[TowerTalk] Grounding of cables to tower?

[Jim Brown]

On 10/18/2017 1:47 PM, Wes Stewart wrote:
> A couple of questions:
>
> 1) on page 15 of your referenced document you say a distant tower 
> should not be bonded to house (shack) ground and go on to connect the 
> coax shield.  How is that not a connection between the two?

It is a connection at DC. But at RF, the inductance of that connection 
dominates, so it's not a bond --  a bond must be a low impedance 
connection.   :)

> 2) Where does 200' come from?

A poorly chosen, too conservative number. In editorial discussions with 
Ward in the process of reviewing his book, we sort of agreed that 60-100 
ft was better.

Another point that I should have made is that if mains power is fed to 
the tower, the green wire must, by code, be run with the phase and 
neutral conductors, and it should be bonded to ground at the tower. The 
reason is what Jim Lux articulated earlier in this thread (or maybe 
another thread) -- the bond must be there so that a fuse or breaker 
blows in the case of a fault from phase to ground.

Thanks for catching the conflict -- I'll have to change that when I have 
time.

73, Jim K9YC
>
> Wes  N7WS
>
>
>
> On 10/17/2017 7:09 PM, Jim Brown wrote:
>> On 10/17/2017 11:39 AM, Bob Shohet, KQ2M wrote:
>>> Please share with me what you would do and why.  Thank you.
>>
>> Why not just buy and study the new ARRL book by Ward Silver, N0AX, 
>> which covers all of this, and to which I contributed?  Or "Up the 
>> Tower" by K7LXC, for which I contributed the chapter on Grounding. Or 
>> study the slides for the talk on Power and Grounding for Ham Radio 
>> that I've given at Pacificon and the Visalia DX Convention?
>>
>> http://k9yc.com/GroundingAndAudio.pdf
>>
>> 73, Jim K9YC
>
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