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

Sun Jan 15 15:30:46 EST 2017

The use of the RadarScope iPhone app (or similar app providing real time radar & lightening data) allows you to get the big storm picture. Using any zoom level desired, the advance of storm cells toward your station can be monitored and timed. This allows you to perhaps make better decisions about when to disconnect than if just using sight or sound alone. I operated 7 hours yesterday in the NAQP CW contest with reduced fear of lightening thanks to RadarScope. I was disconnected however for about 3 hours in the afternoon.

73, Bill K6WSC

-----Original Message-----
From: SADXA [mailto:sadxa-bounces at mailman.qth.net] On Behalf Of Jerry
Sent: Sunday, January 15, 2017 12:25 PM
To: Southern AZ DX Association E-Mail Reflector <sadxa at mailman.qth.net>
Subject: Re: [SADXA] Tucson NWS Lightning Forcast -- Sat Jan. 14th, 11am to 10pm

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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