Date: Wed, 20 Jun 2007 11:07:01 -0700
Reply-To: Jack <john.cook58@VERIZON.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Jack <john.cook58@VERIZON.NET>
Subject: Re: Grounds (was Quality Inverters) NVC
In-Reply-To: <675765.25616.qm@web82713.mail.mud.yahoo.com>
Content-type: text/plain; charset=US-ASCII
Well, when you're speaking of RF antennas, then the "ground" should really be
known as the "counterpois" whether it's the actual earth, as with a long-wire
antenna, or as the Vanagon's body or as the radials common to VHF vertical
antennas.
This isn't to say that a transmitter or all the station electronics shouldn't
be grounded when you have that option - I've used a copper-steel rod driven
into the earth outside the window for that purpose regardless of what antenna
or transmission line is in use. But this is getting into a technical field too
far removed from Vanagons. Not to mention that my RF background is gradually
slipping away from disuse.
//Jack
W6SGA
Date sent: Tue, 19 Jun 2007 23:31:57 -0700
From: David Kao <dtkao0205@YAHOO.COM>
Subject: Re: Grounds (was Quality Inverters)
To: vanagon@GERRY.VANAGON.COM
Send reply to: David Kao <dtkao0205@YAHOO.COM>
> To me ground means ground (the earth). When I hang a long wire (antenna) for
> my HF transceiver the ground has to be physically connected to ground. If
> not
> I won't receive signal from far away or my signal won't reach too far. But
> you sure can fake it. For example when I set up a CB antenna on my westy The
> Westy chassis is no problem as a good ground for the antenna.
>
> Maybe this is just a different ground that has nothing to do with the ground
> you guys are talking about. Never mind. I don't want to steal the thread.
>
> David
>
>
> --- Jack <john.cook58@VERIZON.NET> wrote:
>
> > Not directly related to inverters but perhaps of some interest.
> >
> > A pet peeve of mine regards the word, "Ground". As used in electricity
> and
> > electronics, the word is an unfortunate historical artifact which, in my
> humble
> > opinion, should be removed from use, since it's too often misunderstood.
> It
> > implies some magic iso-potential conductor connected to earth which rarely
> > exists outside of a text book. Given common conditions such as high fault
> > currents, fast rise/fall surges (e.g., sparks), that "ground" is anything
> but
> > iso-potential. This misunderstanding can lead to serious problems, even
> from
> > designers who should know better. (This isn't even beginning to deal with
> high
> > speed digital circuitry, analog instrumentation, A/D, D/A and RF systems.)
> >
> > Much better to use the words, frame, shell, chassis, shield, common, 3rd
> wire,
> > green wire, etc. Those more descriptive terms provide better understandings
> of
> > what the conductor is and (sometimes) what its purpose is. In large
> system
> > schematics, we might see the identifiers, frame-1, frame-2, frame-3,
> shield-1,
> > etc., even though the connections may be tied together somewhere.
> >
> > Sorry to rant. And sorry if the above makes little sense to you. You have
> to
> > have been there.
> >
> > //Jack
> >
>
>
>
>
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