[TenTec] Station and AC Ground

Robert & Linda McGraw K4TAX RMcGraw at Blomand.Net
Wed Nov 30 08:52:47 EST 2005


If you have a "tuned" ground system, consider that it is part of the 
radiating system.  Otherwise, your ground is radiating RF.   If current 
flows on a conductor, it radiates.  Usually this is an invitation to RFI 
issues on phones, TV's, and such due to the placement of the conductor.

73
Bob, K4TAX


----- Original Message ----- 
From: "Martin AA6E" <martin.ewing at gmail.com>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Tuesday, November 29, 2005 4:25 PM
Subject: Re: [TenTec] Station and AC Ground


> You can have a tuned "ground" but it only works at discrete
> frequencies.  Besides, any current-carrying wire of appreciable
> length, tuned or not, becomes part of your antenna system.  If, as it
> should, the RF ground carries no current, an open circuit will work
> just as well. ;-)
>
> For lightning (a broadband pulse), what matters is impedance of your
> ground connection.  Resistive (considering skin effect) and reactive
> (inductance).  Wide copper stap as short as possible minimizes
> effective resistance and inductance.   A half wave wire (cut for some
> wavelength) is unlikely to be good for lightning.
>
> 73 Martin AA6E
>
> On 11/29/05, Gary Hoffman <ghoffman at spacetech.com> wrote:
>> >
>> > The first (RF) is somewhat hopeless, as was pointed out, because a
>> > real (broadband) RF ground has to be very short, say not more than
>> > 1/10 wavelength, to avoid reactive and resonant effects.  That means
>> > shorter than 1 meter for 10 meter operations, etc.  That's not
>> > practical in most installations.  You don't really need a "true" RF
>> > ground, if your antenna system is balanced properly - no common mode
>> > RF on the feed lines, etc.
>> >
>>
>> Or....a half wave ground wire, to repeat the low impedance at earth right 
>> at
>> the radio.
>>
>> And, since lightning is RF, I feel that a real RF ground is important, 
>> even
>> for lightning.
>>
>> 73 de Gary, AA2IZ
>>
>>
>>
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>
>
> --
> martin.ewing at gmail.com
> http://blog.aa6e.net
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