[SADXA] Tucson NWS Lightning Forcast -- Sat Jan. 14th, 11am to 10pm

Sun Jan 15 14:25:23 EST 2017

The arcing on the antenna was probably aided by a certain amount of dirt 
and crud on the insulator but still the voltage had to be high. I still 
have some items and photos, not sure where they all are that I took and 
collected at the time of when my antenna got hit. Maybe what I can find 
I will bring to radio club and do a show and tell. I will look around 
and see what I can come up with.

My neighbor said he saw the strike and there was a shower of sparks off 
my antenna. All the elements on that antenna were also floating as in 
the case of Bills KLM.

Its nasty stuff.

W6XI

On 1/15/2017 11:59 AM, W7EXG (Bill) wrote:
> Along these same lines, I once had a 36 ft, KLM 6 ele 15m Monobander at
> about 40 feet. All the parasitic elements on the KLMs were insulated from
> the boom. The Boom to Element minimum Spacing was approximately 1/2 inch
> (1.27cm)
>
> If I were outside when distant lightning occurred, I would hear/see
> electrical arcing from the isolated 20 foot parasitic elements to the
> grounded boom, long before I heard the associated thunder. This was scary to
> observe. It was a subtle hint for me to get inside.
>
> Voltage to Arc across a 0.5 inch gap (1.27cm) is: [www.kronjaeger.com]
> 	Between 2.5 cm spheres = 40kV
> 	Point to Point Needles = 12kV
>
> This 20 ft element voltage was strictly induced by the distant
> Electromagnetic Wave of the lightning strike.
>
> If I were hanging on to an elevated 20ft "rod", with my feet on the ground
> during a lightning storm, I would most likely experience from 12kV to 30kV
> of voltage on the "rod". The type of "ground" might matter to me.
>
> Of course common sense would tell us not to do such a stupid thing!!
>
> That's why when we hear or see Lightning, we all disconnect our antennas, by
> possibly hanging onto this 40 to 80 foot "rod" in the process.
>
> In Summary, I believe it is possible to experience lightning shock, without
> a direct hit on your antenna.
>
> I have worried about this possibility, when disconnecting, based on my past
> experience with the KLM.
>
> Jerry W6XI is stating that not only is it possible, but it happens.
> Fortunately, Jerry is still standing to tell us about it.
>
> It may be possible to engineer a disconnect, so we are not at risk.  Not
> sure how many of us have considered, or done this?
>
> 73s,
>
> Bill W7EXG
>
> -----Original Message-----
> From: SADXA [mailto:sadxa-bounces at mailman.qth.net] On Behalf Of Jerry
> Sent: Sunday, January 15, 2017 6:33 AM
> To: Southern AZ DX Association E-Mail Reflector
> Subject: Re: [SADXA] Tucson NWS Lightning Forcast -- Sat Jan. 14th, 11am to
> 10pm
>
> Through the years I have had to go out and disconnect antennas when a
> storm approached and I actually took a shock in the process with having
> disconnected  the antenna but still holding it in my hand when a strike,
> perhaps three miles away, occurred.
>
> That always goes  through my mind when messing with the antennas.
>
> W6XI
>
>
> On 1/14/2017 9:47 PM, Wes Stewart wrote:
>> I was on my computer thinking of getting back to the rig when I heard
>> the first "bolt out of the blue (grey)".
>>
>> I ran outside to disconnect the coax cables and heard another (close)
>> one and was immediately drenched before I got back under shelter.
>>
>>   On 1/14/2017 9:16 PM, W7EXG (Bill) wrote:
>>> Using Lightning Maps, I detected 9 strikes in about an hour ending
>>> 0330Z in
>>> the Tucson Area on 1/14/17.
>>>
>>> My AcuRite Lighting detector detected most of these strikes.
>>>
>>> One strike detected by Acurite was about 6 Mi NW of Oracle Junction,
>>> about
>>> 30 mi from my QTH. I did not hear Thunder for most of the strikes
>>> detected
>>> with the MAP or my detector.
>>>
>>> Was interesting to hear/see the Acurite Detection alert, then see the
>>> location of the lightning strike on the Lightning map a few seconds
>>> later.
>>>
>>> I commend Tucson's NWS for correctly forecasting a "Slight Chance" of
>>> Lightning for today. This was a nice warning -- issued yesterday.
>>> Apparently
>>> "Slight Chance" should not be ignored.
>>>
>>> Lightning In January.. How About THAT! Guess lightning is possible
>>> for any
>>> month of the year in Tucson.
>>>
>>> 73s,
>>>
>>> Bill W7EXG
>>>
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