RF will not flow thru the chassis from one side to the other.
Remember "skin effect"?
73
Gary K4FMX
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
> On Behalf Of Bill, W6WRT
> Sent: Wednesday, March 17, 2010 3:53 PM
> To: amps@contesting.com
> Subject: Re: [Amps] placement of RF choke bypass cap.
>
> ORIGINAL MESSAGE:
>
> On Wed, 17 Mar 2010 07:24:00 -0700, "Jim Thomson" <Jim.thom@telus.net>
> wrote:
>
> >## How do u know there will be RF flowing on the underside
> >of the chassis ?? ... asuming it has a ..'normal' chassis .
> >If the grid trip is below the chassis, and also uses rf bypass caps,
> >it should not be a problem. ... at least on paper.
>
> REPLY:
>
> The RF will be flowing through the thickness of the chassis, both
> sides. This is not a transmission line or piece of coax.
>
> And the problem with the grid trip or other circuit is not easily
> cured with bypass caps used in the ordinary way. The problem there is
> a ground loop condition, which acts like a little "RF generator",
> injecting RF into anything connected across part of the loop or from a
> point on the loop to a different ground. . It's best to just stay away
> from the loop entirely. And better yet to not create one that long in
> the first place.
>
> A certain amount of ground loop in the tank circuit is unavoidable if
> the tune and load caps are mounted to the chassis, but to create a
> second one 11 inches long is ridiculous.
>
> 73, Bill W6WRT
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