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B101 HD No More?

THE B NOW IN HD AND THEIR HD-2 IS ALL 80'S
« on: September 13, 2009, 03:28:53 pm » Quote

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Finally WBEB has their main signal in HD, and their side HD-2 is all 80's and a good mix I might add, plenty of harder edged stuff, just heard Great White and Poison, also their HD-2 is much stronger than the local stations.....good to see HD opening up with more formats....


Posted over a week ago.....
 
WOGL's HD signals are awful and I wish they would shut the HD signals off. On the other hand now that B101 is back in HD its sounds great the HD2 signal doesn't drop out here in Bucks county like WOGL.
 
bigtom101 said:
But as for FM - IBOC doesnt cause this horrible sidechannel interference that you speak of. It was designed to fit within the pre-existing mask. I have 3 HD radios, and using them my reception has only gotten better, not worse. The only place that it would possibly cause interference is on the fringes of the signal. Unless you can show me hard technical evidence of the FM jamming, then I remain unconvinced that it's actually happening.
Click to expand...

Take a look at 91.7/91.5 and 98.9/99.1 in the San Francisco Bay area. I only jumped to this thread because someone else pointed it out, but we have two stations derated in power because of their high elevation (91.5 and 99.1) and two others running significant IBOC power, with nothing but the San Francisco Bay between the HD transmitter sites and the listeners receiving the interference. Add some terrain shielding and you have some real problems. Also, the concept that IBOC fits within the mask is a smoke-and-mirrors charade. Think about it. HD power is -20 db right now. That's -23 db per sideband.

Part 73.317 (b) says: "Any emission appearing on a frequency removed from the carrier by between 120 kHz and 240 kHz inclusive must be attenuated at least 25 dB below the level of the unmodulated carrier. Compliance with this requirement will be deemed to show the occupied bandwidth to be 240 kHz or less."

Currently, some of the IBOC carriers are between 100 and 120 KHz. So the existing -20db HD level actually satisfies this rule - just barely. But wait - in order to be able to say they are compliant after the suggested power increase, Ibiquity measures spurious radiation on a spectrum analyzer with a resolution bandwidh of 1 KHz. How many FM receivers do you know of with 1 KHz IF bandwidths? Where's all that RF? On one hand, we hear that digital power is -14 to -10 db of Analog (-17 to -13 per sideband). On the other hand, we hear that it's down by more than 25 dB. Huh?

Dave B.
 
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