In article , inch (Peter
H.) wrote:


Not knowing the dates when KYW moved to Philadelphia, or when the "NARBA" was
ratified, I assume that the move of KYW occurred well before the "NARBA"? If
this is the case, how did the KYW pattern come to have such a deep null
towards
WINS, which wouldn't have even existed at the time?


NARBA was signed in 1939 and was implemented in 1941. It was in 1941 when the
great AM frequency change occurred, and when stations in the same market could
be reduced to 40 kHz from 50 kHz spacing.

I believe the move of KYW to Philadelphia from Chicago occurred after two
stations were consolidated into one (KYW) in Chicago, but before the
1050 Class
II-B assignment in New York was agreed to.

Yes, KYW seems to have moved from Chicago to Philadelphia in 1934.

However, before NARBA, 1050 was a U.S. de-facto Class I-A clear (KNX, Los
Angeles), and the ceding of 1050 to Mexico as a new Class I-A clear for that
nation, and the allocation (but not the construction) of a Class II-B to New
York would have been simultaneous with the codification of 1060 as a
Class I-B,
in-fact, in Philadelhia and a similar station in Mexico City.

So, these changes could have been (and probably were) coordinated.

So it would seem. Do you know if there are any other class A (I) stations
that protect adjacent channel class B (II) stations in this way?

KYW's prior operation in Chicago, and its early operation in Philadelphia was
10 kW ND-U, on 1030.

A 10 kW omni signal would have been much stronger to the northeast than
the current KYW signal.


Regards,

John Byrns


Surf my web pages at, http://users.rcn.com/jbyrns/

So it would seem. Do you know if there are any other class A (I) stations that
protect adjacent channel class B (II) stations in this way?


Other Class II-Bs that receive protection from Class I-Bs include WLAC
protecting Boston's 1510.

Other Class I-Bs that now protect other Class I-As or Class I-Bs include
WSAI/1530, protecting Buffalo's 1520 (first adjacent) and Bahama's 1540 (also
first adjacent). (KXEL/1540, a Class I-B, also protects the Bahamas, and has
from the git-go, even though the Bahama Class I-A operated with 5 kW, later 10
kW, and now 50 kW ... when moving to 50 kW, as required by "Rio", the Bahama
Class I-A installed a DA to protect KXEL, and perhaps the Class II-B in Albany,
NY).

KYW's DA-1 pattern appears to be similar to WRVA's DA-1 pattern, but it it not.

WRVA's is a side-fire, and is symmetrical in two axes.

KYW's is an end-fire and is symmetrical in only one axis.

The nulls towards 1050 are filled by a little. They could be made equal to zero
by a minor parameter change.

The minima towards Mexico is a characteristic of the wide spacing of the
towers, and is not controllable except by reducing or increasing the spacing
between the towers.

The fundamental point here is that KYW's groundwave is protecting the
groundwave of a station of lower class, located somewhat less than 100 miles
away from it.

If KYW were to change its pattern to loosen it up towards 1050, it would be
interfering with a station which was authorized by an international treaty.

Usually, international treaties trump national regulations.