Pattern Changes, etc

Dan Strassberg
Fri Feb 17 07:58:48 EST 2006

The New England station that switches to night pattern at Dallas sunset is
WTIC. WQEW switches at Bakersfield CA sunset and WCKY at Sacramento CA
sunset. KFAB switches to day pattern (ND) at Charlotte NC sunrise. AFAIK,
that's the only case in which a Class A AM's daytime operation is extended
in the morning hours. Suggests that KFAB has some kind of priority over WBT
because WBT does not stay on day pattern until Omaha sunset. If the
situation in which one Class A operates on day pattern/power at night as
long as the other is in daylight is valid, you'd think it would work at both
ends of the day. Of course, nothing can be changed now because all of the
protections to co-channel Class Bs would be altered. 1560 is the best
example of what happens when the FCC tries to fool mother nature. Most of
the Class Bs west of New York and east of Bakersfield (in other words, in
about 90% of the land area of the 48 contiguous states) have bizarre
operational modes that require them to change patterns or powers when the
sun sets at New York or Bakersfield, or both, as well as in their own

Critical hours runs from local sunrise to TWO hours after and from TWO hours
before local sunset until local sunset. The Boston area stations that use
different powers and/or patterns during CH, in addition to WWZN, are WBIX
and WILD.

Dan Strassberg,
eFax 707-215-6367

----- Original Message -----
From: "Robert F. Sutherland" <>
To: <>
Sent: Friday, February 17, 2006 12:23 AM
Subject: Re: Pattern Changes, etc

> Generally, a station is required to switch to night pattern & power at
> sunset
> and to day pattern & power at local sunrise,
> and a day-only station to switch off / on at local sunset / rise.
> Local sunset / surise of course is constantly changing, dependent on the
> calendar.
> There are exceptions to everything, including post-sunset authorization
> and pre-sunrise authorization  for a day-only,  or for day/ night
> Some stations are allowed to switch when sunset / rise  occurs at a
> station
> (ie a New England station (can't recall which at the moment) that changes
> per a Dallas(?) station)
> Caution, some stations have "critical hours" (like WWZN 1510 Boston)
> which require a change in pattern and/or power at 1 hour before local
> / rise  and to night
> power 1 hr after local suset / sunrise.
> The FCC is the primary source :  on-line service "public" listings (not
> always quite up to date with
> actual FCC files).
> For individual stations:   AM Query
> Easy to use., highly recommended.
> There is the complete FCC CDBS public database, but it takes complex
> "decoding" to be useful.
>    (expect a 50M+ download,
> unzip)
> Programs exist to decipher it, such as MW Database Viewer    by Neil
>  not sure if still available (can't  find more current URL)
> expensive:   trial for a month(?), then  $50 (last I knew).
> Using the  whole FCC database is not recommended for  "casual" interest.
> If you want the FCC rules which list the change  time requirements,
> they are in  CFR: Code of Federal Regulations
> Title 47--Telecommunication,   chapter 1 (FCC),    PART 73--Radio
> Services
>    such articles as    (I know, this is overwhelming)
> 73.1700  Broadcast day.
> 73.1705  Time of operation.
> 73.1710  Unlimited time.
> 73.1715  Share time.
> 73.1720  Daytime.
> 73.1725  Limited time.
> 73.1730  Specified hours.
> 73.1735  AM station operation pre-sunrise and post-sunset.
> Hope I have helped, without making it seem like excessive
> Bob Sutherland,   Concord, MA
> ----- Original Message -----
> From: "Rob Trovato" <>
> To: "BRI" <>
> Sent: Thursday, February 16, 2006 11:05 PM
> Subject: Pattern Changes, etc
> > Anyone know where on the internet is the scheduled
> > times for stations on the East Coast to change
> > patterns?  And for most daytimers to sign off?
> >
> > I know there are some exceptions to the rules...but
> > are the general East Cost times on the net anywhere?
> >
> > Thanks!
> >

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