[BC] IBOC and the Law of Unintended Consquences

[Tom Bosscher]

	I have a friend who just lit up a IBOC FM system. Since he had a new 
digital/analog exciter, he had to set levels. Well, with the IBOC mask 
on the air, the typical off air modulation monitor reads rather high, 
seeing the digital subcarriers. He had to set mod at the tx site, 
putting the mod monitor on the test port of the analog exciter.

	Then it was noticed that another newly "IBOC'd station in town,  is now 
really loud on the analog side. Quite loud. You cannot take a look at it 
with your standard monitor, as stated above. But you can tell it is not 
aggressive processing, it is just that this station is running about 
125% mod.

	And guess what? It looks like you can get away with it. How is anyone 
going to tell anyone what the analog modulation is, unless you are at 
the tx site? "Use a spec analyzer Tom". Tried that. Tried all kinds of 
filters, sweep rates etc. It just looks like a way cool (for those that 
don't care about rules) way to beat the competition. Who is going to 
measure you?

	Remember the classical station that was complaining on this forum about 
sounding so soft? Most all here said, you have to be somewhat softer due 
to your format, and then, make sure you are reading the modulation 
accurately. Then we all said, what for? The FCC just does not care if a 
station in any market is running 125%.

	As an aside, is anyone aware of any station in the US that has been 
cited for over modulation, that was not part of a larger lack of GEP 
inspection? That is, all the station got cited for was over mod.

	So, is this something I should hurry into IBOC so that I, too, can be loud?

	tom bosscher