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Re: [RFI] A quick Question about CMC placement

To: Jim Brown <jim@audiosystemsgroup.com>
Subject: Re: [RFI] A quick Question about CMC placement
From: David Eckhardt <davearea51a@gmail.com>
Date: Mon, 28 Jun 2021 11:45:36 -0600
List-post: <mailto:rfi@contesting.com>
There is no true "ground" for RF fields.  Only returns.  The space station
doesn't require a "ground" for comms to/from earth stations.  The Crab
Nebula does not require a "ground" to fill deep space with copious amounts
of RF energy.   I disagree with your statement:  " That indicates a problem
with grounding and bonding ".

There is absolutely no way I could establish an adequate "ground" in my
decaying upper Permian / lower Triassic mudstone.  And, what's more, I do
NOT have "RF in the Shack".  Any good installation should have a lot of RF
in the shack if the antenna is operating as intended, just not experiencing
RF 'bites'.

Dave - WØLEV

On Mon, Jun 28, 2021 at 11:15 AM Jim Brown <jim@audiosystemsgroup.com>
wrote:

> On 6/28/2021 9:40 AM, David Eckhardt wrote:
> > and the second at the shack end of the coaxial transmission line.
> >
> > They are also good for keeping local RFI from the receiver.  I recently
> ran
> > another test without / with the CMC only in the shack at the end of the
> > feedline.  This time I chose 20-meters as my 450-foot long doublet just
> > happenes to show less than 2:1 SWR on that band so I don't have to invoke
> > the L-Network for a match.  I measured 9.6 dB less white noise (no
> > suggestion of 60 Hz or harmonics) with far more signals on the waterfall
> > with the CMC than without on the Icom 7300.
>
> That indicates a problem with grounding and bonding.
>
> 73, Jim K9YC
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-- 
*Dave - WØLEV*
*Just Let Darwin Work*
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