Automatic lightning protection for radios, .... an off the wall idea

[Bob McGraw - K4TAX]

Just remember that ALL lightning protection must be accomplished outside
of the house or structure.  Do not think for one minute that one can
provide lightning protection inside the equipment or structure.

Any and all driven ground rods and systems MUST be bonded back to the AC
Mains ground.   This is per NEC.   Many hams violate this rule and
actually create a condition where equipment WILL BE damaged by a near-by
lightning strike.  This occurs by not bonding the station ground to the
AC Mains ground outside of the house. Hence by this not being done,
there are 2 or more ground points with resistance between the points and
the path of current is through ones equipment regardless, if antennas
are grounded, disconnected, and the equipment is turned off.

73

Bob, K4TAX


Message: 4
Date: Sun, 17 Jan 2021 22:33:47 -0500
From: Bill Frantz<[hidden email]>
To: Elecraft Reflector<[hidden email]>
Subject: [Elecraft] Automatic lightning protection for radios, an off
        the wall idea
Message-ID:
        <[hidden email]>
       
Content-Type: text/plain; charset=UTF-8; format=flowed

I've been thinking about some kind of automatic lightning
protection for radios, specifically ones like the K3 and K4. The
idea is that when you turn the radio off, all the things that
are subject to damage are protected by disconnecting them from
the external world and shorting their inputs to ground.

This approach probably wouldn't protect against a direct hit to
one of the wires coming into the radio, which are most likely on
the antenna input and the power from a solar system. But I
understand that the most significant part of the problem is
voltage spikes introduced when the external wires act as
antennas and pick up nearby lightning strikes.

I'm not a hardware engineer, so I'm going to assume that relays
are used in this device. Some of the things I see this device
doing are:

USB connection: Elecraft tells us that blown USB chips are one
of the more common forms of lightning damage in the K3. There
are 4 wires in the USB interface, two of which carry power from
the external world. The relay(s) would float the USB wires and
ground the connections to the internal USB chip. Since power
from the external world is present when the radio is off, we
can't ground the power leads, although we can ground the power
input to the radio's USB chip.

Note that currently a computer attached to the K3 can see its
USB chip, even when the radio is turned off. This change would
mean that the computer would no longer see the radio over USB,
which might have annoying software effects.

A similar thing could happen to the antenna inputs.

Key/Paddle, microphone, headphones, RS232, etc. would be treated
the same way.

The AUXbus would be treated similarly, but anything that can be
turned on via the AUXbus would need special handling.

The 12V power input is needed to turn the radio on with the
power button. I don't know how often radios are damaged through
their 12V power input. This input may not need protection.
Otherwise, the relay that protects power and the switch to the
radio could be the only things powered when the radio is off. If
it can't be protected, it could be made easily field replaceable.

It would be neat if there's enough room inside a K4 to put this
kind of protection "under the covers".

73 Bill AE6JV


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[Bill Frantz]

While serious lightning protection for structures and other
robust things must be done outside the building, I have heard
reports of K3S USB chips being fried from currents induced in
the USB cable attached to the radio, with the suggestion of
disconnecting the cable to protect the chip. I don't see how to
do this disconnect outside the building.

When I consider a direct strike on my shack's lighting rods, I
see massive currents flowing down the thick aluminum cables from
the rods to the grounding system. I see these currents inducing
currents in any wires in the house, including the USB cable. The
lightning rods are the first level of protection, but may not be
enough to protect sensitive electronic equipment. Remember, when
we work on these radios, we have a grounding wrist strap and a
conductive mat on the work surface etc.

73 Bill AE6JV

On 1/18/21 at 11:38 AM, [hidden email] (Bob McGraw) wrote:

>Just remember that ALL lightning protection must be
>accomplished outside of the house or structure.  Do not think
>for one minute that one can provide lightning protection inside
>the equipment or structure.

-----------------------------------------------------------------------
Bill Frantz        | gets() remains as a monument | Periwinkle
[phone]      | to C's continuing support of | 150
Rivermead Rd #235
www.pwpconsult.com | buffer overruns.             |
Peterborough, NH 03458

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[Rich NE1EE-2]

On 2021-01-18 10:38:-0600, Bob McGraw wrote:

>Just remember that ALL lightning protection must be accomplished outside of the house or structure.�  Do not think for one minute that one can provide lightning protection inside the equipment or structure.

...and I just last summer discovered another reason to do this...After I installed my ground grid, the last step was to connect to the house grounds. There were 3 of them, and every one was loose on the ground rod. They all appeared to be regulation listed connectors, but poorly installed. Glad I was there to find that.

~R~
72/73 de Rich NE1EE
The Dusty Key
On the banks of the Piscataqua


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[Bill Frantz]

To add to what I just posted, Wayne just posted a link to a K4
manual that states:

ESD and Lightning Protection: Even though the the K4 has
extensive internal protective circuitry, external protection
against lightning strikes is strongly recommended, especially in
lightning-prone areas. During storms and when the station is not
in use for an extended period, disconnect ALL equipment from the
radio, including antennas, the power supply, routers or hubs,
and computers. Ethernet, USB, and RS232 cables are a frequent
source of damaging surge voltages.

73 Bill AE6JV

-----------------------------------------------------------------------
Bill Frantz        | gets() remains as a monument | Periwinkle
[phone]      | to C's continuing support of | 150
Rivermead Rd #235
www.pwpconsult.com | buffer overruns.             |
Peterborough, NH 03458


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[Jim Brown-10]

On 1/18/2021 9:09 AM, Bill Frantz wrote:
> While serious lightning protection for structures and other robust
> things must be done outside the building, I have heard reports of K3S
> USB chips being fried from currents induced in the USB cable attached to
> the radio, with the suggestion of disconnecting the cable to protect the
> chip. I don't see how to do this disconnect outside the building.

Right. That is the kind of failure that proper grounding and bonding are
able to protect against. It's also the kind of destructive failure that
the use of MOV surge protectors can CAUSE.

> When I consider a direct strike on my shack's lighting rods, I see
> massive currents flowing down the thick aluminum cables from the rods to
> the grounding system. I see these currents inducing currents in any
> wires in the house, including the USB cable. The lightning rods are the
> first level of protection, but may not be enough to protect sensitive
> electronic equipment. Remember, when we work on these radios, we have a
> grounding wrist strap and a conductive mat on the work surface etc.

That's another thing the proper grounding and bonding protect against.
But lightning induces current not only on that external wiring, but also
wiring within the building. IEEE studies show that up to 3kV can be
induced on internal wiring by a strike!

73, Jim K9YC
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[Jim Brown-10]

On 1/18/2021 9:12 AM, Rich NE1EE wrote:
> After I installed my ground grid, the last step was to connect to the house grounds. There were 3 of them, and every one was loose on the ground rod. They all appeared to be regulation listed connectors, but poorly installed. Glad I was there to find that.

Electrical wiring, including grounding, was a mess at the home we bought
in NorCal in 2006. I found multiple mis-wired outlets, including several
in a laundry room/half kitchen fed by phase (hot) and ground from the
240V circuit for the adjacent dryer.

That was in a garage/apartment which now houses my shack; power enters
the house, and is fed to a breaker panel in the second building. The
house had no ground at all -- a #10-#12 (painted) bare copper wiring ran
from the service entrance panel to an outlet for a garden hose, which
was fed by PVC pipe. The ground for the panel in the second building
wandered from the panel up to and through the attic crawl space to the
other side of the building, then run neatly down the outside wall next
to the facings for windows to a ground rod. It was the only ground for
the entire system.

73, Jim K9YC
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[hb9cvq]

Yes, Jim,  but:  "It's also the kind of destructive failure that the use of
MOV surge protectors can CAUSE".

MOV can be used even in AC power applications (50/60Hz) , but only if the
potential thermal run away effect ( drawing more leakage current after
energy absorption/exposure or by aging ) is controlled by a series connected
high impedance (no-fire mode)  spark gap. What is however critical under
non-fire RF conditions (MOV -ZnO has big nF capacitance and is a
semiconductor) is the nonlinear diode effect. This can lead to RF
rectification (harmonics, emission issue)  before the firing level is
reached.

73 Andy HB9CVQ


-----Original Message-----
From: [hidden email] <[hidden email]> On
Behalf Of Jim Brown
Sent: Montag, 18. Januar 2021 19:16
To: [hidden email]
Subject: Re: [Elecraft] Automatic lightning protection for radios, .... an
off the wall idea

On 1/18/2021 9:09 AM, Bill Frantz wrote:
> While serious lightning protection for structures and other robust
> things must be done outside the building, I have heard reports of K3S
> USB chips being fried from currents induced in the USB cable attached
> to the radio, with the suggestion of disconnecting the cable to
> protect the chip. I don't see how to do this disconnect outside the
building.

Right. That is the kind of failure that proper grounding and bonding are
able to protect against. It's also the kind of destructive failure that the
use of MOV surge protectors can CAUSE.

> When I consider a direct strike on my shack's lighting rods, I see
> massive currents flowing down the thick aluminum cables from the rods
> to the grounding system. I see these currents inducing currents in any
> wires in the house, including the USB cable. The lightning rods are
> the first level of protection, but may not be enough to protect
> sensitive electronic equipment. Remember, when we work on these
> radios, we have a grounding wrist strap and a conductive mat on the work
surface etc.

That's another thing the proper grounding and bonding protect against.
But lightning induces current not only on that external wiring, but also
wiring within the building. IEEE studies show that up to 3kV can be induced
on internal wiring by a strike!

73, Jim K9YC
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[Jim Brown-10]

On 1/18/2021 11:53 AM, [hidden email] wrote:
> MOV can be used even in AC power applications (50/60Hz) , but only if the
> potential thermal run away effect ( drawing more leakage current after
> energy absorption/exposure or by aging ) is controlled by a series connected
> high impedance (no-fire mode)  spark gap. What is however critical under
> non-fire RF conditions (MOV -ZnO has big nF capacitance and is a
> semiconductor) is the nonlinear diode effect. This can lead to RF
> rectification (harmonics, emission issue)  before the firing level is
> reached.

There's FAR more to it that these issues. The problems include 1) where
they dump the current when they short out a strike; 2) accumulation of
discharge current over time degrades their performance, causing them to
fail shorted or open; and 3) they can start a fire! When an MOV shorts
the strike to the equipment ground ("green wire") it raises the chassis
potential of connected equipment; when that equipment is connected to
other equipment by "low voltage" wiring (audio or video cables, Ethernet
or other computer cables) to equipment plugged into different outlets
(or even a different MOV device), the potential difference between the
two pieces of gear is likely to fry I/O circuitry.

Many years ago, we in the world of pro audio learned this, with
equipment for large audio (that sometimes included video systems) spread
out over wide areas. As long ago as the '90s, very well-educated EEs
recounted stories of computers in their design offices networked by
wired Ethernet being fried by lightning induced on the Ethernet cables
and computers with MOV surge protectors. No intentional antennas
involved (not hams).

All of this is a great reason for using WiFi rather than wired Ethernet
unless the added latency of WiFi cannot be tolerated (remote operation,
for example). I dumped the use of wired Ethernet a couple of years
before moving from Chicago in 2006. Decent WiFi hardware provides plenty
of bandwidth for my uses, including streaming audio and hi-res streamed
compressed video.

73, Jim K9YC
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[Jim GM]

Did I read this right regulation connector?If the clamps on the ground rod, or water pipe, it is not UL stamped, it's not approved.Jim K9TFSent from my T-Mobile 4G LTE Device
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[Rich NE1EE-2]

On 2021-01-18 20:23:-0600, Jim Borowski wrote:
>Did I read this right regulation connector?If the clamps on the ground rod, or water pipe, it is not UL stamped, it's not approved.Jim K9TFSent from my T-Mobile 4G LTE Device

Unfortunately,
the email footnotes don't include a link to the archive thread, and
there is no context, so I don't know to whom you reply...

but I am part of the thread, so I'll clarify for my part.
the loose connectors are UL listed. Two were loose, and 1 was incorrectly installed. I actually saw a web page that showed //an incorrect installation// as part of a "help page". I sent them a note, but didn't follow up.

Ah! Had not used nabble in the past, and I now see that this is in response to Bob McGraw - K4TAX, but the context is not clear.

~R~
72/73 de Rich NE1EE
The Dusty Key
On the banks of the Piscataqua

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[Elecraft mailing list]

 It's been quite a while since I worked in the biz, but IIRC, UL is a NRTL, "Nationally Recognized Testing Laboratory."  They don't approve devices per se, but rather certify a device passed statutory safety standard testing.  A certification only means samples and manufacturing process passed the specific tests. Other NRTLs can do the same, and there are quite a few. A manufacturer needs to have their products certified by an NRTL if fed, state, or local regulations require it, or customers (often large entities) require it.  At the time I was in the biz, "harmonization" was going on, that was bringing all the disparate standards of various entities into alignment.  IDK what the current situation is.

I'm sure there are more knowledgeable and current guys on this reflector.
    On Tuesday, January 19, 2021, 5:03:58 AM MST, Rich NE1EE <[hidden email]> wrote:  
 
 On 2021-01-18 20:23:-0600, Jim Borowski wrote:
>Did I read this right regulation connector?If the clamps on the ground rod, or water pipe, it is not UL stamped, it's not approved.Jim K9TFSent from my T-Mobile 4G LTE Device

Unfortunately,
the email footnotes don't include a link to the archive thread, and
there is no context, so I don't know to whom you reply...

but I am part of the thread, so I'll clarify for my part.
the loose connectors are UL listed. Two were loose, and 1 was incorrectly installed. I actually saw a web page that showed //an incorrect installation// as part of a "help page". I sent them a note, but didn't follow up.

Ah! Had not used nabble in the past, and I now see that this is in response to Bob McGraw - K4TAX, but the context is not clear.

~R~
72/73 de Rich NE1EE
The Dusty Key
On the banks of the Piscataqua

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[Jim Brown-10]

On 1/19/2021 7:08 AM, Louandzip via Elecraft wrote:
>   there are quite a few.

Last I looked (retired 10 years), there were two in the US, UL and ETL,
and CSA in Canada. There were reciprocal agreements between UL and CSA,
and UL, CSA, and ETL were recognized in the US. That's not "quite a
few," unless we include those on other continents.

73, Jim K9YC
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