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Old December 31st 05, 03:16 PM posted to rec.radio.amateur.antenna
jawod
 
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Default 2nd Floor grounding

After reading the archive regarding 2nd floor grounding, a couple of
questions.

Outside of sufficiently thick gauge wire and proper depth to grounding
rod. Are there any ELECTRICAL (nonRF) issues left to resolve for a 2nd
floor ground?

Several articles referred to long grounding lines being close to 1/4
wavelength as being a problem. Is this eliminated with balanced feedline?

Thanks,

john
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Old December 31st 05, 03:51 PM posted to rec.radio.amateur.antenna
Bill Turner
 
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Default 2nd Floor grounding


ORIGINAL MESSAGE:

On Sat, 31 Dec 2005 10:16:19 -0500, jawod wrote:

Several articles referred to long grounding lines being close to 1/4
wavelength as being a problem. Is this eliminated with balanced feedline?

Thanks,

john



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

No. You can not "ground" your station for RF, at least not in the
sense of running a wire to ground. Don't bother because it isn't
necessary anyway. You do need two kinds of ground, one for the AC
mains for safety, and one for lightning.

RF energy is expensive to generate. Don't waste it by running part of
it into a lossy "ground". Keep it up in the air where it belongs.
Baluns are your friend.

73, Bill W6WRT
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Old December 31st 05, 04:07 PM posted to rec.radio.amateur.antenna
Amos Keag
 
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Default 2nd Floor grounding

jawod wrote:
After reading the archive regarding 2nd floor grounding, a couple of
questions.

Outside of sufficiently thick gauge wire and proper depth to grounding
rod. Are there any ELECTRICAL (nonRF) issues left to resolve for a 2nd
floor ground?

Several articles referred to long grounding lines being close to 1/4
wavelength as being a problem. Is this eliminated with balanced feedline?

SNIPPED


NO NO NO !!!

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Old December 31st 05, 05:14 PM posted to rec.radio.amateur.antenna
Amos Keag
 
Posts: n/a
Default 2nd Floor grounding

jawod wrote:
After reading the archive regarding 2nd floor grounding, a couple of
questions.

Outside of sufficiently thick gauge wire and proper depth to grounding
rod. Are there any ELECTRICAL (nonRF) issues left to resolve for a 2nd
floor ground?

Several articles referred to long grounding lines being close to 1/4
wavelength as being a problem. Is this eliminated with balanced feedline?

Thanks,

john


1) Make sure you have a good connection from equipment cases to AC Power
main ground/earth. I use a 1/2 inch copper pipe on the table where my
station is mounted. Each piece of equipment on the table, transceivers,
amplifiers, power supplies, computer, are individually bonded to this
copper pipe. This 1/2 inch copper pipe is then connected to earth ground
by a #6 AWG wire run directly to the electrical service panel where it
is connected to the earth connection.

2) If you use a 1/4 wavelength, or equivalent, vertical antenna you need
a counterpoise, often called 'ground', at the base of the antenna.

3) A balanced feedline is used for a balanced antenna, e.g. dipole etc.,
to minimize RF coupling to the transmission line. The balanced line
needs to run away from the antenna for a minimum of 1/4 wavelength at
right angles to be effective. A dipole fed with coax cable needs a balun
to produce a balanced signal to the antenna. The coax should also run
away from the antenna at right angles for 1/4 wavelength to be effective
in minimizin current on the coax. If you need to run from the antenna at
less than 1/4 wavelength then a series of chokes or ferrites should be
used to keep RF out of the house. These chokes/ferrites should be
mounted at least 1/4 wavelength from the antenna.

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Old December 31st 05, 05:54 PM posted to rec.radio.amateur.antenna
Roy Lewallen
 
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Default 2nd Floor grounding

Amos Keag wrote:
. . .
3) A balanced feedline is used for a balanced antenna, e.g. dipole etc.,
to minimize RF coupling to the transmission line. The balanced line
needs to run away from the antenna for a minimum of 1/4 wavelength at
right angles to be effective. A dipole fed with coax cable needs a balun
to produce a balanced signal to the antenna. The coax should also run
away from the antenna at right angles for 1/4 wavelength to be effective
in minimizin current on the coax. If you need to run from the antenna at
less than 1/4 wavelength then a series of chokes or ferrites should be
used to keep RF out of the house. These chokes/ferrites should be
mounted at least 1/4 wavelength from the antenna.


A symmetrical feedline is no guarantee of balance. Balance is achieved
only when the two conductors carry equal and opposite currents, and that
can be achieved with either coax or symmetrical feedline. Likewise,
imbalance can occur with either type of feedline. You can learn more
about the issue at http://eznec.com/Amateur/Articles/Baluns.pdf. That
article doesn't mention imbalance caused by coupling to the antenna,
which can occur if a dipole isn't symmetrical or if either type of
feedline is asymmetrically placed relative to the antenna.

Roy Lewallen, W7EL




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Old December 31st 05, 09:16 PM posted to rec.radio.amateur.antenna
Bill Turner
 
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Default 2nd Floor grounding


ORIGINAL MESSAGE:

On Sat, 31 Dec 2005 12:14:38 -0500, Amos Keag
wrote:

The balanced line
needs to run away from the antenna for a minimum of 1/4 wavelength at
right angles to be effective.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Nonsense.

An unbalanced antenna and/or feedline can be VERY effective. Hams have
used them since the days of spark. All the unbalance does is change
the antenna pattern, not the effectiveness. It will be better in some
directions, worse in others.

73, Bill W6WRT
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Old December 31st 05, 09:16 PM posted to rec.radio.amateur.antenna
Bill Turner
 
Posts: n/a
Default 2nd Floor grounding


ORIGINAL MESSAGE:

On Sat, 31 Dec 2005 12:14:38 -0500, Amos Keag
wrote:

1) Make sure you have a good connection from equipment cases to AC Power
main ground/earth. I use a 1/2 inch copper pipe on the table where my
station is mounted. Each piece of equipment on the table, transceivers,
amplifiers, power supplies, computer, are individually bonded to this
copper pipe. This 1/2 inch copper pipe is then connected to earth ground
by a #6 AWG wire run directly to the electrical service panel where it
is connected to the earth connection.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Why?

73, Bill W6WRT
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Old January 1st 06, 08:10 PM posted to rec.radio.amateur.antenna
west
 
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Default 2nd Floor grounding


"Bill Turner" wrote in message
...

ORIGINAL MESSAGE:

On Sat, 31 Dec 2005 10:16:19 -0500, jawod wrote:

Several articles referred to long grounding lines being close to 1/4
wavelength as being a problem. Is this eliminated with balanced

feedline?

Thanks,

john



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

No. You can not "ground" your station for RF, at least not in the
sense of running a wire to ground. Don't bother because it isn't
necessary anyway. You do need two kinds of ground, one for the AC
mains for safety, and one for lightning.

RF energy is expensive to generate. Don't waste it by running part of
it into a lossy "ground". Keep it up in the air where it belongs.
Baluns are your friend.

73, Bill W6WRT


Bill,

I like your answer but it leaves me to want a bit more. Would you mind
expanding on your 2 paragraphs? Thanks.

west
AF4GC


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Old January 1st 06, 10:44 PM posted to rec.radio.amateur.antenna
Bill Turner
 
Posts: n/a
Default 2nd Floor grounding


ORIGINAL MESSAGE:

On Sun, 01 Jan 2006 20:10:08 GMT, "west"
wrote:


"Bill Turner" wrote in message
.. .

ORIGINAL MESSAGE:

On Sat, 31 Dec 2005 10:16:19 -0500, jawod wrote:

Several articles referred to long grounding lines being close to 1/4
wavelength as being a problem. Is this eliminated with balanced

feedline?

Thanks,

john



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

No. You can not "ground" your station for RF, at least not in the
sense of running a wire to ground. Don't bother because it isn't
necessary anyway. You do need two kinds of ground, one for the AC
mains for safety, and one for lightning.

RF energy is expensive to generate. Don't waste it by running part of
it into a lossy "ground". Keep it up in the air where it belongs.
Baluns are your friend.

73, Bill W6WRT


Bill,

I like your answer but it leaves me to want a bit more. Would you mind
expanding on your 2 paragraphs? Thanks.

west
AF4GC



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

OK.

1. Running a wire from your rig to ground will not do what you think
it will. Any wire is a significant portion of a wavelength at HF and
may be many wavelengths at VHF and UHF. On ten meters, for example,
eight feet is almost exactly 1/4 wavelegth. If you recall your basic
transmission line theory, whatever condition is present at one end of
a 1/4 wave line has just the opposite at the other end. If you really
do have a good ground connection at the grounded end of the wire, the
other is an open circuit. Not very effective for grounding, is it?

The effect becomes less as you lower the frequency, but never
completely disappears. It is possible to tune out this effect with a
suitable coil and capacitor combination, but it really isn't needed
anyway. MFJ makes a "ground tuner" or whatever they call it, and I
suppose it does work, but think about this: If getting a good RF
ground actually improves your signal, you have a SERIOUS problem in
your antenna. More on this in the next paragraph.

2. RF does no good flowing through the earth. None at all. Dirt is a
poor conductor at any ham frequency and you should do your best to
keep your RF out of it. I suspect the idea that "ground" helps your
signal came from the very early days of radio when frequencies were
very low and wavelenghts were very long... miles long in fact. At
those frequencies there are two factors which might make use of ground
desireable: The earth is much more conductive at very low frequencies,
and miles of wire for an antenna is not easily done. Under those
circumstances, working a long wire against ground might actually be a
good idea. None of that applies to ham frequencies, of course. At ham
frequencies, RF works best when it's up in the air, all of it. Not in
the ground, not in your shack, up in the air.

Keep that in mind and you can't go wrong.

73, Bill W6WRT
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Old January 2nd 06, 12:17 AM posted to rec.radio.amateur.antenna
Dan Andersson
 
Posts: n/a
Default 2nd Floor grounding

jawod wrote:

After reading the archive regarding 2nd floor grounding, a couple of
questions.

Outside of sufficiently thick gauge wire and proper depth to grounding
rod. Are there any ELECTRICAL (nonRF) issues left to resolve for a 2nd
floor ground?

Several articles referred to long grounding lines being close to 1/4
wavelength as being a problem. Is this eliminated with balanced feedline?

Thanks,

john



Forget about balun's and other widgetry!

Get a virtual earth! They are easy to build for all ham bands!

It's basically a phasing unit for the earth connection which can null the
voltage on the earth at the RF Rig!

If you don't want to build one, MFJ sells one!

Cheers

M0DFI




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