Re: Longest practical ground cable?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-uswest-dot-net>" <m.j.watts-at-massey.ac.nz>

On 2 May 01, at 18:00, Tesla list wrote:

> Original poster: "Garry Freemyer by way of Terry Fritz
> <twftesla-at-uswest-dot-net>" <garry-at-ndfc-dot-com>
> 
> What's the longest RF ground cable I can have?
> 
> I've been thinking maybe I could drive a rod on the edge of my porch.
> Trouble is, the thing is 30' away. That seems to be too long. With ham
> radio, if I remember correctly, the ideal ground cable has to be
> shorter than a quarter wave of the frequency you are transmitting on
> or it could act as an antenna.

It *will* act as an antenna and if it's longer than the TC secondary 
it will radiate more effectively than the secondary itself although 
the effect can be killed to some extent by running it along the 
ground. In effect, the ground will will behave as a horizontal 
radiating element with the secondary acting as a capacitive top hat.
 
Anyone else?

Malcolm