Hi Wes,
That may have happened before I trenched a wire around the shack and
connected the station ground to the electrical box ground. No problems
since then.
Chuck W5PR
On Thu, Sep 5, 2019 at 3:58 PM Wes Attaway (N5WA) <wesattaway@bellsouth.net>
wrote:
> Chuck:
>
> I don't want to start a grounding uproar but it sounds like you didn't have
> a good single-point ground system, like what Jim Brown describes in his
> papers. You may have good solid grounding but somewhere there is (or was)
> apparently a path between your station ground system and another ground
> system (your house electrical ground) even though you probably didn't
> intend
> to have two separate ground systems. That is really the only explanation
> for lightning going to ground via a clock and down through your amp to the
> amp's ground.
>
> TV and radio station transmitter/antenna sites routinely get hit by
> lightning and they rarely go off the air because of a strike. I worked as
> a
> control room engineer during summers at Channel 12 in Shreveport (a long,
> long time ago when we used vacuum tubes) and I don't recall the station
> ever
> going off the air because of a lightning hit.
>
> I no longer have any beams on tall towers but at my previous station I did
> have stacked beams on a 70' tower. I also had a 2M vertical sticking up at
> the very top, which I didn't use very often because I never really enjoyed
> 2M. I remember walking down my driveway to get the morning paper and
> noticing little pieces of fiberglass and metal on the concrete. It took a
> few episodes of this to get me to look up and then I realized that
> lightning
> was hitting my 2M antenna and slowly whittling it down. It was only 2' or
> 3' tall when I noticed this. Nothing ever happened inside my house or
> shack, despite all these hits over a period of 20+ years.
>
> For grounding the antenna coax cables I used ICE arrestors bolted to a
> heavy
> copper bar outside my shack window. The bar was securely fastened to four
> 8' copper plated ground rods. Everything in the shack was grounded to one
> single piece of copper strap that ran through the wall to the bar outside.
> I
> also tied this ground to the electrical service ground which, luckily,
> wasn't too far away.
>
> At my current QTH I have the same old ICE arrestors, still doing fine.
> When
> we built our current house about 15-years ago I drove two copper-covered
> ground rods into the trench where one of the slab beams was about to be
> poured, and directly behind the soon-to-be wall of my operating position.
> Four ICE arrestors are mounted to 4" copper strap clamped to the tops of
> the
> rods. My station ground strap (about 4' long) also goes to this spot.
>
> My thought was, rightly or wrongly, that maybe pouring the slab around the
> two ground rods would create some form of Ufer ground. I don't know
> whether
> this is true or not.
>
> The antenna cables are RG-8 BuryFlex run from shack to 4 spots out in the
> backyard. The cable goes through conduit in the slab and then underground
> to the 4 ICE arrestor points. The arrestors are each mounted on a piece of
> 4" copper strap tightly clamped to the tops of 8' ground rods. I covered
> the ground points with slightly decorative clay pottery pots.
>
> I also ran another piece of 4" copper strap from the point behind my
> operating desk through the side wall of my shack and out to the same point
> where the house electrical and telephone service is grounded. This is about
> 15' of copper strap.
>
> All I can say is that we get some pretty big thunderstorms at times here in
> NW Louisiana with regular hits in various Pine trees in the area and I have
> yet to find or experience any damage anywhere. I do not ever disconnect
> anything, or switch anything to ground, at any time.
>
> I had the advantage of being able to do all this as we were building the
> house. Moving into a house and dealing with whatever you have is another
> story and I can see that a lot of hams will encounter some frustrating
> problems. Nevertheless, the single-point theory is good advice from Jim.
> Unintentionally having separate ground systems is not good and contributes
> to a lot of problems.
>
> -------------------
> Wes Attaway (N5WA)
> (318) 393-3289 - Shreveport, LA
> Computer/Cellphone Forensics
> AttawayForensics.com
> -------------------
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
> Chuck
> Dietz
> Sent: Thursday, September 05, 2019 8:37 AM
> To: john@kk9a.com
> Cc: Towertalk Reflector
> Subject: Re: [TowerTalk] Grounding
>
> I had everything disconnected but the ground and a clock on top of an amp.
> Lightning surge came through the power lines, through the clock and in to
> the amp on its way to ground.
> Now I disconnect the ground.
>
> Chuck W5PR
>
> On Thu, Sep 5, 2019 at 8:01 AM <john@kk9a.com> wrote:
>
> > What ground? Do you use a seperate ground going from your radio
> > chassis to a ground rod? I have my equipment bonded together but no RF
> > ground and no RFI issues.
> >
> > John KK9A/4
> >
> >
> > K9MA wrote:
> >
> >
> > My theory has always been that, with the station equipment well bonded
> > together, it is safe to leave the ground connected, as long as
> > EVERYTHING else is disconnected. That leaves no path for current to flow
> > through anything. I can disconnect the transmitting antennas with one
> > coax, all the control cables and rx antennas with another big connector,
> > and power with one 120 and one 240 V plug. That just leaves the ethernet
> > cable, which I try not to forget.
> >
> > In any case, my primary goal is to prevent a fire, and disconnecting the
> > ground from the equipment probably wouldn't help there. I hope I never
> > have to test that theory.
> >
> > 73,
> >
> > Scott K9MA
> >
> > _______________________________________________
> >
> >
> >
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> >
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