HD Callsigns --> Question re AM HD

Sid Schweiger sid@wrko.com
Tue Nov 20 10:03:12 EST 2007

>>Will *all* AM stations be able to broadcast in HD?<<

They can now.

>>We all know the racket that WBZ makes from 1010 to 1050 kHz, but what
if WBIX were also
transmitting HD. Would it affect WBZ's HD signal, or vice-versa? (I
WBZ would let it). And WCRN and WEEI are even closer on the
their HD signals interfere with each other or with the analog

The reports that have appeared across the Internet on message boards,
remailers and newsgroups seem to confirm that HD on AM has some
wide-ranging effects on other stations, and during nighttime propagation
conditions those effects can extend for hundreds of miles from the
transmitter sites.  Bob Savage, the owner of WYSL, 1040 kHz in Avon NY
has filed an action with the FCC claiming damaging interference at night
from WBZ so as to substantially reduce his nighttime interference-free
contour.  According to Savage, that interference doesn't exist when
WBZ's HD is off.  Citadel's DOE has ordered HD operations to cease at
night on all the AMs they own, even though nighttime HD operation has
been legal since September 14th, because of some reports of interference
between Citadel stations and others (including other Citadel
stations...for example, WJR and WABC, which are on adjacent channels).

To balance things out, it should be noted that at least some HD
operations on the AM band don't seem to interfere with other signals. 
Those DOEs who have posted on the subject of HD-AM claim their occupied
bandwidth with the HD carriers on meets FCC specs, and I have absolutely
no cause to doubt them.  Whether their mask being in spec is an absolute
defense against an interference complaint is for the FCC to determine.

IMO, with so few HD operations on AM at this point (I think the last
figure I saw was 75 stations), it's difficult to say for sure that this
system will or will not work, or can be fixed if it's determined that
it's broken.  YMMV.

Sid Schweiger
IT Manager, Entercom New England
20 Guest St / 3d Floor
Boston MA  02135-2040
Phone: 617-779-5369
Fax: 617-779-5379
E-Mail: sid@wrko.com

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