Randy -
Right you are!! Years ago when I had a Cushcraft R-4 vertical, mounted on a
high-rise
roof, I followed the recommended grounding instructions. A year later it
got a direct hit, which blew the matching box and a couple of traps.
Needless to say, I replaced the antenna with an R-5 but left it ungrounded.
Once hit, made
aware (hi). It has been up at the same location for the past 10 years
without any lightning
problems. As a protection in the shack, the coax is disconnected when the
rig is not in use, and the AC power cord is pulled, just in case of a near
EMF hit.
73 - Don, VE1BN
----- Original Message -----
From: "Randy K4QO" <k4qo@earthlink.net>
To: <tentec@contesting.com>
Sent: Friday, May 05, 2006 11:19 AM
Subject: [TenTec] If you ground it - it will come!
> With apologies to "Field of Dreams", what I mean is that just grounding
> things sometimes means that you are inviting lightning to go to ground
> there... through your equipment.
>
> In my line of work with commercial radio towers, I have found that
> sometimes it is a mistake to ground certain items. Improvements in
> survivability were gained when certain protection points were removed.
> For example, a serial communication line was protected with a device and
> was always getting fried along with the device it was hooked to.
> Removing the protection actually caused the devices to survive for more
> than three years with no problems.
>
> At my QTH, I look for ways to remove paths like was described by the
> "RIP" post. Details like replacing switcher wall warts with
> transformer based ones provide a slight measure of advantage. The
> transformer ones have (admittedly small) isolation from ground and the
> AC lines. This isolates the router and cable modem (which is attached
> to the cable!) from the AC mains and doesn't "invite" the surge to use
> this path to go to ground. I won't go into a full treatise about
> grounding but if you take the time to personify lightning surges and see
> what paths it can take to ground (via your AC power plugs), you might
> see some opportunities for isolation. One more thought - I use a large
> linear supply with better transformer isolation to power the cable modem
> and router and my radio supplies are all linears for the same reason.
> No switchers for me!
>
> BTW, I have heavy surge arrestors at the cable entry point with ferrites
> on the cable on the house side of things to encourage the surges (that
> are basically an RF signal) to go to ground at the points I have
> provided outside the house. Its my own brand of voodoo but it is based
> on observations garnered at the commercial sites.
>
> This is a topic fraught with lots of opinion and some science and I
> don't mean that you shouldn't ground your station. The commercial sites
> frequently have some of the best grounding known to man and still see
> damage. Of course, at the end of the day, your best defense is to
> totally isolate your prized possessions during the storms.
>
> 73,
> Randy
> K4QO
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