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WCAP 980 IBOC ?

R

Radioman59

Hi,
Sunday morning I was picking up iboc hiss on 980 wcap lowell. Wondering if they are going HD.
does anyone know anything about this.
 
If you're hearing the "white noise roar" of IBOC digital on 980 then it's not WCAP. The digital carriers for AM IBOC are mostly in the adjacent channels so it's a station on 990 or 970 that you're hearing. Or a intermod product.
 
The IBOC spec shows a secondary sideband from approximately 5 to 10kHz. Is this not used?

If I look at WBZ's audio spectrum, the audio abruptly cuts off around 4800Hz and since my reciever has a 7kHz bandwidth there's considerable noise from 5kHz up. If I want to record a 'BZ show I'll filter everything above 4800Hz and it sounds much better.
 
If you were hearing the hash on the adjacents of 980 (970 and 990), you may have been hearing the IBOC from WOFX Troy, NY, if there was still skywave around.
 
If the IBOC hash you heard was only on the upper sideband (985)....another possibility could be the 990 station from Rochester, NY (don't remember the calls).
 
990 in Rochester changes there calls a couple years ago. They were WLDZ I think for Legends 990. I forget they're current calls. And they're the only 990 around with IBOC.

990 WALE in Greenville/Providence can barely keep an analog signal going.

990 WXCT in Southington/Hartford is owned by DMG and I was once told DMG doesn't believe in IBOC.

990 WNTP in Philly is owned by Salem. I believe Salem doesn't beleive in IBOC.
 
aaronread said:
If you're hearing the "white noise roar" of IBOC digital on 980 then it's not WCAP. The digital carriers for AM IBOC are mostly in the adjacent channels so it's a station on 990 or 970 that you're hearing. Or a intermod product.
Click to expand...

Not necessarily. I have a couple of radios that have wideband tuners and I get plenty of hiss in the background of stations that are running the hissmaker. Basically, the frequency range of the analog audio is narrowed and the hiss surrounds it - causing the radio with filter in the wideband setting to mix the sidebands with the narrow analog signal. Ever compare the analog audio of WBZ with WRKO? WRKO uses their entire bandwidth for analog audio, WBZ's is narrowed to accommodate the digital hash that about 35,000 radios in the market can decode into "HD".

When the given station turns the exciter off, the signal is loud and clear and the fidelity is 10 times better (and adjacent signals rejoice!). My GE Superadio III is an example of a radio that exhibits this characteristic; I have a couple of Sangean 'walkman' type radios that do it too.
 
BRNout said:
Not necessarily. I have a couple of radios that have wideband tuners and I get plenty of hiss in the background of stations that are running the hissmaker. Basically, the frequency range of the analog audio is narrowed and the hiss surrounds it - causing the radio with filter in the wideband setting to mix the sidebands with the narrow analog signal. Ever compare the analog audio of WBZ with WRKO? WRKO uses their entire bandwidth for analog audio, WBZ's is narrowed to accommodate the digital hash that about 35,000 radios in the market can decode into "HD".

When the given station turns the exciter off, the signal is loud and clear and the fidelity is 10 times better (and adjacent signals rejoice!).
Click to expand...

That also depends on whether the station still processes their analog audio for HD broadcasting, with that abrupt drop off at 4800 Hz (or lower), even when they drop the HD exciter. Apparently, the WBZ auxiliary transmitter has different processing, with more analog audio high end, than their regular main transmitter which is set up for HD.

Listen to how muddy and muffled WILD 1090 is, especially noticeable when they play music after 4 PM, or on weekends. They briefly broadcast in HD a few years ago, then shut it off, but it sounds like they left their analog high frequency roll-off set for HD. Either that, or it's just lousy or maladjusted equipment. There's nothing above 5 Hz, maybe even lower. No difference on my wideband receiver on 1090 regardless of how I set the bandwidth switch, but there's a huge difference on stations like WJIB which, though no longer in AM stereo, is still broadcasting with the full allowed analog fidelity for AM.

WKOX 1200 also seems to have nothing there above 5 Hz (or lower), a setting probably in preparation to make HD broadcasting allowable someday.
 
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