[Elecraft] Lightning Strike - Metal Roof attracts?

[Alan D. Wilcox]

All,
Thanks for words on the roof ... kind of late in the game to do much 
about that now. Don't think I want to go the "lightning rod" approach, 
because even a great ground is still likely to raise hob inside the 
house with ground-fault currents.

Had I unplugged the 2 audio cables to the K3, it would probably still be 
alive today. My homebrew keyer was connected, and it isn't working either.

The funny part of it is that my Carolina Windom was knocked down (copper 
at end was melted), but nothing inside the house was connected to the 
coax, and no direct damage. The wall-wart power supplies shorted and 
just one 20A circuit breaker tripped.

Dick,
Yes, the wireless approach will solve some of it. I put in a gigabit LAN 
for the speed, but breaking it up sure makes a lot of sense. The new 
D-Link router has wireless, so that'll work with the MBPro and Mac Mini 
whenever they come back from the shop.

Cheers, Alan

Alan D. Wilcox, W3DVX (K2-5373, K3-40)
570-321-1516
http://WilcoxEngineering.com
http://eBookEditor.net
Williamsport, PA 17701


On 9/14/2011 6:04 PM, Dick Williams wrote:
> Alan,
>
> I would not think a metal roof would be any more of a "lightning rod" than
> any other structure;  from what I remember, sharp pointed objects are good
> "lightning rods".
>
> Sorry to hear about all the damage there; am wondering if you have all your
> computer stuff "hard wired" to the router?  If so, you might consider
> changing to a wireless router;  that might at least prevent damage to your
> whole system if you take another strike.
>
> I believe that I took a strike or good static discharge on one of my towers
> during the last storm;  when I plugged the disconnect from the rotor cable
> to the control box in for my M2 R2800 rotor, there was the sound of an arc
> and the display dimmed.  Upon further investigation, I found one side of
> line going to the DC motor was grounded.  Took the antenna and rotor down
> and after dis-assembly of the rotor, I found there are .01 and .001
> capacitors from the each side of the motor to ground.  One of the .001s was
> blown in half, and the other .001 on the other motor lead had a big black
> burn mark in it (the one that ended up being shorted to ground).
>
> After further investigation for other problems, I found a blocking diode in
> one of my rotor relay control boxes for my Tailtwisters/Ham IVs was shorted.
> Interesting enough, that switch box is not connected at all (other than via
> the common ground) to the tower with the R2800 on it.
>
> Lightning can do strange things!!
>
> Dick K8ZTT
>
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Alan D. Wilcox
> Sent: Wednesday, September 14, 2011 1:56 PM
> To: elecraft at mailman.qth.net
> Subject: [Elecraft] Lightning Strike - Metal Roof attracts?
>
> Hello,
> Unusual electrical storms here on top of hill on Sunday evening (9/11).
> On Saturday, the roofing contractor finished putting half of metal roof
> on house. Received lightning strike to roof (I think), but saw flash
> onto front walkway. Heard explosion right at my wall. Couldn't find
> point of hit though. Roof was finished Monday.
>
> Is that new metal roof a target for the next storm? Never had a
> lightning strike near here before this.
>
> For the curious: Damage was everything connected to my LAN ... Apple
> MBPro, Mac Mini, MacPro I/O, router, hub, soundcard connected to K3 on
> old Windows PC. The K3 ant and power were disconnected (but two audio
> cables from old PC were connected to K3): my K3 is shot and on its way
> to Elecraft. A Comcast TV box was shot, and the tel and Internet all
> needed reset from Comcast. Still finding problems ...
>
> Limping along with old Win-2000 PC.
>
> Cheers, Alan
>
> Alan D. Wilcox, W3DVX (K2-5373, K3-40)
> 570-321-1516
> http://WilcoxEngineering.com
> http://eBookEditor.net
> Williamsport, PA 17701