[BC] 100W Class C AMs

[Dan Strassberg]

Scott Bailey asked which Class C AMs are licensed for 100W and mentioned
WSAJ Gtove City PA (whose license has just been surrendered)

The other is WMAM, Marinette WI on 570. WMAM operated for years with
250W-D/100W-N ND-U and had been classified as a Class IV on a Class III
channel. That classification was apparently later changed to Class D,
however.

WMAM's tower was only 64.7 degrees at 570 and presumably the ground system
wasn't full length because the efficiency was only 138.7 mV/m @ 1km--more
than adequate for Class C but a tiny bit below the Class D minimum of
140.85. Well, WMAM lost its Tx site and is moving to what I have to assume
is a pre-existing tower a couple of miles away. This tower is 98.3 degrees
at 570, but it must be closer to some station or stations that would receive
increased interference from WMAM if it maintained an efficiency of 138.7
mV/m @ 1 km. Or maybe the size of the ground system at the new site is
severly restricted. In any event, WMAM is dropping its power to 196W-D and
78W-N, yielding RMS fields of 122.86 mV/m @ 1km days and 77.31 mV/m @ 1 km
nights. These fields just barely exceed the Class C minimum efficiency of
241.5 mV/m/kW @ 1 km. If WMAM is to continue being called a Class D, this
low efficiency requires that it be granted a waiver. Presumably such a
waiver has been granted because the FCC has issued a CP.

--
Dan Strassberg, dan.strassberg at att.net
eFax 707-215-6367