WKFD 1370 Ri (deformatted)

[Scott Fybush]

> It's amazing that an operation in Rhode Island and Providence Plantations
> would have to worry these days about first-, second-, and even
> third-frequency separation over dozens and dozens of miles, while
> WAZN-AM 1470 blithely plops itself down in the midst of what was once 
> the reasonably decent coverage area of the former WBET-AM 1460 in Brockton!
> I know WAZN is uber-directional, but still...

The rules on these moves are, if nothing else, well set out in black and 
white and equitably enforced.

In a nutshell: there's a table that sets out what the protected contour 
for each class of station is, for co-channel, first-adjacent, 
second-adjacent and third-adjacent. You can read the whole table here:
http://sujan.hallikainen.org/FCC/FccRules/2006/73/37/

In the case of first-adjacent class B signals, which is what both WXBR 
1460 and WAZN 1470 are, the rule says that the 0.25 mV/m contour of one 
station can't overlap the 0.5 mV/m contour of the other, and vice versa. 
  The combination of lousy ground conductivity between Lexington and 
Brockton and the very directional 1470 pattern more or less takes care 
of that requirement. In the case of WKFD, though, salt water is very 
conductive, and so the signal spreads and spreads and spreads as it 
heads away from Charlestown, creating more interference concerns. The 
FCC will allow interference over water, but they get picky about ANY 
interference over land, only rarely granting waivers when it's 
noncontiguous and outside the station's home market. (An example would 
be WAMG interfering on paper with WCBS on Cape Cod.)

In this specific case (WXBR/WAZN), I suspect there was existing 
grandfathered prohibited overlap between the old Marlborough WSRO signal 
and WBET. In a case like that, the FCC wants to see a reduction in the 
amount of overlap, but will approve an application that doesn't 
completely eliminate the overlap. That might have been what happened here.

As for WKFD, the relevant issues stack up like this:

WNRI 1380 - can't overlap 0.25/0.5 contours. WNRI's 0.5 just comes down 
to Warwick, and it's 0.25 brushes the north end of Aquidneck Island. 
This severely restricts ANY signal to the north from WKFD.

WFEA/WALK 1370 - WKFD's 0.025 mV/m (a vanishingly weak signal) can't 
overlap either of these stations' 0.5, and vice versa. This is a further 
limitation to the north (WFEA) and to the southwest (WALK).

The other nearby AMs are less of an issue. WDRC on 1360 has the same 
protections as WNRI, but it's more distant. WPLM on 1390 and WNBH on 
1340/WHTB on 1400 have even less protection - for second-adjacent 1390, 
the 5 mV/m contours can't overlap, and for third-adjacent 1340/1400, the 
25 mV/m contours can't overlap. Even with the water path between 1340 
and 1370, the powers involved are still small enough that the 25s don't 
come close to overlapping.

That said, the WNRI issue is just a killer for this signal.

(This analysis looks only at daytime protections; at night, a class B 
signal gets only co-channel protection, but here's where protection of 
WFEA becomes a killer. And because you can't apply for a new daytimer, 
you have to have a licensable night signal to apply for anything at all.)

s