In article ,
Earl Haase wrote:

Thanks for the input and info about the Icom 802. I have a couple of
other questions.

First question
Does anyone know anything about the Furuno 1503EM?

Next question.
My Chris Craft had a counterpoise installed into the fiberglas bottom of
the boat when it was manufactured. I started asking around about how
much area this covered but have not gotten an answer yet. All I have so
far is that copper mesh was installed on another boat after the first
layer of fiberglass, after the gelcoat. So the question is - can I
install copper mesh as straps on the floor of the bilge and still have
it work. Meaning it will still act with the sal****er and not be
defeated by the existing copper that will be between it and the sea?
These boats were built with solid fiberglass. In other words, there was
not any foam core used. Just layer after layer of FG.


The Rf Ground in plastic hulls, is an interesting concept. What you are
trying to achieveis a Giant Capacitor, that couples RF energy into the
Sal****er that your plastic hull floats in. The water is one plate of
this cap. and the copper screen is the other plate. How does one
increase the coupling or Capacitance of a capacitor, you ask? Well,
either you decrease the distance between the plates, or you increase the
surface area of the plates. Since the water is one of the plates, it is
finite in size, so then you must increase the surface area of the copper
screen, right? That means MORE of IT, but it must be connected
(electrically) to what is already there. On all the plastic hulled
vessels which I have seen, there is always a RF Ground Bolt somewhere in
the bilge that is electricall connected to the screen. You just need to
find the one on your vessel. Putting more screen inside the existing
screen doesn't help at all and actuall would reduce the RF Ground by
vilating the "Proximity of the Plates Rule", by increasing the distance
between the plates. This is also the reason that copper screen in the
cabin overhead doesn't do SQUAT FOR RF GROUND SYSTEMS. The distance
between the plates make the coupling or capacitance almost negligable.

Bruce in alaska who has seen 35 years of folks not getting these
simple concepts......

--
Bruce (semiretired powderman & exFCC Field Inspector for Southeastern Alaska)
add a 2 before @
Bruce Gordon * Debora Gordon R.N. Bruce's Trading Post
P.O. Box EXI Excursion Inlet South
Juneau, Alaska 99850 Excursion Inlet, Alaska 99850
www.btpost.net www.99850.net