To correct, FM iboc does not produce "annoying hiss" AM
will if you are not center tuned.
ANSWER- FM HD CAUSES INCREASED NOISE IN ANALOG STEREO FM TRANSMISSION BY INTERFERING WITH THE STEREO SUBCARRIER.
AM HD CAUSES "ANNOYING HISS" ON MOST ANALOG AM RADIOS EVEN WHEN CENTER TUNED. THE VAST TESTAMONY IS POSTED RIGHT HERE ON THIS SITE.
The "vast testamony" of the dozen or-so here that share your viewpoint (and credability) are hardly authoritative.
FM iboc does not cause "fidelity reduction"
ANSWER- FALSE. HD FM PRODUCES AN INCREASE IN ANALOG STEREO NOISE BY INTERFERING WITH THE ANALOG STEREO SUBCARRIER.
That's a new one. The only way your assertion makes sense is if you are working from outdated information concerning the problem of spurious emission caused by the interaction of the COFDM carrier with the baseband analog carrier due to non-linearities in the PA or antenna. Last I read, this had been solved by TX software preconditioning, or, the use of separate antenna/transmitter for the iboc carrier.
AM iboc does however the degree to which the listener notices depends on the bandwidth of their receiver.
ANSWER- THAT IS INCONSISTANT WITH YOUR PREVIOUS STATEMENT ABOUT NO NOISE WHEN CENTER TUNED.
-Got me there..that 5-6 db s/n reduction in a
wideband tuner sure blows holes in my statement
has very poor building penetration
AM yes, FM is approx the same as analog with the bebefit of eliminating multipath, a big problem here in the City.
ANSWER- HD FM RADIO'S CLAIMED IMMUNITY TO MULTIPATH HAS BEEN PROVEN FALSE. WHEN THE HD FM SIGNALS ENCOUNTER SIGNAL DEGREDATION OR CANCELLATION FROM MULTIPATH THE HD RADIO RECEPTION JUST SWITCHES BACK TO ANALOG.
-Well, no it doesn't not in my daily experience over the last year of hd radio ownership. Station suc as WNYC-fm are plagued by multipath to the point of being annoying when the set switches to digital the problem goes away. I will say that on very bad days the hd-2 and 3 streams will occaisonally drop out but the use of a rabbit ears seems to have helped.
a reduction in receivable analog stations
FM -no,
ANSWER- FALSE. FM HD BLOCKS OR INTERFERES WITH THE "STATIONS BETWEEN THE STATIONS", AND WITH OTHER HD STATIONS WHOSE DIGITAL SIGNALS SHARE THE SAME CHANNELS.
I can't see how that is correct. Almost all of the NYC fm's have implemented iboc and it hasn't affected the reception of surburban stations. Everything I could receive 5 years ago, I still do. Perhaps a wee bit of puffery on your part?
AM it's largely an issue of concern to DX listeners.
ANSWER- ALSO FALSE. HD AM CAUSES LOUD HISS ACCROSS WIDE AREAS OF THE AM DIAL. THE CLOSER YOU ARE TO THE HD AM TRANSMITTERS, THE LOUDER AND WIDER THE ANNOYING DIGITAL HISS.
No worse than back in the days when you guys used to spike the 6-10k region and compress to the point of producing a constant wash of splatter. Isn't that why we got the 10K roll-off?
However there may be some situations where AM iboc will not be practicable due to adjacent channel issues.
ANSWER- MOST SITUATIONS, ESPECIALLY AT NIGHT.
Well, here in market 1 three of the four stations that started 24hr iboc last September are still doing so. The exception is Citadel's WABC which stopped night iboc company wide pending individual-case evaluation. I expect WABC will resume 24hr eventually although for the brain-dead programming they offer they'd better serve society by conserving electricty and going dark altogether. That would be real
conservatism.
Lino