[RFI] RFI cured with 1/4 wave wire

[Jim Brown]

On Sat,2/20/2016 6:15 PM, Gerald Wolczanski wrote:
> Jim, I totally understand antenna return currents in an unbalanced
> antenna....having once built a vertical with 110 radials.

Even a dipole center-fed with two-wire line can be unbalanced by its 
surroundings, and even with a "balanced" tuner.  Balance is defined as 
impedances in the system being equal to the reference plane , NOT by 
voltages or currents. Indeed, voltage and current imbalance is the 
RESULT of imbalance in the system, which includes the antenna (and its 
surroundings), the line, and termination of the line in the shack 
(including a tuner or other matching network).

> My current 135' end-fed inverted-L is a superb performer with my fan of
> radials laying in the backyard.

I have a Tee vertical for 160M with a bunch of radials, and it works 
well too,

> So let me ask a practical question:
>
> Can I attach my radial system (which I would disconnect from the copper
> pipe driven into the ground) to my L-network coupler and ISOLATE THAT
> COUPLER FROM GROUND WITH A BALUN?

That is a bad idea.

> That would separate the RF ground from the Shack (lightning ground).

That's also a bad idea.  Remember that lightning is NOT a DC event, is 
an RF event, with peak energy broadly centered between about 100 kHz and 
10 MHz.  A radial system provides capacitive coupling to the earth, so 
if it's part of the building ground, it lowers the impedance to earth, 
so it improves lightning protection.

Second, there is no such thing as RF ground.  For decades, we have heard 
the same nonsense from the high-futility audio world about separating 
the "clean audio ground" from the rest of "ground," which is "dirty." 
Separated grounds are a really bad idea, especially at RF.  Now, we DO 
use "isolated ground" wiring in power systems in buildings to minimize 
circulating noise currents on sophisticated technical systems, but every 
part of those systems IS grounded and bonded in a very well controlled 
way, and all grounds are ultimately bonded together.

73, Jim K9YC

> BTW, I have a spark-gap lightning arrester outside my shack window.
>
>
> Thanks
>
> Jerry
> KI4IO
> Warrenton, VA
>
>
>
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