[BC] IBOC Interference to 1st-adjacent FMs

[Cornelius Gould]

I have heard this "BUZZ" sound people describe on FM-HD on one FM station
here in town, but it was something that was caused by a malfunctioning HD
transmitter, apparently.  The HD info was there, but no audio data for the
receiver to decode..it would only do analog.

This transmitter seems to fail on a regular basis, each time putting out
this "buzzing" sound on the 1st adjacents to either side.

All the other HD-FM stations do not do this (but the HD-Radio transmitters
don't croak like that one does either...)

-Cornelius

On 3/23/07, Kent Winrich <kwinrich at gmail.com> wrote:
>
> Hopefully we can keep this a reasonable discussion.....
>
> I have not had the chance to drive the area you describe.  There is
> another
> example that I have driven.  WDRV - 96.9 Chicago, and WWDV 97.1 Zion, IL.
> The stations are directional (and simulcast), WWDV more so than
> WDRV.  WDRV
> is on the Amoco tower in the Loop.  The stations are 73 kM apart.
>
> WDRV:
> http://www.fcc.gov/fcc-bin/FMTV-service-area?x=FM69531.html
>
> WWDV:
> http://www.fcc.gov/fcc-bin/FMTV-service-area?x=FM97092.html
>
> The overlap is in the highly regarded northern suburbs.
>
> Though I have not taken the time to pull out test equipement or the like
> (I
> like to get through Chicago as fast as I can), I have tried a number of
> car
> radios... some HD, some not HD.
>
> I have not heard any "buzz" or hiss on the main channels.  I have,
> however,
> seen the HD signal drop.  There is an area Buffalo Grove, where both
> stations at analog only.  Of course the HD2s are gone as well.
>
> Kent Winrich
>
>
>
>
>
> On 3/23/07, Mark Humphrey <mark3xy at gmail.com> wrote:
> >
> > To anyone in the New York-Philadelphia area interested in evaluating
> > the impact of IBOC on first-adjacent short spaced FM stations, you'll
> > find a real-world case near Trenton, NJ:
> >
> > WUSL 98.9 in Philadelphia (Roxborough antenna farm) is only 85 km
> > (52.9 mi) from WAWZ 99.1 in Zarephath, NJ, which transmits from a
> > ridgetop near Somerville.  Both are full Class B facilities with no
> > protection to one another, spaced at about half the normally-required
> > distance, and both are currently running IBOC.
> >
> > >From these coverage maps, you'll see how far their predicted service
> > areas overlap. Practically all of Mercer County, NJ and Bucks County,
> > PA fall within the overlap area:
> >
> > WUSL:
> > http://www.fcc.gov/fcc-bin/FMTV-service-area?x=FM274154.html
> >
> > WAWZ:
> > http://www.fcc.gov/fcc-bin/FMTV-service-area?x=FM667957.html
> >
> > Most of the other Philadelphia Class B stations have a first-adjacent
> > neighbor on the Empire State Building in New York City, but the
> > spacing between these pairs is about 82 miles so the problem is not as
> > severe.
> >
> > Mark
> > _______________________________________________
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-- 
--


- Cornelius Gould
________________________________
"The significant problems we face cannot be solved at the same level of
thinking we were at when we created them."
- Albert Einstein (1879-1955)