[BC] Pre 1960 radios...

[K7qa at aol.com]

In a message dated 9/1/2008 7:18:57 AM Pacific Daylight Time, 
rcarpen at comcast.net writes:
It must have something to do with field
strength, since we have 1580 and 1600 on opposite sides of DC.

The 1580 50kW upgrade back in 1984 was designed to just kiss the 
existing 5 mV/m contour of 1600. That was based on actual 
conductivity meaurements, not M3. FCC rules require 2nd adj stns 
protect each other's 5 mV/m contours. I recall measuring those areas 
where the 5 mV/m contours were predicted to fall in Silver Spring and 
Rockville. They are pretty much right where they are supposed to be 
with only indidental overlap. Richard Mertz and I did an NAB paper 
back in the early 90's on how the newly deployed NRSC filering made 
it possible for both stations to co-exist reasonably well serving common areas.

tom mcginley