[Elecraft] OT: Ground rods and concrete

[Jim Brown]

I'm with you, Wes. And I strongly agree with AB7E's excellent post.

The cited article does NOT say that "The Broadcast industry doesn’t seem 
to put their faith in Uber grounding." It DOES say that a Ufer ground 
done improperly can be a problem structurally. Notice also that the 
author "is national program manager for Copper Development Association 
Inc."  I see nothing in the way of engineering credentials. The author 
quotes extensive advice from "a power quality expert, Martin Conroy," 
again with no credentials given. That said, Conroy's advice is pretty 
good, and is mostly in agreement with good engineering practice. He did 
not say that the Ufer ground was a bad idea, but he did recommend 
supplementing it with deep rods around the tower, spaced radially out 
from the tower, and a buried ground ring, all robustly bonded together 
and to the tower.

If you read the new ARRL book on Grounding and Bonding (by N0AX), you 
will see a recommendation for a Ufer ground within the tower base, 
bonded to the tower, and to multiple ground rods around the tower base, 
spaced at least a rod length from the tower and from each other. If the 
tower is close to the building, it calls for bonding between the tower 
ground system and the building ground. If the tower is more than 60-100 
ft from the building, bonding is NOT recommended (or useful) because 
that bonding conductor (and the coax shield) have too much inductance to 
be a low impedance at RF.

I was one of several engineers who Ward consulted for peer review, and 
much of the book parallels my tutorial on Grounding and Bonding for ham 
radio.

73, Jim K9YC

On Tue,4/18/2017 10:35 AM, Wes Stewart wrote:
> I don't know whether I would call that "extensive" damage but whatever...
>
> I have my own photos of me standing next to this anchor, but since I 
> can't send attachments, here is a link: 
> https://en.wikipedia.org/wiki/KVLY-TV_mast#/media/File:KVLYPylon.jpeg
>
> I didn't see any extra grounding conductors.  BTW, my GPS said this 
> was 1/4 mile from the base of the tower :-)
>
> I'm not saying that extra grounding isn't required or is a bad idea, 
> just that concrete encased steel isn't a bad idea.
>
> Wes  N7WS
>
> On 4/18/2017 8:01 AM, Rick Dettinger wrote:
>> Here is an article that described a Ufer ground failure that prompted 
>> the installation of an extensive external grounding system on a 1900’ 
>> BC tower.
>>
>> http://www.radioworld.com/headlines/0045/proper-grounding-and-bonding-are-crucial/338510 
>>
>>
>> The Broadcast industry doesn’t seem to put their faith in Uber 
>> grounding.