue on the Flexstar.  Or had we?

All I know now is that it is fixed and we are covered as we should.  Making discoveries this way sure drives you nuts.