Hecht and Alonso

Dan.Strassberg dan.strassberg@att.net
Tue Jun 2 21:28:25 EDT 2009

Completely agree on single-source vs multiple-source NIFs. Best
examples of single-source around here are 890 and 1060. And
comparisons should be particularly valid because they share a site.
However, NIF calculations now include the effects of first-adjacent
10% skywaves in addition to the co-channel 10% skywave. So WRME could
be affected by WJR and/or CFZM (or whatever) as well as by WSB.

As for the listening experience with first-adjacents, for the moment,
WBIX seems to have it better than WAMG does, apparently because WCBS
runs IBOC and WEPN doesn't (and won't until its new site goes on the
air). Despite WBIX's lower night power and WEPN's pattern, which sends
a stronger signal this way at night than WCBS's ND signal, WBIX
survives WEPN quite nicely, whereas, unless I rotate the radio just
right, which either maximizes WAMG or minimizes WCBS or both, WAMG is
pretty well wiped out by what I assume is WCBS's IBOC hash. The one
anomalous thing about this observation, which makes me wonder whether
the continuous buzz that destroys WAMG really is WCBS's IBOC, is the
total absence of fades in what I am assuming is IBOC buzz. If the buzz
comes from WCBS (I doubt whether CHML is running IBOC, and it isn't
that loud here anyhow), it is skywave and I would think that skywave
carrying the dense IBOC buzz would be just as susceptible to fades as
are ordinary AM sidebands.

Dan Strassberg (dan.strassberg@att.net)
eFax 1-707-215-6367

----- Original Message ----- 
From: "Scott Fybush" <scott@fybush.com>
To: "Dan.Strassberg" <dan.strassberg@att.net>
Sent: Tuesday, June 02, 2009 8:41 PM
Subject: Re: Hecht and Alonso

> Dan.Strassberg wrote:
>> I've never been in Hampden ME; I don't even know the closest I've
>> ever
>> been to Hampden. But I do know that the areal view of the proposed
>> WRME site at CDBS certainly LOOKS nice. Appears to be just the
>> right
>> shape and size for the array and it looks like nice flat land that
>> seems to be covered with grass and has no trees on it. All of the
>> trees are beyond the periphery of the site. Also, the NIF from that
>> site appears to completely encompass Bangor (and lots of other
>> places
>> in central Maine).
> NIFs are tricky things. Looking carefully at the map they filed, the
> 9.9 mV/m NIF contour for WRME gets most - but not quite all - of
> Bangor, and doesn't get up toward Old Town at all. (Though in
> fairness, 9.9 mV/m is a considerable signal, and real-world
> usability of the signal will probably extend a good ways out from
> the filed NIF contour.)
> On the other hand, my guess is that nearly all of the interference
> that factors into that NIF figure comes from one source: WSB. It's a
> widely-held opinion among the AM gurus I know that single-source
> interference is much more detrimental to real-world listening than
> the sort of multiple-source interference that manifests itself as
> background noise on the regional and graveyard channels at night.
> Still, that drop from the big 50 kW ND day signal to the directional
> 10 kW night signal on those early, early sunsets in winter will be a
> killer, especially against all the big class C FMs that blanket the
> whole region with no dead spots.

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