Talk:Clear-channel station

This article gets a bunch of things wrong. For starters, a "clear channel" is by definition a station which does not share its channel with any other. The old I-Bs were never "clear channel" stations, nor were the I-Ns, and this status was completely eliminated by the "Rio accord". The long list of stations ought to be labeled something like "List of stations in North America which are called out as being of class A under the ITU Region II Mediumwave Coordination Agreement of 1981" or some such.

There are important differences between class A stations and class B stations, even though the clear channels as such no longer exist. Specifically:

• Class A stations must operate with at least 10 kW, and are restricted to specific locations and frequencies set out under Rio and previous international agreements. CBE and CBN are the last 10-kW class-A's.
• Class A stations, unlike all others, have a protected nighttime skywave ("secondary") service area.
• Class A stations, unlike all others, are entitled to protection from daytime skywave interference to their groundwave ("primary") service area (mostly a factor on the high end of the band, 1500 to 1560 kHz).
• Class A stations must meet a higher minimum antenna-system efficiency than class B stations.
• Once a station has lost class A status, it can never regain it. By contrast, a class B station may relinquish nighttime authority (thereby becoming a class D) and then later be returned to class B upon grant of an application to resume night operation. This has happened, in the case of WOWO, which was demoted from A to B in order that WLIB might be promoted from D to B. (With WOWO protected as an A, WLIB could not operate at night; as a B, WOWO no longer has a protected secondary service area, so WLIB need only protect WOWO's groundwave.)
• Class A stations have generally not been subject to the "ratcheting" rules which require modifications to AM station facilities to reduce interference by at least 10%.

Class A includes all of the stations formerly designated as class I-A, I-B, or I-N. Class B includes the former classes II (secondary assignments on I-B channels) and III (regional channels, limited to 5 kW nominal power), except II-D and III-D which became class D. Class C is the former class IV (graveyard channels).

The breakdown of the clear channels began in the 1960s, when the FCC began assigning class II-B stations in the West on Eastern class I-A channels; in one case (KOB Albuquerque versus WABC on 770) the matter went all the way to the Supreme Court (and was decided in the FCC's and KOB's favor). In a last-gasp attempt to preserve their relevance, several of the I-A stations asked the FCC to increase the power limit from 50 kW to 750 kW. This was eventually turned down when even many of the I-A stations came out against it.

Protection of foreign class-A stations is still much stronger than protection of domestic class-A stations, in all three countries. This is an artifact of the requirement in NARBA that all stations on another country's I-A channel protect the entire border of the assigned country.

Oh, and nearly all of the callsigns in that big long list are wrong as well. Tain't no such thing as "-AM".

18.26.0.18 05:45, 25 Jan 2005 (UTC)

Data source

The data in the updated version of the table comes from the FCC's Consolidated Database System (CDBS). The following SQL query was used to extract the relevant information from the public CDBS dumps:

 select distinct fac_callsign as "Call",
                 fac_frequency as "Freq.",
                 comm_city as "City",
                 station_class as "Cl.",
                 region_2_class as "R2",
                 old_station_class as "Old"
     from facility join am_eng_data using (facility_id)
     where station_class = 'A' and 
           fac_country in ('US', 'CA', 'MX')
     order by fac_frequency, fac_callsign

I then filtered the data for known errors and silent stations, and added ZNS1 back in (since The Bahamas counts as "North American"). 121a0012 19:04, May 30, 2005 (UTC)

CKLW

Weird question, the CKLW page lists it as a Class A, but it's not on the list. Any thoughts?--RAult 08:52, 26 September 2007 (UTC)

I believe the CKLW page is wrong. 800 was/is a Mexican clear channel; all of the Canadian allocations on that frequency are old-class-IIs (modern class-Bs). The FCC database, while not authoritative for Canadian or Mexican stations, agrees -- and since the FCC records determine the protection offered by U.S. stations to those stations, I would expect the authorities to correct errors of that sort very quickly. It shows 31 class-Bs in the U.S. (and the rest are all class-Ds, which are treated like class-Bs for international purposes); 10 class-Bs in Canada; 7 class-Bs in Mexico; and one class-A in Mexico.

Under the ITU Region 2 Mediumwave agreement, AM stations are notified to national authorities throughout the Western Hemisphere. The FCC database shows class-A assignments on 800 in Brazil (2), Colombia, Cuba, Mexico, Venezuela, and the Netherlands Antilles. None in Canada. 121a0012 03:09, 27 September 2007 (UTC)

I'm not sure what class CKLW (AM) used to be in the 1970s or before, but I'm certain it's currently a Class B (normal 50kW station) sitting on a Mexican clear channel, not a Class A (clear channel station) sitting on a Canadian clear channel. Here's a rundown of the stuff I found:

• Official sources:
  • Template:Amq (U.S. government records) says CKLW is notified to the U.S. as a class B. It also is notified as having a multi-antenna directional pattern, which would probably not be as important for a clear channel in the middle of the continent.
  • Industry Canada's dBase III files (linked from [1] - it's hiding in AMSTATIO.DBF if you care) show CKLW as a class B.
• Wikipedia articles:
  • Border blaster says (unreferenced): "While licensed as a normal Class I-B station, its 50,000 watt directional signal blanketed Michigan and northern Ohio east to Cleveland. American-owned until 1970, it functioned as a Detroit-market station during the 1960s and 1970s." Old Class I-B is now Class A; I suspect that's supposed to say "normal Class B", not "normal Class I-B".
  • CKLW (AM) says Class A in the infobox but says in the text: "Even more impressive is the fact that this is not known to be a a clear channel station."
• External sites:
  • http://www.thirteen.org/blogs/index.php?itemid=99 says: "Clear channel stations, once designated as Class I-A and I-B stations, are now designated as Class A AM stations. (There are other 50,000 watt stations but they are not clear channel stations, and are not protected from interference and have no recognized wide area coverage at night. Examples include WRKO 680 Boston, WEEI 850 Boston, WINS 1010 and WEPN 1050 New York, CKLW Windsor, Ontario, KTRH 740 Houston, and KCBS 740 San Francisco, among many others.)"
  • Robert Meuser in [2] says: "CKLW is not an A and is not Omni (they are DA-2)"
  • Neil S. Adams in http://www.dobe.com/wts/funk/clears.txt on 1997-02-03 lists 800 kHz as "Mexican clear" (not "Canadian/Mexican Clear" like 940). He shows some Canadian I-B stations on Mexican clears in this chart, but not for 800 kHz — CKLW is shown as Class II (now called Class B):

800 (Mexican Clear)

XEROK	Ciudad Juarez, Mexico	150kW	I-A	ND
CKLW	Windsor, ON	50kW	II	DA-2
CHRC	Quebec City	50kW	II	DA-1

I'll try and change the articles on Wikipedia to reflect this. --Closeapple 22:22, 29 September 2007 (UTC)

KTWO 1.030 MHz in Casper, WY is not class A?

Excuse me, I once edited this page, edit was removed, but as far as I know, KTWO Casper, is class A, and both WBZ Boston, and KTWO must use directional antennas at night to keep down co-interference. KTWO is also one of only 10 Primary Emergency Alert System AM Stations in the USA (Source: FEMA Manual 1550.2 Page D-3 (http://www.vdem.state.va.us/library/handbooks/nawasmanual2001.pdf)). I seriously doubt this responsibility would be given to less than a true clear channel station with wide service area. Also please note WBZ Boston, a clear channel on the same frequency, is on that list. Please check your sources, and I re-submit KTWO for inclusion in the list. —Preceding unsigned comment added by 69.145.40.116 (talk) 06:10, 30 November 2007 (UTC)

You are incorrect. KTWO is a class B station, and has been since the system of lettered classes was introduced. Prior to that, it was a class II-A station. (There are 36 Primary Entry Point stations in the Emergency Alert System according to references more recent than your 2001 FEMA document, but the class of station is not relevant to this status. It's hard to find a list of which stations are currently participating as PEPs or NPs, although I have seen the equipment at most of them.) 121a0012 (talk) 06:34, 30 November 2007 (UTC)

I agree, I was incorrect, doubly so for excluding the AM qualifier. I wish to change my post to read...

Perhaps this list is a little too tight only allowing class A stations. KTWO, in Casper Wyoming, is known very far and wide as a Clear Channel AM station (Not to be confused with it's owners, Clear Channel Communications) But is listed as clear channel in other federal documents, and is of national importance. KTWO is one of only 10 Primary Emergency Alert System AM Stations in the USA (Source: FEMA Manual 1550.2 Page D-3 (http://www.vdem.state.va.us/library/handbooks/nawasmanual2001.pdf)). I seriously doubt this responsibility would be given to less than a true clear channel station with wide service area. Also please note WBZ Boston, a clear channel on the same frequency, is on that list. I submit that a Class B 50KW Day/50KW Night class B list also be included in this article. (As a note of trivia, KTWO has sent QSL cards to every continent, including Amundsen-Scott South Pole Station in Antartica)

( I had only edited this page 20 minutes before your reply, give me some time for recheck. :) zaphodb777(at)gmail.com )