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

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

"Richard Harrison" bravely wrote to "All" (18 Jan 06 12:17:51)
--- on the heady topic of "Amoskeag Lightning Arrestor Questions"

RH From: (Richard Harrison)
RH Xref: core-easynews rec.radio.amateur.antenna:222822

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

There seems to be a problem with the compression. I wrote "remote
control fried." not "head."!


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

RH A good tower ground should mitigate lightning`s fiversion through a TV

What is a "fiversion"... ah "diversion", right! Damn that compressor
is F&^^%$@@**


RH remote control. But, I`ve seen stories of "ball lightning" chasing
RH about inside a house.

That is what he said. Briefly saw a fireball wizz around the room.

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

Dan Richardson wrote:

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

The general no pun intended Military design requirement is the the
equipment cases carry no intentional or credible fault currents.
[Therefore no inadvertant shocks, in MIL STD terminolgy no personnel
RISK, from a hot chassis]. [RISK is assign for personnel, HAZARD for
equipment]. Accordingly, the cases and circuit returns are isolated
typically by a 500K resistor. There is one system ground point, not a
distributed grounding system.

RF circuit design includes isolation between onbly for the output from
the low level circuits. Coax shields, shielding on shielded
circuits/wires carry no intentional currents and to the maximum extent
possible no fault currents.

Example: the output stages of a 5 GHz telemetry transmitter is on a
circuit board that is physically isolated from the low level stages and
the power source. The isolation may be either capacitive or inductive
coupled; in my last design [c.a. 1986] we used 1/4 wave stubs on the
same board, top circuit to bottom circuit, woking against two separate
returns [top surface base copper versus bottom surface base copper]

In the Nuclear safe environment for example, the primary and secondary
of power transformers MUST be 100% isolated and each winding separately
shielded with the shields connected independently to the chassis.
Therefore a transformer short circuit on the primary cannot propagate
through to the secondary. Or, a primary short to chassis cannot
propagate to the secondary. And the design MUST include 100% absolute
disconnect from primary power in the event of a transformer failure or
power out of spec condition. The requirements go on and on and on ...

Bottom line, equipment cases carry no current, share no current carrying
path [exception is RF output stages only].

So, the ASTRON RS 35 is not suitable for MIL usage. Now the ASTRON
becomes 100% MIL suitable with the removal of just one [1] jumper in the
supply [the connection from 13 volt return to chassis. The secondary of
the PS is 100% isolated from the primary and the regulator circuits are
100% isolated from chassis]. But, the ICOM radios being powered also
violate the MIL requirements and corrupt the system. Remember, HAM
equipment is generally operated in COMMERCIAL circuits and must comply
with local electrical codes.

In article ,
Amos Keag wrote:

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.]

*yoicks*!

The latter, I can believe is common practice.

The former - tying the powerline neutral directly to the case -
strikes me as being *extremely* contrary to electrical code and common
sense. It'd turn the supply into a deathtrap-waiting-to-happen if it
were plugged into an outlet having the hot and neutral reversed... and
these are (alas) not at all uncommon.

Now, having the utility power safety ground wired directly to the
case, I can very well believe... this is quite common.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
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