[BC] AM RF challenges

[PeterH5322]

>I assume there are also other contributions that could be made to the noise 
>factors regarding interference to AM signals and the reduction of service.

On an historical note, Alaska was not provided with any Class I (now 
Class A) allocations by NARBA, nor was any other U.S. Territory.

Alaska, did, however, get ND-U operation on two of the then new Mexican 
Class I-A Clears, 800 and 900, grandfathered at 5 kW (Mexico, in return, 
got the same on 830 and 1030).

Later, the U.S. created a new class, Class I-N, which was intended for 
non-contiguous use, i.e., outside the contiguous 48 U.S. States, only.

Presently Class I-Ns are allocated only to Alaska.

And, many former Class II-B (Class B) and Class IV (Class C) Alaskan 
stations have converted to Class I-N (Class A).

In fact, Alaska now has more Class A allocations than any other state.

So, the Local and Regional frequencies have been vacated, to the greatest 
degree possible, in preference for Clear frequencies.

These former Class I-Ns (now Class As) receive all the protection of a 48 
State Class A, but these do not necessarily have Class A efficiency (I 
believe only two do).