Richard Clark wrote in
:

On Sun, 14 Nov 2010 02:25:50 GMT, Owen Duffy wrote:

I meant to elaborate on this a bit more. (Did I hear someone groan?)

If for example, the feedpoint Z of a 0.6 wave vertical over four
quarter wave radials...

I'll bite (or groan as the expectation demands) - why "quarter wave"
radials? A rule of thumb?

It is just what I modelled, so I was declaring the context. The thread
started on 2m, my discussion was in that context, and the usual
application would be elevated radials, I modelled free space.

I used a quarter of the free space wave length. It is not that important
because as you note, matching the feedpoint impedance deals with the
length issue. The reason I didn't specifiy any slope is that they were
horizontal.

Other configurations are possible, but the numbers will vary.

I suggest that as the vertical length approaches a half wave, a set of
shorter radials, and perhaps three might well provide adequate
decoupling... but Z will differ again.

I was not trying to publish a working design, rather to give some info
on the way these things behave.

Owen

....