[IRCA] Fw: [BC] Critical flaw in HD sub-channels?

["Dan Strassberg" <dan.strassberg@xxxxxxx>]

I'm forwarding this on behalf of Grady Moates, who, as explained below, is
experiencing e-mail problems that affect his ability to send mail to lists.

--
Dan Strassberg, dan.strassberg@xxxxxxx
eFax 707-215-6367

----- Original Message -----
From: "Grady Moates" <Grady@xxxxxxxxxxxxxxxx>
To: "Dan Strassberg" <dan.strassberg@xxxxxxx>
Sent: Friday, October 13, 2006 8:47 AM
Subject: Fw: [BC] Critical flaw in HD sub-channels?


> Dan,
>
>     My ISP has gotten listed with Spamcop, and I can not
> post to the list.  Here is a response I wrote to your post.
>
>     Feel free to post it to the list if you like.
>
> Grady
>
>
> ===================================================
>
> > BUT on the HD subchannels (mostly, if not entirely, HD-2), the
> > flip was, of course, to just silence. In other words, the HD
> > subchannels had very limited range--such limited range that
> > their viability in a car would seem to be very much in question.
> > When I read his posting, my immediate reaction was
> > "Of course; why didn't everybody foresee this fatal flaw?"
>
>     This is eXACtly why my public stations will never do HD2 (or 3, or 4),
> as long as we are in hybrid mode. . . my listening experience is that the
> HD coverage is "about the same as" the 65-dBu-or-so contour with
> a class "C" or full class "B"  FM station.  Past that it gets real
> "flippy".  It turns out that, as you drop the power and height of a
station
> (going toward lower classes, such as B1, A, etc.), the interfering
> first-adjacent signals are more numerous and closer-in, so you have
> lots more little 'bites' taken out of your HD coverage in the fringe
> area.  Because of this, HD2 coverage on WUMB-FM (660 Watts
> at 63 meters HAAT) is only useful within a few miles of the transmitter.
>     As I drive the fringe of WUMB's coverage I find that, at every place
> that the HD drops out, if I actually tune to the first-adjacent channel,
> either up or down, I'll hear another station's analog signal 'blipping in'
> under my HD noise.  None of my receivers seem to work with only
> one set of carriers (high-side or low-side).  I have a Kenwood, a JVC
> and a Panasonic, and they all fail with interference to only one side
> of the HD.
>
>     In addition, the HD receivers I have are just as (if not more) prone
to
> overload as analog receivers are, so as you drive past the Great Blue
> Hill, where WGBH has it's 100 kW 89.7 with it's magnificent downlobe
> that is "toasting the tarmac" on the route 128 beltway, just about ALL
> other stations' HD signals fail.
>
>  Grady
>
>



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