Working on a fire line in a national forest I've seen 75 foot pine trees
that had been completely exploded from a lightening strike. The sap
reaches boiling point in an instant and burning parts of the tree gets
distributed over the ground which leads to a fire crew being dispatched.
Most wildland fires in these parts are due to lightening and ocurr 5-10
times per year.
My own antenna system has never had a direct strike despite the high
lightening activity here in the high Rockies (8200'+). But several
times surges have blown the fuses on my lightening protectors. One near
strike even got past that and destroyed my switch box - which was also
fused.
K0DXV
On 4/18/2017 11:41 AM, Guy Olinger K2AV wrote:
Part of the mental imaging problem here is that our brains, in their
internal emotional response to orders of magnitude, simply cannot scale the
destructive power in lightning. Lightning is quite capable of melting the
leads to six properly done ground rods, AND at the same time blowing up a
perfectly done to code concrete base with reinforcing rods.
It just needs to be a big enough strike. I would guess (zero proof, just a
nagging inclination) that the odds of this are considerably reduced by the
presence of decently tall trees in the immediate vicinity (another loooong
discussion).
Anyone who has seen a lightning strike turn three or four cubic yards of
ground dirt into glass in milliseconds, or seen a huge strike on a lake
surface boil water within a 10 foot radius has a good gut based lightning
strike power scaling device.
Every now and then I will get on YouTube and watch the cellphone videos of
the 2011 Japanese Tsunami to remind myself of the absolutely enormous
kinetic energy in a twenty foot high wall of water moving at 20 miles per
hour.
Nature can completely blast any one of us to smithereens if it wants to.
Thankfully that is nowhere near norm.
The question is how much moolah do you want to lay down, how many otherwise
good solutions do you want to shelve, for a rarity? Like how to invest,
that is a very personal decision. Good luck to all.
73, Guy K2AV
On Mon, Apr 17, 2017 at 11:32 PM, Doug Renwick <ve...@sasktel.net> wrote:
That myth refuses to die. I have 5 concrete tower bases with ground rods
partially encased and never a worry about an exploding base.
Doug
-----Original Message-----
-NEVER- encase a ground rod in concrete ... especially a tower base.
As a retired 2-way radio tech, I'm aware of two towers that had to be
re-installed because of lightening strikes exploding their concrete bases.
73!
Ken - K0PP
---
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