[Icom] Strike

Thu May 6 15:41:35 EDT 2004

Hi Andy,

My location is not so dangerous in respect of lightings, but anyway May
through August require some precautions.
I live in a 12-store apartment building. The building itself got quite some
lighting protection which is good enough to make me sure, a direct stike is
very unlike.
I don't have any antenna with a top point higher than 8 m above the roof. I
did it in purpose, in order not to attract direct strikes.

During the lighting season normally I keep my antennas disconnected. I
connect them to radios only when I am sure, there is no serious static or
possible strikes coming.
The radios are grounded, normally I don't disconnect them from the ground
except if I go somewhere for long time, for example, for a vacation trip a
couple of weeks long. Then I leave my radios completely disconnected from
all possible mikes, wires, etc.
The what I've described is only acceptable for cases like mine when I live
in quite a safe place and the building itself is protecting me.

If I leaved in a dangerous location, during a lighting season I'd keep
radios not used at any particular moment disconnected from everything else
and at a maximal distance from any wires, cables, etc. Let's say, I'd put
them on a dedicated table in the middle of a room, and with a maximal
distance among eachother. Tha radios in daily use I'd only unwire in
dangerous moments.
That's the main principle, your mileage may vary.

73,
Vladimir, EU1SA

> 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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> | >
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> |
> | ----
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> | Icom Users Net: Sundays, 1700Z, 14.316 MHz
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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/