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.

4nec2 wrote in news:1180088067.768928.159030
@k79g2000hse.googlegroups.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,

Perhaps this is the paper of which you are thinking:
http://k6mhe.com/BLE.html .

Great work on 4NEC2, thanks.

Owen

4nec2 wrote in news:1180088067.768928.159030
@k79g2000hse.googlegroups.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.



I should also have mentioned LB's article at
http://www.cebik.com/gp/gr.html .

Owen

For what it's worth, you might want to check out the ARRL antenna
handbook. It isn't exactly a study, but it gives data related to the
different number of radials and their respective lengths in
relationship to the antenna efficiency.

N4PGW


On 25 May 2007 03:14:27 -0700, 4nec2 wrote:

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.

--
73 for now
Buck, N4PGW

www.lumpuckeroo.com

"Small - broadband - efficient: pick any two."

4nec2 wrote:
"When someone asks me what`s the optimal radial ground screen, I mostly
answer: 120 radials with a length of 0,4 lambda."

That`s sufficient, but RCA`s Brown, Lewis, and Epstein did extensive
research in the mid-1930`s resulting in an FCC requirement of 120
radials with a length of 0.25 wavelengrh, equally spaced around the base
of a tower.. It wasn`t exactly what B, L, & E had recommended but it
became the minimum for broadcasters.

For amateurs, my 19th edition of the ARRL Antenna Book has a Table 1 on
page 3-3 that is more economical.

I seem to remember that Reg J. Edwards had a program for optimising
padials and I think it is still available.

Best regards, Richard Harrison, KB5WZI

"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 Fri, 25 May 2007 17:10:20 -0500, (Richard
Harrison) wrote:

4nec2 wrote:
"When someone asks me what`s the optimal radial ground screen, I mostly
answer: 120 radials with a length of 0,4 lambda."

That`s sufficient, but RCA`s Brown, Lewis, and Epstein did extensive
research in the mid-1930`s resulting in an FCC requirement of 120
radials with a length of 0.25 wavelengrh, equally spaced around the base
of a tower.. It wasn`t exactly what B, L, & E had recommended but it
became the minimum for broadcasters.

snip


http://www.fcc.gov/mb/audio/amgnd.html

--
-fb-

OK. The devil makes me do it.

Enhanced earthing systems are very old. Take note of this US patent filed
in 1903: 767974. For even more education about earthing, do note US patent
782181.

These patents popped up when looking for something entirely different.

Enjoy. 73 Mac N8TT

--
J. Mc Laughlin; Michigan U.S.A.
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