[BC] Can traditional AM and IBOC co-exist?

[PeterH5322@aol.com]

>Since the use of 500 kHz as a maritime
>distress frequency has been phased out in the Western
>Hemisphere ...

Which accounts for the following changes:

1) BC band from 550 to 1500, until 1941, recognizing a 50 kHz "same 
market" channel spacing (of course, every market, everywhere, had to 
protect 500 kHz, so there could be no BC stations below 550),

2) BC band from 540, after 1941, recognizing a 40 kHz "same market" 
channel spacing, while retaining 500 kHz as before,

3) BC band from 530, recognizing that 530 is being used as a "graveyard" 
frequency in Canada, as a TIS frequency in the U.S., and that Mexico 
typically has a 30 kHz "same market" channel spacing, and

4) 520 on some very late receivers.

Surely someone will want to put a 100/50 kW clear on 520, someday ;-) .

Incidentally, in about 1980, when Region 2 was considering going to 9 
kHz, General Electric made a very nice digitally tuned "clock radio" 
which has switch selectable 10/9 kHz channel spacing. Also, I have a 
Volvo which has firmware selectable 9/10 kHz channel spacing.