>A grounded tower is NOT less likely to be hit by lightning.
> Actually a grounded tower is a little more likely to be hit than a non
> grounded one.
> However you are still much better off with a grounded tower as you have
> some
> control of where the strike energy goes after the hit. You can route it
> safely to earth when it is grounded. Ungrounded, the lightning finds its
> own
> way to earth usually by a path not wanted by you.
>
> Grounding the beam elements to the boom is probably a good idea so that
> you
> don't have arc overs from lightning strikes or near strikes.
In my system, http://www.rogerhalstead.com/ham_files/Tower29.htm "As I
recall" none of the elements of the 144 and 440 antennas are grounded. (top
array at 130 feet) I believe all elements are grounded on the 6-meter
antenna while the parasitic elements on the TH-5 are grounded (bottom
antenna at 100 feet). This system gets hit about 3 times a year on average
since it's been up. Since finishing the ground system I've had no damage
to equipment even from direct hits.
The old tower which was 90 feet was up for 12 to 15 years and was only stuck
twice that I remember.
Normally, none of the equipment gets disconnected during storms as they are
too difficult to get at. By the time I'd get everything shut down and
disconnected the storm would be past and I have no desire to be working on
antenna cables during a thunder storm.
BTW, the unshielded CAT-5e gigabit network cable has a 130 foot run to the
shop which goes within 10 feet of the tower base. That, I'd like to replace
with wireless when they get the *affordable* speed up to one gigabit (or
faster).
Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
www.rogerhalstead.com
>
> 73
> Gary K4FMX
>
>
>> -----Original Message-----
>> From: towertalk-bounces@contesting.com [mailto:towertalk-
>> bounces@contesting.com] On Behalf Of StellarCAT
>> Sent: Friday, February 10, 2006 4:09 PM
>> To: tower
>> Subject: [TowerTalk] lightning and insulated elements..
>>
>> has there been any previous discussion on the merits (or lack
>> thereof) of insulated
>> elements visa vie lightning? I recently installed a tower system
>> will 5 f12 antennas -
>> all having insulated elements... the tower I believe is well
>> grounded as are the cables.
>>
>> Last night we had a storm pass by maybe 5 miles away and I was
>> standing outside
>> watching - wondering.... and there was a bolt that was well
>> maybe a few miles away
>> and almost immediately I heard kind of a slow sizzling sound
>> from around the tower.
>> I was standing - 200' from it (next to the house). Nothing
>> visible... all was disconnected
>> (in the house) at the time and all works fine today.... but it
>> made me wonder. Normally
>> a well grounded tower is LESS likely to get hit (I have never in
>> many years with towers
>> been hit on the tower) but with insulated elements - one would
>> think a charge could
>> readily build up on these things!
>>
>> thoughts?
>>
>> Gary
>> K9RX
>>
>>
>> _______________________________________________
>>
>>
>>
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>
>
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