[Prev][Next][Index][Thread]
Re: grounding - this doesn't make sense - wire size
Subject: Re: grounding - this doesn't make sense - wire size
Date: Fri, 09 May 1997 16:12:43 GMT
From: jim.fosse-at-bjt-dot-net (Jim Fosse)
To: Tesla List <tesla-at-pupman-dot-com>
References:
1
On Thu, 08 May 1997 15:20:29 -0500, Tesla List <tesla-at-pupman-dot-com>, you
wrote:
>Subject: RE: grounding - this doesn't make sense - wire size
> Date: Thu, 8 May 97 14:01:22 UT
> From: "William Noble" <William_B_Noble-at-msn-dot-com>
> To: "Tesla List" <tesla-at-pupman-dot-com>
>
>
>ok, now this is interesting, if correct - I can see the need to keep the
>ground "solid" at RF freq driving the need for short wire and thick wire
>although it seems to me that putting a large steel plate on the floor
>might work better at RF freq (does anyone do this - like run the coil
>connected to a drip pan or something?).
Bill,
Yes a large plate will work. It's called a counterpoise when
used in this type of application. On my first coil, I successfully
used a 4' by 10' sheet of window screen laid on my driveway as a
ground for my TC.
> Anyway, I don't see how the current, once in the wire, could build
>up somewhere in the ground, after all, Kirkov's law still applies.
>
At RF frequencies, a wire (node for DC) starts looking like an active
component. That simple wire at DC starts exhibiting inductance
(because of it's length), resistance (because of skin effects), and
capacitance. If it's length starts approaching 1/4 of a wave length,
it starts acting like a tuned circuit also.
Last year, I was having problems with TVI on my neighbor's TV set. I
was using ~20' of #4 A.W.G stranded copper wire. I changed to 25' of
#2 welding cable; the TVI was reduce a little. I changed to 20'ish of
2" wide 0.01" thick Al tape; TVI was greatly reduce.
jim