----- Original Message -----
From: "Larry Robertie" <[EMAIL PROTECTED]>
Subject: catalina27-talk: RF
Ground
> I'm about to install a Raymarine fish finder
on Cheeky Monkey and upon
> reviewing the manuals that came with it there are three wires for the power.
> There are the usual positive and negative, but it also has an "RF ground".
>
> Does anyone have advice on where this is connected? >
> reviewing the manuals that came with it there are three wires for the power.
> There are the usual positive and negative, but it also has an "RF ground".
>
> Does anyone have advice on where this is connected? >
Larry Robertie
> Cheeky Monkey
> Cheeky Monkey
Larry,
This question is a lot more complicated than it
looks on the surface.
But the Simple (?) answer is..
Connect it to the SHORTEST lead to "Earth
Ground" as possible. Less than 10 feet if possible.
So how do you make an Earth Ground on a boat
? Not easy.
Again, the Simplest (?) answer is to connect it
to the largest metal object that's
NOT insulated from the
Water.
What the idea is , to make sure the Pulses of
the Fish Finder (Possibly rich in RF) do not radiate into your Stereo,
TV, VHF or Marine HF radios you may have on board.
Can you tell if the lead is part of a SHIELD
around the Positive and Negative leads ?
Probably so. And that is the coupling to Earth
of spurious RF.
It's all about RF induction, Impedances,, and
all that kind of Smoke and mirror stuff .. :-)
And boy you want to start a Flame
war.. Just get a bunch of Hams and would be engineers started on
this one.. LOL
once or twice I tried to get folks to clarify
terms.. To no avail.
RF Ground, Earth, Common, Ground Plane,
Negative, and Return (ugh, never use that one) Are all different
cats.
UW
Ralph Ahseln
Oblio
Gresham OR
