This may be old news to some of you, but it's the first I've heard of it, 
and I thought I'd share it with the list.

Steve

========================================

From the MT American Bandscan blog website:

Thursday, March 22, 2007
Nighttime AM IBOC approved - final IBOC rules adopted

The Radio Ink online news site reports the FCC has this morning approved 
final
rules for digital terrestrial radio in the US.

Read the link for more details. A few highlights:

No prior FCC approval is necessary to begin digital operation.

AM stations, previously limited to daytime-only digital operation, will be
allowed to run their digital signals at night.

Stations must offer at least one free-to-air program stream, simulcasting
their analog signal. Additional program streams may be broadcast, either 
free
or subscription (FM only; AM IBOC lacks the technical ability to multicast).

Content rules - EAS, legal IDs, etc. - will be applied to all streams of the
IBOC signal.

Digital-only stations will not be allowed at this time (apparently this will
stymie the plans of North Carolina stations WHDX and WHDZ which had 
reportedly
planned to sign on as digital-only operations). IBOC stations must maintain
their analog operations.

No deadline has been set for shutting down analog radio and going
digital-only.

The FCC has not yet released a Public Notice on this (keep an eye on the FCC
website). Usually, this kind of proceeding takes effect 30 days after
publication in the Federal Register; said publication will take between a 
few
days and a week. So one might expect AM stations to begin operating in 
digital
mode at night in about 5 weeks, around the beginning of May. I would not 
rule
out the possibility of stations that are already operating IBOC during the 
day
receiving Special Temporary Authority to engage in nighttime digital 
operation
before the new rules go into effect. Indeed, I would not rule out blanket
Special Temporary Authority to cover all IBOC stations.

Many of the 50kw clear-channel stations are already equipped for IBOC and 
will
likely begin operating at night as soon as the rules go into effect. The
likely result will be massive interference in the 640-1220 and 1500-1580KHz
bands. I don't see the new rules spurring many stations to add IBOC though, 
if
they aren't already running it. IBOC is not particularly popular among the
smaller stations in 540-630, 1230-1490, or above 1580KHz and I don't think 
it
will become so particularly quickly.

I guess time will tell.

--
Charles J. Hargrove - N2NOV
NYC ARECS/RACES Citywide Radio Officer/Skywarn Coord.
US Coast Guard Auxiliary Flotilla 5-10 VFC & Div 5 Comms Officer