Pattern Changes, etc

Robert F. Sutherland
Fri Feb 17 00:23:42 EST 2006

Generally, a station is required to switch to night pattern & power at local
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

There are exceptions to everything, including post-sunset authorization
and pre-sunrise authorization  for a day-only,  or for day/ night switching.
Some stations are allowed to switch when sunset / rise  occurs at a distant
(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 sunset
/ 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, then
Programs exist to decipher it, such as MW Database Viewer    by Neil Adams,
 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 Broadcast
   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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