On My Way Back From Gillette Stadium...

[Dan.Strassberg]

The splatter suggests that the 4.75-kHz-bandwidth low-pass sideband
filters (required on the analog channel when a station runs AM-band
IBOC) have been temporarily disabled. Presumably, the filters have
been installed because the WKOX installation (and I suspect also the
also the WRCA installation) are almost surely IBOC-ready. Both CCU and
Beasley have been big proponents of IBOC (including AM-band IBOC). I
suspect that Hoffman doesn't really care about IBOC, so WUNR may not
have such filters. When WKOX switches on 50 kW and IBOC, the sidebands
should not wipe out 1150 or 1260 at a reasonable distance from the
site, but who knows what a reasonable distance is--maybe the 1V/m
contour, which is the FCC's official blanketing area for AMs.

Meeting the FCC's population limits for the 1V/m contour is difficult
in built-ip areas. (I believe that the population residing within the
1V/m contour is not supposed to exceed 1% of the population residing
within the 25 mV/m contour.) Many applications for new or modified AM
facilities cannot meet this requirement and include waiver requests
stating that the 1V/m requirement is excessively conservative and that
7 V/m is more realistic. However, I don't think anyone has made
measurements to determine what effect AM IBOC sidebands (which contain
a lot of energy) have on blanketing of adjacent-channel signals. In
connection with an FCC NPRM (notice of proposed rule-making) that
would allow FM IBOC sidebands a 10-fold increase in power, NPR has
done a lot of work on those sidebands and their effect on
adjacent-channel reception. NPR opposes a 10-fold power increase but
might be amenable to a smaller increase.

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

----- Original Message ----- 
From: "Laurence Glavin" <lglavin@mail.com>
To: <boston-radio-interest@lists.BostonRadio.org>
Sent: Saturday, September 13, 2008 3:42 PM
Subject: On My Way Back From Gillette Stadium...


I had some surplus pieces of electronic gizmos hanging around the
house, so
I brought them down to the Sony/Waste Management pickup zone
established at
Gillette Stadium today.  Very nice...they directed each person's car
to a designated
spot like at Tanglewood, and retrieved everything anyone had in his or
her car;  it
was not required to get out of the car.  Anyway, I returned northward
on Route 1,
and since I was travelling that way anyway, I ventured over to the
tri-partite
antenna array in Newton.  WKOX-AM was blasting away from there and
even in STA
status may very well be the most powerful signal emanating from 750
Sawmill Brook
Pahkway.  Oak Hill is a mixed-income neighborhood (although it appears
that in
the recent past, some folks have come in, torn down the housing stock
and built
a few McMansions).  If there are any Spanish-speakers there, they have
three
outlets from which to choose.  (But if they want to hear the Red Sox
games en Espagnol,
they may be out of luck:  WKOX at less than full wattage just
splatters over WWDJ-AM
1150.  And Disney radio 1260..not a chance.

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