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[K0SJZ]

Hello,

I have the following setup:   

-  Buckmaster OCF Dipole in some trees in my back yard.  Feedline from Balun in tree to 8 foot ground rod via a lighting arrestor.  Ground rod is next to house.  Feedline then from lightning arrestor to my shack.
-  All shack gear is grounded to ground bus on wall in shack (via half inch tinned copper braided straps from each piece of equipment directly to the bus - no daisy chaining).  The ground bus on the wall in the shack is then connected to the main house ground rod.
   
The problem I have is that I am unable to bond the grounded rod in bullet one above with the house ground.   We built on to our house and have a ton of concrete to deal with to get back to the house ground rod.

How big of deal is this from a -  1). safety standpoint. 2). shack radio/gear damage standpoint. 3) rf standpoint?   

Is there a creative way to bond the two ground rods?   My understanding is that I should need to keep the 6 gauge wire for bonding the ground rods in the ground the entire way.   The concrete makes this virtually impractical unless I want to rip up a bunch of nice concrete.   

Would welcome and appreciate any advice.

Thank you.

[WB6TIX]

Please engage an electrician.  They have all sorts of tricks for dealing with situations like this and the cost of their services would likely be less than a 2 meter radio.

I'd not tolerate having the situation you have described.

Eric
WB6TIX

[K6BRN]

Hi Dale (K0SJZ):

While it's important in good grounding to bond your external coax ground rod to the house electrical entrance panel ground, it's not necessary to keep the ground wire buried.  Above ground works just fine.  But there are also other considerations....

So...

I strongly suggest that you get a copy of the ARRL's "Grounding and Bonding for the Radio Amateur", available on Amazon OR HERE (with some other useful information references on the page with regard to this topic):

http://www.arrl.org/grounding-and-bonding-for-the-amateur

https://home.arrl.org/action/Store/Product-Details/productId/133989

Welcome to Amateur Radio and hope to hear you on the air soon!

Brian - K6BRN

[KD6VXI]

So as not to get really technical......  And you can when it comes to grounding and bonding, very quickly.....

I second K6BRN.  Wards book is pretty much the standard for ham radio.

He and Jom Brown have rewritten the grounding section of the ARRL manual as well...  So good stuff.

But no.  I wouldn't use what you are describing.  The possibility of blown gear and step voltage induction is too great.

--Shane
WP2ASS / ex KD6VXI

(runs a few million watts of power generation in the Caribbean at a facility with a couple hundred foot plus tall towers. Lightning city.)

[KC5BKS]

You've asked a great question and as other posters have shared, getting a copy of the ARRL grounding manual is a great idea.  I'd also suggest a PDF "Motorola R56 Standards and Guidelines for Communication Sites" about grounding towers and radios.

The initial problem that I see in your description is your use of two separate grounds - one for the antenna and one for the electrical wiring.  Your radios are wired between these two grounds...and these two grounds are not at the same potential (if using the term "potential" is foreign to you, then that is an indication that you likely need to do more research and/or hire an electrician).  This difference in potential is the reason the two ground rods need to be bonded together. 

With your radios located between these two differences in potential, when a voltage fluctuation occurs (e.g., lightening flash in the area), the difference in the potential (i.e., voltage) between the ground rod for your antenna and the ground rod for your electrical wiring can be rather large, and this difference in potential (i.e., voltage) is looking for some way to equalize.  With your radio between these two extremes, the circuitry inside your radio will act as a conductor to equalize the difference between these two voltages.  Unfortunately, the internal circuitry of a radio tends to act more like a fuse than a conductor during these events, and your radio acting like a fuse will tend to "blow" causing expensive, if not irreparable, damage.

Large electrical events like lightening are strange things...many of us tend to view voltage as DC, yet lightening tends to be AC at a variety of frequencies.

I'm sure that someone on the forum will read my posting and point out the inaccuracies with it - that's okay.  I'm not an expert, but rather an amateur, and this is my simplistic understanding of the OP's dilemma and one of the potential problems he might face.  Regardless of the specific physics occurring with grounding and bonding, the jest is this...please do your due diligence of research on this topic, follow the recommendations of reputable publications and/or hire a licensed expert (i.e., electrician) for guidance ...and then pray that you never experience a nearby (or direct) lightening strike :-)

-acm

[KT4WO]

"Feedline from Balun in tree to 8 foot ground rod via a lighting arrestor. "


I would remove the connect to that ground until I got them bonded.
My .02 cent

[KT4WO]

And I 2nd the R56 Motorola... was required reading when
I worked for a dealer.

[VE1YY]

Hi, All
KC5BKS said "lightening tends to be AC at a variety of frequencies" and I am glad that he did. I often am shocked (ahem) to find installations, amateur and professional, that have coiled ground leads. That's an inductor which poses an impedance between the earth system and the 'protected' installation. Please no coils just straight runs or, if you must, long radius bends.

73 and GL
Bill
VE1YY

[WB6TIX]

I apologize if I seemed curt...my 12 year old dog was whining to go outside and I didn't want to keep him waiting.

Dale, since you asked the questions, it seems you have the understanding that "This doesn't seem right.  I need to find out more." My hat is off to you for that.   ARRL's book on grounding and bonding, Motorola's R56 and the various MIL standards on bonding and grounding will certainly help with the "I need to find out more."  However, don't get discouraged if some of the theory gets a bit deep.  Grounding and bonding has been known to get the propeller on an engineer's hat spinning fast enough to lift the engineer off the ground.  :-)

These references are also a good source of information of "what not to do" as some seemingly minor things can have a huge impact on the performance of the system....like Bill's mention of the coiled wires.  Telephone installers are *always* doing this when tying their protection boxes to the grounding system.

Unfortunately, the references may be short on ideas for actually getting the wire across *that* concrete slab.  It's not a criticism of the references as they can't cover *every* possible situation that might be encountered when trying to add onto existing systems. 

One method I thought of is using a "wall chaser" or a cement saw to cut a slot in the slab to put the wire into. I've never had good luck matching a concrete patch to the existing concrete so I resort to camouflage, such as making it look like an expansion joint. 

Eric
WB6TIX

[AA4PB]

The NEC does not require the ground RODS to be bonded together. It requires grounding SYSTEMS to be bonded together. You could bond to the ground rod or to the grounding conductor anywhere between the rod and the electrical service panel. The point is to ensure that the two grounding systems (radio and electrical) are at the same voltage with reference to ground. I agree that it is ideal to bond the rods together with an underground cable, but it is not required to be done that way.