[Icom] Auto Noise in MKIIG

Wed, 15 May 2002 09:34:23 -0700

Ok Larry. I see what you mean. Maybe you should think about making more of
your home brew filters  and make a few dollars yourself. Do you think it
would be worth it?Rick VE7RiK
----- Original Message -----
From: "Larry Benko" <[email protected]>
To: <[email protected]>
Sent: Wednesday, May 15, 2002 9:18 AM
Subject: Re: [Icom] Auto Noise in MKIIG


> Rick,
>
> Generally audio power line filters are either capacitors to
> ground or a series inductor and parallel capacitor.  Their
> primary intent is to stop alternator noise which is less than
> a 100KHz.  As such they may attenuate RF noise but no guarantees.
> "Filter cons" are generally PI(C-L-C) or Tee(L-C-L) filters
> housed in small shielded enclosures with the purpose of
> attenuating RF.  They come in various sizes based on DC current
> rating and the RF frequency that the attenuation is spec'd for.
> I also had fuel pump noise with my 2000 Toyota 4Runner. I found
> a small copper can (~1"x1.5"x1.5") that was open on 1 side.  I
> built the equivalent of 2 "filter cons" of the PI type by
> mounting 1000pF feed-through caps on the ends of the can and
> using inductors made from #43 ferrite material.  The inductors
> were designed to handle >2A DC and the inductance was ~30uH.  The
> can was then filled with RTV and mounted just where the wires came
> out of the gas tank with a <1" connection to chassis (the wires
> need to be cut as the filter goes in series).  My noise was worst
> on 17m and this cleared up the noise completely.
>
> 73,
> Larry Benko, W0QE
>
> Rick Gouge VER7RiK wrote:
> >
> > Doug. Check out car audio power line filters, there small and large.
I`am
> > sure they would do the trick. 73 Rick VE7RiK
> > ----- Original Message -----
> > From: "Davies, Doug A FOR:EX" <[email protected]>
> > To: "'Icom'" <[email protected]>
> > Sent: Wednesday, May 15, 2002 8:40 AM
> > Subject: [Icom] Auto Noise in MKIIG
> >
> > > In researching how to eliminate the fuel pump noise in my pickup, I
find
> > > that the recommended way is to install "filter cons" on each lead
where
> > they
> > > enter the fuel tank.  I finally located a couple of sources for these
but
> > > the price is in the stratosphere, roughy $36.00 US each, which is
about
> > > $100.00 Canadian!! <grin>  Pretty steep and they may not even do the
job.
> > > Does anyone know of a less expensive source for these things or have
some
> > > they would sell for a more reasonable price?
> > >
> > > In the event that I can't find any of these at a reasonable price, has
> > > anyone manufactured a low-pass pi network filter and used it to get
rid of
> > > fuel pump noise?  I'm not beyond doing is myself but I wouldn't know
how
> > to
> > > design one.  Thanks in advance.
> > >
> > > Doug  VA7DD
> > >
> > >
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