The antenna is a 7.5 m vertical used for 40m and up with an ATU.

Due to space limitations I have radials in only about 90 deg of the circle
around the antenna.
30 wires app 5m long on the ground.

How will this affect the efficiency in the directions with no radials ??



Cant figure out how to model radials on/in the ground in MMANA...





/js

..J.S... wrote:
How will this affect the efficiency in the directions with no radials ??

EZNEC says one loses about 3.5 dB in the direction of
no radials.
--
73, Cecil http://www.w5dxp.com

On Fri, 18 May 2007 07:57:34 -0500, Cecil Moore
wrote:

.J.S... wrote:
How will this affect the efficiency in the directions with no radials ??

EZNEC says one loses about 3.5 dB in the direction of
no radials.
I am not doubting your word but I am curious how you modeled this in
EZNEC?

John Ferrell W8CCW
"Life is easier if you learn to
plow around the stumps"

"Cecil Moore" wrote in message
. ..
.J.S... wrote:
How will this affect the efficiency in the directions with no radials ??

EZNEC says one loses about 3.5 dB in the direction of
no radials.
Uhhh, not good !

Going to see if I can sneak a few radials under the grass outside of my
garden...


/js

John Ferrell wrote:
I am not doubting your word but I am curious how you modeled this in
EZNEC?

I modeled it on 40m with radials elevated one
foot above ground. Note: one foot is 0.007 WL
on 40m, admittedly ballpark, but roughly half
the power seems to be lost in the direction
of no radials. Maybe someone with NEC-4 can
provide a more accurate simulation.

The good news is that losing half the power is
roughly half an S-Unit.
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:
John Ferrell wrote:
I am not doubting your word but I am curious how you modeled this in
EZNEC?

I modeled it on 40m with radials elevated one
foot above ground. Note: one foot is 0.007 WL
on 40m, admittedly ballpark, but roughly half
the power seems to be lost in the direction
of no radials. Maybe someone with NEC-4 can
provide a more accurate simulation.

The good news is that losing half the power is
roughly half an S-Unit.

Hi Cecil,

Just curious. Half the power of what?
120 radials 1 foot off ground? Input power?

73,

Chuck

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Chuck wrote:
Just curious. Half the power of what?

Sorry for the confusion. The 3.5 dB is the front to back
ratio where the front is the side with radials.
--
73, Cecil, w5dxp.com

On Fri, 18 May 2007 13:29:44 GMT, Cecil Moore
wrote:

John Ferrell wrote:
I am not doubting your word but I am curious how you modeled this in
EZNEC?

I modeled it on 40m with radials elevated one
foot above ground. Note: one foot is 0.007 WL
on 40m, admittedly ballpark, but roughly half
the power seems to be lost in the direction
of no radials. Maybe someone with NEC-4 can
provide a more accurate simulation.

The good news is that losing half the power is
roughly half an S-Unit.
Thanks!
I have been using the same tactic for my modeling but I was unsure
about the accuracy of the answers.

John Ferrell W8CCW
"Life is easier if you learn to
plow around the stumps"

John Ferrell wrote:
I have been using the same tactic for my modeling but I was unsure
about the accuracy of the answers.

I am also unsure about the accuracy of the answers.
But halitosis is better than no breath at all. :-)
--
73, Cecil http://www.w5dxp.com

".J.S..." wrote in message
k...

"Cecil Moore" wrote in message
. ..
.J.S... wrote:
How will this affect the efficiency in the directions with no radials ??

EZNEC says one loses about 3.5 dB in the direction of
no radials.
Uhhh, not good !

Going to see if I can sneak a few radials under the grass outside of my
garden...


Or - just turn on the sprinklers while you're on the air.
Maybe the ground will compensate for the shortage of copper if its wet.
w4pmj
Hal