[Icom] Strike
Vladimir V. Sidorov
[email protected]
Thu May 6 14:08:14 EDT 2004
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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