"4nec2" wrote in message
oups.com...
When someone asks me what's the optimal radial ground screen, I mostly
answer: "120 radials with a length of 0.4 lambda".

This answer is somehow fixed in my mind, based on a study and
experiments undertaken long time ago by ...?

Does anybody have a pointer/link/url to this study or can someone
deliver me more details ?

I already did some Googling, but could not find the article I once
red.

Thanks in advance,
Arie Voors.


Hi Arie,
thanks for all the work on 4NEC2!!!!

Let me just bring to attention that just about all the radial studies deal
with either 1/4 wave or shortened radiators and current distribution in
their radials - typically showing higher current concentration close to the
base and reasoning that one needs only shorter radials, so many good enough,
etc.

When dealing with longer radiators, say 3/8 to 1/2 wavelength and using
longer radials, situation is different. Longer radiator has longer and
higher current portion radiator and is "looking" further out than its own
base for the radials and good ground. This, combined with good ground or
sloping terrain helps significantly with pulling the lobe down and increased
gain at low angles.

This works in reality very well, I have observed it when operating from
W8LRL, using his 200 ft vertical with 360 radials 200 ft long. When low
angle propagation prevails, this is beating "regular" 4 squares, (contrary
to W8JI claims of being "impossible"). The same goes for long Beverages of
some 3.5 wave long.

Interesting question is how well can modeling capture this effect and the
transition from radials to "far field ground" condition or its extension by
longer radial field and elevated radiator current distribution.

73 Yuri, K3BU.us

Thanks all, for the input and observational feedback.

I also found my own 'small' reference back again. For others
interested in antenna design it could also be of use:

http://sujan.hallikainen.org/Broadca...52Handbook.pdf

Greetings from (at the moment) rainy Netherlands,

Arie.

On 26 May 2007 01:31:14 -0700, 4nec2 wrote:

Thanks all, for the input and observational feedback.

I also found my own 'small' reference back again. For others
interested in antenna design it could also be of use:

http://sujan.hallikainen.org/Broadca...52Handbook.pdf

Greetings from (at the moment) rainy Netherlands,

Arie.

Hi Arie,

For those interested that book can also be obtained printed and bound
for a very reasonable price from an on demand printer.

http://www.lulu.com/content/159004

Danny, K6MHE

On May 26, 8:30 am, Danny Richardson wrote:
On 26 May 2007 01:31:14 -0700, 4nec2 wrote:

Thanks all, for the input and observational feedback.

I also found my own 'small' reference back again. For others
interested in antenna design it could also be of use:

http://sujan.hallikainen.org/Broadca...adioAntenna195...

Greetings from (at the moment) rainy Netherlands,

Arie.

Hi Arie,

For those interested that book can also be obtained printed and bound
for a very reasonable price from an on demand printer.

http://www.lulu.com/content/159004

Danny, K6MHE

I enjoy reading these books as well as anyone (don't always understand
the calculus, but that's another issue).. The reality for us is that
after roughly 50 radials it becomes academic... I have over a
hundred (roughly half wave long - varies) radials under my 160
tower... This was done over an entire year of crawling through dense,
nearly impenetrable thorn bushes, ripping my skin, wrecking my knees,
and convincing my wife she was correct all along i.e. I'm crazy as a
loon... After roughly 25 radials I could not discern any improvement
in performance ya, ya, ya, all subjective - I know...

Anyway, theoretical discussions are enjoyable but you have to keep in
mind this is a real world hobby, not a physics lab...

denny / k8do

On 26 May 2007 01:31:14 -0700, 4nec2 wrote:

Thanks all, for the input and observational feedback.

I also found my own 'small' reference back again. For others
interested in antenna design it could also be of use:

http://sujan.hallikainen.org/Broadca...52Handbook.pdf

Greetings from (at the moment) rainy Netherlands,

Arie.

Hi Arie,

Just a short note to let you know that I worked with Jess Epstein, the Epstein of BL&E while working at the
RCA Antenna Lab (at David Sarnoff Research Center) I was also personally acquainted with George Brown, the
Brown of BL&E. While at the RCA Lab I also became acquainted with Ed Laport, as he stopped in to consult with
us on various occasions. Of course I have his book, 'Radio Antenna Engineering' in my library. I also knew Bob
Lewis, the Lewis of BL&E, through ham activities, although he had left RCA to go with IT&T before I came to
RCA.

Walt, W2DU