With 940 now officially vacant

[Dan.Strassberg]

One thing that happened around that time was that what were then US
Class II-D stations on what were then Mexican Class I channels were
allowed to operate at night. The affected frequencies were (IIRC) 540,
730, 800, 900, 1050, 1220, and 1570. Also, US Class II-D stations on
these Mexican Class I channels were allowed to increase their D power
to 5 kW (the previous maximum had been 1 kW) if such an increase did
not adversly affect adjacent-channel US stations. I believe that the
all-night operation by US II-Ds on Mexican Class I channels happened
in phases. IIRC, the affected stations were initially granted
post-sunset authority. A few years later, they were allowed nighttime
operation with a maximum of 500W. Use of 1050 in New York City and
1220 in Cleveland by US stations operating with 50 kW DA-1 had been
part of a much earlier treaty.

Oh, and 540, like 940, became a Mexican/Canadian Class I channel at
some point. Apparently, at least some US II-Ds on the channels on
which there had been Class I stations in both Canada and Mexico were
allowed more nighttime power than US II-Ds on channels on which there
were Class I stations only in Mexico. This issue becomes very murky
and hard to follow because Canada now has Class A (the modern
equivalent of the old Class I-B) stations on what had been Mexican
Class I channels. Previously, Canada had been allowed only Class II
stations on these channels. For example, on 730, CKAC and CKLG became
Class A AMs, whereas, before the treaty was modified, they had been
Class IIs with no protection of their nighttime-skywave service. When
these stations were "promoted" to Class A, they still had no skywave
protection, however. This subject makes my head hurt.

-----
Dan Strassberg (dan.strassberg@att.net)
eFax 1-707-215-6367

----- Original Message ----- 
From: "A. Joseph Ross" <joe@attorneyross.com>
To: "Garrett Wollman" <wollman@bimajority.org>
Cc: <boston-radio-interest@bostonradio.org>
Sent: Tuesday, June 22, 2010 12:50 AM
Subject: Re: With 940 now officially vacant


> On 21 Jun 2010 at 21:25, Garrett Wollman wrote:
>
>> > For that matter perhaps it is time for Canada, Mexico, the US et
>> > all
>> > to redo the treaty. A lot has changed in 70 years.
>>
>> Not so much has changed in twenty-five years, when they last redid
>> it.
>
> They did?  What happened then?
>
> -- 
> A. Joseph Ross, J.D.                           617.367.0468
> 92 State Street, Suite 700                   Fax 617.507.7856
> Boston, MA 02109-2004                    http://www.attorneyross.com
>
>