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@gmail.com>
To: "Discussion of Ten-Tec Equipment" <tentec@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@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@gmail.com
> http://blog.aa6e.net
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