Hello:

The more I read up on this subject, the more confused I get.
Have some pretty basic questions on lightning protectors, if anyone has a
spare minute or two.
Would sure apprerciate any clarifications on the following points which I am
really confused on.

Will be putting up a simple receive only antenna once it warms up a bit
around here; probably a simple Inverted-L type, most likely the PAR EFL-SWL

Have been thinking about incorporating a lightning arrestor into the antenna
system Again, this is a receive only application.

The vertical leg of the antenna will terminate in the PAR Balun, which will
be pretty close to ground level. I will have a ground bar at that point to
which
the Balun ground(s) will be connected.

From the Balun to the radio will be coax.

Looking at the Polyphaser in line coax unit (dc blocked), and also the ICE
300 series units.

Questions:

a. For either unit, is the arrestor placed between the Balun and the
antenna, or between the Balun and the radio ? Why ?

b. The Polyphaser unit apparently, when triggered, shunts the charge (only)
to the coax shield. The only path to ground would then be up to the radio,
thru the
chassis, and then to the AC power ground.

Or, I guess, possibly back the other way via the Balun's ground ? Or both ?
I would also image that the Balun's windings would probably blow too quickly
to truly shunt any pulse to its ground ?

There doesn't seem to be any separate ground lug, like the ICE units
have from their pictures.

I'm a real novice with this lightning protection stuff, so I am
probably missing something, particularly with the Polyphaser
shunting-to-the-shield-only approach which
doesn't seem too great regarding how an adequate RF ground is reached for
any
diverted strike/pulse.

What am I missing or not considering with the Polyphaser approach ?
Thoughts on ?

c. Any opinions on the Polyphaser vs. the ICE units for a receiving only
application ?

Much thanks,
Bob

"Robert11" bravely wrote to "All" (16 Jan 06 11:58:01)
--- on the heady topic of "Lightning Arrestor Questions"


A wire antenna will be instantly vaporised when directly struck by
lightning so the point is moot: you want to protect the equipment
inside, and the house inhabitants.

Asimov


Ro From: "Robert11"
Ro Xref: core-easynews rec.radio.amateur.antenna:222762

Ro Hello:

Ro The more I read up on this subject, the more confused I get.
Ro Have some pretty basic questions on lightning protectors, if anyone
Ro has a spare minute or two.
Ro Would sure apprerciate any clarifications on the following points
Ro which I am really confused on.
[,,,]

Robert11 wrote:

Hello:

The more I read up on this subject, the more confused I get.

SNIPPED

Questions:

a. For either unit, is the arrestor placed between the Balun and the
antenna, or between the Balun and the radio ? Why ?

First, the comment in another response regarding direct strike is mostly
valid. No arrestor will protect from direct strike. [up to 100,000
amperes in less than 1 microsecond, with a 20,000 volt per meter E field.]

Second, for near strike, the arrestor should be installed depending on
arrestor design. For coax based designs installation should be between
balun and radio. For open wire design it should be installed at the wire
to balun interface. Near strike is a non precise technical term. For
near strike in the 10,000 E field zone the arrestor probably won't
provide the protection you seek. For the 1,000 E field zone you should
get some protection.

Why? When the arrestor ignites, fires, actuates there still is a voltage
across the arrestor. This is the net voltage from the plasma in the
spark gap or in the ionized internal gasses. This net voltage transient
has a power density that extends from BC/MF [160 meters] to the HF/VHF
boundary around 30 MHz. It is a broadband pulse. The question is how
much voltage can the radio be exposed to without damage?


b. The Polyphaser unit apparently, when triggered, shunts the charge (only)
to the coax shield. The only path to ground would then be up to the radio,
thru the
chassis, and then to the AC power ground.

Or, I guess, possibly back the other way via the Balun's ground ? Or both ?
I would also image that the Balun's windings would probably blow too quickly
to truly shunt any pulse to its ground ?

There doesn't seem to be any separate ground lug, like the ICE units
have from their pictures.

I'm a real novice with this lightning protection stuff, so I am
probably missing something, particularly with the Polyphaser
shunting-to-the-shield-only approach which
doesn't seem too great regarding how an adequate RF ground is reached for
any
diverted strike/pulse.

What am I missing or not considering with the Polyphaser approach ?
Thoughts on ?

c. Any opinions on the Polyphaser vs. the ICE units for a receiving only
application ?

Much thanks,
Bob


The best solution is to disconnect the antenna and move it away from the
radio when not in use.!!

I'm a retired Aerospace/Electrical engineer who spent years designing
for lightning strikes both direct and near strikes. My station is 100%
conforming to electrical code and lightning mitigation techniques. Last
July, a near strike lightning pulse caused the ground fault interruptors
for the pool, the bathroom and the kitchen to function. The circuit
breakers in the service panel for the basement power distribution
opened, and the power transformer on the utility pole about 1/2 mile
away exploded. I lost my ICOM 756 ProII which was disconnected from the
power lines, notebook computer, USB damage in a second computer on the
in-house LAN, and one telephone. The ICOM 756 Pro II was disconnected
from the antennas, and the lightning surge protectors did not actuate. A
post fault failure analysis indicated that there was a surge in the
utility power neutral to ground. The entire neighborhood of over 50
homes suffered some degree of damage. It is estimated by the power
utility that the strike was 1/2 mile away.

My ICOM 746, my Kenwood TM-G707, and the numerous power supplies
suffered NO damage. Go Figure :-)

CONCLUSION: Lightning finds way to kill electronics no matter how well
the equipment is installed.

Hi

FYI, seems your email addr here dosn't work, if it's a real one

Dear Amos

i saw your post and hope you wouldn't mind if i asked you a quick
quesiton


Your Icom that was damaged, was unplugged from everything so how did
lightning 'get to it'??

I was kinda distrubed trying to figure it out


V sory to hear of your damage

ml


In article ,
Amos Keag wrote:

Robert11 wrote:

Hello:

The more I read up on this subject, the more confused I get.

SNIPPED

Questions:

a. For either unit, is the arrestor placed between the Balun and the
antenna, or between the Balun and the radio ? Why ?

First, the comment in another response regarding direct strike is mostly
valid. No arrestor will protect from direct strike. [up to 100,000
amperes in less than 1 microsecond, with a 20,000 volt per meter E field.]

Second, for near strike, the arrestor should be installed depending on
arrestor design. For coax based designs installation should be between
balun and radio. For open wire design it should be installed at the wire
to balun interface. Near strike is a non precise technical term. For
near strike in the 10,000 E field zone the arrestor probably won't
provide the protection you seek. For the 1,000 E field zone you should
get some protection.

Why? When the arrestor ignites, fires, actuates there still is a voltage
across the arrestor. This is the net voltage from the plasma in the
spark gap or in the ionized internal gasses. This net voltage transient
has a power density that extends from BC/MF [160 meters] to the HF/VHF
boundary around 30 MHz. It is a broadband pulse. The question is how
much voltage can the radio be exposed to without damage?


b. The Polyphaser unit apparently, when triggered, shunts the charge (only)
to the coax shield. The only path to ground would then be up to the radio,
thru the
chassis, and then to the AC power ground.

Or, I guess, possibly back the other way via the Balun's ground ? Or both ?
I would also image that the Balun's windings would probably blow too quickly
to truly shunt any pulse to its ground ?

There doesn't seem to be any separate ground lug, like the ICE units
have from their pictures.

I'm a real novice with this lightning protection stuff, so I am
probably missing something, particularly with the Polyphaser
shunting-to-the-shield-only approach which
doesn't seem too great regarding how an adequate RF ground is reached for
any
diverted strike/pulse.

What am I missing or not considering with the Polyphaser approach ?
Thoughts on ?

c. Any opinions on the Polyphaser vs. the ICE units for a receiving only
application ?

Much thanks,
Bob


The best solution is to disconnect the antenna and move it away from the
radio when not in use.!!

I'm a retired Aerospace/Electrical engineer who spent years designing
for lightning strikes both direct and near strikes. My station is 100%
conforming to electrical code and lightning mitigation techniques. Last
July, a near strike lightning pulse caused the ground fault interruptors
for the pool, the bathroom and the kitchen to function. The circuit
breakers in the service panel for the basement power distribution
opened, and the power transformer on the utility pole about 1/2 mile
away exploded. I lost my ICOM 756 ProII which was disconnected from the
power lines, notebook computer, USB damage in a second computer on the
in-house LAN, and one telephone. The ICOM 756 Pro II was disconnected
from the antennas, and the lightning surge protectors did not actuate. A
post fault failure analysis indicated that there was a surge in the
utility power neutral to ground. The entire neighborhood of over 50
homes suffered some degree of damage. It is estimated by the power
utility that the strike was 1/2 mile away.

My ICOM 746, my Kenwood TM-G707, and the numerous power supplies
suffered NO damage. Go Figure :-)

CONCLUSION: Lightning finds way to kill electronics no matter how well
the equipment is installed.

"ml" bravely wrote to "All" (18 Jan 06 01:59:16)
--- on the heady topic of "Amoskeag Lightning Arrestor Questions"

ml From: ml
ml Xref: core-easynews rec.radio.amateur.antenna:222810

ml Hi

ml FYI, seems your email addr here dosn't work, if it's a real one

ml Dear Amos

ml i saw your post and hope you wouldn't mind if i asked you a quick
ml quesiton


ml Your Icom that was damaged, was unplugged from everything so how did
ml lightning 'get to it'??

ml I was kinda distrubed trying to figure it out


I'm guessing his radio was most likely damaged from EMP. An
acquaintance had a direct hit on his tower and even his tv's remote
control fried.

A*s*i*m*o*v

ml wrote:

Hi

FYI, seems your email addr here dosn't work, if it's a real one

Dear Amos

i saw your post and hope you wouldn't mind if i asked you a quick
quesiton


Your Icom that was damaged, was unplugged from everything so how did
lightning 'get to it'??

I was kinda distrubed trying to figure it out
\

Ground Loop. Took time to find it though.

The Astron RS-35 power supply connects utility power neutral to the
case. It also connects the 13.8 volt return to the case. [This is
commercial common practice but is prohibited in Military Systems
design.] Although everything on the operating table was isolated from
the utility power and external antennas, everything was connected
together by coax braid, connections to the operating position common
'ground', and the 13.8 volt return.

Remember, this strike caused large area damage. Close to 50 homes
suffered some damage. Several homes took up to 6 weeks to have their
internet functioning again.

The lightning strike tripped all [ALL] ground fault interruptors in the
house. The ground loop in my system connected chassis and power returns
and coax cable together. The weak link were circuit boards in my 756 Pro
II filter and tuner. The boards VAPORIZED. Smoke all over the place.
Pungent smell, etc. That failure protected my IC-746, Kenwood TM-G707,
etc from damage. [Expensive fuse!!]

I wonder if it also protected my swimming pool pump and heater from
damage grin?

On Wed, 18 Jan 2006 08:24:40 -0500, Amos Keag
wrote:

The Astron RS-35 power supply connects utility power neutral to the
case. It also connects the 13.8 volt return to the case. [This is
commercial common practice but is prohibited in Military Systems
design.]

You've tweaked my curiosity what does the military do?

73
Danny, K6MHE




email: k6mheatarrldotnet
http://www.k6mhe.com/

On Wed, 18 Jan 2006 07:18:57 -0800, Dan Richardson wrote:

The Astron RS-35 power supply connects utility power neutral to the
case. It also connects the 13.8 volt return to the case. [This is
commercial common practice but is prohibited in Military Systems
design.]

You've tweaked my curiosity what does the military do?

Hi Dan,

They use ground as a shield, not a current carrier. This is also
suppose to be code for commercial and retail electronics devices.
Connecting the metal cabinet to neutral was supposed to have slipped
into La Brea tarpits with the dinosaurs. Back before polarized plugs,
you could electrocute yourself by guessing wrong, touching the metal
surface and also being grounded. The bridging between toasters and
water taps (or stove tops or fridges) come to mind.

Also common, but nearly as fatal, was the practice of putting two,
series capacitors across the AC line into receivers to cut down on
noise from the lines. They would also take the tap of the two caps
and tie that to the chassis, thus insuring half the line potential was
always on its surface, unless you provided a ground connection. This
was one of those suicide connections where if you were holding the
chassis and pulled the ground lead, you automatically became a fried
line fuse. Members of our hobby have preserved this suicide
connection by grounding their remote antenna (or equipment) through
the coax shield instead of through a separate ground wire (this is why
we have codes).

GFI breakers sense the common mode current (that current that has
escaped the neutral/hot loop) on the shield path (although it is
called a safety ground for 60Hz service).

73's
Richard Clark, KB7QHC

Asimov wrote:
"An acquaintance had a direct hit on his tower and even his tv`s remote
control head."

Did he hear a voice boom from the clouds saying: "Dammit! Missed
again!"?

A good tower ground should mitigate lightning`s fiversion through a TV
remote control. But, I`ve seen stories of "ball lightning" chasing about
inside a house.

Best regards, Richard Harrison, KB5WZI

Robert 11 wrote:
"For either unit is the arrester placed between the Balun and the
antenna, or between the Balun and the radio? Why?

It likely is superflous.

Coax connectors make lightning arrestors of sorts. They clamp voltage to
the arc sustaining voltage (less than 100 volts), once they fire. If you
are transmitting, r-f may keep the arc alive. Broadcast transmitters
sense the arc and shut the transmitter down for an instant to quench the
arc. Communications radios usually don`t bother as their transmissions
are sporadic and usuallly short.

Remember, coax shield is impenetrable to r-f. D-C conducts right
through. R-F does not due to skin effect.

In countless VHF antenna installations atop tall towers around rhe world
we never used a Polyphaser or similar arrestor on the coax, yet never
had damage to radio antenna circuits, even to transistorized radios.

We always used folded driven antenna elements. We grounded the coax at
the top and bottom of the antenna tower. The tower due to its size has
lower surge impedance and carries the bulk of the lightning current to
ground. The tower is well grounded.

We found it necessary to use brute-force pi-filters on every power wire
feeding the radio including the neutral wire. We used tower lighting
chokes in the pi-filters to cary the current required to power the
radios. We shunted the filter inputs and outputs to ground with MOV`s
(across the a-c capacitors).This limited surge voltage on the radio and
on the powerline. It eliminated all damage to the power supplies in the
radios. These filters were found necessary only when transistor radios
were introduced. Before that, the grounded antenna system sufficed for
tube-type radios.

Best regards, Richard Harrison, KB5WZI