[Icom] Strike

Thu May 6 15:25:32 EDT 2004

Hi Vladimir--

Very helpful information. Do you ground your radio? What other precautions
against lightening strikes do you take?

Thanks, Andy K5VM

----- Original Message ----- 
From: "Vladimir V. Sidorov" <[email protected]>
To: <[email protected]>
Sent: Thursday, May 06, 2004 8:08 AM
Subject: Re: [Icom] Strike

| Gents,
|
| This topic is complicated enough but also it is extremely simple to
| understand how and what if we take into consideration the nature of the
| strike.
| The strike is a discharge of a huge amount of energy. We talk about
| Megawatts.
| We all know that a radio transmitter induces a certain amount of energy
into
| a quite remote receiving antenna. We are talking about, say, hundreds or
| thousands Watts. So, take the same approach to the strike problem.
|
| The nearby discharge of the famous Megawatts induces some amount of energy
| in every possible receiving antennas. In our case almost everything can
| become a receving antenna, provided, a difference of potentials can be
| applied to that. I mean, only a theoretical point conductor cannot turn to
| be a receiving antenna. Everything longer than the point conductor can
| receive a certain amount of an induced energy. The longer the conductor
is,
| the bigger amount of energy can be inducted on it. Moreover, if one end of
| the inductor is grounded, it's even worse as the inducted amount of energy
| will be even higher. Moreover, the grounding, as it was perfectly
mentionned
| before, might even cause a multiple path discharge, and of course it is
much
| worse than the inducted energy.
|
| With the Megawatts' nearby discharge of energy even a few centimeters long
| conductor can get Watts or even Kilowatts of energy inducted. Once again,
| the longer the conductor is, the higher energy is applicable.
| Accordingly (back to factual damages): standalone units (closest of all to
| the point conductor), like the radios alone with nothing connected to
them,
| might avoid any damage.
| A radio with a mike connected to a mike jack (the conductor is longer and
we
| have Watts or Kilowatts induced) has a very good chance to get blown.
| A grounded radio with mikes, antennas connected, etc, has a very nice
chance
| simply to evaporate...
| You can continue with TV sets connected to power lines, cables, etc.
|
| William, my sincere sympathy to you.
|
| 73,
| Vladimir EU1SA
|
|
|
|
|
| > Hi Joe-
| >
| > This may sound like complete blasphemy but I have had several very
| > knowledgeable people tell me I should not ground my single radio at all.
| It
| > is by necessity on a second floor. What are your thoughts or anyone else
| in
| > the group?
| >
| > I do disconnect from the antenna when not operating. Should I also
| > disconnect the radio from the house AC line? I do disconnect my 4KL
linear
| > when not operating. I live in Texas and we get a fair amount of lighting
| > although I have never heard of a ham strike in Dallas although I'm sure
| > several must have happened.
| >
| >  I use a DSL line for spots so the 756 Pro II radio and the linear are
| > indirectly coupled to the telephone line through a laptop serial port
| line.
| > Should that laptop line be disconnected when not operating?
| >
| > Thanks, Andy K5VM
| >
| > ----- Original Message -----
| > From: "Joe" <[email protected]>
| > To: <[email protected]>
| > Sent: Thursday, May 06, 2004 5:06 AM
| > Subject: Re: [Icom] Strike
| >
| >
| > | It could very well be that the strike went OUT the telephone line and
| not
| > in. The strike may have come in the power line and looked for multiple
| > ground paths.
| > |
| > | I work for a cellular provider and we have experienced many lightning
| hits
| > in the past.  Most damaging hits come in the power lines.  Suprisingly,
| the
| > tower hits are not as damaging as the power line hits.  Tower hits
| sometime
| > cause no damage at all (I've been at the site during a couple of these).
| > The power line is usually the culpret of most of the worse damage, and
it
| is
| > capable of handling tremendous surge currents before the breakers trip.
| > |
| > | The telephone line really does not have the current carrying
capability
| of
| > massive damage.  It sounds like the strike came in the power line and
| found
| > multiple grounds through your equipment and the telephone line.
| > |
| > | The trick to having a good ground system is to ground things so that
| most
| > of the strike goes directly to ground and not through your equipment.
| > Sometimes this is not possible in a ham shack because you cannot provide
a
| > good enough ground to absorb the entire hit.  The strike takes multiple
| > paths.  Unles you have a near perfect ground and ground ring like a cell
| > site should have, disconnecting the radios is the only safe way.
| Sometimes
| > people confuse a safety ground (like a 3 prong plug) with a lightning
| > protection ground.
| > |
| > | As far as damage is concerned, a poor lightning protection ground can
be
| > worse than no ground at all .
| > |
| > | 73, Joe, k1ike
| > |
| > | William Diamond <[email protected]> wrote:
| > | No need to get a thread started on this but the phone Co. claims that
| > their
| > | system is so well protected, they could not induce a strike to the
| inside
| > of
| > | a dwelling. Yea right ...........
| > |
| > | There are 4 separate 110 and 2 220 volt lines ran to the radio room
and
| > all
| > | four of the 110 breakers were tripped.
| > |
| > |
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| > | Your Moderator: Dick Flanagan K7VC, [email protected]
| > | Icom Users Net: Sundays, 1700Z, 14.316 MHz
| > | Icom FAQ: http://www.qsl.net/icom/
| >
| >
| > ----
| > Your Moderator: Dick Flanagan K7VC, [email protected]
| > Icom Users Net: Sundays, 1700Z, 14.316 MHz
| > Icom FAQ: http://www.qsl.net/icom/
|
| ----
| Your Moderator: Dick Flanagan K7VC, [email protected]
| Icom Users Net: Sundays, 1700Z, 14.316 MHz
| Icom FAQ: http://www.qsl.net/icom/