"Larry W4CSC" wrote
"Jack Painter" wrote in
news:A1che.4837$It1.499@lakeread02:

Larry, there may be some safety benefit to that arrangement, but I'm
interested in whether your personal experience is that Decibel Product's
ho-splitter actually has some quieting results as well (besides its ?db


I don't see how a splitter, that would only drop the interference 3 or 4
dB
could reduce the intermod because it would be hitting the front end amp of
the receiver still pretty hard. With the single cavity tuned to 157 Mhz
around the middle of the marine band, the attenuation of the 152 Mhz
paging
and cop bands is quite large, dropping the signal hitting the receiver to
insignificant.

As to the lightning comment, you have to see how far apart the radio's
loop
and the antenna's loop is inside the metal bandpass cavity. They are on
opposite sides of the top plate and the loops go directly to ground after
making just the one turn to excite the cavity. Even the plunger rod is
directly in any path between the loops. They are, probably 9" apart,
physically, and everything is a direct ground. I doubt it would survive a
direct hit, but the radio wouldn't be the only thing destroyed in that
event. Most radios are destroyed by static discharge (St Elmo's Fire),
not
direct lightning hits. The cavity idea completely eliminates those. I
didn't put the cavity in for lightning protection. I got fed up listening
to 10 paging transmitters as we sailed across the harbor.

Roger that, thanks for the recommendation Larry. The pager interference is
awful in Hampton Roads, one of the many areas identified by the Coast Guard
as having serious interference to vhf marine band. The Boston and Cape Cod
areas were another area identified with that problem, I didn't know
Charleston was also so bad. At least part of the problem will be reduced
when the new narrow band radios become prevalent. I can reduce most but not
all pager interference just by setting a receiver to FM Narrow, and this
works even when active splitters, notorious for amplifying pager
interference, are used.

Jack
Va Beach