[Elecraft] I need some grounding-strap guidance, if'n you please

Tue Sep 1 18:45:25 EDT 2009

I've seen enough. There is no purpose in having a "station ground". In fact 
it can be dangerous to have a ground system just for the station and one for 
the electrical entrance. Think of the potential difference between those two 
systems when lightning tickles one of them. Often the ground for the ham 
shack is far better than the ground on your electrical panel. Guess where 
the big surge is going to flow...Through your house then  righ through your 
ham equipment! After all, your ham gear is plugged into the AC outlet. This 
connects the two ground systems together....Not good!
Bonding all the ham gear together is a great idea but don't run it to a 
separate ground rod. It serves no purpose. If you think this helps make your 
signal stronger then think again...Sure a nice radial system will help that 
vertical or random wire antenna BUT be sure you unhook it from your 
equipment during a thunderstorm. All the ground rods in the world won't 
protect your equipment from a strike and having it grounded to a ground 
system AND to the AC mains is begging for trouble.
As for grounding the antenna...That's a different matter. The antennas 
should indeed be grounded when not in use AND disconnected from the 
station...Totally. In fact, your ham gear should be connected to NOTHING 
during a thunderstorm. If you have a big ground wire coming in from outside 
to your station, put a large knife switch in series with it and open the 
switch when the station is not in use.
Picture this.....Lighting hits power line, goes to electrical panel, sees 
wimpy old rusty ground rod and says "shucks there might be something better 
here", travels through your AC house wiring, gets to ham shack, sees your 
super duper ground system with 2" wide copper and 8,000 ground rods and says 
"whoopeee"!!!,,,Goes to AC power cord on DC power supply, then to DC lead 
from your new K3....through K3 to ground post on back of K3....to your 
wonderful ground system and frys everything along the way. No more K3! Same 
goes for your computer and everything else hooked to that nice ground. It's 
all toast.
The same goes for lightning hitting your antenna....Even if you disconnect 
the antenna with a coax switch, the shield is still connected right on 
through to your equipment and then to your ground system. Zap....no more 
rig....   Unhook the antenna and ground it....Don't hook the ground to the 
rig.
Now I can hear someone saying "Hey,,,,without a station ground you'll have 
RFI all over the place". Well maybe so but don't blame it on a lack of 
ground rods....Usually the station's ground wire is some multiple of a 
wavelength and makes a very poor RF ground anyway. If a ground system 
happens to cure your RFI problems it's probably because it just happened to 
resonate near your operating frequency. What you should do is try to 
maintain a balanced antenna system and avoid common mode currents. Try using 
a line-isolator in series with your coax etc etc.
Sorry I used so many words to say something so simple!

Steve
N4LQ
N4LQ at carolina.rr.com
----- Original Message ----- 
From: "NG3V" <ng3v at comcast.net>
To: "'Ron D'Eau Claire'" <ron at cobi.biz>; "'Peter N. Spotts'" 
<kc1jb at arrl.net>; <elecraft at mailman.qth.net>
Sent: Tuesday, September 01, 2009 5:01 PM
Subject: Re: [Elecraft] I need some grounding-strap guidance, if'n you 
please

> Well, I guess I need some advice here as well.
>
> I had not considered the problem of different grounds.  I am building a
> house, now, where the electrical wiring will come in at one end of the 
> house
> while my radio room is 70 feet away, at the other end.  I had planned on a
> separate grounding system at the radio room.
>
> Would it be best to connect the two grounds?  If so, how would be the best
> way to do that?
>
> Or, should I have the electrical wiring come in at the same end of the 
> house
> as the radio room, thus eliminating "two separate grounds"?
>
> Thanks,
>
> Tom
>
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Ron D'Eau Claire
> Sent: Tuesday, September 01, 2009 4:32 PM
> To: 'Peter N. Spotts'; elecraft at mailman.qth.net
> Subject: Re: [Elecraft] I need some grounding-strap guidance, if'n you
> please
>
> Good story Pete, and a reminder that it doesn't take too many mA of 
> current
> to send you flying across the room (or into your grave). Even a bad ground
> provides plenty of lethal current at mains voltage.
>
> When I have a shop setup in a basement, garage or anywhere with a floor 
> like
> that I make sure the outlets are GFI protected. It's cheap insurance.
>
> Over the past 30 years  we've moved back to the electrical equipment 
> designs
> of the 1940's and 50's in which safety is accomplished through insulation
> rather than through a grounded enclosure. The fact that few modern tools 
> or
> appliances have 3 wire plugs testifies to this approach. Such equipment is
> (apparently) very safe. (Safer than many of the old AC/DC radios, etc., of
> the 40's and 50's  - especially after us young Hams unknowingly 
> compromised
> the insulation by taking a knob off exposing a bare control shaft or 
> leaving
> insulators out from under the chassis).
>
> But the reliance on insulation rather than grounding for safety seems to 
> be
> bringing us back many unsafely grounded outlets. It's now very common to
> have even brand new construction, signed off by all the appropriate
> inspectors, turn up reversed wired outlets and missing grounds.
>
> Ron AC7AC
>
>
>
> -----Original Message-----
>>
>>snip<
>
> Many thanks to all! My original question was prompted by an experience
> I had as a teenager visiting my uncle in the mid 1960s (oops, the gray
> hairs are showing). I was working in his garage, using a metal-housed
> electric drill in bare feet on a dry concrete floor. (No cracks about
> natural selection at work, please!).
>
> I got a jolt about 2 volts shy of a hairstyle by Boston Edison!
> (Although this was in a St. Louis suburb.) So that's what led me to
> wonder if an anchor bolt embedded in concrete would constitute a
> sufficient ground. It sure seemed to for that drill!
>
> Thanks again for the helpful advice!
>
> With best regards,
>
> Pete
>
>
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