Gray Shockley wrote:

On Sun, 28 Sep 2003 0:02:29 -0500, starman wrote
(in message ):

Tim Shoppa wrote:

The RX-320 arrived Thursday, I hooked it up to the PC and got nothing
but hash all over the bands. Then I looked at the ground my AC house
wiring is hooked to (it's about a 40 foot run of wire from the AC
entrance panel to the cold water pipe! Maybe it was technically compliant
with the NEC when the house was built but it wasn't worth crap...) and
decided I had to be able to do better. So I went to Home Depot,
invested about $10 in some 1/2" copper pipe, and drove several 5-foot
lengths near a handy window.

Using this ground makes a world of difference. All the nasty noise
went away. I learned my lesson!

Tim.

Nice work. However it's not a good idea to have more than one ground
point for your domestic wiring. I suggest disconnecting the old copper
pipe ground wire near the circuit panel. You can leave the long wire in
place.

Uh, well, uh, but - you do realize that you're suggesting ungrounding the
entire house, don't you?

By code - if he did that - he should replace every 3-conductor outlet with
two-conductor outlets because the ground (green) has been removed from the
system (illegal as it can be, of course).

He did exactly as he should have.

He maintained the electrical ground ("earth") and he created an "antenna"
ground (chassis).

Gray Shockley

I said he shouldn't have more than one ground point for his domestic
wiring. I was under the impression that he made a shorter grounding
system to the main panel from some new ground rods outside a near by
window. If the circuit breaker panel is grounded with his new rods, he
doesn't need to keep the old 40-ft ground wire to the copper pipe.


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Here's a good link on grounding. The primary focus is lightning, but it's
still good:

http://www.polyphaser.com/ppc_PEN1016.asp


"Tim Shoppa" wrote in message
om...
(Tim Shoppa) wrote in message
. com...
I've got a few PC's in nice metal cases. I can actually run most of my
receivers near the PC without too much problem, as long as the receiver
is
powered by batteries. But the instant I hook my sound card to the
receiver,
or I run the receiver off of AC power, all the SW bands are filled with
S9 hash generated by the computer and network equipment.

The RX-320 arrived Thursday, I hooked it up to the PC and got nothing
but hash all over the bands. Then I looked at the ground my AC house
wiring is hooked to (it's about a 40 foot run of wire from the AC
entrance panel to the cold water pipe! Maybe it was technically compliant
with the NEC when the house was built but it wasn't worth crap...) and
decided I had to be able to do better. So I went to Home Depot,
invested about $10 in some 1/2" copper pipe, and drove several 5-foot
lengths near a handy window.

Using this ground makes a world of difference. All the nasty noise
went away. I learned my lesson!

Tim.

Gray Shockley wrote in message ...
He maintained the electrical ground ("earth") and he created an "antenna"
ground (chassis).

Yeah, that's what I did, and it worked very nicely. But it's also clear
that the ground at the AC entrance panel isn't doing so well itself. I've
got to find the relevant section of the NEC and figure out how I can
both comply with the code *and* put a ground there. I'm 100% sure that what
I did (5 foot copper pipes) for the radio ground isn't compliant for the
AC entrance ground.

Tim.

Tim Shoppa wrote:

Gray Shockley wrote in message ...
He maintained the electrical ground ("earth") and he created an "antenna"
ground (chassis).

Yeah, that's what I did, and it worked very nicely. But it's also clear
that the ground at the AC entrance panel isn't doing so well itself. I've
got to find the relevant section of the NEC and figure out how I can
both comply with the code *and* put a ground there. I'm 100% sure that what
I did (5 foot copper pipes) for the radio ground isn't compliant for the
AC entrance ground.

Tim.

Thanks for clearing that up. After posting my first reply I realized
your new ground rods might only be for the radio. I thought they were
for the AC entrance and domestic wiring. That's why I said you didn't
need two ground systems for the house and could disconnect the old one.
If you try another method for grounding the AC entrance, try using the
radio without it's new ground rod system and let us know if the noise
gets worse or stays the same.


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If you drive two ground stakes in about 20 feet apart and measure the
_AC_ voltage between them, it's typically about a half volt. It's
thousands if lightning hits nearby. (The ambient voltage comes from stray
power line ground differences. The earth levels them out as best it can
but it prefers your electronics when available.)

So you don't want your radio to be part of the path between two grounds in
thunderstorms. Disconnectect from the radio ground when you disconnect
from the antenna, is one approach.
--
Ron Hardin


On the internet, nobody knows you're a jerk.

All ground rods have to be connected together to comply with the NEC.
"Ron Hardin" wrote in message
...
If you drive two ground stakes in about 20 feet apart and measure the
_AC_ voltage between them, it's typically about a half volt. It's
thousands if lightning hits nearby. (The ambient voltage comes from stray
power line ground differences. The earth levels them out as best it can
but it prefers your electronics when available.)

So you don't want your radio to be part of the path between two grounds in
thunderstorms. Disconnectect from the radio ground when you disconnect
from the antenna, is one approach.
--
Ron Hardin


On the internet, nobody knows you're a jerk.

Leave the existing AC panel ground alone! Make sure that you tie your new
ground to the existing power panel ground. Failure to do that can result in
unnecessary damage in the event of a nearby lightning strike because the two
separate grounds could be at vastly different potentials. The damage could
be to your equipment or home. I'm sure your homeowner's insurance company
would not look kindly at your having removed the power panel ground,
resulting in damage to your home.

"Tim Shoppa" wrote in message
om...
Gray Shockley wrote in message
...
He maintained the electrical ground ("earth") and he created an
"antenna"
ground (chassis).

Yeah, that's what I did, and it worked very nicely. But it's also clear
that the ground at the AC entrance panel isn't doing so well itself. I've
got to find the relevant section of the NEC and figure out how I can
both comply with the code *and* put a ground there. I'm 100% sure that
what
I did (5 foot copper pipes) for the radio ground isn't compliant for the
AC entrance ground.

Tim.

"CW" wrote in message .net...
All ground rods have to be connected together to comply with the NEC.

Not only that, but at least the version that's applicable to my locality
says that:

1. The point at which they are connected together must be the AC entrance
panel. They absolutely must never be connected together over the inside-
to-the-house ground wiring (and I think I understand why... you do not
want your house wiring to be carrying a couple thousand amps in case of
a nearby lightning strike).

2. The cold water pipe must also be connected to the AC entrance panel.
I'm a little less clear on why that must be, but it doesn't seem to hurt
anything.

There's a whole litany of what type of ground rod must be used and
what gauge of wire too... I've got more reading to do. I think (but I'm
not sure) that the copper pipes I sank for my experiment are not good enough
for a code-compliant ground because they are both too short (5 feet is
too short) and not copper plated steel. The experiment was still worthwhile
in that it showed how bad the 30-year-old house ground was.

There are some additional rules if a tower is involved but I don't have
a tower so I didn't pay any attention to them.

Tim.