I'm expecting a brown truck to pull up today and deliver me a brand
new NRD-545. As you know, Mr. Franklin and about 17 of his friends
have departed this locale, never to return. Due to their absence, I
have a great interest in proper equipment grounding.

Here is my situation. I have two SWL antennae-a 200 foot inverted L,
fed through a transformer which is grounded; and an Alpha Delta sloper
which has it's "down leg" grounded at the same point. Both coaxial
feedlines are fed through a switch with an arc-plug protector, which
is also grounded, but to a different ground rod about 40' from the
first one. FWIW all ground conductors are flat-braid.

My current radio is grounded to the house wiring, which has been
checked and is done properly. I plan to run the 545 from batteries,
though, so this should not be an issue.

Should I tie these grounds together? And then ground the 545 to the
same point? This would result in some rather long ground connections,
but I'm thinking that would protect the radio the most.

Of course, I'm interested in the lowest noise possible, but my main
concern is protecting my new baby.

CaveDweller,

NEC recommends that ALL radios and ALL antennae be grounded to s single
point. The object of the game is that if there is even a milli-mho
difference between one ground used in a system and another, it will result
in a difference in potential (voltage). Yes, it is a pain, but try to bring
all your equipment to one single point.
Do not use your household electrical system ground for your radio grounding.
It's the same cancern, difference in potential. One time I did that
andactually measured a couple volts difference BETWEEN THE HOUSE GROUND AND
THE EARTH GROUND!
Also wind a "drip loop" to all lead in wires (coax etc). All you need is a
couple turns to make a coil that will introduce a little inductance in the
line which will discourage lightning more than a sraight line...and maybe
your slight inductance (which at millions of volts will become a sizeable
resistance) will convince the lightning to travel to ground using YOUR
NEIGHBORS TV ANTENNA WIRE instead- HI
Good luck.

Vern Weiss W9STB
Minocqua, WI

"CaveDweller" wrote in message
om...
I'm expecting a brown truck to pull up today and deliver me a brand
new NRD-545. As you know, Mr. Franklin and about 17 of his friends
have departed this locale, never to return. Due to their absence, I
have a great interest in proper equipment grounding.

Here is my situation. I have two SWL antennae-a 200 foot inverted L,
fed through a transformer which is grounded; and an Alpha Delta sloper
which has it's "down leg" grounded at the same point. Both coaxial
feedlines are fed through a switch with an arc-plug protector, which
is also grounded, but to a different ground rod about 40' from the
first one. FWIW all ground conductors are flat-braid.

My current radio is grounded to the house wiring, which has been
checked and is done properly. I plan to run the 545 from batteries,
though, so this should not be an issue.

Should I tie these grounds together? And then ground the 545 to the
same point? This would result in some rather long ground connections,
but I'm thinking that would protect the radio the most.

Of course, I'm interested in the lowest noise possible, but my main
concern is protecting my new baby.

"CaveDweller" wrote
Here is my situation. I have two SWL antennae-a 200 foot inverted L,
fed through a transformer which is grounded; and an Alpha Delta sloper
which has it's "down leg" grounded at the same point. Both coaxial
feedlines are fed through a switch with an arc-plug protector, which
is also grounded, but to a different ground rod about 40' from the
first one. FWIW all ground conductors are flat-braid.

My current radio is grounded to the house wiring, which has been
checked and is done properly. I plan to run the 545 from batteries,
though, so this should not be an issue.

Should I tie these grounds together? And then ground the 545 to the
same point? This would result in some rather long ground connections,
but I'm thinking that would protect the radio the most.

Of course, I'm interested in the lowest noise possible, but my main
concern is protecting my new baby.

Hi, I saw "Smokey"'s reply here also, and that was very good advice. But a
couple of comments might reinforce his points:

1. There is no "in between" in lightning protection. It's all or nothing,
all the time. Don't be discouraged or intimidated from learning the methods
and materials required for the job, but after the research that applies to
your requirements, don't do anything half-way if you decide to go with the
protection scheme. You could completely isolate and protect by disconnecting
*everything*, or you could completely protect and never disconnect. Anywhere
in between can create very dangerous situations for your equipment, your
home, and yourself.

2. Braid is a lousy RF ground, and an even more useless bonding conductor
for lightning protection. When it's tinned it is better, but still a bad
choice. Replace all your braid with either #2 or #4 solid copper wire
(outdoor bonding) or 3" (minimum) heavy gage copper strapping (indoor
bonding).

3. Following the protection scheme, if the radio will remain connected to AC
power (that includes DC connection to a power supply that is AC-connected),
then the best bonding connection possible from your station's single point
ground to the home's AC entrance panel ground rod is critical.

You can begin your research with less than an hour's read at my website, and
then write me in the group or by email if you have any questions.
http://members.cox.net/pc-usa/station/grounding.htm

Good luck,

Jack Painter
Virginia Beach VA

Thanks, Jack and Smokey, for the tremendous information. Jack, had I
been able to find you website I never would have needed to post the
question....it's very helpful.

Consider me well grounded (well, at least soon...if it ever stops
raining)

"Jack Painter" wrote in message news:tif6d.5749$%t3.78@lakeread01...
"CaveDweller" wrote
Here is my situation. I have two SWL antennae-a 200 foot inverted L,
fed through a transformer which is grounded; and an Alpha Delta sloper
which has it's "down leg" grounded at the same point. Both coaxial
feedlines are fed through a switch with an arc-plug protector, which
is also grounded, but to a different ground rod about 40' from the
first one. FWIW all ground conductors are flat-braid.

My current radio is grounded to the house wiring, which has been
checked and is done properly. I plan to run the 545 from batteries,
though, so this should not be an issue.

Should I tie these grounds together? And then ground the 545 to the
same point? This would result in some rather long ground connections,
but I'm thinking that would protect the radio the most.

Of course, I'm interested in the lowest noise possible, but my main
concern is protecting my new baby.

Hi, I saw "Smokey"'s reply here also, and that was very good advice. But a
couple of comments might reinforce his points:

1. There is no "in between" in lightning protection. It's all or nothing,
all the time. Don't be discouraged or intimidated from learning the methods
and materials required for the job, but after the research that applies to
your requirements, don't do anything half-way if you decide to go with the
protection scheme. You could completely isolate and protect by disconnecting
*everything*, or you could completely protect and never disconnect. Anywhere
in between can create very dangerous situations for your equipment, your
home, and yourself.

2. Braid is a lousy RF ground, and an even more useless bonding conductor
for lightning protection. When it's tinned it is better, but still a bad
choice. Replace all your braid with either #2 or #4 solid copper wire
(outdoor bonding) or 3" (minimum) heavy gage copper strapping (indoor
bonding).

3. Following the protection scheme, if the radio will remain connected to AC
power (that includes DC connection to a power supply that is AC-connected),
then the best bonding connection possible from your station's single point
ground to the home's AC entrance panel ground rod is critical.

You can begin your research with less than an hour's read at my website, and
then write me in the group or by email if you have any questions.
http://members.cox.net/pc-usa/station/grounding.htm

Good luck,

Jack Painter
Virginia Beach VA

CaveDweller wrote:

I'm expecting a brown truck to pull up today and deliver me a brand
new NRD-545. As you know, Mr. Franklin and about 17 of his friends
have departed this locale, never to return. Due to their absence, I
have a great interest in proper equipment grounding.

Here is my situation. I have two SWL antennae-a 200 foot inverted L,
fed through a transformer which is grounded; and an Alpha Delta sloper
which has it's "down leg" grounded at the same point. Both coaxial
feedlines are fed through a switch with an arc-plug protector, which
is also grounded, but to a different ground rod about 40' from the
first one. FWIW all ground conductors are flat-braid.

My current radio is grounded to the house wiring, which has been
checked and is done properly. I plan to run the 545 from batteries,
though, so this should not be an issue.

Should I tie these grounds together? And then ground the 545 to the
same point? This would result in some rather long ground connections,
but I'm thinking that would protect the radio the most.

Of course, I'm interested in the lowest noise possible, but my main
concern is protecting my new baby.


A ground won't protect your radio. Someone once said that your radio is
just a very very expensive fuse serving to protect the three dollar
ground wire.

The main purpose of a signal ground to your radio is enhanced
performance. The tuning circuitry performs a lot better with a signal
ground.

Now, a safety, or electrical ground, is there to protect YOU. Should a
component inside the radio short to the case, the ground will assure a
tripped breaker or blown fuse so that the case isn't unknowingly
energized. This ground doesn't do much to protect the radio either.


Your best protection is a completely separate lighting arrester with
it's OWN ground setup. Disconnecting the antenna during thunderstorm
activity is most likely the most important single thing you can do. a
diode or two aimed from the antenna to ground will protect against
static zapping your radio's front end.

An old bit of advice consists of tying a knot in the power cord going
into the set. The theory being that any huge sudden influx of current
will automatically choke itself off due to a Lenz's law effect...

http://www.physics.ncsu.edu:8380/cou.../lenzslaw.html

I've never had the good fortune of being hit directly by lightning, so I
can't vouch for the efficacy (ten dollar word) of the proposal. It can't
hurt, though...



mike

CaveDweller wrote:

Of course, I'm interested in the lowest noise possible, but my main
concern is protecting my new baby.


This is a nice, simple solution. I had to go back in time to find it for
you.


http://www.gutenberg.net/cdproject/c...ah/fig006c.png


mike




--
__ __ __ __ __ __ __ __
/ /\ / /\ / /\ / /\ / /\ / /\ / /\ / /
/ /\ \/ /\ \/ /\ \/ /
/_/ \/_/ \/_/ \/_/ \/_/ \/_/ \/_/ \/_/

..let the cat out to reply..

©Densa International
'Think tanks cleaned cheap'

"m II" wrote
CaveDweller wrote:

Of course, I'm interested in the lowest noise possible, but my main
concern is protecting my new baby.


This is a nice, simple solution. I had to go back in time to find it for
you.


http://www.gutenberg.net/cdproject/c...ah/fig006c.png


mike


NO!

That drawing, taken on it's own, will allow a nearby strike to blow your
radio into pieces so fine you can clean up with a duster. Why? Becasue the
electric power ground (house entrance), and cold water ground (a different
entrance than AC service 99% of the time), and that phony knife-switch
"protector" ground rod, are all at different locations and will have
*enormous* electrical potential between them . Saturated ground from a
lightning strike anywhere nearby will cause races of destructive energy
betweeen all those points, and your radio will be that expensive fuse Mike
mentioned. That is one more drawing of a dozen I have collected of
terrible, mistaken beliefs that isolating "one part" (ie: antenna) can allow
you to make careless errors in other areas. You can't make even one mistake
with lightning! That cold water ground would have to be disconnected, the AC
power disconnected, and that knife switch would have to have isolation over
a FOOT apart to be even remotely safe.

*Or*, if you guys will take the time to read what bonding is all about, all
those systems could have been bonded, a good coax arrestor used instead of
that deadly knife-switch, the coax shield grounded to the rod before it
reached the arrestor, and *then* all you would have to disconnect is the AC
power. Only proper interior surge suppression can allow the safe connection
of AC power to equipment, and that's after all other lightning protection
measures have been taken. So scrap the "here's a simple old idea", and "tie
some granny knots in the cords for good luck" stuff guys. They don't work.

Jack

Jack Painter wrote:
"m II" wrote

CaveDweller wrote:


Of course, I'm interested in the lowest noise possible, but my main
concern is protecting my new baby.


This is a nice, simple solution. I had to go back in time to find it for
you.


http://www.gutenberg.net/cdproject/c...ah/fig006c.png


mike



NO!

That drawing, taken on it's own, will allow a nearby strike to blow your
radio into pieces so fine you can clean up with a duster. Why? Becasue the
electric power ground (house entrance), and cold water ground (a different
entrance than AC service 99% of the time), and that phony knife-switch
"protector" ground rod, are all at different locations and will have
*enormous* electrical potential between them .


I disagree. A big knife switch will have a few INCHES of air gap between
the common and the radio feed. At roughly 20K volts per inch needed to
jump the gap to the disconnected radio, any few volt difference between
grounding potentials is immaterial.

Check the diagram. The radio is **never** connected to the ground rod.
It's only meant to discharge antenna static to ground

Also, this switch is an ISOLATING switch and not meant in any case to
supplant a proper lightning protection set up.


A metal cold water line coming into the house is the PREFERRED code
ground for the house (system) wiring. An artificial electrode like a
ground rod/plate may be used if plastic line is coming in for the water,
but NOT if metal water line is available.

To make you even more paranoid, the electrical code, at least here, says
the ground rod/pipe may NOT have a resistance greater than TEN ohms
between it and ground. Up to ten ohms is code acceptable.

That means on a nominal 120 volt residential circuit, a fault current of
up to TWELVE amps may be flowing at all times and not even trip the
breaker.



mike


--
__ __ __ __ __ __ __ __
/ /\ / /\ / /\ / /\ / /\ / /\ / /\ / /
/ /\ \/ /\ \/ /\ \/ /
/_/ \/_/ \/_/ \/_/ \/_/ \/_/ \/_/ \/_/

..let the cat out to reply..

©Densa International
'Think tanks cleaned cheap'

From: (CaveDweller)
Organization: http://groups.google.com
Newsgroups: rec.radio.shortwave
Date: 28 Sep 2004 04:19:44 -0700
Subject: Another Grounding Question

I'm expecting a brown truck to pull up today and deliver me a brand
new NRD-545. As you know, Mr. Franklin and about 17 of his friends
have departed this locale, never to return. Due to their absence, I
have a great interest in proper equipment grounding.


(Snip)

Please let us know how you like the 545! Good info from Smokey and Jack -
Thanks!

Greg
NRD-525

"m II" wrote
Jack Painter wrote:
"m II" wrote
CaveDweller wrote:

Of course, I'm interested in the lowest noise possible, but my main
concern is protecting my new baby.

This is a nice, simple solution. I had to go back in time to find it for
you.

http://www.gutenberg.net/cdproject/c...ah/fig006c.png

mike

NO!

That drawing, taken on it's own, will allow a nearby strike to blow your
radio into pieces so fine you can clean up with a duster. Why? Becasue
the
electric power ground (house entrance), and cold water ground (a
different
entrance than AC service 99% of the time), and that phony knife-switch
"protector" ground rod, are all at different locations and will have
*enormous* electrical potential between them .


I disagree. A big knife switch will have a few INCHES of air gap between
the common and the radio feed. At roughly 20K volts per inch needed to
jump the gap to the disconnected radio, any few volt difference between
grounding potentials is immaterial.

Check the diagram. The radio is **never** connected to the ground rod.
It's only meant to discharge antenna static to ground

Also, this switch is an ISOLATING switch and not meant in any case to
supplant a proper lightning protection set up.


A metal cold water line coming into the house is the PREFERRED code
ground for the house (system) wiring. An artificial electrode like a
ground rod/plate may be used if plastic line is coming in for the water,
but NOT if metal water line is available.

To make you even more paranoid, the electrical code, at least here, says
the ground rod/pipe may NOT have a resistance greater than TEN ohms
between it and ground. Up to ten ohms is code acceptable.

That means on a nominal 120 volt residential circuit, a fault current of
up to TWELVE amps may be flowing at all times and not even trip the
breaker.

mike


Hi Mike,

You are very confused about this, and I will try to correct your
misunderstandings.

1. The dwg at
http://www.gutenberg.net/cdproject/c...ah/fig006c.png allows a
path for lightning to the radio at all times, whether the radio is connected
to AC at the time or not. I warned readers that such simple fixes were
dangerous and improper, specifically because such dwgs do not show or
explain that there is a connection via the knife-switch ground, AC ground
and that cold water ground that could have disasterous effects in the event
of a nearby strike. It's also clear that you don't understand how those
paths exist, but presumably you are in this discussion to learn something.

2. Cold water line is not authorized as AC service entrance ground, and a
second ground may never be made to it under any circumstances without
bonding of all systems. Older homes that used cold water ground remain legal
unless modified or upgraded to comply with current code.

But....
When a homeowner connects an external antenna to a radio inside the home,
many electrical principals, code requirements and lightning protection
issues come into play that were not a concern beforehand. When you are
dealing with 100Mv potential from cloud to ground, it is totally immaterial
what you think you know about 20Kv potentials. Now, DC resistance of a
system is almost meaningless, and the inductive effects prevail. Separation
of unbonded systems should be a minumum of 3 feet, not fractions of an inch
as would suffice for 120/240v fault protection. Most lighning protection
designs account for the most probable condition of indirect nearby strikes,
in which the ground will raise from 0v to several hundred thousand volts.
Every part of a home and station's connection to ground will be connected to
part of this potential, and the differential voltages across unbonded
systems are absolutely explosive in such cases.

You were not exposed to such risk before you strung up or erected antennas
in the air and made grounding connections at different places such as your
RF radio ground, outside antenna ground, coax shield at the radio case, and
AC ground from the radio case to your home wiring. When you add a cold water
ground to the mix you increase the potential for damage even more. This is
why electrical bonding of all systems is so critical, and that bonding must
be of extremely low impedance (not just DC resistance!) to maintain the
lowest possible potential between all parts of the grounding system.

You did make one comment that was accurate, and that was the importance of
disconnecting the system to protect it. For the most basic kinds of hobby
listening, tossing the antenna feedline out the window and unplugging the
radio long before a thunderstorm arrives will be suffcient. But making any
kind of ground connection (be it cold water, under-house, external RF
ground, etc) let the user beware! They must disconnect all connections that
are not a permanent, bonded connections designed to withstand the extremely
high potentials from nearby lightning strikes.

The earth is the final destination of all lightning, and all lightning
rasies earth-ground potential to voltages no home wiring was designed or is
capable of handling. Bonding is what prevents our systems from having to
carry current that would violently and completely destroy it. Current only
flows when differences of potential (voltage) occur. Is this making things
a little clearer?

Best regards,

Jack