[TowerTalk] Does prevailing grounding scheme promote large ground loop?

[Dick Blumenstein]

Thanks Jim for your input. I will have to study your presentations in 
more depth. Years ago, I worked building audio amplifiers and tape 
duplicators that also had a small oscillator for some AC bias needed for 
tape recorder recording heads. Ground loops at the time were always a 
concern and we had to make sure that we only grounded the entire system 
at one point to the chassis, and ran a ground rod suspended down the 
center of the chassis and grounded all components to that ground rod.

I noticed in one of your slides that you said to NOT run the tower 
grounding system back to the house AC input ground if it is too long 
(but to depend on the antenna coax sheath). How long is too long?

It is about 40-50' from my shack wall to the tower base, but probably 
100' from the tower base to around the other side of the house to the AC 
input of the house (house ground rod). I am planning on putting in about 
9 ground rods around the base of the 73' tall crank-up tower (3 off of 
each leg in a "Y" configuration).  The first rod off of each Y leg will 
have a wide copper strap connected from the ground rod to the tower leg 
in a gentle arc with no sharp turns. Most installations I've seen have 
maybe a 3" or 4" wide piece of copper.  All three Y base leg ground rods 
will be cadwelded to #2 copper stranded in a ring around the tower. It 
was this ring that I was going to run to the AC house ground rod.  
Finally, the other 2 ground rods in each Y configuration were planned to 
be cadwelded to the base leg of the Y with #2 stranded. Any comments? PS 
- We have heavy clay soil here in NC.

Dick, K0CAT

=======================



Jim Brown wrote on 7/24/2016 2:07 PM:
> On Sun,7/24/2016 9:04 AM, Dick Blumenstein wrote:
>> one huge ground loop. 
>
> Ground loops are a massive fiction, a completely false concept. Here's 
> my take on power, grounding, and bonding for hams.
>
> http://k9yc.com/GroundingAndAudio.pdf
>
> And here's my comparable work for professional audio and video, which 
> I taught for ten years at conventions for audio and video contractors 
> who build systems from the small to the very large. The first link is 
> to a long tutorial, the second two are to Power Point slides for my 
> workshops.
>
> http://k9yc.com/SurgeXPowerGround.pdf
>
> http://k9yc.com/InfoComm-PowerSystems2012.pdf
>
> http://k9yc.com/InfoComm-Grounding2012.pdf
>
> 73, Jim K9YC
>
>
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