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Re: [Amps] Amp causing RFI

To:, Jim Brown <>
Subject: Re: [Amps] Amp causing RFI
From: Glen Zook via Amps <>
Reply-to: Glen Zook <>
Date: Tue, 4 Feb 2020 16:10:24 +0000 (UTC)
List-post: <>
Having spent over 30-years as a telecommunications consultant, and having 
specialties in lightning protection and r.f. grounding, I say that adding 
ground rods, etc., is NOT balderdash!  No, adding such does not always produce 
measurable results.  However, the majority of times adding external grounding 
does contribute favorably.
There are PROPER methods of installing coaxial cable.  NFPA NEC (National 
Electrical Code) requires that the coaxial cable shield be connected to a 
ground rod at the point where it enters the building.  This is for lightning 
protection as well as providing an r.f. grounding point.  Also, when the cable 
is installed on a tower, mast, etc., the shield needs to be grounded to that 
structure as near the antenna as possible and at the point the cable leaves the 
structure to enter the building.  In addition, if the structure is higher than 
around 100-feet, the shield needs to be grounded every 50-feet to 75-feet along 
the structure.
All "other" ground rods, etc., MUST also be connected to the AC mains ground.  
There are several reasons for this of which lightning protection is foremost.
Way too many seem to think that the 3rd wire in the AC wiring in their house 
provides sufficient grounding.  Sometimes it does and, more times than not, 
there can be problems on various bands caused by the length of the wire between 
the outlet and the AC mains ground rod.
The whole idea is to get the lowest impedance path to ground.  When just wire 
is concerned, the length of the lead needs to be no more than around 4-feet 
long and shorter is better.  You can increase the length of the grounding path 
by using something like aluminum flashing which is available in widths from 
around 4-inches wide to more than 36-inches wide.  Aluminum is not as 
conductive as copper.  However, it is much cheaper and having wider widths 
overrides the conductivity.
Just get the flashing as near the ground rod as possible (usually on the inside 
of the building), and then a short piece of large diameter wire through the 
building wall to the ground rod.
There are other things, like using chemical ground rods, that can definitely 
improve r.f. grounding.  One just has to do as much as possible to achieve a 
good grounding system.  Of course, the more that the individual can do 
themselves, the cash outlay is reduced.
Glen, K9STH 

    On Monday, February 3, 2020, 09:57:16 PM CST, Jim Brown 
<> wrote:  
Balderdash. The earth is not a sump into which noise, RFI, and other 
trash is poured. Comments like this bring to mind the infinite number of 
monkeys and typewriters producing Shakespeare.

73, Jim K9YC

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